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Torqueing Lubricated Head Bolts with a dry spec.


ducked
06-15-2023, 10:43 PM
Time to put the head back on, which means deciding on head bolt lubrication and torque, a bit classic and fundamental.

CB20 manual says dry. CB23 manual doesnt say.

Torque specs are slightly different but 40 ftlbs is in the overlap

I have no manual for my CB22 engine but assume dry 40 could apply.

My problem is I've never installed any threaded compnent dry and am rather reluctant to start now with a high torque item.

Engineering Toolbox suggests reducing dry torque by 30-40% for SAE40 oil used as an assembly lube

https://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html

Was going to do that, when I came across this suggestion for deriving a "torque and angle" spec from a dry torque which could then be applied to a lubed bolt.

" Take the dry bolt and torque to a 1/4-1/3 of its published dry torque spec. Then, mark the bolt and the part, and torque to its full value. Note how far it has turned. Now, with the lubed or Loc-Tited bolt, torque he same 1/4-1/3 torque you used earlier, then tighten to the same angle of rotation as when it was dry

.”www.thumpertalk.com/forums/topic/426292-greasing-a.../

Not sure the apparent assumption that the initial torqueing is unaffected by lubrication is valid, but if it is,subsequently you should get the right bolt tension with a lubed thread (though any initial “dry galling” damage is already done),

If doing this, aluslip might be more persistent and thus a better choice.

Tried it. Torqued in 4 X 10 ftlb increments dry (washed with carb cleaner) from finger tight, laying a ruler on the head to record starting angle.

I used a feeler guage set as a carpenters angle gauge (which I dont have here) and read off the angle with a geometry set protractor.

Fiddly and probably error prone. A possible systematic error is I had all the bolts initially finger tight but the outer ones loosen as the the inner bolts are tightened.

Should probably have started them from finger tight individually.

Initial Angle for the first 10 ftlb increament. in order of the tightening sequence was

180 130 160 135 200 180 100 225

Total Additional Angle for the last three increments. in order of the tightening sequence was

139 195 191 245 118 128 127 256

The next step would be slackening off, lubricating, torquing to 10 ftlbs, and tightening it to those angles, BUT variation doesn't give me a lot of confidence in the method (in my hands, at least)

Stealthee
06-16-2023, 06:07 AM
If torque spec says dry, install dry. Period.

ducked
06-25-2023, 10:34 PM
New sentence


Or not.


Replacing the head after packing the cylinders with rope to stop engine rotation (worked, but I still couldn't shift that crankshaft bolt, just bent my cheaters) I used the “torque translation” procedure when I put the head back on, recording the angles while dry torqueing in 10 ft-lb increments


Bit more convincing/consistent this time, though I knocked the box holding the bolts in sequence over, so they are randomised WRT the original order.


Plotted in Calc (which I’ve just started to use. Formats a bit screwed compared to Excel) one can see that Bolt 5 hardly changes angle between 10 and 20 ft lbs, i.e. its stuck. Maybe thats what galling looks like on this view. though I would have expected it at higher torque values.


forumosauploads-12829.kxcdn.com/original/3X/a/9/a9...g (https://forumosauploads-12829.kxcdn.com/original/3X/a/9/a986e90592dee85987d6f146c0c45fbfb543c521.png)


According to the previous owner, this engine has had a head gasket failure, so the bolts have probably been re-used at least 4 times (though of course I don’t know if they were used “dry” by the pros and would doubt it.)



This may be enough to compromise the thin black oxide coating and allow galling.


If I have to do it again (which unfortunately seems likely) I’ll probably lubricate them and use the angles.


I may just start from finger tight and use the total angle, since I’m not sure of the rationale for starting at 1/4 torque.


It seems to assume the initial torqueing is not affected by lubrication, which seems unlikely


Question mark

Stealthee
06-26-2023, 06:25 AM
Torque is affected by lubrication. Do not lube bolts that are supposed to be torqued dry.

Dry threads create more friction which causes the proper bolt stretch to achieve the proper torque value. A lubricated thread is going to take as much as 30% more stretch to achieve the same perceived torque value. That is enough to cause significant damage and can snap bolts.

ducked
06-28-2023, 06:16 PM
Double post, see below

ducked
06-28-2023, 06:29 PM
Torque is affected by lubrication. Do not lube bolts that are supposed to be torqued dry.

Dry threads create more friction which causes the proper bolt stretch to achieve the proper torque value. A lubricated thread is going to take as much as 30% more stretch to achieve the same perceived torque value. That is enough to cause significant damage and can snap bolts.


This misses the point, and doesn't, in detail, make sense.


Friction does NOT "cause the proper bolt stretch" and the "proper torque value" is incidental to the objective, which is to achieve the proper bolt stretch, and hence the proper clamping force.


For a given thread pitch, bolt stretch will depend on degrees of rotation, and will be independent of friction, which will only influence how hard it is to turn. i.e. the applied torque.




However, a couple of other issues did occur to me with the ““Torque Translation”” method outlined above (as well as the fairly critical "where do you start?" issue already mentioned) though, of course only after I put aluslip on the threads.


In a situation where re-torqueing is likely to be required, say because the head gasket compresses further after a few hundred miles, if you use the angle to replace your torque spec, you can’t do it, since the angle wont change.


Only work-around I can think of is to record the final torque reached while setting the final angle, and then re torque to that.


Dunno how accurate that’s likely to be.


There isn’t really any rotational force applied to head bolts in service, so clamping force is whats important, and thread friction doesn’t matter much.


OTOH there definately IS rotational force applied to say…oh… just picked at random…a crank bolt, so I suppose reducing the thread friction there, even while applying the correct clamping force MIGHT be an issue.


Only if I can get the bloody thing off though

Stealthee
06-29-2023, 06:25 AM
Friction absolutely plays a pivotal part in proper torque. Any half ass Google search shows that.

I repeat yet again, if torque spec says dry, install dry. Period.

fredjacksonsan
06-29-2023, 03:34 PM
Lubrication reduces friction. Torque spec requires friction hance, when lubing something that is supposed to be dry torqued, you will overtighten.

As stated, dry is the way to go here. I've never seen a "lubricate then torque" specification.

ducked
06-29-2023, 09:27 PM
Friction absolutely plays a pivotal part in proper torque. Any half ass Google search shows that.

I repeat yet again, if torque spec says dry, install dry. Period.

New sentence.

Friction and torque are of course directly related, half-arsed Google search or no.

Friction and bolt tension are NOT directly related.

If a half-arsed Google search suggests they are, the half-arsed Google search is wrong. Might be using ChatGPT.

Torque (at least in the context of head bolts) does not matter. What matters is bolt tension.

Bolt tension is directly related to how much you turn the bolt.

fredjacksonsan
06-29-2023, 09:33 PM
...

Torque (at least in the context of head bolts) does not matter. What matters is bolt tension.

Bolt tension is directly related to how much you turn the bolt.

Correct! And with lubrication, the bolt will turn more than designed before reaching the torque specification; therefore the ultimate tension will be beyond what is specified.

Torque dry.

/thread

ducked
06-29-2023, 09:57 PM
Lubrication reduces friction. Torque spec requires friction hance, when lubing something that is supposed to be dry torqued, you will overtighten.

As stated, dry is the way to go here. I've never seen a "lubricate then torque" specification.

Its not unknown to see "lightly oiled" recommended, and the Engineering Toolbox ref above gives recommended torque reductions for various lubricants.

https://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html

Aftermarket head bolt manufacturers like ARP spec their own lubricants which I think tend to have molybdenum in them, so lubricated headbolts are hardly some weird heresy.

Here's a general article on it, with some quoted text.

https://www.enginebuildermag.com/2005/07/perfect-engine-sealing-starts-with-proper-head-bolt-use/#:~:text=As%20a%20rule%2C%20the%20threads,before%2 0the%20bolts%20are%20installed.

“As a rule, the threads and underside of the head on most standard automotive head bolts should be lubricated with motor oil before the bolts are installed.”

""Most service manuals recommend using straight 30W oil or 10W-30 multi-viscosity oil. Though 10W-30 is obviously a thinner oil than straight 30W oil, one gasket engineer we interviewed said the difference is negligible and has almost no measurable effect on bolt loading""

The "torque translation" method I'm using isn't very widely recommended, though, and could be regarded as a bit experimental, but if you cfan't get experimental with a 37 year old car with no market value, when can you?

ducked
06-29-2023, 10:03 PM
Correct! And with lubrication, the bolt will turn more than designed before reaching the torque specification; therefore the ultimate tension will be beyond what is specified.

Torque dry.

/thread

I'm using the dry torque to determine the required bolt rotation.
Then I'm applying THE SAME bolt rotation to the lubricated threads

That's whu I'm calling it a "Torque Translation" technique. I don't reference torque for the final tightening.

This seems to bypass this repetitively expressed concern. Unless I'm missing something.

fredjacksonsan
06-29-2023, 11:51 PM
I'm using the dry torque to determine the required bolt rotation.
Then I'm applying THE SAME bolt rotation to the lubricated threads

That's whu I'm calling it a "Torque Translation" technique. I don't reference torque for the final tightening.

This seems to bypass this repetitively expressed concern. Unless I'm missing something.


It's your vehicle, do what you want! Best of luck, hope your eyeball of the rotation is as accurate as the torque wrench, and the applied lube doesn't allow the bolts to back out under vibration.

ducked
06-30-2023, 02:07 AM
Thanks. Im using a cheapo beam type wrench so not very accurate or precise, but less likely to lose calibration than the clicky type.

Im not very concerned about head bolts vibrating around since only the threads were lubricated, not the washers or under the bolt heads.

This would be a concern with the very hard to remove crank bolt, which, unlike a head bolt, IS subjected to rotational forces. Might not do it with that

Blue Bowtie
06-30-2023, 09:43 AM
This is one of the reasons many critical applications are defined in a one- or two-step initial torque plus degrees rotation instead of simply torque.

Stealthee
06-30-2023, 11:02 AM
I would absolutely be concerned about head bolts when you are grossly over torqueing them due to lubrication on the threads.

RidingOnRailz
06-30-2023, 01:55 PM
We've given him all the reasons in here why to do things a certain way, or why not to, another way.

It's his ride, and he's going to do whatever he wants anyway.

As y'all know my passion is tire pressures and alignment. I get the same resistance, refutiation as you guys did, in those aspects.

ducked
06-30-2023, 10:49 PM
I suppose so


My only source, so far, for the "torque translation" method, the motorcycle forum I link to above, uses a torque plus angle approach, since they start at 1/4 to 1/3 of the dry torque specification. They say:-


"The low torque level base point gives a repeatable point of reference that is low enough not to be affected by the presence of lubricants to any great degree if you compare it to really clean, dry threads in good condition without using something more subjective, like, "just snug".

I dunno what "any great degree" is supposed to mean, but I do not find it plausible that lubricating for 1/3 of the torque spec. has negligable effect.


Im starting from finger-tight (which is not at all subjective, though it may not be very well standardised) and applying angle-only, with no initial torque setting.


I've posted to that forum, but no response when I last checked. I suppose its an old, and maybe dead, thread.

ducked
06-30-2023, 11:08 PM
I would absolutely be concerned about head bolts when you are grossly over torqueing them due to lubrication on the threads.


I would be too, if I was over-torquing the head bolts due to lubrication.


But I'm not over-torquing them due to lubrication, for the reason I've explained, which you seem to ignore.


I would not, however, be concerned about over-torqued head bolts vibrating loose, which was the context, which you seem to ignore.

ducked
06-30-2023, 11:14 PM
We've given him all the reasons in here why to do things a certain way, or why not to, another way.




I'm afraid not. Most if not all of the response ignores the "other way" I'm proposing and just repeats the "by the book" mantra.


That's an understandable reaction, but it doesn't qualify as "reasons"

RidingOnRailz
07-01-2023, 05:50 AM
I'm afraid not. Most if not all of the response ignores the "other way" I'm
proposing and just repeats the "by the book" mantra.


That's an understandable reaction, but it doesn't qualify as "reasons"

Does "engineered to be done" a certain way qualify as a reason?

Some bolts are specd to be lube torqued, others, dry torqued. And those tire pressures on that b-pillar sticker weren't just pulled out of a hat, or the leftovers from a bingo match. Engineering and testing went into those also.

ducked
07-02-2023, 03:09 AM
Does "engineered to be done" a certain way qualify as a reason?

Some bolts are specd to be lube torqued, others, dry torqued. And those tire pressures on that b-pillar sticker weren't just pulled out of a hat, or the leftovers from a bingo match. Engineering and testing went into those also.


Its a reason, but its essentially deference to authority, and not a product of reasoning as such.


Manufacturers who specify torque specs dry probably do so to reduce the variables, IOW for the most convenient way of achieving relative accuracy.


I don’t find it very plausible that there is anything inherently superior in a dry thread (apart from possibly vibration resistance in some low torque situations, which could be better addressed by thread locking treatment), but I do find it plausible that a steel bolt in an aluminium thread at fairly high torque could cause damage when unlubricated and repeatedly run down.


Its rather unlikely that durability during repeated re-torqueing of fastners during long term maintenance on a 40-ish year old econobox was a corporate focus.


All the torque specs on this car are specified dry, but I havn’t done any others dry or used a torque wrench on them, (apart from brake caliper bolts) because I didn’t consider them to be critical.


The wheel nuts, perhaps the most often undone on the car, have been “snugged up” greased, many times, with polythene sheeting on the threads. When /if I have some spare time I’ll dig out the torque specs, clean them up and try this “torque translation” procedure on them. Should be instructive.


Those tyre pressures you mention are widely acknowledged to optimise ride comfort rather than handling or mileage. This was at the root of the infamous Ford Explorer blowout/rollover epidemic, which caused fatalities and a big lawsuit. I generally run higher pressures than recommennded, (but always less than the maximum sidewall pressure, where there is one) and have sometimes gone through a tyre pressure tuning procedure.


Heres my favorite example of automotive industry corporate technical BS, from a survey of lubricant shelf life recommendations.


https://www.machinerylubrication.com/Read/172/lubricant-storage-life


It used to be titled "Lubricant Storage Life Limits - Industry Needs a Standard " . Its been toned down over the years, but Table 4 remains instructive (recommended shelf life for indoor storage at 20C) though to be fair it’s a rather extreme example.
Major oil company C+D 10-30W Motor Oil (mineral or PAO) 1 YEAR
Independant oil company A+B: 10-30W Motor Oil (mineral or PAO) Infinite/Virtually unlimited *
1 year (!) isn’t very long, and 1 year to infinity is a pretty wide range.
IF the 1 year had a basis in fact, it could mean that the major oil companies massive (but of course secret) testing of their latest oils, extending over several decades, has told them that their oil is particularly fragile.
OR it could be that their general knowledge of the chemistry of their product makes them think it might be particularly fragile, though its odd that the PAO, plausibly believed to be more stable in an engine, is just as fragile on the shelf.
OR it could be that they wanted to cover their big fat corporate arse, and pulled the smallest number out of it that they thought they could get away with.
But if you follow the THEY KNOW BEST mantra, as you apparently do, you have to make yourself believe that the oil is OK for 10,000 miles in the harsh environment of an operating engine, but 1 year on the shelf in a sealed container is game over.
Sorry, cant do it.
Maybe I’m too cynical, but I’ve found it is generally quite hard to be too cynical, and often very hard to be cynical enough.
p { line-height: 115%; margin-bottom: 0.1in; background: transparent }strong { font-weight: bold }

RidingOnRailz
07-02-2023, 08:09 AM
Its a reason, but its essentially deference to authority, and not a product of reasoning as such.


Manufacturers who specify torque specs dry probably do so to reduce the variables, IOW for the most convenient way of achieving relative accuracy.


I don’t find it very plausible that there is anything inherently superior in a dry thread (apart from possibly vibration resistance in some low torque situations, which could be better addressed by thread locking treatment), but I do find it plausible that a steel bolt in an aluminium thread at fairly high torque could cause damage when unlubricated and repeatedly run down.


Its rather unlikely that durability during repeated re-torqueing of fastners during long term maintenance on a 40-ish year old econobox was a corporate focus.


All the torque specs on this car are specified dry, but I havn’t done any others dry or used a torque wrench on them, (apart from brake caliper bolts) because I didn’t consider them to be critical.


The wheel nuts, perhaps the most often undone on the car, have been “snugged up” greased, many times, with polythene sheeting on the threads. When /if I have some spare time I’ll dig out the torque specs, clean them up and try this “torque translation” procedure on them. Should be instructive.


Those tyre pressures you mention are widely acknowledged to optimise ride comfort rather than handling or mileage. This was at the root of the infamous Ford Explorer blowout/rollover epidemic, which caused fatalities and a big lawsuit. I generally run higher pressures than recommennded, (but always less than the maximum sidewall pressure, where there is one) and have sometimes gone through a tyre pressure tuning procedure.


Heres my favorite example of automotive industry corporate technical BS, from a survey of lubricant shelf life recommendations.


https://www.machinerylubrication.com/Read/172/lubricant-storage-life


It used to be titled "Lubricant Storage Life Limits - Industry Needs a Standard " . Its been toned down over the years, but Table 4 remains instructive (recommended shelf life for indoor storage at 20C) though to be fair it’s a rather extreme example.
Major oil company C+D 10-30W Motor Oil (mineral or PAO) 1 YEAR
Independant oil company A+B: 10-30W Motor Oil (mineral or PAO) Infinite/Virtually unlimited *
1 year (!) isn’t very long, and 1 year to infinity is a pretty wide range.
IF the 1 year had a basis in fact, it could mean that the major oil companies massive (but of course secret) testing of their latest oils, extending over several decades, has told them that their oil is particularly fragile.
OR it could be that their general knowledge of the chemistry of their product makes them think it might be particularly fragile, though its odd that the PAO, plausibly believed to be more stable in an engine, is just as fragile on the shelf.
OR it could be that they wanted to cover their big fat corporate arse, and pulled the smallest number out of it that
they thought they could get away with.
But if you follow the THEY KNOW BEST mantra, as you apparently do, you have to make yourself believe that
the oil is OK for 10,000 miles in the harsh environment of an operating engine, but 1 year on the shelf in a
sealed container is game over.
Sorry, cant do it.
Maybe I’m too cynical, but I’ve found it is generally quite hard to be too cynical, and often very hard to
be cynical enough.
p { line-height: 115%; margin-bottom: 0.1in; background: transparent }strong { font-weight: bold }


What I'm trying to say is: Neither dry or lubed torque is "better".

It's about what is instructed to do, or at least, recommended, in a specific application. Some torque specs are rated for dry, others for lube. Application specific, not necessarily "better", or "personal preference".

Another example:

A 2020 Malibu specified tire pressure is 35psi. An Accord same model year might specify 33. A 1968 Olds might specify 28psi. None of those pressures are "better" than the other. They each serve the vehicle, not to mention the type of tires, they are recommended for. (The Olds originally rolled on bias-ply tires, a totally different animal).

Get it now?

ducked
07-02-2023, 09:57 AM
What I'm trying to say is: Neither dry or lubed torque is "better".

It's about what is instructed to do, or at least, recommended, in a specific application. Some torque specs are rated for dry, others for lube. Application specific, not necessarily "better", or "personal preference".

Another example:

A 2020 Malibu specified tire pressure is 35psi. An Accord same model year might specify 33. A 1968 Olds might specify 28psi. None of those pressures are "better" than the other. They each serve the vehicle, not to mention the type of tires, they are recommended for. (The Olds originally rolled on bias-ply tires, a totally different animal).

Get it now?

Yeh.

I got it before. "THEY KNOW BEST" That's what I said you were saying.

I'm saying they may know best, but their recommendations are driven by commercial considerations, and are not necessarily always optimum for my purposes.

I give some examples where manufacturer recommendations have been flawed, fatally in one example, where IIRC, Ford specified 26psi for the Explorer tyres to give it a more car-like ride than the Ranger pickup from which it was derived, which specd 35psi.

This contributed to a high blowout rate of the weak Firestone AT tyres, causing rollovers and deaths.

Get it now? yourself.

Blue Bowtie
07-02-2023, 10:42 AM
Another variable in this is whether the head bolts enter cooling jackets. I'm not familiar with the CB22 engine, but if the head bolts do not enter blind holes, a thread sealant would be recommended. While not a true lubricant, it probably does provide some lubrication when torquing the fasteners. How would you calculate that?

Of course, head studs (often used in higher performance engines) would completely eliminate that variable, but since studs are frequently a fine thread, fine nuts with hardened washers would have a completely different torque requirement from coarse threaded bolts.

RidingOnRailz
07-02-2023, 11:52 AM
I give some examples where manufacturer recommendations have
been flawed, fatally in one example, where IIRC, Ford specified 26psi
for the Explorer tyres to give it a more car-like ride than the Ranger
pickup from which it was derived, which specd 35psi.


Get it now? yourself.

"to give it a more car-like ride..."

The single biggest misunderstanding surrounding the Ford-Firestone/ Explorer controversy, just like that whopper about Daylight Stupid Time being enacted for the benefit of farmers.

Understand the physics involved, in the late 1980s, during the development of Explorer/ Mountaineer. The challenge at hand was how to reckon with the higher CoG(center of gravity) and rollover potential of the new concept. One solution - a total rework of the front end suspension - was more expensive than just tweaking things like spring rate and/or cold tire pressures.

The latter(tires) was chosen as the ultimate solution, and a smoother ride was a by-product and not the aim of the pressures selected.

I "got this" twenty plus years ago - now do you?

To be sure , you are far far far from the only one not getting this basic explanation for the 26psi tire pressures selected for Explorer 1.0.

ducked
07-03-2023, 01:35 AM
"to give it a more car-like ride..."

The single biggest misunderstanding surrounding the Ford-Firestone/ Explorer controversy, just like that whopper about Daylight Stupid Time being enacted for the benefit of farmers.

Understand the physics involved, in the late 1980s, during the development of Explorer/ Mountaineer. The challenge at hand was how to reckon with the higher CoG(center of gravity) and rollover potential of the new concept. One solution - a total rework of the front end suspension - was more expensive than just tweaking things like spring rate and/or cold tire pressures.

The latter(tires) was chosen as the ultimate solution, and a smoother ride was a by-product and not the aim of the pressures selected.

I "got this" twenty plus years ago - now do you?

To be sure , you are far far far from the only one not getting this basic explanation for the 26psi tire pressures selected for Explorer 1.0.

I understood it was both, plus, again IIRC (I havn't checked sources recently but did read up on it once upon a time) in a follow-up design revision, because the Explorer had record-breakingly poor fuel economy, Ford had Firestone produce a lightened version of the tyre.

A major manufacturer cock-up like that one is likely to have more than one contributory factor, and of course in that case more than one actor.

Its was still a cock-up though, which was, like, The Point wrt an assumption of manufacturer engineering omnipotence.

Manufacturer mistakes, or, in the case of the oil shelf life recommendation, mendacity, (since 1 year is about as bare-faced a corporate lie as I can offhand think of) aren't really involved in the lube-or-not headbolt question, since I'm not arguing that a dry torque spec is wrong, per se.

Up above you suggest that manufacturers spec whatever is optimal for the given situation. I'd suggest it can be more arbitrary than that.

I'd guess manufacturers that spec dry probably do so mostly for convenience and out of habit/policy, but IF the appropriate clamping force is applied (which is of course the trick) lubricated is inherently superior, because it protects from wear, galling and (where relevant) corrosion.

This assumes the lubricant doesn't cause "backing out" rotation of the bolt. This may be a concern in some situations (I mention the crank bolt above) but seems unlikely for head bolts.

ducked
07-03-2023, 01:49 AM
What I'm trying to say is: Neither dry or lubed torque is "better".

It's about what is instructed to do, or at least, recommended, in a specific application. Some torque specs are rated for dry, others for lube. Application specific, not necessarily "better", or "personal preference".

Another example:

A 2020 Malibu specified tire pressure is 35psi. An Accord same model year might specify 33. A 1968 Olds might specify 28psi. None of those pressures are "better" than the other. They each serve the vehicle, not to mention the type of tires, they are recommended for. (The Olds originally rolled on bias-ply tires, a totally different animal).

Get it now?

Since tyre pressures seem to be your thing, you might be interested (though perhaps not appreciative see quote) in this "Tyre Pressure Tuning" procedure

https://tw.forumosa.com/t/new-tires-experience-michelin-pp2/36528/3

"Note here that tire pressures shown in your (car) owners manual are the minimum values, not the optimum. The manufacturers provide these values based on what is safe in all conditions and for the average driver, and biased toward quiet and comfort. Tires may be run at any pressure you like up to the maximum given by the manufacturer."

RidingOnRailz
07-03-2023, 06:14 AM
Since tyre pressures seem to be your thing, you might be interested (though
perhaps not appreciative see quote) in this "Tyre Pressure Tuning" procedure

https://tw.forumosa.com/t/new-tires-experience-michelin-pp2/36528/3

"Note here that tire pressures shown in your (car) owners manual are the minimum
values, not the optimum. The manufacturers provide these values based on what is safe
in all conditions and for the average driver, and biased toward quiet and comfort. Tires may
be run at any pressure you like up to the maximum given by the manufacturer."

I thank you for that reference, but I must beg your pardon for confusing me for someone who hangs, with bated breath, on every musing of talking heads on the internet.

You see, I have consulted these interesting things called Load Tables. And when I divided my particular car's front and rear gross(maximum that is) axle weights per wheel, it turns out that Honda's b-pillar placard specs of 32psi cold exceed the necessary pressures by 10-15 percent. And that's for carrying four passengers, fuel, and luggage(and about 40 CDs in my case :D ). Normally it's just me commuting to work, and add in the wife on weekends.

So the 30psi on my wife's Toyota and the 32psi on my Honda more than satisfy "minimums", and suggest that the ENGINEERS at both car makers knew what they were doing, again, vs. a bunch of talking heads on the internet.

CapriRacer
07-03-2023, 07:06 AM
Since tyre pressures seem to be your thing, you might be interested (though perhaps not appreciative see quote) in this "Tyre Pressure Tuning" procedure

https://tw.forumosa.com/t/new-tires-experience-michelin-pp2/36528/3

"Note here that tire pressures shown in your (car) owners manual are the minimum values, not the optimum. The manufacturers provide these values based on what is safe in all conditions and for the average driver, and biased toward quiet and comfort. Tires may be run at any pressure you like up to the maximum given by the manufacturer."

Ah ..... Mmmm ........ Oh boy! Lots to unpack here!

First is that the page referenced is a discussion page just like this one. Someone is giving their opinion on something. It's stated like it's a fact, but there is no reference to anything official from a tire manufacturer or a car manufacturer.

Second, the fact is that the tire pressures in the owners manual are specifications. They are not stated as minimums or recommendations.

Third is that car manufacturers test at those pressures. They know how the vehicle behaves at those pressures. Deviate from those pressures at your own risk.

Sure, you can run tire pressures at a different value, but the car will behave differently. The smart thing would be to test the vehicle at that different pressure to assure that the vehicle behaves benignly. People don't do that because you have to destroy a set of tires in the process - what would be the point?

So back to the original question: The specs for the bolt torque specify (there's that word, again!) dry, and there's no reason not to do that. Besides, you get different values depending on what lubricant you use. The specification is there because they know it works - reliably. Do otherwise and you run a risk of failure.

And just so you know, I am a retired tire engineer. Called on Ford for a while. I am familiar with how the tire pressure thing works.

Stealthee
07-03-2023, 12:17 PM
"Note here that tire pressures shown in your (car) owners manual are the minimum values, not the optimum. The manufacturers provide these values based on what is safe in all conditions and for the average driver, and biased toward quiet and comfort. Tires may be run at any pressure you like up to the maximum given by the manufacturer."

That is inherently false. The tire pressures in your owners manual are the RECOMMENDED OPTIMAL tire pressures based on engineers data. It is not minimum. If it were minimum it would say minimum. You will not find the word minimum ANYWHERE regarding the tire pressures recommended by the manufacturer.

ducked
07-04-2023, 05:33 AM
That is inherently false. The tire pressures in your owners manual are the RECOMMENDED OPTIMAL tire pressures based on engineers data. It is not minimum. If it were minimum it would say minimum. You will not find the word minimum ANYWHERE regarding the tire pressures recommended by the manufacturer.

I dare say they are optimal for something, and based on someones data, though it could be the marketing dept.

Its suggested in that thread they may be optimal for ride comfort, rather than handling or mileage. Clearly there is no ONE optimum number for all parameters, and the suggestion there is would be “inherently false”

You are correct that I wont find the word “minimum” in my handbook, though.

This is because
(a) not really interested in manufacturers recommended tyre pressures so am unlikely to look.
(B) handbook is in Mandarin (Taiwan only car) which I dont read
C) it got soaked a few monsoons ago and the pages are stuck together.

Which is all quite liberating

ducked
07-04-2023, 10:47 AM
Ah ..... Mmmm ........ Oh boy! Lots to unpack here!

First is that the page referenced is a discussion page just like this one. Someone is giving their opinion on something. It's stated like it's a fact, but there is no reference to anything official from a tire manufacturer or a car manufacturer.

Second, the fact is that the tire pressures in the owners manual are specifications. They are not stated as minimums or recommendations.

Third is that car manufacturers test at those pressures. They know how the vehicle behaves at those pressures. Deviate from those pressures at your own risk.

Sure, you can run tire pressures at a different value, but the car will behave differently. The smart thing would be to test the vehicle at that different pressure to assure that the vehicle behaves benignly. People don't do that because you have to destroy a set of tires in the process - what would be the point?

So back to the original question: The specs for the bolt torque specify (there's that word, again!) dry, and there's no reason not to do that. Besides, you get different values depending on what lubricant you use. The specification is there because they know it works - reliably. Do otherwise and you run a risk of failure.

And just so you know, I am a retired tire engineer. Called on Ford for a while. I am familiar with how the tire pressure thing works.

I note that, as with the “torque translation” technique (though there with one honourable exception), there is no discussion AT ALL here of the technical validity of the method. You just don’t like its provenance. The fact that it doesn’t come as an official recommendation from a car or tyre company is enough to condem it out of hand.

The poster was a consultant engineer working on suspension systems, though mostly, IIRC, for Taiwanese motorcycle companies. This of course proves nothing, one way or the other.

But lets suppose, for the sake of argument, that the procedure is completely valid. There still would be slim to no chance of it being advocated by a tyre or car company.

The method is elaborate, with the possibility of error. It requires potentially hazardous on-road testing. It would perplex your average punter and likely put them off buying from any company that advocated it. [Insult removed by Moderator as it adds no value to the thread]

Companies are constrained by many limitations and potential liabilities, including those of the people they hope to sell to.

ducked
07-04-2023, 11:16 AM
Another variable in this is whether the head bolts enter cooling jackets. I'm not familiar with the CB22 engine, but if the head bolts do not enter blind holes, a thread sealant would be recommended. While not a true lubricant, it probably does provide some lubrication when torquing the fasteners. How would you calculate that?

Of course, head studs (often used in higher performance engines) would completely eliminate that variable, but since studs are frequently a fine thread, fine nuts with hardened washers would have a completely different torque requirement from coarse threaded bolts.

I would assume that if sealant is required the torque spec would allow for its presence.

If it didn't, and gave a torque spec "dry", well tut, tut, but in principle one could use the "torque translation" technique to get the angle, which should be the same whether thread sealant is present or not.

ducked
07-05-2023, 03:45 AM
I dare say they are optimal for something, and based on someones data, though it could be the marketing dept.

Its suggested in that thread they may be optimal for ride comfort, rather than handling or mileage. Clearly there is no ONE optimum number for all parameters, and the suggestion there is would be “inherently false”

You are correct that I wont find the word “minimum” in my handbook, though.

This is because
(a) not really interested in manufacturers recommended tyre pressures so am unlikely to look.
(B) handbook is in Mandarin (Taiwan only car) which I dont read
C) it got soaked a few monsoons ago and the pages are stuck together.

Which is all quite liberating

Ok, I confess I got curious and unstuck some pages, 1.7 kg /sq cm. Which apparently is about 24 psi. I dunno if thAts officially a minimum, because I still dont read Mandarin, but its quite a lot less than i would use unless i was stuck in sand. .I run about 36 psi.

Maybe ill do some comparisons if the car ever runs again

CapriRacer
07-05-2023, 05:38 AM
I am finding this thread very fascinating. I need to study it more to fully appreciate what is going on.

In the meantime:

To the OP - ducked:

Doesn't your car have a vehicle tire placard? In the US, since 2008, it's been required on the driver's doorframe. It's trimmed in yellow. Prior to that there wasn't a required color or shape and it could be anywhere - glove box, other doorframes, trunk lid, fuel filler door, etc.

Also, what do you think is the procedure car manufacturers use to determine the tire pressure?

And lastly, you've referred to the tire pressure in the owners manual using a number of different words and I wonder which of them you think is right: Minimum, recommendation, etc.

ducked
07-06-2023, 09:20 PM
I am finding this thread very fascinating. I need to study it more to fully appreciate what is going on.

In the meantime:

To the OP - ducked:

Doesn't your car have a vehicle tire placard? In the US, since 2008, it's been required on the driver's doorframe. It's trimmed in yellow. Prior to that there wasn't a required color or shape and it could be anywhere - glove box, other doorframes, trunk lid, fuel filler door, etc.

Also, what do you think is the procedure car manufacturers use to determine the tire pressure?

And lastly, you've referred to the tire pressure in the owners manual using a number of different words and I wonder which of them you think is right: Minimum, recommendation, etc.


No tyre pressures posted that I’ve noticed, and I probably would have noticed them unless very well hidden.


Doesn’t seem to matter anyway, since now I have the handbook figure of 1.7 kg/sq cms, which is of some interest. Its the same as that given for the rather similar G10 Charade in one source I have, and probably the same as the very similar Charade G11, (of which the Skywing was essentially a local notchback variant.) though I don’t have any documentation for that.


As to the “specified” v. “recommended”, I think it doesn’t matter either, since, if there IS such an..er...specific term as “specified” in The Language of Smoke and Mirrors (which I don’t, as I’ve said, read), and they use it, in this case I’m going to take it simply as a recommendation anyway, at least for now.


As someone already pointed out. Its my ride, and I’m not much of a “The Handbook is Holy Writ” fundamentalist.


As to what testing the manufacturer did, at that pressure, I don’t know, though I imagine you’ll be in a position to tell me, assuming Taiwanese manufacturers follow industry testing norms, or, more likely, simply adopted the specification of the very similar Charade G11.


Extensive discussion of tyre pressures would take us rather far from the much simpler original topic of cylinder head torque translation, but there doesn’t seem to be any interest in that anyway.


Three pages in and we have a suggestion that estimating the angle with “My First Trig Set”will be less accurate than estimating the torque with “My First Torque Wrench”( OK, but unlikely in my hands, with my second, but still very basic, torque wrench. ) and the suggestion that lubrication will allow the bolts to rotate back out. These are legitimate and constructive criticisms, (and suggest the poster actually may “get” what I am trying to do), though I THINK I can discount them.
If “that’s all you got”, I suppose that might be reassuring, but the repeated statement that “lubrication affects torque”, backing up “JUST DO AS YOU ARE TOLD” from everyone else, rather suggests these respondents don’t “get it”, because they havn’t thought about it, which does tend to be an effect of “JUST DO AS YOU ARE TOLD”.
Not much I can do about that.
You can flog a dead horse underwater, but you can’t make it drink.







p { line-height: 115%; margin-bottom: 0.1in; background: transparent }

CapriRacer
07-07-2023, 08:06 AM
ducked,

Thanks for replying and particularly for replying to all 3 of the questions I asked. Many folks wouldn't do that. Plus it is appreciated that you had expanded responses.

The problem the way I see it is a balance between what is known to work and what might work but is somewhat unexplored territory. People tend not to go in underexplored directions if a solution is available that is known to work. That's the case here.

Looking for alternatives to established procedures is fun to do. But not everyone wants to go on that journey.

ducked
07-07-2023, 10:45 PM
ducked,

Thanks for replying and particularly for replying to all 3 of the questions I asked. Many folks wouldn't do that. Plus it is appreciated that you had expanded responses.

The problem the way I see it is a balance between what is known to work and what might work but is somewhat unexplored territory. People tend not to go in underexplored directions if a solution is available that is known to work. That's the case here.

Looking for alternatives to established procedures is fun to do. But not everyone wants to go on that journey.

Thanks, and fair enough.

Re “Established procedures that are known to work” there ARE obvious downsides to dry torquing, and these seem likely to get worse with repetition and age, though this will be of limited concern to manufacturers.

If its taken as a general spec (as it often is) and applied to things like lug nuts, where corrosion is likely, badness happens. Ive never used a torque wrench on a lug nut or put one on dry, but I have had to deal with it on used cars I bought, and it was no kind of fun.

Anyway, aluslip is on the head bolt threads so the dice are rolled and that dilemma is done

My current one is the crankshaft pulley bolt. As well as being less confident of the wisdom of lubricating that, I dont have a spec for it.

CB20 engine is 37-43 ft lbs
CB23 engine is 65-72 ft lbs, so there was a sizable change between the two

This is a CB22 in an-almost-but-not-quite Charade G11. “Splitting the difference” doesnt seem very defensible, but may be the best I can do.

ducked
07-08-2023, 09:29 AM
Since the average tightening angle corresponding to 40 ft-lbs dry was 220 degrees (see graph up above…er…somewhere) I tightened the head bolts (with the threads lubricated with Permatex Aluminium antiseize) in 4 X 55 degree increments, recording the torque reached.


The first 2 torques, at 55 and 110 degrees, are “nominal”, since the wrench is almost unreadable at these low values. Not very precise at the higher values either, but I think some of that scatter is real.


Unsurprisingly, torque values reached lubricated are less than the dry specification.


forumosauploads-12829.kxcdn.com/original/3X/3/4/34...g (https://forumosauploads-12829.kxcdn.com/original/3X/3/4/3496955ea2a7c282eaf072cf9709a19e13f7400b.jpeg)

RidingOnRailz
07-08-2023, 03:31 PM
Since the average tightening angle corresponding to 40 ft-lbs dry was 220 degrees (see graph up above…er…somewhere) I tightened the head bolts (with the threads lubricated with Permatex Aluminium antiseize) in 4 X 55 degree increments, recording the torque reached.


The first 2 torques, at 55 and 110 degrees, are “nominal”, since the wrench is almost unreadable at these low values. Not very precise at the higher values either, but I think some of that scatter is real.


Unsurprisingly, torque values reached lubricated are less than the dry specification.


forumosauploads-12829.kxcdn.com/original/3X/3/4/34...g (https://forumosauploads-12829.kxcdn.com/original/3X/3/4/3496955ea2a7c282eaf072cf9709a19e13f7400b.jpeg)


You had to do all that experimentation after three... four?.. others on here told you it wasn't necessary?

ducked
07-08-2023, 07:06 PM
You had to do all that experimentation after three... four?.. others on here told you it wasn't necessary?

Evidently. Looking at the graph again, there seems to be a systematic increase in torque across the tightening sequence, IOW from the centre of the head to the outside. I suppose this may reflext a “bowing” of the head, and may not be a good sign.

If the head gasket pops it wont necessarily invalidate this method, but it wont give me much confidence in it.

And vice versa, of course

ducked
07-08-2023, 10:37 PM
If with a constant bolt tension across the head, you get more torque at the ends, as it seerms above, this seems to imply that a constant torque across the head wont give you a constant bolt tension, (and this may not be what you need, as I ve been assuming)

If ive got this the right way round, you”ll get, and may need, more tension in the middle.

Tricky

ducked
07-09-2023, 09:11 AM
Actually, when I plot the final torques (at 220 degrees with aluslip) there is a suggestion that the first central diagonal pair of bolts tightened (front left to back right) may take the tension off for the next pair (front right to back left) and so reduce its torque, but beyond that there isn’t a clear pattern, so I’m not going to worry about it for now.


forumosauploads-12829.kxcdn.com/original/3X/c/4/c4...g (https://forumosauploads-12829.kxcdn.com/original/3X/c/4/c44d217f04d835f2632701b5d4cecc5bcef73d57.png)


I just lost the timing belt tensioner spring, so I'll worry about that instead.

buick8791
07-27-2023, 01:33 PM
An questions(maybe an wrong issue on this thread, sorry) regarding WD-40 used to the rubber parts in the car, for instance the brake caliber rubber o-rings related to the caliber sliding parts:

Is that stuff swelling the rubber parts some how?

BR,

buick8791

ducked
08-04-2023, 02:15 AM
An questions(maybe an wrong issue on this thread, sorry) regarding WD-40 used to the rubber parts in the car, for instance the brake caliber rubber o-rings related to the caliber sliding parts:

Is that stuff swelling the rubber parts some how?

BR,

buick8791


Yeh, I'd say you are a bit off topic, but since we are here, I'd say you shouldn't use it, cos I THINK its an organic solvent base with some wax (something like white spirit, though I dunno exactly what it is) and will likely attack rubber.


My routine is


Ignore the prevailing Internyet advice to blow the pistons out with compressed air, spectacularly daft when you have a brake pedal designed for the job.


(TBH it took me a day or two of messing about for this to dawn on me)

Clean - up pistons and bores with aluminium foil, a gentle conformable abrasive with an anti-corrosion effect


Calipers (and especially the slider surfaces under the stainless steel clips) abrade with a flattened beer can disk in a power drill, finally using sunflower oil as a binder, so you get an aluminium paint in intimate contact with the steel.


Dry lube only (or nothing) on the stainless clip surfaces and pad ears. I rub the clips with a soft "chippy" carpenters flat pencil, and wrap PTFE tape around the pad ears.


Caliper pins wrap with PTFE tape and apply silicone grease (bought in Japan).



I also have some Red Rubber grease I bought in Japan, and some fantastically expensive Bendix Ceramlube I bought in Australia (you can't get anything in Taiwan) but the PTFE/silicone combo seems to work well so I havn't used them.

ducked
08-04-2023, 02:36 AM
I had to remove the head again due to me following the advice in the manual to lock the cam sprocket with a screwdriver. This was quite clearly never going to work, and sho nuf the cam sprocket shifted and jammed.


(I'm quite impressed by the utter bollocks in the manual in this context. The suggestions for locking the crankshaft were similarly reality defying.)



I used the torque-to-turn-translation (tturnslation?) method for aluslip lubricated bolts as before.


Recorded torque values are higher this time, perhaps due to the thinning out of the aluslip and/or compression of the gasket.


https://forumosauploads-12829.kxcdn.com/original/3X/a/c/ac42922f049f890c73d93788cf529d27a93c15b0.png



https://forumosauploads-12829.kxcdn.com/original/3X/0/5/05fdeab3dd09051c09f7681d89c2d7dd82552d7b.png



If I have to do it again (hope not) I'll top up the aluslip a bit, and maybe use some copper spray on the gasket.


Bolt 2 (In the tightening sequence, B3 in position) doesnt gain any torque between the penultimate and final tightening, which seems odd, but happened last time. so it also seems consistent.


I'd guess this is due to the turning of bolt 1 unloading it.

ducked
08-04-2023, 06:20 PM
The increase in torque does seem to support the “received wisdom” that you shouldn’t re-use head gaskets (though I have re used one on an 1800 BMC B series with no issues, and you have to re-use at least once to use this torque translation technique).


Probably contra-indicates installing this gasket again, or indicates reverting to a torque limited procedure if I did re-use it.


If I have to take the head off again, I might re-use the original gasket, (which has only been installed once, though of course its been in the engine for 12 years) or maybe even break down and buy yet another head gasket.

buick8791
08-07-2023, 12:00 PM
Yeh, I'd say you are a bit off topic, but since we are here, I'd say you shouldn't use it, cos I THINK its an organic solvent base with some wax (something like white spirit, though I dunno exactly what it is) and will likely attack rubber.


My routine is


Ignore the prevailing Internyet advice to blow the pistons out with compressed air, spectacularly daft when you have a brake pedal designed for the job.


(TBH it took me a day or two of messing about for this to dawn on me)

Clean - up pistons and bores with aluminium foil, a gentle conformable abrasive with an anti-corrosion effect


Calipers (and especially the slider surfaces under the stainless steel clips) abrade with a flattened beer can disk in a power drill, finally using sunflower oil as a binder, so you get an aluminium paint in intimate contact with the steel.


Dry lube only (or nothing) on the stainless clip surfaces and pad ears. I rub the clips with a soft "chippy" carpenters flat pencil, and wrap PTFE tape around the pad ears.


Caliper pins wrap with PTFE tape and apply silicone grease (bought in Japan).



I also have some Red Rubber grease I bought in Japan, and some fantastically expensive Bendix Ceramlube I bought in Australia (you can't get anything in Taiwan) but the PTFE/silicone combo seems to work well so I havn't used them.

Thank you for very good information! I have used WD40 for cleaning the caliber eyes where are the rubber o-rings for the sliding parts.

I stop to use the wd for all caliber service and using only the grease intended for lubing and doing the the service as you wrote(not using the grease to some parts).

I have that grease in my shelf, was it CRC brake lube grease...


Thanks for all,

Buick8791

ducked
08-08-2023, 09:39 PM
I did wonder if there was a risk of the PTFE breaking down under extreme heat and forming fluoric acid, which is nasty stuff, and had just about decided not to use it any more...but then I came across some Volvo brake grease with added PTFE on the Internyet, so I decided not to worry about it.


If its good enough for the Chinese...

RidingOnRailz
08-09-2023, 06:23 AM
I did wonder if there was a risk of the PTFE breaking down under extreme
heat and forming fluoric acid, which is nasty stuff, and had just about decided
not to use it any more...but then I came across some Volvo brake grease with
added PTFE on the Internyet, so I decided not to worry about it.


If its good enough for the Chinese...

In applications calling for lubrication, I would use a proper lubricant, silicone-base or otherwise. WD40 is primarily a cleaner, a "loosen-upper", not meant for longterm lubrication and wear mitigation.

Unfortunately, the general public has difficulty making this distinction.

ducked
08-14-2023, 11:16 PM
In applications calling for lubrication, I would use a proper lubricant, silicone-base or otherwise. WD40 is primarily a cleaner, a "loosen-upper", not meant for longterm lubrication and wear mitigation.

Unfortunately, the general public has difficulty making this distinction.

Not sure why this is a reply to my post above, since that post does not mention WD40.

It mentions, and I recommend, PTFE tape (sold as a thread sealer and thread lubricant, very widely available, even in Taiwan, and very cheap) in combination with silicone grease, (which was sold to me as a brake lubricant in a motorcycle shop in Rinko, Japan. You cant get anything in Taiwan)

This combination appears to work very well, as it should, since the PTFE tape wrap on the brake pins cannot be displaced by lateral pressure to allow metal-to-metal contact.

I earlier suggested to the enquirer that he shouldn't use WD40.

ducked
08-15-2023, 06:55 PM
The issue here, with brakes, (and the issue raised by the enquirer) is rubber compatability.

Many, in fact probably MOST "proper lubricants" are not rubber compatible, because they have a mineral oil base, as does WD40, though it isn't a very good lubricant.

You need to use rubber compatible lubricants. These might be formulated with silicone oils or castor oil (as in the trad. "red rubber grease" originally from Castrol) and some of them have high solid lubricant content, such as PTFE or ceramics.

Anti-seize (usually with copper or aluminium solids) is often recommended BUT it usually has a mineral oil base so might attack rubber long term.

ducked
08-15-2023, 07:27 PM
You had to do all that experimentation after three... four?.. others on here told you it wasn't necessary?


Of course in general I'd agree that torquing itself isn't necessary, because I seldom use one, but for some things I feel I should.


An alternative in such cases would be to mark the original angular fastner position (too late, didn't think of it) and simply restore it, a turn-of-the-nut method without the need to translate from a torque spec.


www.youtube.com/watch?v=Qs0Kktf-2Uk (https://www.youtube.com/watch?v=Qs0Kktf-2Uk)


Here's yon Hubnut geezer doing essentially this (about 3 minutes in) with a crankshaft pulley bolt.


This does involve the assumption that it wasn't too badly wrong in the first place, but unless you have a blown head gasket, that's probably reasonable.



Too late to do that now with cam sprocket bolt on the front of the engine, since its already off, so I feel I need to apply a torque spec.



My Torque wrench is a cheapo torsion beam type. Not very precise but they are more robust than the “clicky” type, which is why I brought it back from the Yook. Cant get them in Taiwan, according to the Ktown tool shops.


There isn’t clearance to use it on any bolts on the front end of the engine when its in the car, apart from the crankshaft pulley bolt, which is accessible through a port in the wheel well. I cant get a ratchet or a breaker bar on them either so its likely any torque wrench won’t fit.


IOW there probably isn’t a “right tool” for the job


I have to use ring or open-ended spanners on these other bolts, but in principle one could apply a measured force to these with a calibrated spring, giving a torquing capability.


I’m using the luggage scale method outlined here, except I dont have a (working) luggage scale.


engineeringtoolbox.com (https://www.engineeringtoolbox.com/torque-wrench-luggage-scale-d_1909.html)Improvised Torque Wrench (https://www.engineeringtoolbox.com/torque-wrench-luggage-scale-d_1909.html)





Crude substitute is half a bike inner tube, cut ends knotted together, with a few turns of Norfolk whipping bootlace above the knot, finished in a reef knot. Shorter loose end is tied to the spanner, longer gets used to measure (and limit) the applied tension. Steel tube through inner tube loop forms T-handle for the pull.


Calibrated by hanging a jerrycan from it and filling with water. (1L water taken as 1kg.) supplemented with 2 X1.9kg iron weights. Not VERY linear (deviations seem to be after loading up the iron) but probably close enough.


forumosauploads-12829.kxcdn.com/original/3X/4/0/40...g (https://forumosauploads-12829.kxcdn.com/original/3X/4/0/40a1962e1cf033598b33c4f4c166fd9848d19560.png)
forumosauploads-12829.kxcdn.com/original/3X/4/4/44...g (https://forumosauploads-12829.kxcdn.com/original/3X/4/4/44bea5c03426f5b04660112cd5379d82ad9613e7.png)
forumosauploads-12829.kxcdn.com/original/3X/4/4/44...g (https://forumosauploads-12829.kxcdn.com/original/3X/4/4/4466a7e3a65d4c416279cf0e9d2ac85139b197bc.png)

Torque = Force X length =mgL
Torque spec. for cam pulley bolt 40nm. Ring spanner 0.22m long ring to ring
m =40/(9.8X0.22) =18.55kg


from above regression line eqn, length for this mass =1.65x18.55+25.13 =55,73cms


Snags? (apart from maybe getting the arithmetic wrong)


(a) If that spanner comes off it'll likely whack the operator pretty hard. Should probably give it a tether.


(b) A “clicky” torque wrench stops applying torque as soon as the spring pressure is exceeded. With this the operator has to stop applying torque, as with the torsion beam type. Likely both clicky and these are affected by operator technique, but to different extents.

buick8791
08-16-2023, 01:04 PM
The issue here, with brakes, (and the issue raised by the enquirer) is rubber compatability.

Many, in fact probably MOST "proper lubricants" are not rubber compatible, because they have a mineral oil base, as does WD40, though it isn't a very good lubricant.

You need to use rubber compatible lubricants. These might be formulated with silicone oils or castor oil (as in the trad. "red rubber grease" originally from Castrol) and some of them have high solid lubricant content, such as PTFE or ceramics.

Anti-seize (usually with copper or aluminium solids) is often recommended BUT it usually has a mineral oil base so might attack rubber long term.

Thanks for very good information to all to when servicing the brake calibers.

So, I haven´t used WD for final lubing, only for cleaning the caliber fastening bolt holes with the spray and after that the CRC brake lube inside to the bolt holes. Maybe this lube is not good for the o-rings inside the the holes in the question. I have on my shelf also the silicone lube/grease, if it is better than CRC brake lube/grase(what is it containing really), will see after some examination....


Thanks for all!

BR, buick8791

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