can i rule it out???

[GreyGoose006]

i'll try to keep this concise.

my 3.8L chevy V6 has been 'clacking' at idle while in drive. it dosent do it in park or neutral. it dosent do it on load. it is bad when the engine is cold. i suspected either a bad lifter, loose rocker, unseated/bent pushrod/valve (theres a reason to suspect this as a 5/8" X 1/16" piece of metal was inhaled into the engine during a carb rebuild) or a cracked flexplate.

i suspected the flexplate only because it is a slow enough clack that it could POSSIBLY be a crack that was hitting unevenly.

to try to rule out the lifter, i changed the 10W - 30 oil to 20W - 50.
it got worse at cold startup, but got better as the engine heated up.
recently on a long trip, i stopped to get gas and noticed something odd.
no clack.
in my mind, this rules out the pushrod/valve, and flexplate.
the rocker is still suspect because the heavier oil could have added enough load in the valvetrain that the frequency of the whole thing changed slightly and the clack was no longer noticable.

i think that the problem is the lifter, but would like any advice on how to make sure before i tear apart the heads.

how hard is it to do?

my uncle (very experienced) says its a 3 hour job for a newb (like myself) but isnt very hard to do.

as i understand, changing the lifter means removing the valve covers, and the intake manifold. carb and all.
i will then have to remove the rockers, valve springs, and pushrods. i've heard that re seating the pushrods is a pain in the ass.

is there any way i can eliminate the lifters as the problem. (although it would be a fun project)

[curtis73]

First... are we talking about the chevy 3.8 (229 ci) or a Buick 3.8 (231) installed in a chevy?

What year is it?
roller or flat lifters?
is the noise a clack or a snick?

Flexplates are usually more of a dik-a-dik-a-dik-a noise, lifters are more of a snick, and piston slap is usually a clack or clock noise.

If its a flat lifter you can't change it. You'll wipe the cam lobe in a very short amount of time. You have to change the cam as well as all 16 lifters. No way around it.

I agree that the oil change fix rules out the flexplate.

The fact that a huge piece of metal was inhaled makes me think its gotta be piston slap. You probably scored the heck out of a cylinder and its letting the piston slap around.

Eliminate the "heavier oil could have added enough load in the valvetrain" thing... heavier oil won't really affect upper valvetrain at all. It gets a little oil here and there, but its not relying on its viscosity to operate upper valvetrain components.

Changing a lifter for a pro is a 5-hour job. For a newb with a 40-hour a week job, its a three weekend deal. One weekend to tear it down and order parts, another week to return the parts you ordered incorrectly, and the third to get the right parts and reassemble. That's pessimistic, but you always have to bank on the worst possible scenario.

[GreyGoose006]

Originally Posted by GreyGoose006

my 3.8L chevy V6

its late, i know. its the 229. 1984.
the piece of metal was inhaled over a year ago, and the engine is still running fine. the clacking is a more recent development. maybe 4-6 months ago. as far as weather it is a clack, a snick, a dic-a-dic, or a clock, i have no f-ing clue. i'd say its a clack that seems to be at about 1/2 the engine speed, which leads me to believe its in the valvetrain.

do i have flat lifters? i thought they were hydraulic. oh wait, does flat tappet mean flat? i think i've heard that term used about my engine.

so if the lifters are flat lifters i have to replace all 12 lifters AND the cam?

Originally Posted by curtis73

You have to change the cam as well as all 16 lifters. No way around it.

you really dont do well late at night do you?
well why not? why cant i change the lifter. what do you mean, wipe the cam?

[GreyGoose006]

i think my uncle was talking about adjusting the rockers. shoulda made that clear...

[UncleBob]

adjusting the valves, assuming the valve covers are easy to remove, is a very quick and simple job.

replacing the lifters is definitely a bit more involved. I'm not a strong believer in it, but I have seen it work....but only a couple times, a product called "seafoam", can remove varnish and crud in the lifter valving, to remove ticks....but don't hold your breath if you use it....

[GreyGoose006]

oh... believe me, i've TRIED seafoam.
it worked wonders on the carbon in the engine.
when i first got the car, it pinged so bad i was scared to drive it.
a whole lot of seafoam helped that.
got a lot more power too.

i put half a can in the oil 100 miles before the oil was changed and it worked even more wonders on how the engine ran.

i'm scared now that putting seafoam in the oil will thin the oil and make the problem worse. otherwise i'd use it.
btw, its good in gas too to gently clean out the jets and such in your carb. i use 2 cans in 10-15 gallons of gas.




any other suggestions? is it definately the lifters?

[MagicRat]

Originally Posted by curtis73

its gotta be piston slap.

I agree. The loose/burned/collapsed pistons I've had in the past behave the same way as this, worse when cold and worse at certain loads and revs.

[curtis73]

Ah... OK, I do evenings better

Your cam is a flat-tappet hydraulic. Meaning you can't swap out one lifter, you have to do all 12 (or 16 if you want ) lifters and the cam. The reason is this. A cam is made of relatively soft cast iron then hardened on the outside, much like an egg... hard shell, but if you break through it, its very soft. Picture a cam lobe and its corresponding lifter like two pieces of identical sandpaper. Rub them together and eventually they wear into each other. The roughness wears off and you basically have two pieces of paper rubbing on each other. It will last a very long time. Now switch out one piece of sandpaper for a new one (like putting a new lifter on the old cam) and you can imagine that the fresh sandpaper will tear through the old worn paper in a heartbeat. Its not always cut and dried. According to comp cams their tests reveal that about 70% of the times they put new lifters on an old cam it wiped the cam lobe. You'll get old-timers tell you that it can be done, but I don't like the odds.

Now that brings me to your car... If it has developed a valvetrain tick, there isn't much you can do about it. Hydraulic valvetrains are a set-it and forget-it proposition. If after 100k things start making noise, its not because it has come out of adjustment, its because something is failing. The tick has come from one of two things: a collapsing lifter or a wiped cam lobe. Both would increase the tolerance between the components and allow lash which makes the snick. If its the collapsed lifter and you readjust the valves, you'll not help matters. Hydraulic lifters suspend the plunger by a metered oil orifice. If oil starts slipping out too fast, (collapsing lifter) the valvetrain will tick. Adjusting it down won't help since its not a distance thing, its a speed of bleed-down thing. Make sense?

The other option (wiped cam lobe) means the cam has exceeded its useful life, the hardened shell has been worn off, and you're into the soft iron underneath. In that case adjusting it down will just put more pressure on the lobe and wipe it faster.

Distant other options include: bent pushrod, rocker stud pushed up out of the head, bent rocker, smashed pushrod tip. I'm not exactly sure why this sometimes happens but it does. I had a freshly rebuilt 389 pontiac and I ran it trouble-free for 12,000 miles. Then one day when I went to start it, it kicked back like it was hitting something, then all of a sudden it started and I got a tink tink tink. For some reason, one lifter seized up, smashed the pushrod tip, bent the rocker, and lifted the press-in stud out of the head a little.

Now... all of that above is just if its a valvetrain issue. We're assuming its not something else. You can pull the valve covers and check for obvious problems like the bent components, and you might be able to identify a wiped cam lobe with a flashlight down beside the pushrods. You can run it without the valve covers on (messy) and you should be able to hear a valvetrain noise right away. Sometimes you can isolate which valve(s) it is by pressing your thumb on the pushrod end of the rockers while its running and see if the noise changes. You can also try moving the rockers around at various degrees of the cycle. See if any are loose when not under lift conditions.

The good news is replacement lifters should be about $1.50 each, and a replacement cam can be had from a machine shop for about $40. Additional cost for obvious things like oil pan gasket, timing cover gasket, intake gaskets, etc. The labor is the bummer part of replacing it. Its kinda a tossup. You can pull the radiator, AC condenser, and grille... or you can remove the motor. I personally remove the motor. It makes getting all the gaskets sealed so much easier. Its also a chance to freshen things up.

[GreyGoose006]

thats interesting.

since i cant afford to have the car out of comission for more than a few days, would it make more sense to get some used heads from the same engine from a junkyard, build the heads out of the car, and pull a switcheroo.
the cam will complicate things i guess, but that was my original plan.
to swap the cam, i wold proply have to take the engine out because there isnt much room.

this may be a little beyond my abilities.
its getting a lot more complicated.

could i at least try to just replace the lifter and see what happens?
if i'm going to be changing the cam either way, i could at least see what happens.


maybe this is an idiotic idea, but what if i pulled a lifter from another car, so that it would be pre worn?
have i reached the peak of stupidity, or is this possible?

[curtis73]

Although your logic is solid, the problem is that lifters wear in a pattern specific to the lobes they ride. That's why you have to carefully number or organize them if you remove them to make sure they get back on the same lobe... so, no. You can't use a used lifter, but your logic makes sense

Well, I guess it can't hurt to try a new lifter but here's my thought on that... As it is now, it clicks. That's all. It might have another 50k of ticking happiness left in it. Putting a new lifter in there means a 70% chance of it not lasting 50 miles. I like the odds of leaving it alone.

My 454 has ticked since I built it two years ago. One of the new lifters I bought was out of spec and had a fast bleed down rate. Instead of swapping everything out and needing new gaskets and all that time, I've decided to let it tick. It now has 23,000 happy ticking miles on it with no change.

Of course, we're still operating on some assumptions. I wouldn't proceed with anything until you diagnose the problem. Once you diagnose the problem I'll probably recommend the same thing regardless of what you find and that is... start casually looking for a running 3.8. Freshen it up, rebuild it, do what ever you want to make it a reliable engine. Continue to drive your current engine until it dies or gets noticeably worse. Then take a weekend and swap them out. A running 3.8 shouldn't cost you more than $150 if you wait for it. The only difference in your search for a 3.8 is time... if you have a collapsing lifter, you probably have a while to look. If its a wiped cam lobe or a scored cylinder, start looking a little harder.

[GreyGoose006]

well that makes sense i guess.

so since heavier weight oil caused the noise to go away, then it surely means that the noise is a faulty lifter? if it can be driven and isnt causing any serious damage, i should just let it tick then i guess.

my only thought is that a 3.8 that costs $150 will be in terrible shape.
then again, i've heard horrible things about 'rebuilt' engines.
would it be hard to swap in a 305 or a 350 instead?
the current engine kinda runs out of power at around 70 mph and merging is a test of nerve... like playing chicken.

[GreyGoose006]

oh, and does it matter that the car only has 57,779 miles?
it seems like a pretty young engine sholdnt be having such problems.
especially since it is all stock and i havent 'built' it or anything...

[UncleBob]

if you're going to put any engine in there, I'd put a 350 in. I would greatly surprised if it wasn't a direct bolt in deal. You can get crate motors for very little money, or find a good shape used one for a lot less. I just sold a used 350 for $200 that was in great shape....had to lower the price from $400 because no one was biting.

If you keep an eye out, you can find a pretty dang good price.

[curtis73]

Originally Posted by GreyGoose006

oh, and does it matter that the car only has 57,779 miles?
it seems like a pretty young engine sholdnt be having such problems.
especially since it is all stock and i havent 'built' it or anything...

Ah... That makes me think that its a wiped cam lobe. With such low mileage, that means the car spent long periods of time sitting. What happens is the oil drips off the cam lobes after a few months, then when you start it up you have metal-to-metal grinding between the lifters and lobes. It scores the hardened surface and its only a matter of time before a wiped lobe.

A 350 will bolt it. You'll have to check on certain things like the position of accessories. It will probably require modification to the wiring harness for things like the fact that the V8 is longer and the wires might not reach. It is proabably a pretty easy project, but for a first-timer its not a weekend swap. You'll run into little snags here and there. Remember you'll need all the peripheral parts; accessories, motor mounts, flexplate, fan shroud, radiator hoses, maybe power steering hoses, exhaust, etc. Pretty much anything that goes from the car to the engine will need changing; wires, hoses, etc. Verify your tranny, too. If it came with the 3.8, chances are it came with the THM200 tranny which will last about three days behind the 350 A TH350 tranny swap is literally a bolt-in, so it might be wise to get a 350/TH350 combo. As you can see, its relatively straightforward, but a $250 engine can turn into a $750 project really fast.

I agree, that thing needs a 350, but since (I assume) you've yet to do a swap like this one, the project won't likely meet your time goals.

[UncleBob]

just take your time, wait until you find a good deal on a motor, do the same for the tranny, piece together the exhaust manifolds, carb, intake, distributor, etc (if needed) etc and have it all together and ready before you start tearing into it. If you're frugal, and take your time, there isn't a part you will need that you can't get for nearly free.

This is assuming the noise doesn't get worse of course, but otherwise, you have time to assemble what is needed