Timing and valve adjustment questions? My motor is apart and I am stuck

[kevn83]

I have a 88 caprice 4.3L.

I am in the middle of putting the car back together after a head gasket replacement. My main questions have to do with the distributor and valves.

When I disassemebled the motor I did not find the TDC for the #1 piston ( I had no idea that I would need it for the valve adjustment). I did mark everything to make sure it went back together the same way I took it apart. Now I am concerned that something went wrong, because my distributor #1 position is not in the same place as shown in my haynes manual. Also I am having a hard time lining up the timing mark on the vibration damper, I can not tell which mark is the zero one as the little gage is all rusted. I took lots of pictures and I can see that the firing order is correct, its just that it seems that the #1 piston location on the distributor is one position counter clockwise from the position in the manual.

I was just wondering if there was a way that I can make sure the timing is correct so I don't hurt the motor when I try to get it started.

Also, How important is the valve adjustment? I have tried to adjust according to finding what I think is TDC for each piston... The problem is that some of the pistons the valve nut bottoms out before I make the required 3/4 turn. I thought I had to tighten them all the way down in the begining so thats why I did not bother trying to find TDC when I first took everything apart. Thanks for any help.

The only thing I can think of is that I will have to take the timing cover off and line up the timing marks on the sprockets, however if i do that... How do I make sure the distrubutor is lined up correctly? I really do not what to take the timing cover off as I will also have to take the oil pan off.



Kev

[silicon212]

It doesn't really make any difference where your #1 tower is on the distributor, as long as your oil pump is indexed properly and you have the wires laid out in the correct firing order.

The valve adjustment is very important if you don't want bent valves, broken parts or a noisy engine. You don't need to find TDC on any particular cylinder - adjust whatever valves are not obvoiusly open, rotate the engine 1 full turn and do it again. You can adjust them with the engine running - here you adjust until the tapping goes away, then 1/2 turn more - in 1/8 turn increments.

[kevn83]

Hey Scilicon212 do you have any suggestions about how to check the timing? my timing gage on the motor is all corroded so I can't read the numbers.. there is a tube on the right side of the timing gage (when facing the motor). When at TDC should the distrubutor be facing the #1 spark plug terminal?

also, if the nuts holding the rocker arms are tightened all the way down (would that mean they are too tight? Should I tighten the valve nut just until the pushrod has no vertical movment then go another 1/2 turn? I have been reading that the turning method is more likely to result in over tightened valves (which is the method that I used and at least 2 of my rockers were tightened all the way down).

Thanks For your Help.

[silicon212]

What I do when setting up valves on a new engine build (or reassembly) is set cylinder #1 to TDC, then adjust the valves that aren't open, opening or closing. I then turn the engine over one complete revolution to adjust the other valves. The correct way to do it is with the lifter sitting on the cam base circle, but this can be a time consuming method - the method I outline above works in almost all cases and saves time. What I do is rotate the pushrod with my left hand, back and forth, while slowly tightening the rocker nut until you encounter resistance turning the pushrod. Then, 1/2 turn more. You don't want to tighten the nuts all the way down unless you want 12 bent valves (assuming you can even turn the motor over).

Sometimes, a valve isn't fully adjusted using my method, and the cure for that is to adjust it with the engine running, using the method I outlined in my first post. If it's not too loud, I'll let the engine run through cam break-in before I attempt to adjust it.

The tube on the front of the timing cover (a part of the tuning 'fork'), is for use with an inductance-style probe for computer timing of the engine. Even if you can't see the marks on the fork, there is one larger 'valley' than the rest - this is TDC. It is marked on each valley/peak, i.e.



If you count the teeth, you can adjust the timing correctly without seeing what's scribed into them. The above image isn't the best, and it's out of memory, but it should be close. Assuming your harmonic balancer outer ring hasn't slipped, this should get you set up.

[kevn83]

Hey, I got the car back together and fired it up yesterday. It started but it ran kinda rough. I heard some loud ticking so I took off the valve covers and re adjusted the valves... The sound is still present. It sounds like it is coming from inside the motor (it still sounds like the valves). I am just wondering if they are noisy due to the fact that it sat without oil in if for 2 months or so? Is this normal? Also, oil was not spilling out of the valves. I think its because I greased the pushrods and the little hole in the end was plugged with the grease. However, as the motor got hot the grease got pushed out of the hole and it started spitting out of the one rod. I don't know how the oil is suppose to move around under the valve covers... SO I hope everything is ok there.

Also, I think the timing might be off. THe car will start and run really rough for a few seconds then the check engine light comes on and the car starts running better, but still kinda rough. How do you check the codes? I heard it can be done by shorting out a pin on the computer harness.

Thanks for all the help. RIght now I am stuck and don't want to keep running the motor for fear that I may damage it. Any other suggestions/insights to my problem would be helpful.

[j cAT]

get white caulk and mark groove for timing on crank shaft.use timing light and rotate distributor until engine speed increases slightly and seems normal then test drive and if pinging rotate in opposite direction take note of where you have moved adjusted the timing by location of marks.this method will get you very close to spec. also if timing is too retarded engine will run hot...........

[G.A.S.]

I myself would remove the pushrods and get the grease out of them. Everytime I remove pushrods and re-install them I pour oil over the rockers and let the oil drain down the pushrod and that does the trick.
If you wana double check your distributor, you need a helper. remove #1 plug, I use my finger or thumb, and press it over the plug hole. have your helper bump the engine over untill you feel compression.
Now, get a wire hanger and straighten it out and stick it in the plug hole till you feel the top of the piston. use a breaker bar and turn the engine over slowly. While rolling over the engine with the bar, slowly pull the wire out with the piston untill you feel it is at top dead center.
Stop right at tdc. now look at the timing mark on the vibration damper in relation to the tab and mark that.
Your now at top dead center on the compression stroke.
Pull your distributor cap and see where your rotor is pointing. should be pointing to the #1 wire on the cap.
Your fireing order is 1-8-4-3-6-5-7-2. check to make sure whitch way your rotor is turning and that fireing order follows suite to the rotation.
Just double check your wires too.
It is easy to mix one wire and that will cause a rough run and a tick as well.
If the engine has not run in a while, you could have a collapsed lifter or partial collapse. In this case I back off the rocker nut untill it ticks very slightly and let it tick, one at a time. this lets the oil wash through everything easyly and can wash out a small piece of restriction.
Ideling an engine for an hour or so can do this as well as heat will soften things up.
Once you have double checked all this, then I would go from there because I would know that all of the above is correct.

[kevn83]

What is a "collapsed lifter or partial collapse"? Also, the engine that is in my car now was a new replacement motor. I do not know when it was put in, but the mechanic that decked the heads said that it looked like they were off a 95' 4.3L (the actual car is an 88). I am wondering if that means that I have hydralic lifters? I am just wondering as I heard that those are self adjusting.

anyways to adjust the timing do I need to loosen the dist, hold down bracket, start the motor and rotate the dist. cap until the motor calms down? Also what wire do I need to disconnect to keep the computer from taking over? I heard it was the ECM wire, but I do not know where it is.

I got the motor at TDC for the #1 piston and the dist. is pointing at the #1 terminal, But now I think it needs to be adjusted.

Also, I checked the engine code and got err. code 12. I cannot find any info that tells me what it means. The lowest err code I can find info on is 13. Thanks Kevin.

[silicon212]

A 12 means "no distributor reference pulse received" and is the same thing as a 41, but a 12 won't occur when the engine is running.

If your system displays a 12 when you check it, and that's it, then you can effectively consider yourself to have no trouble codes. The system will always throw a 12 due to the engine not running - it basically tells you the system is up and functional.

A 41 on the other hand can indicate distributor issues - it's the same as a 12 but it sets when the engine is running.

You need a timing light to set the timing - you can NOT do it by ear. You will also have to disconnect the distributor ECM harness (which, ironically, sets a Code 41) in order to set the timing - you can't do it with the distributor connected to the ECM (the ECM will compensate but the static timing will not be correct). The harness is a 4-wire connector that will be right on the distributor base. The other terminal, a 2-wire, is power for the distributor and a trigger for the coil.

A 'collapsed lifter' is a hydraulic lifter which does not maintain hydraulic pressure internally. This results in a noisy rocker arm and a valve that won't time correctly. There are many causes - severe overheating, excess wear, sludge, low oil pressure etc.

[kevn83]

Ok, Hopefully, I will be able to get my hands on a timing light tomorrow.

Tonight I am going to take out the push rods and make sure all the grease is off of them. Then I am going to change the oil again. When I change the oil. Should I dump some over the rockers and down the push rods? If so how much should I dump? The internal ticking really concerns me and I just want to try to salvage this head replacement. I want to make sure that the oil gets down into the lifters to keep the oil pressure up.


Any other tips? I know Things will be much better once I get the timing correct.

Also, With the oil pump... I want to make sure that the oil pump is fitted correctly at the bottom of the distribuitor. Is it ok to assume that the oil pump is fitted correctly if the distribuitor sits flush on the manifold? In other words if the oil pump was not fitted correctly could the distribuitor still fit flush on the manifold?

Thank you guys for all the help. I still have alot to learn.

[silicon212]

If the oil pump drive is not indexed with the distributor, the distributor clamp flange will sit about 1/4" over the intake. If it's flush, it's put together correctly.

Just run enough oil on the parts, so the engine doesn't fire up with them dry. Once running, and oil pressure has been built, they will receive oil from the lifters.

[bobss396]

I wouldn't necessarily change the oil right now, I'd work on getting the engine sorted out first. If you feel that it is important, remove the push rods and blow them out with air. Look at each end closely, it should be smooth and shiny. Look for metal shavings or a galled surface. Keep track of where they came from as you remove them. I use a piece of cardboard and punch holes in it with a screwdriver, really high tech.

You might have a sticky lifter that is causing the noise. I would try to sort out which one it is if possible first. I used to "pre oil" mine by immersing them in a pan of oil over night and pushing a push rod into each one a few times while it was still immersed. This way you know they are full of oil and if you have a bad or sticky one, you find it right away.

By now you're an expert at setting valves, put it back together and give it a try.

Bob

[kevn83]

Hey guys thanks for all the advice. I have not been able to work on the car for the past 2 weeks... Its been really cold here in IL and other things inside needed my attention, but I will hopefully get out and be ready to work all day saturday. Tonight the temp is suppose to drop to -5 with a -20 wind chill.