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post #1 of (permalink) Old 05-02-2007, 07:02 PM
cliffoflancing
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Question Collapsed Valve lifter

Well I just collapsed a valve lifter on #6 in my 88 YJ I6. Does any one have any do's or don'ts that they would like to share before I delve into it this weekend?
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post #2 of (permalink) Old 05-02-2007, 11:20 PM
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depends on how many miles on the engine....
You have to pull the head to get to the lifter.....might be a good time to do the head.....and while the head is off, measure the ridge on the cyl wall....someone else should chim in with what the max should be.....I'm thinking you want it to be about .004 or less.

I would also suggest doing a compression test before you tear it down....obviously you can't get a good measurement on 6....but if the other 5 are above 140 then you can assume 6 is ok.

Truth is....if you are over 150, it just might be time for a rebuild.....

Good luck...

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post #3 of (permalink) Old 05-03-2007, 05:19 AM
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Quote:
Truth is....if you are over 150, it just might be time for a rebuild.....
I don't understand this.

As for the lifters, depending on the engine mileage, you should consider replacing the camshaft and all the lifters - not just one.

Cams and lifters are more compllicated than they look. Cams aren't cylindrical, they're slightly conical. And lifters aren't flat on the bottom, they're slightly convex. That combination causes the lifter to spin as the cam rotates, and that evens out the wear on both. It also means that the lifter adopts a wear pattern matching the cam it's riding on. A new lifter can quickly wipe out an old cam, and vice versa.

It doesn't happen every time, but often enough that it's standard practice to always replace camshaft and lifters as a complete matched set except on very low mileage motors.

Or you may get lucky and find that a piece of debris has gotten into the lifter and blocked the check ball open, so that you can just clean and reinstall it.

And welcome to the board!

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post #4 of (permalink) Old 05-03-2007, 08:09 AM
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Shouldn't that be LESS?

Compression test yes - but make sure the engine is somewhat warm, remove ALL the plugs first, and block the throttle open. Otherwise you might condemn a perfectly good engine.

New on old often doesn't last even 100 miles.

A trick - soak the lifter in Lacquer thinner, then carefully take the it apart. Carefully take the piston out, clean it again with lacquer thinner. Lacquer thinner seems to get the varnish off better than other solvents.
If the lifter's piston and cylinder aren't scored, and it fits close but freely - you may be able to use it again.

Not sure about yours - but look close - sometimes the hole in the head where the pushrod goes through is big enough to use a lifter puller through that hole. If so, it saves alot of work!
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post #5 of (permalink) Old 05-03-2007, 09:29 AM
 
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Can he test the lifter after disassembly and cleaning by any sort of reliable method? It would be a shame to reinstall the head and find it still collapses.

Do you always prime lifters by immersing them in oil and pumping them up before installing? I seem to recall once getting a set that said not to do that.
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post #6 of (permalink) Old 05-03-2007, 11:55 AM
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There is a test fixture for lifters. It's a weight, lever and pushrod affair that applies a certain compression force to the lifter. Then you measure the rate at which it bleeds down.

EVERYTHING's easy for the guy who doesn't have to do it.
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post #7 of (permalink) Old 05-03-2007, 12:34 PM
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Jim....I meant 150K miles.....I'm getting impatient in my old age.......

What really sucks on these engines is that you have to pull the head to get to the lifters....by the time you do that much work....I wouldn't want to replace just one lifter...much less repair it....all that work and you get how much more life out of it?

And if you replace the lifters...you should really replace the cam.....but to pull the cam you basically have to pull the front cowl off the jeep to have enough room to pull it out...

So....if the mileage on the engine is over 150,000 'miles' and/or the compression is bad.....some consideration should be given to a total rebuild...unless there is a shortage of funds...

If funds are an issue...I would try the following before pulling the head....
Pour a can of Barimans B12 in the crank case...start if up and let it run for about 5 min...then let it sit for a few hours...this should get the solvent into the lifter....after a few hours crank it back up and run it for a few min...then it's a good time to change the oil. I have also gotten a lifter to go quiet by using a quart of ATF. If funds are short, mileage high...you can't really do that much more damage....

BTW....it could also be a bad lobe on the cam (that would be one really bad lobe)...but I kind of doubt it.

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post #8 of (permalink) Old 05-03-2007, 01:04 PM
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The 1 258 I did lifters on I had to use a lifter puller, about $20 at napa for one, kinda looks like a slide hammer. If you have a blind hole puller for a slide hammer that gets small enough you should be able to use it. It doesn't hurt to plan on dropping the head off at the machine shop to get cleaned/ checked either, though if it's a high mileage just keep it together engine I'd just slap it back together and go. I did new lifters/ push rods and high mileage stock cam on my 258 and didn't kill it, prbably put a good dozen runs on it before I pulled it and then sold the jeep.
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post #9 of (permalink) Old 05-03-2007, 01:34 PM
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I agree replacing the cam and all the lifters is the best way - and you might as well do the chain and gears while you are there. And of course might as well do the - Hey, where does it all end? Sometimes we have to make a choice and take a chance.

These little I6's are very good engines - they can last nearly forever. I know of quite a few still going strong long after 300K miles. Mileage alone isn't really enough reason to kill it. The compression test will help that decision.

Feel lucky? Would you win in Vegas today?

Taking the "possible shortcut" would be to try to repair the one lifter and use it again. The old one is already "seated" into that lobe. Replacing ALL the lifters on the old cam is inviting more trouble - Murphy's Law says it won't be that lobe that goes flat from new lifters - it'll be another one! Ya never know.

Supposedly almost 50% of the wear on the cam lobes it will ever get during it's lifetime happens in the first few minutes of running when the lifter and cam "seat" together. "Seating in" a second lifter may wear it through the thin case hardening - then the lobe goes round in short order.

There may be something to try - before taking it apart - run it with the chemical suggested - and let it get nice and warm. Then try pouring some of that solvent down the pushrod - if the piston is stuck at the bottom it may unstick.
Let it soak, then keep pushing the pushrod up and down. The thin solvent will wash the oil out and maybe dissolve the varnish till it moves again. It's worth a try anyway.

You can tell the difference between a flat cam lobe and collapsed lifter -
A collapsed lifter will still follow the rise and fall of the cam lobe when you crank it - it just doesn't have the "cushion" of the oil. It also probably is loose.

Flat Cam lobe - it doesn't move much, or any when the engine is cranked. Compare it with another valve's lift. Be sure to compare like with like - intake with intake etc.

You may luck out too - the pushrod may have just bent or slipped! Hopefully that's the case here.
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post #10 of (permalink) Old 08-21-2007, 09:41 PM
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Ok guys, well I finally got enough time to thank all of you folks for your good and useful advice.
The engine had about 80,000 mile on it after a rebuild by a reputable engine rebuilding company.
It had been clicking for quite a while and I couldn’t find time to check it out , just knew it was something to do with the lifters, so just drove the heck out of it, then the back cylinder went completely dead. Lifter collapsed from wear on the cam end of the lifter, cam lobe was almost completely round. So during the cleaning process I found a chunk of something in the oil passage that oils that end of the cam. I replaced cam, cam bearings, all lifters, one push rod, timing chain, crank shaft gear and cam gear. All of this gave me the opportunity to pull the pan and clean most of the oil contact area, was amazed at how much gunk that was caked on everything. Wonder what kind of oil the previous owner used. There was no wear in the cylinder walls so that was one good thing
All is well now and again thanks a lot to a great bunch of guys
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