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'fix' collapsed lifter:with lash cap?

('99 Cavalier, 2.2L, 115K miles)

We have what appears to be a collapsed lifter - it’s very noisy, and one rocker arm has nearly 1/8" of play with the engine off. (The others are all tight.)



I’d rather not replace the lifter. We don’t plan to keep the car for long, and I’d rather not spring for what it would take to replace the bad one. (Gaskets, bolts, lifter, and time.)



Someone suggested we could fit a ‘lash cap’ on the valve stem, and run it as a solid lifter.



I’d appreciate any thoughts on this idea. If it is feasible, what sort of clearance would I want to set, when the engine is cold? The rocker arm is not adjustable - it just bolts down on a post in the head.



Or anything else?



Thanks,

George

Personally, I think doing this is a gigantic waste of time. A clearance of about .006 would work but there’s a number of things to consider.
Finding a cap that will take up that much space.
What to do if the cap takes up too much space. (good luck with machining the cap down)
The assumption that the clearance in question would remain the same, even minute by minute.
The condition of the cam lobe. If the lobe is damaged due to the clattering then all bets are off.

If I was going to the trouble of tearing into this to install a single lash cap I’d just throw a set of lifters at it instead (assuming the cam lobe is good).

Is it an exhaust valve or intake valve? Exhaust valves need a larger lash, like .010, because they tend to get hotter. An intake valve lash is more like .006. This is off the top of my head back when I had an old Toyota with manually adjusted lifters.

Getting to the lifters requires removing the cylinder head on this model. If it was just like an intake manifold like the V8’s or a side access panel like the old I6’s, I’d agree with you. But I see the OP’s problem and think a cap, if found, is a much more simple option just to get by.

I’m just tossing the .006 figure out there because any actual spec is pretty much meaningless when doing something like this.

The lifters are also hydraulic rollers so maybe the reason the thing is rattling is because the roller bearings have disentegrated instead of the lifter actually going flat.
If this is the case a lash cap is pointless and some degree of engine destruction will soon occur when the roller comes apart, snaps the camshaft, or whatever.

Further info:

Further testing: I found a piece of (steel) flat stock, 0.1" thick, that just fit between the rocker and the valve stem. With the engine off, that made it tight. But, with the engine running, it’s as noisy as before.

So, among other things, it doesn’t look like the lash cap would solve anything. At the same time, does this tell me anything about where the problem is? What I have is …

  • One (exhaust valve) rocker arm has ~.1" of lash, with the engine off.
  • Much noise. Listening with a stick, it seems to emanate from that lifter/push rod/rocker arm.
  • The push rod is bringing oil up - possibly even more than the others.
  • Taking out the rocker arm lash doesn’t affect the noise.

After looking at car prices, the idea of replacing the lifter is getting more appealing But, I’m wondering if the problem may be more than that.

Any insights would be appreciated.

Thanks,
George

Since you’re going this route, consider a complete camshaft kit, with a new camshaft and complete set of lifters. The existing camshaft may be damaged because of the bad lifter, and other lifters may go bad soon. With the engine torn down as far as you have to go, may as well do the job right.

Shop around, and locate the best salvage yard engine you can find and negotiate with someone to install it…But with todays emissions laws, this route can lead to endless “check engine lights” and other computer problems that end up producing a big loss and nothing gained…

If your crude “valve adjustment” did not stop the noise, I don’t think a new lifter will stop it either…

I think a “lash cap” is a fantasy part someone just made up…Wishful thinking…A more reasonable approch would be a custom made, slightly longer push-rod…

Maybe the cam lobe or lifter roller bearing is gone already and that is why the continued noise anyway.

Valve lash caps are designed to prevent valve stem mushrooming, etc. on performance engines that use high spring pressures, rev to high RPMs, etc.