Lifter falling apart?

[Rat72]

I've been having vacuum issues so I thought I'd adjust the valves. One of the lifters was really spongy at zero lash. I've seen this before where the lifter just loses it's oil pressure so all that is providing pressure is the spring. But something was strange, at zero lash the rocker arm was about 1/8 of an inch higher on the stud than all the other rockers. And the other rockers were almost exactly the same heighth on the stud as each other. I'm wondering if the c-clip in the lifter broke or came out somehow? Has anyone ever seen this happen?

And if it did happen, I would guess that I'm getting very little lift out the valve (intake) or possibly more lift. Could this cause the low vacuum problem I am having?

Thanks,
Whit

[Bob D]

I had a similar problem with my 355. One push rod went slack, so I pulled the intake to find the guts of the lifter laying in the valley. Odd part was that the retainer was still in the lifter. I also found out I had several styles of pushrods and a chip in one cam lobe.

It snow-balled from there and I ended up replacing the cam,timing chain and gears, lifters and pushrods.

Bob

[Rat72]

The lifter did come apart but everything else looks pretty good. However, having the manifold off, it sure is tempting to drop in a new cam/lifters/timing chain etc. I've heard it's not a good idea to just replace lifters but that advice may have come from the cam companies.

I'm still wondering if the lifter would have caused the low vacuum issue. I would think that the spring force would hold the lifter together and that it might even work like a normal lifter until somehow the preload changed.

Whit

[Green Machine]

New lifters on an old cam is usually ok provided the cam is not worn out. If any of the old lifters have any cupping then the cam is not so good anymore.
I would examine all of the other lifters while you are in there and then decide. If the other lifters are pretty good, I would be tempted to just replace the defective lifter and leave the rest alone.

[el curioso]

I dont know but I guess im that bad influence saing do it !!do it!! do It!!JAJA just blame it on me when the whifey get angry.lol

J/K Do whats best for you engine and your pocket.

[Rat72]

It's an old thread but we finally have the conclusion to the blown lifter. Apparently big block Chevy's are famous for flatening cams. The intake lobe was flatened which creates a bunch of pressure on the exhaust valve as it tries to open. That pressure compresses the lifter more than it should and it falls apart. Roller cam, here I come.

Whit