lifter noise

[Schack394]

Hey, I was wondering if anyone could give me a little advice on noisy lifters. First question: Why do they make noise? Next question: Why did that stuff that I put in the oil (for noisy lifters) make the noise MUCH less? I'm planning on fixing the problem when I get the time and money. Hopefully the 360 wont blow up before that. :eek:

[ January 23, 2004, 10:58 PM: Message edited by: Schack394 ]

[Josh D]

The main reason is non-adjustable valvetrain. As parts wear (cam lobes, lifter foot, rocker arms, pushrods) there is no adjustability to take up the slack. Poor oil pressure and gunked up oil passages in the pump up style hydraulic lifters also contribute. Oil additives with high viscosities just fill in the gaps for awhile to quiet the noise down until they thin out. Really no reliable fix other than a rebuild, and replace all parts that are out of spec.

[Bob Barry]

To be more precise, hydraulic lifters make it an automatically-adjusting valvetrain. The travel of the inner cup on the lifter takes up the slack in a valvetrain system that comes about due to wear and tear.

On such a system, the valvetrain "ticks" when the wear on the parts exceeds the ability of the lifter to automatically adjust and take up the slack. The wear can be on the cam-lobes, lifter base, pushrod ends, rocker-arm tips, rocker-arm pivots, valvestem, or most likely, a combination of some or all of them.

Adding stuff to the oil won't help your lifters if they're already maxed-out to the extent they can self-adjust. In that case, you might be able to get back within the automatic adjustability of the lifters by changing the most worn component (often time the rocker-arms themselves), but that's just buying you time for the inevitable cam/lifter/cam-bearing replacement, which is usually only economical when you're doing a full teardown.

[Schack394]

Thanks, guys.

[710 Burner]

I would never dispute Dr. Bob, but another explanation is that the tiny oil passages that allow the lifter to get pumped up get clogged and you can do very little to unclog them. They will likely need to be replaced.

[710 Burner]

I would never dispute Dr. Bob, but another explanation is that the tiny oil passages that allow the lifter to get pumped up get clogged and you can do very little to unclog them. They will likely need to be replaced.

[Schack394]

I will probably be doing a rebuild sooner or later. Hoping for later. smile.gif