So,was hearing very noisy lifters,almost to a loud clatter.Removed the valve covers and was about to try to adjust them(I had already converted the rocker studs to adjustable type years ago)and with a mechanic friends help we found two collapsed lifters,bummer.My question is is it OK to replace the lifters only or do I need to do a cam swap also.The current cam and lifters are ones I installed in 2012 and have about 75,000 miles on them.I did oil changes every 3,000-4,000 with 10W-30 Castrol conventional oil.
I'll be removing the intake manifold soon to see if there's any damage anywhere,too check the size of the lifters and to see if there is any cam damage.
Thoughts?
Forgot to mention...the cam & lifters are from Comp Cams
Greetings grampadirt,
Some lifter noises can be fixed with a good cleaning, while other noises will require parts replacement.
The good news is that a collapsed lifter caused by stuck internals is in the former category.
To be a little more specific, here's a good photo of a disassembled lifter:
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In order to understand where the noise is coming from, the lifter body's position is set by the cam lobe.
The inner plunger sets the position of the pushrod. As long as the plunger can move freely inside the
lifter body while the lifter travels from the top of the cam lobe back to the base circle (valve closing), then it
is this freedom of movement which allows the mechanism to take up any excess clearance in the
pushrod > rocker arm > valve tip areas.
But by the same token, in order for the same hydraulic lifter to stiffen up and act like a 'solid lifter' (due to
the incompressability of oil) during the valve opening cycle (ie: from lifter base circle to the top of the cam lobe)
now it's critical for the check valve to seat completely. If it doesn't, then again there will be excess play when the lifter
collapses due to the opposing force from the big valve spring.
In English, debris & accumulated varnish can lead to 'frozen' internal parts, and cause ticky/sticky/collapsed lifters.
With any luck, you will look for and *not* find any excessive wear on the exterior surfaces of the hydraulic lifters
and cam lobes. This will then allow you to carefully disassemble & clean the interior bits, put it all back together,
and then hopefully these parts will 'take' a careful preload adjustment. (Similar to scott2093's post referenced above.)
Please keep us updated as to your progress and what you discover.
Best of luck --
Let
