Comp 850-16 lifter preload???????
04-21-2014, 10:34 AM
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Comp 850-16 lifter preload??????? It seems a lot of us are running the Comp Cams 850-16 lifters but there seems to be some mystery as to what is the correct preload to run with these lifters.
stock .060 - .120 preload
850-16 .030 - .050 preload
comp R .004 -.010 preload
Comp cams recommends .030" - .050" preload, but it seems the majority of those running these lifters go with .060 - .100. From what I read, .060 and up is WAY too much for these lifters.
Like a lot of people running these lifters, with a decent sized cam (mine is 228/232 .571/.573 112) the valve train is quiet until the engine warms up, then its a little noisy from 2000-3000ish.
From what I read it sounds like too much preload is causing excessive noise, but it would seem just the opposite is happening. At start up, the motor is quiet...after it warms up, it starts to get loud. Is it because you lose .010" preload (aluminum expansion) or because the oil is thinning out?
For those of you running these lifters, what preload are you using to keep the valve train quiet? Did you try the Comp Cams recommendation for these lifters (.030" - .050") and then decide to increase the preload to quiet the valve train?
Any thoughts, suggestions?
Thanks for the help!
stock .060 - .120 preload
850-16 .030 - .050 preload
comp R .004 -.010 preload
Comp cams recommends .030" - .050" preload, but it seems the majority of those running these lifters go with .060 - .100. From what I read, .060 and up is WAY too much for these lifters.
Like a lot of people running these lifters, with a decent sized cam (mine is 228/232 .571/.573 112) the valve train is quiet until the engine warms up, then its a little noisy from 2000-3000ish.
From what I read it sounds like too much preload is causing excessive noise, but it would seem just the opposite is happening. At start up, the motor is quiet...after it warms up, it starts to get loud. Is it because you lose .010" preload (aluminum expansion) or because the oil is thinning out?
For those of you running these lifters, what preload are you using to keep the valve train quiet? Did you try the Comp Cams recommendation for these lifters (.030" - .050") and then decide to increase the preload to quiet the valve train?
Any thoughts, suggestions?
Thanks for the help!
04-21-2014, 08:25 PM
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When I measured my zero lash pushrod length and gave it to Martin@Tick, he spec'd a pushrod that would give .075" preload on the comp 850-16 lifters. He was confident it would give a quiet valvetrain, not that it matters for me as the motor is on open headers and I wouldn't be able to hear it anyhow.
04-21-2014, 09:55 PM
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When I measured my zero lash pushrod length and gave it to Martin@Tick, he spec'd a pushrod that would give .075" preload on the comp 850-16 lifters. He was confident it would give a quiet valvetrain, not that it matters for me as the motor is on open headers and I wouldn't be able to hear it anyhow.
I'm running .075" preload as well. It isn't noisy until it warms up and then its only noisy from 2000ish-3000ish at part throttle.
Seems like most people are running .075" preload even though comp cams says .030-.050.
Is anybody running .030-.050 on the 850-16s?
