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Dan
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57 Posts
Discussion Starter · #1 ·
I have a 385 sbc, It has a comp xtreme energy hyd. roller cam with comp roller lifters, ive been hearing some valve train noise from the passenger side towards the rear, now ive tried adjusting my rockers twice and still hearing the noise. What do you guys think? bad lifter? (the motor is brand new, and only has maybe 3.5 hours of run time) Thanks for any input,
Dan
 

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WFO
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5,030 Posts
87monte385 said:
I have a 385 sbc, It has a comp xtreme energy hyd. roller cam with comp roller lifters, ive been hearing some valve train noise from the passenger side towards the rear, now ive tried adjusting my rockers twice and still hearing the noise. What do you guys think? bad lifter? (the motor is brand new, and only has maybe 3.5 hours of run time) Thanks for any input,
Dan
The lobes are steep on the XE series cams; that along w/the roller rocker can give some noise.

If the valve lifter preload is holding, in other words the rocker doesn't keep getting loose after the preload being set, the chances are the cam and lifter is still basically OK as far as wear on the bottom of the lifter and the lobe caused by the cam not breaking in right. But if the rocker keeps loosening up after the preload is correctly set... the cam didn't make it, and further engine run-time is not advised until the cam and lifters are replaced and the engine cleaned of debris.

If the noise is limited to just one lifter, I'd suspect it might have a bit of dirt or debris causing it to not pump up fully. Taking the lifter apart and cleaning will cure it if that's the problem, or you can run some Sea Foam or Marvel Mystery oil through it to see if that will free it up (as long as the cam is fully broken in and the oil contains a full dose of ZDDP anti-wear additive). Just don't replace the lifter w/a new/different lifter if you can help it.

As far as setting valves on a running engine: messy, yes. But it is probably the most accurate way of setting hydraulic lifter preload. IMO. YMMV. ;)
 

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Dan
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57 Posts
Discussion Starter · #5 ·
i can only hear it from the same spot, and the motor runs fine minus the noise, so i dont think a lobe wore off the cam. its happend to me before with a flat tappet cam, this is why i switched to hydrualic roller
 

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WFO
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87monte385 said:
i can only hear it from the same spot, and the motor runs fine minus the noise, so i dont think a lobe wore off the cam. its happend to me before with a flat tappet cam, this is why i switched to hydrualic roller
My mistake- I missed that it's a roller.
 

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WFO
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The fact is you may have a noisy valve train and there's nothing much you can do about it.

But there are some things you can try. I would start by using more than 0.004" preload. That's on the verge of being zero lashed and in my experience unless you're racing and worried about the lifters pumping up, you need to use more preload. I'd use 1/2 turn past zero lash and see what that sounded like. You could use a little less or quite a bit more preload than that if it's still noisy at 1/2 turn. I wouldn't expect you to need more than one full turn or 1-1/2 turns max, but you can use that much if it's needed, if you're using standard hydraulic roller lifters.

If the valve train geometry is not correct, there may be more noise than necessary. Be sure there's no interference between any of the valve train components. Here's a list of things to check.

The oil still needs to have a minimum amount of wear additives even though you have a roller cam. Use whatever oil is recommended by the manufacturer. Lacking that info, if the motor oil you're using has the latest API service rating, it'll be OK. I'd use a multigrade oil, 10w-30 or 10w-40 is fine IMO. Anti wear additives like GM EOS or ZDDP will not hurt.
 

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Dan
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57 Posts
Discussion Starter · #10 ·
I will try to adjust them one more time. Im going to change the oil first, its the same oil that has been in it since first start up. It has 10-30 in it now so ill use that again with some additive. And also I had problems with the rod bolts hitting the cam on the last stroker motor i built, just needed to get a small base circle cam and everything is clearenced. its not very loud, but enough to concern me on first breaking in the motor. I appreciate all the input guys
 
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