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valve train noise-Mysterioussss

danomite02

danomite02

New member
alright here is the lowdown- 06 L32 gen V, xp cam, modified intense stage 2 heads fresh back from the machine shop. new si valves, valve job, new guides seals etc,(installed height correct) new LS7 lifters, new comp pushrods, cometic .052 head gaskets, new comp 105 springs(shimmed to exacly 105lbs), new retainers, locks.
Checked preload just cuz of head machining, thin gaskets etc. Preload good with betw 1 and 1.25 turns. (correct length pushrods now) also measured w dial indicator. all good. Checked oiling to heads-flows good. assembled with cam/lifter prelube. went thru all bs "break in" crap.

i have a mysterious "tap" coming from the front bank of cylinders in the vicinity of cylinder 5. Its def not a lifter tick, not a knock.
i can only describe it as a tap.
I had it runnin with the valve cvr off, oiling is good, nothin funny goin on. even swapped out the rockers with another set i have just to be sure its not them. Swapped the pushrods from cyl 5 to 1.
NO change.... everything looks and assembled perfectly.
Cant hear it at idle, only between 1500 and 2000rpms. very distinct noise then.
I am at a loss on what it may be. Need to get the car tuned and dont want to till i know its not gonna blow up! HELP! :(
 


Have u tried taking out the spark plugs and checking them seeing if electrodes smashed up etc one time I did a cam swap and had a dam washer in one of the cylinders quiet at idle then tap tap tap wen rpms went up jus throwing a idea out there
 
yeah spark plugs ok... considered taking it to a shop and having the cylinders scoped to see if anyting looks funny..
 


would you think that a "wristpin" noise would change if i pulled the spark plug for any given cylinder? Tried that, revved it to the typical rpms where it makes the noise, and no change of the tap/tick whatever noise..
 
can you post a video of it? under the hood. if you havn't tried already, use a garden hose, hold it up to your ear, try to pinpoint the noise exactly. or something like that.



does it do this in neutral? does it do it only in a certain gear? only while driving?
 
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ill try and get a vid. its tough to do cuz its only at like 1400-2000 rpm. in park. doesnt do it while idling, most of the time. cant hear it while driving.
 


and i took the stethescope to each rocker bolt while the engine was idling and didnt hear anything out of the ordinary.
To me the noise almost sounds like a valve slapping closed.. idk
 
danomite02 said:
ill try and get a vid. its tough to do cuz its only at like 1400-2000 rpm. in park. doesnt do it while idling, most of the time. cant hear it while driving.
Click to expand...

open the throttle by pulling the throttle cable on the TB to get it to rev, while holding the camera :P
 
have the same dam noise in mine in the same rpm range, same cam and headgaskets as you but in a l67, made the noise before the cam swap, put new lifters and cam bearings in at the time of the swap and still has it, also measured lifter preload and got that all good and still have the sound. mine first started making noise about 5000 miles after a complete rebuild, put about 500 miles on it since and hasnt gotten louder or come apart
 


danomite02 said:
^^^ car looks good ^^^
ya i have just been driving it like i usually do, not sure what else i can do.
Click to expand...

thanks, i dont have mine out much, keep it out of rain most of the time:th_winking: and ive tried and checked everything i can think of, so im just going to run it and hitting the track with it in a month or 2
 
I know this highly unlikely but did you check piston depth vs valve clearance since I saw u went to a thinner head gaskets and a cam with more lift might be the valves slightly tapping one of the pistons from bad grind on 1 of the lobes, throwing another idea out there
 
hmmm. well i ran the xp with these heads for at least 6 k miles without any noises. before that the xp was in an l67 eng b4 i chipped a piston and replaced it with the current L32. i dunno.. prolly just gonnna run it and hope for the best LOL
 
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