I have a 96 Z-24 LD9 manual transmission and the original engine blew a rod and it was the lowdest noise I ever heard from a motor in my life. The engine I have now has about 60,000 miles on it and I am hearing a high pitched tapping noise that is only heard in the 1,000 - 2,000 rpm range when letting off the gas and while sitting at idle. If acceleration off idle there is no noise once it leaves idle and if the shift does not allow rpms to fall below 2,200 rpm I hear no tapping.
What do you suppose this is? Is it the timimg chain? Is it in the valve train? I do not think it is a bearing because it is inconsistant. Please let me know what you think...
Thank you,
Chris
Is that created by a loose timing chain?
errrrr im not sure but i think you can only have valve lash with you have rocker arms... dohc so no rockers
im going through the same issue only i had a knock above 2000ish rpms. after dissassembiling the engine there was obvious nicks where the valves were hitting the piston but luckly it wasnt bad enough to have any of them be bent.
compression test would be a good first step...
z24 - CAI - Magnaflow Cat - PaceSetters
--exhaust and unorthadox pulley soon
