PDA

View Full Version : Valvetrain Noise, After 15 Or So Miles


thedave
01-20-2005, 09:38 PM
hEY GUYS NEW HERE AND TO THESE CARS, JUST BOUGHT 87 TURBO T AND IT HAS "NEW" ENGINE BUT SUPPOSEDLY REUSED ROCKERS SHAFT ASSEMBLIES. The noise i have sounds high up on the pass side, and is enough to set off knock sensor, and that occurs at approx. 2100- 2400 rpms, regaurdless of what gear i'm in. I pulled the rockershaft off as i ordered a SET,and the damn thing looks brand new, and i'm not sure what to look for on them to see if theyre worn. What else could it be? thanks for your help.
Dave

Keller
01-22-2005, 09:19 PM
I'm curious where the 'new' engine came from? Was it properly assembled? Was the oil pressure run up before start? Cam broken in? Are all the lifters pumped up? Oil pressure good?

Could be a bad/sticking lifter. Some aftermarket lifters are known not to work that well with these motors. Many use only the GM lifters.

Some people resort to adjustable or aftermarket pushrods with aftermarket cams to adjust for small discrepancies. I know one person who grabbed a few 'junk' pushrods and swapped them around to quiet a small 'tick' in his motor with a cam which he bought used. (Not saying that's the proper way to do it, but a thought about the possible causes...)

Note that you may always have a tick from another source as well. It may just sound like its "up top".

thedave
01-23-2005, 11:22 AM
I have no idea about how engine was assembled, stack of paperwork and reciepts says it has postons gn110t camshaft, but that doesn't help find out what lifters. Thats whats soo weird is it hauls ass under WOT, with no sign of detonation, i just didnt want to risk hurting anything running it around, and its anoying to have the knock lamp flashing at cruise...gets your paranoya going....the pcv valve check valve couldnt rattle loud enough to activate knock sensor could it?

Keller
01-23-2005, 03:21 PM
Probably not.

I wouldn't trust the "knock gauge" alone. Do you have a scan tool? If not, get one or borrow one. See what it reads for knock and see if it agrees. Best to double check!