hihighost

Hey all, I'm trying to diagnose a consistent noise my car's been making. I did some searching, but can't find clear enough answers.

I recently swapped a carb'd L31 into my 1987 RS. I kept the 700R4 which seems to be in good working order. Stock drive shaft and rear end.

At 2500 rpms and up, my car makes a distinct metallic crinkling noise. It's volume/frequency increases with RPMs. It's very sharp and loud and can be heard clearly even with the radio on. It seems to come from the bell-housing area. It only happens in gear (not in park/neutral) so I think that rules out exhaust (the noise sounds like flanges rattling together). I also suspected a warped flex plate or loose TC bolts, but I replaced the flex plate and TC bolts are secure.

Any ideas what the problem might be? I don't mind plugging away at any possible causes until I find the right one. Thanks!

OrangeBird

iTrader: (1)

Crazy idea , I know , , but when you described "crinkling" , my mind jumped to spark knock (pinging) ?

hihighost

I suspected pinging at some point but my timing is spot on and I always run 93 octane. I also threw in some octane booster to see if that helped - no change. I also believe my noise is much louder than spark knock/detonation/pinging/pre-ignition. I am getting my exhaust replaced soon, maybe that will fix the issue.

hihighost

For the record, it was pinging as OrangeBird suggested. A few people agreed that the noise sounded unusual for pinging - and spot on for exhaust rattle - but I guess it's true that pinging comes in all sorts of flavors! Anyways I checked the timing and although my initial was solid (12*), my total was 4* over. I set it at 32* (from 36*) and the pinging went away.