Hey, I just bought a 91 turbo supra a few days ago. The guy said it had 2k miles on a rebuilt motor. Two days after I bought it I started hearing a knocking sound coming from the engine. It would do it around 2-3000 rpms. It started off quiet but it got worse and worse. Now it knocks really loud even at idle. We first thought it was a piston but the compression seems to be okay. Then we thought it was a rod but i checked the oil filter and found no metal shavings or anything. The noise sounds like its coming from the head. Does anyone know what could be wrong? Thanks

could be valve tick, best thing is to have a certified mechanic listen to it, if you have one you trust, they can listen and most wont charge you to just listen and let you know.

from the head it's probably a valve, you'll have to have the shims checked and replaced as necessary to get them back to spec, and they aren't cheap from what I hear :(

Make sure it's that though, as it could be an injector, or exhaust leak too.

well

it was described as knocking :(

if it was ticking i'm sure he would have described it as so... how is the oil level?
is it brand new oil? (this can also be a sign someone ran it out and topped it right up) causing rod knock

try using a screwdriver... put it in one area and listen to the other end and see if you can determine where it's coming from

just a suggestion,maybe the knock sensor is malfunctioning,making the engine unable to adjust detonation.on a rebuilt engine(if yours is truely)sometimes they don't replace sensors,maybe the sensor failed or is failing causing this problem.i don't know for sure,however this is another option.sometimes failing blow off valves tick alot too(but don't knock).

Im in the process of taking the engine out right now, so I cant really listen to where its coming from now. The oil was low when i got it, I added some more and when it started knocking I added some more. When I took off the Intake manifold I found a good deal of oil in the lower part of the pipes, is this a bad sign or is this normal?

oil in your intake tract in no good at all,there may either be a failed turbo oil seal,or just as bad a blown head gasket or really bad valve seals.if there is oil in the intake,check the oil for water also inspect the oil as it is drained from the pan.it will be easy to tell if there is water in the oil , it will look like light mixed milk chocolate if there is alot of water mixed in.if this is so then a leaking valve seal or a blown head gasket may be your problem.look in the radiator and see if there is oil in the coolant too ,if this is tru it is most prone to be a hg.thats all i got,good hunting!

this is for your first posted question,maybe this knock is a thrown rod bearing or main bearing?i hate cars cause they drive me up the wall fixing them,i love cars cause they drive me up the street.like women aren't they,and if yer a girl vice versa.damn it all!

finding oil is normal in the "3000" pipe
you'll also usually find some where the i/c piping goes into the body up front by the air filter

Its not oil in the 3000 pipe, its in the intake manifold. And its not a bhg cause he said he put in a hks hg. Ive gotten everything ready for pulling the motor, I have one question though. Is it easier to pull the trans. with the motor or just the motor itself? Thanks for all the help guys.