Question..

[mongoose]

kinda of a weird one... but here goes...

put a new top end on a old motor.. bottom end had some miles on it but it looked good nice and tight.. vortec/voodoo cam, nothing wild. anyways, Started it up today to do the timing.. and it started to screech after about 5 minutes of idling, cam break in is done, and i've run it a few time now just in the driveway, I tried to locate it with the stethoscope but couldn't. wasn't low on oil.. or anything like that either.. oil pressure never got anywhere near low, always above 30 psi. also has new cam bearings..


let it cool back down and i started it up again.. this time no noise.. just like every other time.. nor any ticking.. now.. is there something else that can cause it? cause i dont wanna know it what i think it is..

[68gmsee]

Automatic or manual transmission?

Going to be hard to diagnose unless you can duplicate it. I'm sure you already thought of lack of oil to a bearing or a spun bearing. Maybe an obstruction of some sort in an oil passage.

Some of the noise causes could have been the fan clutch, a bearing in the alternator or p.s. pump, oil in a belt, if manual transmission a throw out bearing or if automatic something in the t.c. or transmission.

One thing I would do is ditch the stethoscope for a 3 foot section of garden hose. I have a stethoscope and have found that garden hose is more versatile and I can place it on any part of the engine without getting my hands close to the end.

[mongoose]

no belts on the thing... so that part is easy.. could be a pilot/throw out bearing.. sounds like right at the front at the balancer.

[68gmsee]

If the noise was from the rear of the engine that makes sense. Easy enough to check out.

It's possible that may maybe something in the distributor was making the noise. Maybe the lower bushing and noise stopped as oil got up to it. Possibly never do it agian though.

[prostreetC-10]

Sometimes flex plates can cause some unreal noises though you can usually tell where it's coming from.

[mongoose]

hmm happened again today.. while i was setting up my 2 step...

I think ima pop off the timing cover and have a look.. ugh lol

[68gmsee]

If it seems to be coming from the rear of the engine, why are you popping off the timing cover? Did you determine it was in the front instead of the rear?

[luvbowties]

Originally Posted by mongoose

hmm happened again today.. while i was setting up my 2 step...

I think ima pop off the timing cover and have a look.. ugh lol

You said sounds like it was right at front near the balancer: did u mean harmonic balancer? Are you suspecting front timing cover seal? If seal should be incorrect id (or installed improperly...I know you didn't!), it could squeal as it heated from hb spinning. Any oil leaking from around harmonic balancer/timing cover seal?
Let us know what you find.
sam

[68gmsee]

Originally Posted by 68gmsee

If it seems to be coming from the rear of the engine, why are you popping off the timing cover? Did you determine it was in the front instead of the rear?

Disregard. Since you mentioned the pilot bushing/throw out bearing I assume it was coming from the rear of the engine. My old brain missed the balancer part.