I ve finally start my new motor(lt4) everything seems to be right except of one thing...It whistle like hell

-When i start the car it goes at about 1500rpm and you could hear a clear whistle.Then at idle 750rpm the whistle is barely hearable.

-When you driving it over 2000rpm in every gear the whistle is so loud ,it does the same type of sound has a jet engine

I ve check with a friend who was keeping the idle to 2000rpm in the garage and it seems to be coming from the front of the engine.

I also notice that my idle is not perfect.

Ive check for a vaccum leak or an unplugged one but they are all good.

I then pass my hand everywhere to feel if there is any air leak,all good.

This is not my cai/no silencer setup that create this sound because thats the same that was on my last motor.Also this is not an accessories noise since i took off the belt for a test and the whistle was still there.

Ive done some search on the board nad saw that it could be my tb but im not running an aftermarket .Im running a 52mm tb with airfoil.This is a stock unit ported to 52 by i guy on ebay that does great job.This is a new unit that was not on my last motor.

So whats my problem and how do i fix this?

Thank you

 

Have you checked for vacuum leaks?

 

Check your tensioner pulley. They tend to squeel or "whistle" especially if you have had to pull it out of place to remove the belt any time recently. But tensioner pulley's wear out.

 

No problem....?

Give that supercharger hell!

 

i have the same problem now. it sounds exactly like a supercharger. i havent found the problem yet.

 

do you have or know someone who has a stock tb. get a new gasket and try that .

 

Probably your TB...try taking the airfoil out..or a different TB.

 

Yep i ve check and everything is fine.

 

I took the belt off so no accessories would turn.That didnt change a thing so the pulley of alternator/tensionner/power steering are not the problem.

 

Im gonna take my elbow off and see if the whistle come from the TB wich would be plausible.

 

Get a mechanics stethoscope and start probing.

 

I think thats what i gonna need to do.

I tok off the elbow and start it then i put my finger on the iac inlet hole and the whistle didnt change.I also took off the air foil but it didnt change nothing.

So mechanics stethoscope here i am.

 

Well i ve tested my TB and its not the culprit.I also look for the water pump and opti and they are not the problem.

The sound seems to be coming from the timing chain,so the assumption that the motor has been assembled thight would be the good one.

I would think that has the time and the miles go by the chain will take some slack and the noise will disapear or at least be less loud.

 

what timing set did you use?

 

Its a factory brand new GM lt4 crate motor.That was the last one available in north america from GM.

So it has the lt4 timing set.