I am having a problem with a new motor (bone stock gm 5.0). I didn't do any thing crazy I just wanted a cruiser (it's in a 64 chevelle) . I had no problems with the old motor other than it was tired and would loose oil pressure.
So when I unbolted my old manifold it was caked with nastiness underneath. I cleaned an power washed it . I removed the tray underneath and cleaned that up.

I just fired the motor yesterday and as I was setting the timing and getting it in order I start to hear a low whistle. I figure it's the belt. I continue and it grows to a crazy whistle. This took about 10 minutes.

The motor is sucking air through the rear main seal . I disconnect the pcv and breather and no more noise . Hook it back up and noise again. I change the pcv valve to another one I had from a tpi motor and still noise.
Could I have put the manifold gasket on wrong or is it something to do with the windage tray under the manifold I removed to clean.

Thanks for the help

 

What intake set do yo have? TPI, TBI or carb? post a pic?
If your pcv valve is going from valvecover to intake plenum, on your other valve cover you need a line going to top or front side of the motors throttle plates.

 

It's a tpi intake. I have the pcv going to the intake manifold . On the other side the breather is going up to the throttle body.
This is the way it was on the old motor with no problems. The only thing I did was clean the manifold up and put it on the new motor. Now my car sounds like a tea pot .lol

 

Proly pulling to much vacuum.

 

Ok, I had the same problem yrs ago.
Can you post a pic of the line from cover to the T-body? It should be going to the top port on the pass side. That vents to the top of the T-body infront of the T-body blades.
Is the TPI base and runners stock? T-body stock?

 

The line from the passenger side breather to the tb is hooked up on the 2nd port from the top on the passenger side. I have the same motor in 2 other cars hooked up the same way.
i didn't put a gauge on it for vacum ,but it seems like it is pulling a lot. The car is running rough also.

 

The pass valve cover line is supposed to go to the T-body top port. That will make it work properly because its pulling fresh air from the front of the throttle blades. The 2nd port down pulls vac just like driverside pcv line going to the plenum because its behind the throttle plates.
The 2nd port down is supposed to go to the EVAP vapor canister.
Your other 2 cars are wrong also but the motors could be loose enuff or gaskets are leaky so that it isnt a problem.
You could block the 2nd port down and put a filterd breather in the pass valve cover.
Is the TPI parts all from the same motor or is it pieced together?

I hope this makes sense..

 

Makes perfect sense and you are correct. I went out and swapped the lines and the whistle is gone.
I owe you some beers if you are ever around northern jersey.
All my motors are set up the same way (wrong). I guess they are just so loose they don't whistle. The hose coming off the breather was smaller than the nipple on the throttle body. That was why it was on the lower nipple it fit better .I figured it must go there.
once again thank you very much.

 

No problem, I have been known to drink a fair amount.. lol