• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

High pitch sound from behind the carb..sounds like is in the intake manifold

T

toddwallace

Member
I thought it was my alternator making the whining noise, but its not...I replaced it..

It sounds electronic or a bearing. I have a Hipo 289 with a paxton which was working find until today. It started making a high pitch noise that gets louder with rpm. It sounds like it is coming from the back of the manifold behind the carb. I can't find it and have no idea what it is.. Could it be a rear main bearing or something in the bell housing (clutch)? It almost sounds electronic, but is probably a bearing related noise..

Thoughts
 
Other observations...

I noticed more than usual smoke coming from the valve cover breather and it is constant.

I just put a new radiator and noticed the new water/antifreeze looks rusty on tom (or oily). I drained a bit from the bottom and it was clean.

Seems like it might be bad news..
 
Is it a reed type noise? Like blowing on a blade of grass between your thumbs?

That would likely be a wicked vacuum leak.
 
No..it is higher pitched...almost like a high pitched like a squeaky belt. I thought it was a bearing in the alternator, but ruled that out. It is definitely coming from behind the carb..
 
You know... It may have. I really haven't driven it that much because I took the front windshield out about the same time as I did hte radiator. It could have... What are you thinking???
 
excessive smoke from valve cover indicates pcv valve or that circuit is not working correctly. Check the pcv valve and hose back to carb spacer and report back.
 
Not sure what I'm think and not familiar with your setup.

Noises that start after doing repairs are often related to something done during that process.
 
"opentrackerSteve" said:
excessive smoke from valve cover indicates pcv valve or that circuit is not working correctly. Check the pcv valve and hose back to carb spacer and report back.
Click to expand...
I agree my 72 did that too it was a pcv valve, when driving it would make a LOUD high pitched squeal then die-10 mins. later it would start right up
p.s. have you driven the 289/paxton combo yet? do you like it?
 
"S8NS 289" said:
I agree my 72 did that too it was a pcv valve, when driving it would make a LOUD high pitched squeal then die-10 mins. later it would start right up
p.s. have you driven the 289/paxton combo yet? do you like it?
Click to expand...

ok.. my setup is a Hipo 289 with the Cobra Intake and Holley Carb inside the Paxton Supercharger bonnet. I have a PCV hose coming out of the passenger side valve cover goint to the Air Cleaner box for the supercharger. In the attached picture, the hose is just laying across the engine, but it is connected to the passenger side valve cover. The other valve cover has a breather cap. The carb "does not" have a pcv hose does not go to the carb spacer.. Prior to installing the supercharger, the PCV hose went int a fitting on the back of the Intake manifold that I plug'd. Is this setup wrong??
 

Attachments

  • IMG_2005.JPG
    5 MB · Views: 32
I would think you'd want manifold vacuum on it so it pulls the fumes/oil in under the carb like the original setup did.

Right now you're blowing crankcase gases and probably some oil through your blower and carb.

I'd run it with the hose disconnected and plugged to see if the noise changes. Your PCV might be stuck.
 
look at the install instructions for your supercharger, specifically where it states you should hook up your PCV. That valve needs vacuum and the intake manifold port you used to have it connected to now will be pressurized as the supercharger is going to push air thru the carb and into the intake manifold.
 
I don't have it routed through the intake manifold any more per the instructions. I put a plug in the old Intake manifold fitting. The PCV is currently routed from the passenger side valve cover PCV hole to the round air cleaner box that feeds the supercharger. I would imagine the supercharger is sucking air creating the needed vaccum. Craig Conley from Paradise (the guy who bought the Vintage Paxton Line) told me to use a open breather cap with no hose fitting and eliminate the hose, which I am not sure I agree with. I am most like going to move to a carb spacer with the PCV fitting
 
You don't need vacuum to make a PCV work. The crankcase pressure opens and closed the valve. You typically hook up the hose to a vacuum port on the manifold/carb so the vapors are "inhaled" back into the engine. The same pressure would also simply force the fumes out the hose. Lots of guys simply run the hose down the trans tunnel a bit and let it exhaust naturally. Over time it gets messy but it does allow the pressure to be vented without putting dirty oil fumes into your intake charge.
 
You must log in or register to reply here.
Back
Top