68 427/435 "squeal"

[Rich G.]

I have not had a chance to do any trouble shooting yet, but here are the symptoms:

1. Squeal sounds just like disk brake noise, but it's not, because it comes from the motor when the car is stopped (or moving)

2. Only starts doing it after more than 30 minutes of driving

3. Pitch DOES NOT change with RPM

4. Starts and stops. Not constant. 5 seconds on, 2 off, 10 on 5 off,etc

5. Did this several months ago the last time I drove more than 30 minutes. Since then I have driven at least 3 times a week on shorter trips and it has not happened. Until yesterday when I drove more than 30 minutes.

6. Car still has the AIR pump and has PS. But the noise sounds like it is coming from more toward the center of the motor.

Any ideas? Could I be hearing a Vacuum leak? The first time this happened, I think the idle went down, too. Since then I raised the idle and it has stayed OK.

Any thoughts are appreciated

Rich Giannotti 38594

[Chuck R.]

Re: 68 427/435 "squeal"

I would venture the vacuum leak as you state that the pitch doesn't change with rpms.

The pilotbearing, throw out bearing and alternator's pitch should change with the rpms I would think if they were starting to go south on you.

Not familiar with the A.I.R. system, but isn't there a filter on that as well?
Just trying my best to confuse the situation Rich

I'd start wiggling hoses with the car idling at elevated rpms

Chuck

[Howard P.]

Re: 68 427/435 "squeal"

Suggest you check your carb base gaskets. Particularlly the centre carb as I have experienced something similar with my 67 427/435 and it was the centre carb base gasket.I replaced it and all has been well since

[Rich G.]

Re: 68 427/435 "squeal"

Thanks guys. I'm leaning (hoping?) toward the carb gasket issue. The rear carb hold down nuts were loose. I have not tried a long drive yet. I'll post if and when I find it.

Rich