mysterious high pitched whine - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

351ZAFairlane · 10-19-2005, 23:22

Hello everyone, I’m wondering if anyone has any ideas on how to solve this problem:

I just finished swapping a short-block: put my heads on, set preload, extractors back on, and reinstalled the manifold with carby. The carby stayed on the manifold and was untouched during the swap. It ran perfectly well with the same parts before but now I have a high pitched whine and it wont idle.

Manifold vacuum increases with rpm and never dips down on application of the accelerator whilst in park. I’m not sure if that’s normal or a clue to my problem.

Otherwise it runs very smoothly as long as I don’t try to idle it.

Swapped to a different carb – no change.

Any help much appreciated!

brenx · 10-19-2005, 23:52

You definately have a vacuum leak. Most likely it'll be at the manifold. One of your blocks may have been decked where the other may not have been decked.

xdclevo · 10-20-2005, 00:57

I would still make sure there is no leak at the carby, or atleast the nuts are all tight. Decking the block/heads wont affect sealing at all, but it still sounds like an airleak somewhere.

351ZAFairlane · 10-20-2005, 01:46

Yes, Brenx. It was the manifold. I removed the carby and retorqued the manifold bolts and the sound went away.

That was easy. Can you believe I’d been wondering about it for two days?

I took the manifold off with carby on and having it still bolted there on re-installation may have prevented the manifold flexing enough to seal up properly. . . . It’s a crazy world.

Thanks for the replies.

brenx · 10-20-2005, 01:49

Least it's sorted. Thats all that matters.

Rhett · 10-20-2005, 19:46

Attention to detail always pays off. Never rush.

I glue my gaskets in place on the heads and the block before fitting the manifold. This way there are no vacuum or oil leaks.

Glad you sorted it out.

Work Horse · 10-21-2005, 03:45

Glad you found the problem 351ZAFairlane.

I was going to suggest checking to see if my wife was under your bonnet!!
Get it, high pitched whine!!!

Lookout it's Friday night and Work Horse has been on the turps!!

Move away from the computer Work Horse!!

I better go guys, if my wife comes in and reads this I will get a slap