Odd squeeking noise w/ new intake manifolds

[BionicPhil]

All,

Long time reader, first time writer. I just installed the CB Performance Space Saver reversed manifolds on my 2016cc Type I, with Weber 44IDFs. All of that is in a 1957 Beetle, and I got sick of having to ask the 6 year old nieghbor kid to adjust my carbs since I couldn't fit a hand in there.

Anyhow, I've now got an odd noise I've never heard before in 24 years of Beetle ownership. I sounds like the squeek from a dog's chew toy coming from cylinder #1. It only happens when the engine is hot. The squeek is directly in time with engine RPM, and changes frequency with revs. If I apply the slightest pressure inwards (towards engine centerline) on the airfilter housing, the noise stops. This has me thinking there's an intake manifold leak or the odd shape of the manifolds are rubbing on some tin (I first thought the sound was engine tin rubbing on my crank pully or the fan hitting the housing...) The sound is loud enough that people look at me funny in traffic.

Has anyone experienced something like this before?

Thanks in advance,

Phil

[Marc]

Yes, that's a classic induction leak. We'll assume for now that there's no defect in the manifold's seating surface, although that's a possibility. More likely the manifold casting is just a little bulky on the inboard side and it's interfering with the overcylinder tin or one of the head studs. Some heads also have protrusions in their castings that stand above the gasket surface, so a manifold with a large "footprint" is impeded from tightening down against the gasket.
I'd expect there to be a visible shiny spot wherever the interference is, once located it should be a simple matter of filing off a little aluminum.
Here's a technique you may find useful, apply a coat of Prussian blue (lipstick or even grease will work too) to the gasket surface of the manifold and fit it - with no gasket. Remove and inspect, anyplace the stuff's not squished out to a film is where there isn't good contact. Once you've achieved 100% contact with no gasket, clean it up and do your final assembly with gasket. Bye-bye birdie.

[BionicPhil]

Ok, I will take a look, and try that. Although, removing the carb/manifold has a PITA factor of about 10 (back hair waxing is a 9) I'll give it a try. If it is clearance issues , I'm inclined to drive it around for the length of time required for it to self-clearance.

Thanks,

Phil

[Marc]

I wouldn't recommend that, it's more likely to get worse than to fix itself.
Do you have a swivel-socket? Most manifolds come off fairly easily with one of those and a couple of extensions (perhaps with a universal between). Definitely a worthwhile addition to your toolbox with dual carbs...

[BionicPhil]

Yes, I've got all of the extentions, swivels, flex-heads, and so ons that I need. I still need the hands of an 8-year old Asian to get in there, and unfortunately, I can palm a basketball. Oh well. I'll try to get in there and seal it all up. If it is an imperfect casting on the new manifolds I'll be pretty ticked off (the heads didn't do this before, so I'm guessing they are fine/good enough with the old manifolds).

Thanks,

Phil