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- Just completed a carb rebuild on my '50 Deluxe Eight (Carter WDO 644sa carb), and noticed a hole between the two intakes of the manifold just below the carb. (see pic) Wondering if this is hole is by designed, or became an "automatic modification option" with age.

Also, the first start-up & test drive after the rebuild, the carb seemed to be starved for gas when accelerating beyond idle - however, it did seem to improve with more "blow-out" passes up and down the test route. Float height was adjusted to proper spec and of course idle valves were adjusted. Is there any suggested adjustments or opinions - or should I keep up the test runs with hopes of more improvements.

Thanks in advance for the advice & comments!

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That port between the two throttle bores in the intake manifold must be for some mixture balancing function. I don't recall seeing it before, but probably was not looking close enough.

(o{I}o)

Nice job on that Carb. Looks great!

Sure looks rough around the edges for factory. How thick is the separation?

Houston, we have a problem!

Or should I say? Sam, you have a problem.

Whatever way it's said, there is a problem because the broken intake manifold passage wall has probably resulted in the exhaust manifold passages not being separated any longer from the intake manifold passages. Most probably caused by the exhaust gases blowing holes through the manifold walls. Results in a serious loss of vacuum and exhaust gases in your intake. If the flapper valve is working, might not be so noticeable when the car is warmed up but is still a problem. This happened to us with a couple of pre-war intake manifolds(similar construction to the post-war) a little while ago. Solution is a new intake manifold or sleeving of your old intake manifold. But because it looks like a pretty big hole I'd recommend another manifold. If you choose the sleeve route, we were lucky to have a length of stainless steel exhaust pipe on hand that was a perfect press fit! Whichever way you go, it means pulling both manifolds off, breaking the seal between them, repair(sleeves) or replace(another intake), ensure intake and exhaust manifold block mounting surfaces are straight and aligned(if not will need to be machined), check surfaces of hot box mounting(can be a source of hidden exhaust leaks) and bolt together carefully using hi temp silicone sealer. Anyone have an intake manifold available for Sam?

BTW, Nice looking carb, I'm impressed!

Will find some pic's of the holes we found and post them later.

Quote:Sam,

It wasn't just "a little while ago". It was actually February 2009 and happened to my mate Wade's '37 Super 8. Pic's below. There was also a prior occasion with his '34, I think, could have been the '37 120. Time clouds the memory. I also said your hole looked pretty big, but so was one of Wade's, so sleeving might well work for you. Good Luck!

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Howard
- the hole is about 1/2" diameter x about 1/8~3/16" thick (from memory). The bottom is smooth contoured - top half is rough edges (looks broken)

- Sam

Thanks Ozstatman for the information. I'll look into the manifolds and consider the stainless inserts.

Don't Jump the gun yet!

I'm pretty sure my 4bbl had a hole between the bores (not into the hot spot area, but between each venturi) and my spare 2bbl is in the garage with the carb off, i'll go check, but i think it did too, and it's off a 50. If the hole is between the bores, it'd be to let the cylinders pull from both venturis during high rpm runs. Some factory V8 dual plane manifolds do it, and others have a notch put in to do the same thing. These are dual plane manifolds i believe.

I had both manifold sets apart for blasting and a good cleaning, and no exhaust blow through holes were found.

Now if the hole was in the side of the bore like ozstatman's pics, then yes, the exhaust gases get up there.

I believe it's rough because there's no easy way to get in there and drill a hole...must be casting flash.

Attached is a pic of my 50 manifold with the same hole, you can see it's a solid "tunnel" between the two venturis and not broken into the exhaust jacket around the carb.

While i had a rough idle with this manifold, i suspect the rebuilt carb and not this manifold. Also, this manifold ran AMAZINGLY on my 288 about a year or so ago. Idled smooth, great WOT, plugs correct color, good vacuum etc.

If the hole doesn't seem to break into the exhaust chamber around the carb base, don't worry about it.

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