1942 Crab Distributor Vacuum Seal

[Joe KCMO]

What is the seal between a crab distributor and the engine block? My crab developed a wicked vacuum leak from that seal failure. I never heard an engine run so bad!

[Chris Nelson]

I believe that there is supposed to be a gasket between the crab dist. and the timing cover.

[JSeery]

There should not be a great deal of vacuum at the distributer - timing cover interface. If there was it would be sucking oil into the distributer and back up into the carb base like a PVC. The vacuum is from the carb base to the vacuum brake.

[supereal]

The vacuum is sealed by two rubber rings that look like O rings. One goes into the timing rear cover, the other in the side of the distributor that faces the timing gear cover. They are usually included in a distributor gasket set. You can use O rings of a proper size top fit the cavity. I haven't seen them sold separately. The whole gasket set is only $8 at C&G.

[JSeery]

Originally Posted by supereal

The vacuum is sealed by two rubber rings that look like O rings. One goes into the timing rear cover, the other in the side of the distributor that faces the timing gear cover. They are usually included in a distributor gasket set. You can use O rings of a proper size top fit the cavity. I haven't seen them sold separately. The whole gasket set is only $8 at C&G.

Thanks for the input!

[Bruce Lancaster]

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The brasscenter of the seal in the distributor pulls right out. Use any screw that will catch a good hold on it and yank, clean the area drop in o-ring, put center back...it may help hold the ring, depending on ID/Od of that. Original was not a true O-ring,it had straight sides. C&G had a rebuild kit that worked well here, but it seems to be gone from their catalog, and an O-ring seems like an excellent substitute.

[Mart]

I don't think there is an o-ring recess in the timing cover, just a flat face onto which the gasket mounts. The seal in the distributor sticks proud a few thou to form a seal against the gasket.

Mart

[Bruce Compton, Canada]

I use a section of the right size vacuum hose cut squarely to the right length to just protrude about 1/16" so it crushes flush to the timing cover when the distributor is bolted up. Bruce

[Charlie ny]

What Bruce just said. Dig the old seal out and grab a 2 inch long piece of fuel hose or
vac hose , so you have something to hang on to, and work it in to the recess. Trim
like bruce says with something real sharp.
Charlie ny

[Joe KCMO]

Thanks All. Problem fixed and on to the next fun task!

[36 ford]

Sorry to re-open this thread. I have a Bubba crab for my 59A which has the long snout cam so I needed the spacer from Speedway which came with 2 gaskets ....one for the spacer to the timing cover and one for the dist. to the spacer. Will I need the cork gaskets? See image

Thanks,

Phil

[Bruce Lancaster]

I think you are talking about the gaskets for crab cap and 59A cap and gasket...
Many non original caps lack the necessary recesses for those. Look at the parts catalog diagram, then see if they will go in!

[bbrust]

Is there a gasket that fits into the recess of the spacer/adapter? Only the paper surface gasket was included.

[BUBBAS IGNITION]

Use paper gasket on both sides ......

[bbrust]

Thanks, Jim. That's what we did. just wanted to be sure before we cranked it over.