The MGA With An Attitude

At 06:09 PM 5/13/05 -0600, Stan Watkins wrote:
"Is there supposed to be any sort of O-ring or seal at the base of the distributor?"

No, and don't worry about it. The original Lucas dizzy has no provision for a seal, and does not seem to leak in spite of it.

My Mallory Dual Point dizzy does have what appears to be an intentional o-ring gland near the top of the shank, but this is not mentioned in any vandor sales literature or in any information I can find from Mallory. An o-ring gland should have depth of 2/3 to 3/4 the thickness of the o-ring, and should be 50% wider than the o-ring. By measuring the gland I was able to find a proper fitting o-ring at the local Ace Hardware store (for cheap).

With the o-ring of course it doesn't leak, but I suppose it probably wouldn't leak even without the o-ring, same as the Lucas dizzy. But I like the o-ring as it keeps out external dirt and water which may cause rust and/or clogging which makes removal of the dizzy sometimes quite difficult. I have had cases where it was necessary to use a band wrench or a pipe wrench to turn the dizzy body to break it loose.

In the absence of an o-ring I would advise clean surfaces for easy slip fit assembly, and a little grease to be smeared around the shank at the top 1/4" of the bore a dust and moisture excluder. From there down a little oil or left dry should be okay. I would not advise greasing the entire shank, as the grease could dry in place if the part is not moved for many years, which could again make it difficult for removal.

"and wondered if oil leaks out much."

`No. The slip joint between the shank of the dizzy and the cast iron mounting sleeve is quite long and has minimal clearance. Apparently it would require some significant pressure in the crankcase to force any oil (uphill) out of such a long close fitting joint. If you had that much pressure in the crankcase you would have MUCH worse oil leaks in other places, like from the front and rear of the crankshaft and especially lots of vapor venting from front the tappet cover draft tube.

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