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MG MGA - Rear Seal for 18G 1800 3 bearing Engine

I have my engine out to adapt a modern rear seal to the early 1800 3 bearing engine. Barney Gaylord's tech pages states that a Chicago Rawhide #39921 seal is to be used. That particular seal is larger in the i.d. than the 3.871 inch diameter of the crankshaft. So it won't work. Can anyone advise which seal (part #)they used for this engine?
Frank Nocera

Hi Frank. I assume you know the outside diameter of the seal required from Barney Gaylord's drawings. Then Measure the outside diameter of the rear crankshaft flange on your engine. (where the lip of the seal will ride) Then go to a bearing and seal store with your dimensions. Tell the seal people what you will be using the seal for. The staff at the bearing and seal shop should be able to calculate the sizes of the seal needed, and supply you with a seal that will work for this application. Good luck! Glenn
Glenn


Barney responded to me by email; I now understand how the rubber seal works on this application. It does not ride on the crankshaft where the oil groove is located, but rather on a smooth steel ring that is press-fitted onto the real crankshaft flange and held in place with a pressed in pin. And two holes need to be drilled into the main bearing cap for the oil to return to the sump.OK, back to the machine shop on Monday.
Frank Nocera

Hi Frank
I would be very interested in how your rear seal works out. I have a rebuilt 1800 3 main waiting to into my 61 and have thought about getting the rear seal added.
Kris
Kris Sorensen

Progress report:
This mod is much more invasive than I originally thought. At this point I would only recommend it to someone who has either is in the process of rebuilding their MGA or 3 bearing MGB engine, or who has such a severe rear main leak that it warrants the invasive process. At this point the engine is out and the bottom end of the engine is partially disassembled. The crank is removed and at the machine shop so exact measurements can be made for the ring that will slip over the end flange (on which the seal will ride). Machine shop is recommending a new LocTite product instead of drilling and pinning the ring in place. I'm still thinking about that one. They will also be drilling the rear bearing cap. I think the machine shop owner just made his boat payment for next month.
Frank Nocera

Frank Nocera,

Hi, could you please supply either a link or a drawing of this installation, seems to be very usefull for avoiding the oil leaks at the back of engine.
Let us know please. regards.
Renou

Renou, here is the link to Barney's page with all the details. http://mgaguru.com/mgtech/engine/cs202a.htm
Bill Young

Renou,

I am following the rear seal modification procedure found on Barney Gaylord's MGA Guru web site:

http://www.mgaguru.com/mgtech/engine/cs202a.htm

Note that this procedure (CS202) contains five pages. I hope this helps.
Best regards,
Frank
Frank Nocera

Many thanks for your replies gents. very helpfull link that of course I bookmarked .
Best regards .
Renou


Kris,

Per your request, here is my report:

I have been driving with the rear main seal mod installed for about a week. So far, so good: nary a drip. It is not an inexpensive fix. My total tab just for the machining was in excess of $500, plus about $60 (including shipping for the special order) for the seal and another $30 for miscellaneous parts (front seal...since the crank was out.... pan gasket, etc.). Machine shop prices tend to be expensive where I live, so I do not doubt that the machine work can be done cheaper in other cities (with more shops and more price competition). So would I advise doing it? I would first recommend to anyone who is thinking about putting an 1800 engine in their MGA to go with a 5 main bearing engine which has a rear main oil seal. But anyone who has a 3 bearing 1800 engine, or an MGA engine, it is a trade off between cost and desire to not drip oil. I might advise it during an engine rebuild, or, as in my case, where the leak was getting severe.
Frank Nocera

Frank

I have the 5 main bearing engine and had the machining done on my back plate. It cost me £30 (abot $55). $500 is certainly a bit steep. Wothwhile modification, not dropped any oil in the last 5 years.

Steve
Steve Gyles

Steve

Which engine do you have? Frank seems to indicate that the 5 main engines have the rear seal. Which ones do and which ones don't.

Thanks

Larry
58 A and looking ahead
Larry Hallanger

Larry

I am struggling to remember the exact details of what I did 5 years ago. At the time I fitted the 1800 5-bearing engine I also did the 5-speed Sierra gear box conversion. I recall I neeeded to fit an MGA backplate so I had it milled out to take the oil seal. I also fitted an MGB clutch which seems far superior to the MGA. Bob West advised me on all the parts I needed so I will give him a ring tomorrow and come back to you.

Steve
Steve Gyles

Larry

I have just spoken with Bob West. I understand that the MGB backplate has a lower starter mounting than the MGA and that the starter is likely to foul the chasis. I fitted the MGA backplate with the high starter position.

Steve
Steve Gyles

This thread was discussed between 11/02/2005 and 04/03/2005

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