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MG MGA - Engine assembly

In the W/S manual it states to use a thin film of Wellseal on the rear main bearing cap joint. What should we use instead, or is it really necessary? Also the manual talks about nut retaining tabs for the main cap nuts, but mine are Nylocks with lock washers.
Art Pearse

It sounds like your engine has been rebuilt using nylock rather than the origional nuts with lock tabs. You will see them available in the Moss catalog. You don't normally see lock washers used with nylocks. Nylocks seem to be the way things are done lately. I just rebuilt a Healey 3000 engine and nylocks were used. I didn't use any seal on that joint when I did my MGA engines. Have a good day!

John Progess

Wellseal appears to be available from several sources. However, since it just a "Blend of petroleum oil in chlorinated solvent" (per their data sheet) and is used to make disassembly easier, I'm guessing your local parts store or engine shop could recommend something. Personally, I just use engine oil.
G T Foster

GT, the manual is specific about he rear cap only, and it is to stop oil leaks. I would have thought the fit was tight enough to do that on its own, and there is a drainage channel in the scroll area before oil can get "outside"
Art Pearse

Did mean to imply it doesn't seal, only that it facilitates easy dissassembly (compared to gasket cement, etc). Check the Pegasus Racing site:

They carry Wellseal and similar products.

From their site:
"Genuine Hylomar is perfect for sealing gearbox covers or any other parts that need to be disassembled easily and without a lot of scraping to clean up the residue. Seals gaps up to .010 inch and since it never hardens, it makes disassembly a snap (cleans up with acetone, even after use). Hylomar is also an excellent gasket dressing and it will not cause corrosion of any metal surface. Supplied in 100 gram (3 ounce) tubes as a medium consistency paste or 8 ounce brush-in-cap cans as a liquid (part #3318).

We also stock Wellseal, a similar product preferred by some engine builders".


G T Foster

Gerry, it seems the intent of the W/S manual instruction is to actually seal the rear cap joining faces against oil leakage. I don't see the point. The bearing will leak oil itself via the running clearances, and is caught by the oil flinger and the reversing scroll. I can't see any point in the joint where high pressure oil is next to the outside of the cap.
So my question really is, does anyone who rebuilds the B engines regularly, take note of this instruction?

I have another question. I installed new thrust bearings and the end float is definitely < .002 (smallest feeler I have) and in fact I cannot feel any at all, but the crank spins freely. Spec is .002-.003, but I'm inclined to let it go. Any comments?

Art Pearse

This thread was discussed between 31/03/2009 and 01/04/2009

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This thread is from the archive. The Live MG MGA BBS is active now.