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MG MGA - Timing Chain Cover Oil Seal

Can the timing chain cover and oil seal interchange between an MGA and an MGB? I have an MGA with a felt type oil seal and it always leaks. Why can't I replace it with the rubber type seal used on MGB's?
Jerry Kline

Jerry:
I don't think the MGB seal will fit in the MGA timing cover. I've been considering the same change for the same reasons.
I don't know if the MGA's crank pulley boss has the same OD as the MGB's, which would be critical to the conversion. Possibly, the MGB pulley will fit the MGA crank (????).
My approach, so far, is to obtain an MGB timing cover.
But that's as far as I've got!!!
I'll be interested in the REAL answers.
Fraser Cooper

Jerry,

Read Barney Gaylord's site at:

http://www.mgaguru.com/mgtech/engine/cs201.htm

I have quoted some on Barney's article, but should read all of it.

"An early MGB timing cover may be available and can also be used on the MGA. It is formed differently, with the rubber seal pressed in from the inside of the cover, so the cover must be removed to replace the seal. The MGB cover is also flat faced with the seal nest extending forward from the face (no large moat around the seal), so you also have to use the different (almost flat) oil thrower ring from the MGB. If you use the MGA oil thrower ring with the MGB cover it will rub and quickly chew a circular slot through the face of the cover making for a much worse oil leak. Been there and done that once before I knew better.
The MGB timing cover has 5 timing pointers in 5 degree increments from 0 to 20 degrees BTDC. It also has a thick stiffening ridge stamped in the bolt flange between the bolt holes.

When the traditional oval flat washers are installed, the ends of the flat washers will contact the raised ribs to press the cover against the gasket. The oval flat washers will most likely be bent slightly as the bolts are tightened, but all of this helps to prevent puckering of the cover flange around the bolt holes and improves sealing of the gasket. Some puckering may still occur, so you should still tap the flange flat before installation. When the oval wahers are to be re-installed it is also a good idea to tap them flat again with a hammer before installation.

The MGB type oil thrower ring is nearly flat with a small step just outboard from the sprocket hub. The ring is stamped with "F" on the front side. When properly installed the flange will be closer to the timing chain (but will not touch the chain). If this one is installed backward the flange might touch and rub on the inside of the cover".


Mick

Mick Anderson

A number of years ago I picked up 4 covers at an MG garage closing down auction. All of them had the rubber oil seal which was what I was after. Interestingly, one of them also had the timing marks on the top instead of underneath. Not sure which version of the 1800 it came off but it makes timing the ignition a lot easier, being able to look down from on top.

Steve
Steve Gyles

Mick and Steve:
Thanks for the info. I SHOULD have checked with Barney's site! Give my head a slap.
When I've had my engines apart (1500 A and 1800 B) I've soldered a pointer onto the top left just above the pulley rim. Then added new timing marks to pulley, labelled 'D' for dynamic and labelled the old ones 'S' for static. As Steve says, it makes timing from above using a strobe light much more convenient.
Fraser Cooper

I did some catalogue searching: Victoria-British and Moss.
1. The oil thrower for all MGA and all MGB engines carries the same part number from both V-B and Moss
2. The oil seal for MGA 1600/1622 carries the same part number as that for all MGB, both V-B and Moss
3. The cover gasket is the same part number for all
4. The crank pulley for all MGA and 3-main MGB carries the same part number from V-B. Different numbers from Moss.
So, it appears that the conversion can be done easily. I'll add it to my 'to do list'. I'll be careful of that advice on the oil thrower, though.
Fraser Cooper

Steve,
My MGA 1500 motor has the later style 1800 cover with the top timing marks as you describe. Does anyone know what 1800 version it came from? -M.S.
Martin Straka

Fraser

The part numbers may be the same, but the parts are DEFINITELY not freely interchangeable.

The later cover MUST be fitted with the later thrower. The A one has a much more pronounced dish and bowl, the B one is just dished in the centre, and then flat. You could use a B thrower with an A cover, but not vice versa.

The two pulleys can be interchanged freely on the crank, but are not at all the same - and the repro ones that are probably available under the part number are SO different to the originals that I sent mine back as unusable for my application. (The distance of the V from the crank end was not the same as the original, and there was a very deep dish at the front). The B pulley is a heavier one with a harmonic balancer, the A one is a simple pair of dished plates riveted to a central boss (like the generator pulley)

I am interested in the cover with the top marks. Does anyone have more details?

The B oil seal does not fit the A cover - it has a larger OD.

Jerry, if you fit a new felt seal, it should not leak (actually better for a crank that has a lip worn in the end by a oil seal, because the sealing area is bigger).

If you fit these B covers, you have to make sure you centre the cover wrt the crank, (cf workshop manual on the front gearbox cover) as they don't seal at all if things are off centre.
dominic clancy

Best way of fitting a felt seal is to remove pulley and timing cover. Remove old seal, fit new, then fit the pulley to the cover taking care to ensure that the felt is fully contained in the groove on the inside and does not push out as the boss on the crank pulley is pushed in.

Fit cover and pulley as an assembly to the engine.

Cheers
ian f
Ian Fraser

I have an NOS timing chain cover in original packaging which is supposed to be for an MGA. It came with a rubber seal, and the timing marks are on the bottom of the cover. I don't know which oil thrower ring will be correct. The box is labeled with BMC Part No. 12H2281.

G Goeppner

Thought I read somewhere ( Maybe Clausager) that the last couple of hundred 1622"s came through with the newer cover with the rubber seal.
Al
A. Tirella

Late A's and maybe some early B's have a timing cover with the runbber seal inserted from the front side rather than installed inside. It is the same rubber seal as for later covers, but definitely much different cover. These early rubber seal covers use the same cup shaped oil thrower ring as the MGA cover with the felt seal. For pictures of all, see here: http://mgaguru.com/mgtech/engine/cs201.htm
Barney Gaylord

This thread was discussed between 09/06/2006 and 13/06/2006

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