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MG MGA - Engine upgrades

Is it worthwhile to upgrade the timing cover to MGB with lip seal vs felt ? Also is there any advantage switching to the B front pulley with harmonic balancer ?
Art Pearse

Yes & Yes
D Sjostrom

I used the MGB Harmonic pulley, one disadvantage is that it covers up the MGA timing pointer (larger diameter) and I beleive the timing notch on the pulley is 180deg.
Dave Swinburne

On subject of timing marks, my 1800 cover has the graduations on the top, making it more convenient to use a timing light looking down into the engine compartment.

The rubber seal is a definite improvement. Not sure what a harmonic pulley is so cannot comment on that one. I will probably find I have one fitted when someone explains!

Steve Gyles

Steve, the harmonic balancer pulley is the drive belt pulley which is attached to the hub by rubber, and the pulley weighs more than the pressed metal MGA type. It somehow evens out the torsional vibrations in the crankshaft, for smoother running and less chance of fracture of the crank. I'm interested in how effective it is; they are not at all cheap new, but my MGA pulley is a bit bent (by PO) and I have to get it straight or replace it.
Art Pearse

An early MGB pulley and cover are the right size and have the timing marks in the right place. Be sure to mechanically check that the pulley mark is indeed TDC. Sometimes the outer pulley ring can move relative to the inner seeing as there is only a large O-ring between them.
D Sjostrom

The other advantage to the MGB harmonic balancer is that it removes the possibility of catastrophic failure of the MGA pulley due to rivet fatigue.
G Goeppner

I installed the MGB harmonic pulley and front timing cover with proper oil seal. The timing marks are as Steve suggested on the topside of the pulley and far easier to read. However I had to mark a new TDC notch on the front pulley at 180 degrees to the original so that it lined up with the new timing cover. This would suggest that the keyway in the MGA crank is 180 degrees out to the one in the MGB crank. Surprised others have not seen this?
Robert (Bob) Midget Turbo

Are all 1800 front covers the same? My 1800 (18GK) has the timing marks on the bottom of the cover, and I was wondering if a different year engine would have the on the top of the cover. It would make it easier to read, but also my timing marks get fouled on the steering rack when I remove the engine.
Mark J Michalak

They started underneath, but later models had them on top. I do not know the model number at the changeover.

Steve Gyles

My 18G engine has the timing marks on the bottom and the balancer has it's mark on the bottom just like the 1500 it replaced. The being an early model timing cover seal is installed from the outside.


Jim Ferguson

Hi Art,

Have you read Barney's article?

M F Anderson

I have now! Thanks Mick.
Art Pearse

I have the original pressed pulley on mine - this is similar to the one fitted to my '61 midget which had the catastophic failure (in 1973) that G Goeppner mentions - it took out the radiator as it flew to pieces. cheers Cam
Cam Cunningham

By the sound of all that I have an early pully (notch at the bottom) with a later timing cover (markers on top) Not to worry with TDC marked by me to match the timing merks everything is fine.

I too had the riveted pully on my car originally. I was on holiday in France (Loire) when I heard the rivets become loose. Fortunately we were just about to set of home so we drove home carefully fingers crossed hoping it held together. Which thankfully it did. I repaired it with countersunk machine screws in place of the damn rivets but was pleased when I eventually got the MGB pully and cover to replace it.
Robert (Bob) Midget Turbo

This thread was discussed between 23/03/2009 and 25/03/2009

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