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MG Car Repair/MGB Timing Cover



I have a 1971 US spec MGB GT.  The timing cover has the marks on the bottom and it is a real pain to time it.  I'd rather not lay on my back with my timing gun and then have to keep jumping up, adjusting the dizzy, and laying back down to check the time.

I have two other MGBs, a 1972 roadster and a 1980 Limited Edition roadster and, of course they are both timed from the top and I can adjust the distributor while timing the engine.  Makes setting the timing very easy.  

My question is, since my 1971 MGB GT has a 5 main engine and the crankshaft seems to be the same part used in later engines, is it possible to fit a newer timing cover and harmonic balancer on the 1971 engine so that the timing marks are on the top vs. the bottom?  I haven't done all the research but assume that the timing mark on the pulley must be 180 degrees or so different to make the pulley mark line up with the fingers on the cover.

I have a cover and pulley from a 1980 junk engine and was considering the cover and pulley swap to make maintenance easier on my 1971.  Do you have any knowledge of such a mod?

Thanks in advance.


Hi Dave,

I have not made that switch but I do believe the cranks were the same in all of the 5 main engines.

It is easy to do a fit check and the way to check it is to remove #1 plug and put a rod of any kind in on top of the piston and hand rotate the crank to be sure of TDC and if the pulley and the TDC mark on the cover match you are finished. If not put your own marks on it.

If you didn't have the top reading parts you can always make your own marks on the old cover and pulley. Just locate TDC with the rod in the plug hole and file a notch or even drill a small hole in the pulley and put a white paint mark on the notch or hole and then paint marks on the cover to match TDC. For the 5, 10, 15 degree marks just measure the orginal cover from the TDC to each pointer on the bottom of the old cover and just paint lines on the cover the same spread as the old marks were.

I do this all the time because I missmatch front pulleys and engines often. I used the timing marks in a front cover of a Olds 215 V-8 for another purpose so I just painted a TDC mark elseware where I could easily see it and since I was using a Honda Civic front pulley I had to put my own marks on it anyway.


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Howard M. Fitzcharles III


MG from 1956 (USA versions only) up and Engine theory.


Dealership line mechanic on MG, Triumph, Jaguar for 15 years, Instructor in commercial mechanics school 2 yr. Product information manager for piston and valve manufacture, Instructor & hotline answer man for import car parts importer 15 yrs.

Associate member SAE EAA member

Import Car magazine

ASE Master Auto with L-1 certification up to 2000

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