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MG Midget and Sprite Technical - 1972 Midget 1275 distributor

I have had the distributor out of my wife's MG midget 1275 - it a 1972 model.

I did this to change the points as I thought it would be easier. Having changed and set the points I lined up the pully mark with the various options ( pointers ) at 4 Degrees before top dead centre.

Now I find the rotor arm is facing the complete wrong way. Because the drive lug on the distributor is offset I cant for the life of me work out what I have done wrong.

Can you help please ??

Thanks for your time.

Kevin Peacock.
Kevin Peacock

If you have not removed or disturbed the offset drive from the cam in the engine block and only removed the dizzy, then it should be just a case of popping it back in by hand and rotating the rotor arm shaft until the offset drive dog of the dizzy locates into the offset drive socket of the gear drive within the engine.

Its usually best to mark the dizzy position before taking it out so you can pop it back in without having to bother with re-timing.
richard b

Kevin, the crankshaft does 2 revolutions for 1 revolution of the distributor, having set the marks on the crankshaft at 4 degrees this can either be the firing point for cylinder 1 or 4. I would suggest lifting the rocker cover and checking which pair of valves are open, if the valves are open (rocking) on cylinder 4 then cylinder 1 is on the firing stroke and that's where the rotor arm should be pointing and vice versa.

Bob
R.A Davis

Bob . And Richard .
Thanks for your inputs on this guys . I nipped into a local garage today and I know they love old motors . The guy I spoke to says the same as you bob . Sonibwff we not back to the car and maybe I’m a idiot but I cranked the engine ( plug less) one full turn and everything was exactly the same , so ;
Bob can you talk me through this please . In 6” high letters .
The flipping car started on Tuesday so it can’t be major

Many since thanks
Kevin Peacock

Kevin

If you've rotated the engine one turn, the rotor arm is now bound to be correct. Are you sure you've seated the drive dog correctly? Also, to rotate the engine, select top gear and push the car backwards (with plugs in) - well that's what I do.
Bill Bretherton

Kevin, the reason for having an offset drive for the distributor is exactly this reason, so that you can't get it 180 degrees out of line. You say the car started on Tuesday, was this after you'd re-installed the distributor? If so this shows you don't have an issue.

If as I believe you're saying, the engine starts and runs, then all you need do is set the timing accurately. From what you say, you seem to be ok doing this if not let me know and I'll do a short explanation of how I would set it.

Bob
R.A Davis

Ok . Latest news . But first a big thanks to all who gave me their time. I had NO IDEA the crankshaft travels twice round for one whole turn of the distributer .
I do now 👍👍
So the timing is set . Unfortunately by shear coincidence the starter motor has failed and I have one on its way and fully expect the old girl to fire up. Thanks to everyone. I’ve had company cars for 37 years now but before that I used to work on Vauxhall Viva and victors all the time . I must of genuinely been REALLY lucky when doing the timing .
Happy new year to all and thanks again
Kevin Peacock

This thread was discussed between 07/01/2022 and 10/01/2022

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