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MG MGA - Have I got the timing wrong?

I have just had my distributor reconditioned and set about the task of refitting it this morning. I followed the instructions in the Workshop Manual for Static Ignition Timing, setting it at 7 degrees BTDC, but when I tried to fire up the engine it turned over fine and then backfired big time! Tried a second time with the same result. I'm guessing I've got the timing wrong?
Robert Sinclair

Have you made sure cylinder no 1 is on its compression stroke before you do the timing procedure? A simple way is to take plug 1 out and test with your thumb for pressure as the piston is raised with the starter handle.
J H Cole

I don't know how I managed to do it, because I deliberately left the engine exactly as it was when I removed the distributor in the first place, but when I replaced it I got the timing 180 degrees out! What a wally. I've now swapped the HT leads around and it's working fine. Live and learn!
Robert Sinclair

Robert

You are probably not the wally that you think you are. The 180 degree error probably occurred in the reconditioning by the supplier. The upper shaft of the distributor can be inserted in one of 2 positions (180 out) to engage the bob weights as shown in the attached photos I have just taken.

The only error perhaps you made was not noting the position of the rotor when you removed the distributor. You will already be aware that the distributor can only be engaged one way round on the engine off-take drive shaft, so this can be the only explanation why you ended up 180 degrees out.

Steve


Steve Gyles

Thanks for that, Steve. I've been trying to figure out how it could have happened, but that explains it.
Robert Sinclair

Steve,

There is a second possibility besides the one you mentioned.
The dog drive item 10 in the attached diagram could also have been fitted 180 degrees out by the repairer.
Although the one you mentioned, item 14, is also a possibility.

Mick


M F Anderson

Mick

Yes. I buy that option. Good spot.

Steve
Steve Gyles

This thread was discussed between 07/01/2013 and 09/01/2013

MG MGA index

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