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Correct way to fit dizzy drive gear

Posted: Sat Apr 17, 2010 10:59 pm
by SvMinor
I had an oil leak so I removed the sump and decided to put the timing back to the way it was before I replaced the crank.,I had to re arrange the leads on the dizzy so now I want to put them back the way they were.what is the proper way to refit the drive on a 1098 engine,I looked through the the haynes manual and the Minors owner manual and they both state different ways to fit the drive,

The haynes says the drive slots should be in the 10 to 4 position,to allow for rotation when fitted,on all bmc a series engines except sprite mk1 ROTATE THE DRIVE 180 degrees.

with the drive pully home the drive slots should be in the 20 to 2(o'clock)position,on all bmc a series engines except sprite mk1the larger segment is at the top.


In the official minor manual it says to fit the drive with the slots vertical and the smaller offset segment towards the front of the engine


I will add a pic of my dizzy drive and I will point to what I think is the small segment.

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Re: Correct way to fit dizzy drive gear

Posted: Sun Apr 18, 2010 12:09 am
by rayofleamington
I've used the Haynes positioning* and it worked ok.
If in doubt, check with your dizzy that the rotor arm is pointing to exactly where you want it for #1 on the dizzy cap when #1 is at TDC on compression stroke.


* The Haynes method is flawed but the positioning check was ok on the times I've done this. On the 1098 the nearest piston skirt can foul the drive as you try to assemble it, so you need that piston anywhere that's NOT at the bottom. Then insert the drive (making an adjustment relating to 50% of how much you turned the crank) and after inserting, move the crank back to previous position to check how the drive looks (and if ok, do a quick fit of the dizzy to check rotor arm position).

Re: Correct way to fit dizzy drive gear

Posted: Sun Apr 18, 2010 1:52 pm
by bmcecosse
The Manual is perfectly correct - just follow that. But really - it doesn't matter - as long as you get the leads on the plugs and the vacuum unit not fouling up on the oil pipe of the pressure switch. Just don't drop it in the sump - although not such a calamity as it is if done on a Mini engine!

Re: Correct way to fit dizzy drive gear

Posted: Sun Apr 18, 2010 5:23 pm
by SvMinor
Everything sorted. Car starts BUT with the coil lead removed the engine spins fine then after re attaching the lead to the coil the engine seems to stick halfway round while turning over.If I pull quickly and let go the engine will start.But if I pull and hold the starter the engine sticks on half a turn then frees then sticks until the engine starts.

Would this have something to do with the adjusting wheel on the dizzy?

Re: Correct way to fit dizzy drive gear

Posted: Sun Apr 18, 2010 5:30 pm
by MarkyB
It sounds like the ignition is too far advanced.
You might get away with turning the adjuster all the way towards R, but otherwise the dizzy will need to be turned a fraction.

Re: Correct way to fit dizzy drive gear

Posted: Sun Apr 18, 2010 6:41 pm
by bmcecosse
Yes - it is too far advanced and will break the starter! Retard slightly.

Re: Correct way to fit dizzy drive gear

Posted: Sun Apr 18, 2010 7:57 pm
by SvMinor
Sorted.job done.thanks Everyone