mk1-forum.net

I am restoring a Mk1 Cooper with a 997 engine and an early flywheel - probably fitted in about 1962 as part of a Deva bush conversion. Although the starter was working OK, on dismantling the coil spring clutch I see that the starter ring has some seriously worn teeth. With these early flywheels no longer available, I would like to fit a new starter ring to the existing flywheel. Does anyone have any advice on how difficult this job is on a mini flywheel? Is it a matter of heating the ring and knocking it off, then heating up the new ring to refit it - or is this a job for a specialist? If anyone has direct experience and can offer advice I shall be grateful.

cut the old ring off

put new ring on a bbq and allow it to warm up equally and not get too hot (or it will expand too much and buckle)

drop ring onto flywheel and allow to cool

don't be tempted to weld it on unless you have a method of monitoring and controlling the localised expansion that will occur around the welds.

you also have to be careful to ensure that the ring drops square onto the flywheel, or it will be out of balance, we use a hydraulic clamp that forces the two parts together until they have cooled to solve this

The way I fit them is, suspend it off the bench on a hook or similar, heat it gently with oxy-acetelene don't make it glow though. Takes about 5mins to heat it, but don't exceed 230degs (I think) carefully fit it on with mole grips or pipe grips. If my memory serves there's a raised lip on the flywheel, so try testing the fit, once it goes over the lip it's hot enough.

If you want, I have a new old stock starter ring that I won't be using and would be willing to sell.

rich@minispares.com wrote:cut the old ring off

... The gear ring will be case-hardened - Buzz between a pair of teeth with
an angle grinder to get through the skin, then finish the job with a hacksaw...

You can go almost right through, then get a cold-chisel between the teeth
and give it a whack. This is quite often enough to get them off without
sawing right through the ring which normally does a small amount of
damage to the flywheel.

rich@minispares.com wrote: put new ring on a bbq and allow it to warm up equally and not get too hot

Baking tray in the oven, at maximum temp for half an hour..

Just don't get caught!
If you put foil on the tray first, you'll probably get away with it...



Ian

I watched a guy do mine. He placed the ring gear on the flywheel then heated it up around the circumference with an acetylene torch. Eventually the ring gear slipped over the lip. Job done.

Pretty much what everyone else has said, from the Factory Workshop Manual;-

"Starter ring
If a new starter ring is needed, split the old one with a
cold chisel. Clean the bore of the new ring and the mating
surface of the flywheel, heat the ring to a temperature
of 300 to 400° C. (515 to 752° F.), indicated by a light
blue colour, and fit it to the flywheel with the lead of the
teeth towards the flywheel register. Allow it to cool
naturally."

making sure the ring goes on the right way round.
....the lead in on the teeth facing away from the clutch face and the
step on the ID against the shoulder.
oxy torch works the best.

My sincere thanks to all for your helpful advice.

I am currently exploring an NOS flywheel from 1962 that might resolve this for me. But if this is not the correct part I will take all of the advice given and replace the starter ring.

This is a brilliant forum and great source of advice for a newcomer to Mk1 restoration. Many thanks.