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Defective flywheel ring gear...


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My late '64 Herald 1200 convertible has a Dolomite 1300 engine. For some time now the starter has 'meshed' occasionally - once the ominous 'click' has happened I have just put the gearlever into 4th & either pushed the car a foot or so forward or backwards so that the starter would engage......invariably she would start instantly.

Needless to say the situation has got worse with the occasional severe locking up which no amount of rocking the car will free. A spanner on the starter 'pinion' has saved the day on a couple of occasions...

My question is, is it better to look for a replacement flywheel - or would it be better to get some new ring gear for the existing flywheel? I am presuming the gearbox is original Herald so what flywheel should be sought if it needs to be replaced?

Any comments or advice, gratefully received...  

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What makes you think that the ring gear is at fault?

Far more likely is the starter motor pinion throw-in mechanism.  I think the original had a Bendix gear, that uses the inertia of the pinion on a screw thread to throw the pinion into gear with the ring.
The Bendix notoriously becomes fouled with clutch wear debris and oil.
Remove the starter, clean the Bendix gear and lubricate with graphite powder - never oil or grease.

More modern starters, and the Hi-Torque versions retro-fitted to Triumphs, had a 'pre-engaged' pinion, pushed into place by a solenoid, identified as a second cylinder on top of the starter.
They are nore difficult to service.


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Thanks very much for your prompt response, John - the starter motor was replaced 6 or 7yrs. ago.....The only thing that I have to go on was that I was told that the fault was due to some broken teeth on the flyheel, a few years ago. The problem has got considerably worse.  

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Worth removing the starter and doing what John suggests first off as it's free and won't take very long.  Check the condition of the starter teeth - if they are mangled then that won't be helping.

While the starter is out, take a look at the ring gear through the starter hole.  Wear will be noticeable at two diametrically opposed points (or 3 points @ 120º on a 6 cyl) because the engine usually comes to rest near the top of a compression stroke.  The wear will be on the back side.  If the teeth have almost gone then you'll need a new ring gear or a better flywheel assembly.  If they are just ragged and burred then a tidy-up with a file in situ will help.


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Quoted from Scimher
Thanks for the advice, Nick and Tony, will see if I can sort it without having to get someone to strip it all down. I'll start with the starter motor...

If you could post a pic of the starter showing the bendix, it would give us a better idea as to the main culprit
Cheers, Tony.

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  • 1 year later...

I've decided today, with a little spare time on my hands, to go back over my original posts (not many) in the last few years, & bring them up to date. I seem to have 'doubled up' for which I apologise, about some particular problems - this being a primary one!

If anyone has a simple, foolproof way of uploading an image that I have on the computer already (now don't get excited, it's not one of those!! 😀)...then do let me know!

In a nutshell, the engine gearbox came out, a 1500 Spitfire flywheel with good ring gear went onto the engine (neither of the job lot of two 1500engines - one Spitfire & one Midget were good enough to go straight in to replace the somewhat asthmatic 1300 Dolomite unit.) The starter motor bendix was totally crozzled & all the flywheel teeth were chewed! This started a chain of events that saw one of the job lot of two, presumably 1500, gearboxes replacing the increasingly synchromeshless unit - that in turn necessitated 3.5" being chopped out of the propshaft & a different flange added. This was done at a very reasonable price, locally, by GKN who I cannot praise highly enough! The upshot is that I have my little baby back on the road & starting better than ever & the gearbox is all sychro.....& works. Just need to get a bespoke speedo. cable now.

See 'Marketplace' for surplus stuff for sale & the other thread re. this, for talk of the starter motor spacer/shim!



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