Starter Pinion

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chris68
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Starter Pinion

Post by chris68 »

After already swapping one flywheel due to damaged ring gear (and never fully understanding what caused it), I decided to check the pinion on my high torque starter, see image below ..

Image

It's got practically no lead in chamfer so I'd prefer to replace it. Anyone know where I can find one?

It fits on a 12.7mm, 18 spline shaft. It has 9 teeth with 25.4mm diameter. In total it's 23.1mm long.

Thanks
'68 swb 911L
'62 Lotus 22
100cc Historic Karts
Lightweight_911
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Re: Starter Pinion

Post by Lightweight_911 »

Andy

“Adding power makes you faster on the straights;
- subtracting weight makes you faster everywhere”
chris68
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Re: Starter Pinion

Post by chris68 »

Thanks, I tried Auto Electric Supplies. They have something similar only, but non in stock at the moment.
'68 swb 911L
'62 Lotus 22
100cc Historic Karts
911hillclimber
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Re: Starter Pinion

Post by 911hillclimber »

Thought you had that one sorted Chris.
Brise might help, they are 'techie' enough to help or know somebody who might.

Fosseway show pinions as a separate item, so may be good too.
Outsiders are:
Green Spark who sell hi-torque starters, quite a large company in Derbyshire, and another who I can't quite remember the name of but used to do a lot of Healey spares, but do a lot of these units now, will post if I find them.

Probably many in the UK selling the same units from the supplier Andy has stated.

http://www.fossewayperformance.co.uk/wp ... ons-03.jpg
73T 911 Coupe, road/hillclimber 3.2L
Lola t 492 / 3.2 hillclimb racer
Boxster 987 Gen II 2.9
911hillclimber
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Re: Starter Pinion

Post by 911hillclimber »

Just remembered, Cambridge Motorsport, EDGE starters
https://storage-cambridgemotorsport-com ... efault.jpg
73T 911 Coupe, road/hillclimber 3.2L
Lola t 492 / 3.2 hillclimb racer
Boxster 987 Gen II 2.9
chris68
DDK slapper chatter
Posts: 449
Joined: Thu Apr 28, 2005 12:54 pm
Location: Burton On Trent

Re: Starter Pinion

Post by chris68 »

That's a great help, I'll try them all.

It's been niggling me that I had to swap the flywheel because of ring gear damage but never got to the bottom of what caused it. Couldn't resist pulling the high torque starter to check the lead in profile of the pinion gear. Surprise, surprise - there isn't any! Reckon now that this may have caused the horrible chewed up ring gear and not willing to risk it again. Options are to replace the pinion gear (my starter measures up fine, and believe me I've checked it over and over again), get a new Wosp unit (they seem to be a safe bet) or put the lazy original Bosch starter back in.

Probably a good idea for anyone running a high torque starter to check it isn't dining on your flywheel :cry: .

Cheers
'68 swb 911L
'62 Lotus 22
100cc Historic Karts
Winston Teague
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Re: Starter Pinion

Post by Winston Teague »

If you're trade, you can talk to Wosp. Very helpful. Proper good people. I fitted one of theirs to my 2.1 T25 WBX 15+ years ago. Powerful, but noisy, sort of screamy as engine fires. Fast forward to last years engine rebuild, and teeth on the old engine were worn but not mangled. Fitted new engine, fire her up. 5 starts later it took 7 teeth half off. Much measuring and checking, which is difficult as it is tricky to get the full plunge out of the starter motor static on the bench, and the engagement depth was wrong. They sent me a different depth face plate and all is much happier. Never fully trust the aftermarket supplier to have exactly the right information to make something that fits your individual engine.......Measure and measure again. Good luck, W
Winston
'61 356 BT5 & a lot of broken chain driven stuff
Winston Teague
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Re: Starter Pinion

Post by Winston Teague »

And, obvs, many 3rd party agent suppliers of these things are just repeating the part number blurb from their supplier....and will probably not have ever fitted one.......so they are of no practical use in a tech snag situation. W
Winston
'61 356 BT5 & a lot of broken chain driven stuff
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Re: Starter Pinion

Post by Winston Teague »

And as to your original question about lead in, if you know for certain which way the lead in points, just grind it yourself with an angle grinder, a gentle kiss with a disc will do it. But i'd also expect a lead in on the ring gear. Going back to plunge depth vs engagement, the pinion must plunge to engage with the whole tooth on the flywheel, but the plunge must not go so far as to allow that collar to hit the face of the teeth. If it does, it can move a shrunk on ring gear, or damage the starter pinion to armature mount.....
Winston
'61 356 BT5 & a lot of broken chain driven stuff
chris68
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Re: Starter Pinion

Post by chris68 »

Thanks Winston.
Good point about double checking engagement depth. Had a look last night (a bit chilly under the car :lol: ). Reckon front edge of flywheel teeth are 37mm from starter mounting face of 901 gearbox. This suggests starter engagement is 8mm into flywheel (for original Bosch or my high torque starter). Seems a bit low to me?? Flywheel tooth depth is about 10mm, so would expect a bit more throw from the starter ...
Cheers
'68 swb 911L
'62 Lotus 22
100cc Historic Karts
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