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13 minutes ago, john.r.davies said:

I have several.   Long or short end?  Send pic of back of crank if not sure.

I'm glad this came up and also glad you have several lying around John.

I have a query about ring gear fitment, I don't know anything about starter motors don't know the difference between inertia type, pre-engaged or whatever.  I've just had a flywheel balanced as part of the whole assembly and while the machine shop was at it I had them fit a new ring gear, they've fitted it with the chamfer onot the teeth facing the gear box. 

Is that the correct orientation for use with a hi-torque (WOSP) starter?

Sorry if this is hi-jacking.

Stay Safe everyone!

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4 hours ago, Richard71 said:

I'm glad this came up and also glad you have several lying around John.

I have a query about ring gear fitment, I don't know anything about starter motors don't know the difference between inertia type, pre-engaged or whatever.  I've just had a flywheel balanced as part of the whole assembly and while the machine shop was at it I had them fit a new ring gear, they've fitted it with the chamfer onot the teeth facing the gear box. 

Is that the correct orientation for use with a hi-torque (WOSP) starter?

Sorry if this is hi-jacking.

Stay Safe everyone!

Thank you, Richard! Yes, long back.

Starters, Richard.   The old Bendix drive was an inertia starter.   The pinion was mounted on a screw, so as the starter started, the pinion's inertai kept it still as the screw thrust it into engagement with the flywheel ring.

A 'Pre-engaged' starter has, instead a seperate servo on top of the actual starter, so tweo cylinders built together.     When you press the starter button/turn the key, the servo is energised and pushes the pinion into engagement, when it is the movement closes a switch and the starter iteslf moves, not before!   

As the pinion approaches the flywheel ring from the same direction in either case, to my mind the bevek should be on the front, but I've heard that it doesn't matter.  What do others think?

"WOSP" is, I think, a company name.   Many other starters are available.

 

Eddie, I'll look and see about a flywheel.   Starters?   Buy a new/reconditoned one!   A "Hi-Torque" one, which will be a pre-engaged type.

 

JOhn

Edited by john.r.davies
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Eddie, 

I'm sorry, none of my flywheels conform to the definition of a 'Long'back' flywheeel on the Revingtons pages - 9mm recess in clutch face.    They are all deeper but not as deep as 'short back' 28mm!  Probably from Salloons or 2L.    Shpul;d have kept better notes!

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Thanks John and Tom for clearly clarifying the difference between the (older) bendix and more modern pre-engaged starter motors. Something new for me to forget:)

Based on this, I think the chamfering of the teeth of the large gear ring should be on the side “where the pinion comes from”. Otherwise it has little value.

Regards,
Waldi

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8 minutes ago, Eddie Trickett said:

John,

Thanks for looking. At least I know there are different types of fly wheel. As I said the engine is actually from an early TR6. Revington part number 148041SH appears to be for early cars, the engine number is CC4763E.

Thanks

Eddie

 

Early TR6 was fitted with the long back crankshaft as in the TR5 and I would expect the 250. Keep looking, someone will have one somewhere or there are lightweight steel flywheels available from the usual suppliers.

Richard.

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Tom,

The original engine number was CC/2033E. I assumed the replacement was early TR6 but could be TR250.

I bought it from Manchester, USA 4 years ago . The heritage certificate says it was shipped from Manchester UK in 1968 on the ship Manchester Skipper. I live in South Manchester.

Clearly a Manchester car.

Regards

Eddie

 

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The bevel on my ring gear faces the gear box.  My starter has a bevel on the pinion gear which engages from the front.  My understanding is that the two bevels shouldn’t meet. Ie if the pinion has no bevel, then the ring gear pinion should have the bevel on the engaged side.  

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14 minutes ago, aardvark said:

The bevel on my ring gear faces the gear box.  My starter has a bevel on the pinion gear which engages from the front.  My understanding is that the two bevels shouldn’t meet. Ie if the pinion has no bevel, then the ring gear pinion should have the bevel on the engaged side.  

That's precisely the explanation my machine shop gave me earlier. Two set of straight cut teeth won't mesh, two sets of chamfered teeth will wear prematurely.....words to the effect.

Richard.

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5 minutes ago, Richard71 said:

That's precisely the explanation my machine shop gave me earlier. Two set of straight cut teeth won't mesh, two sets of chamfered teeth will wear prematurely.....words to the effect.

Richard.

OK, since the pinion has a bevel and you don't want it to mesh with another bevel, why bevel the ring gear at all?

 

Tom

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Why would 2 bevelled teeth wear out if they “catch” each other? I would like to learn.

Thanks,
Waldi

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6 hours ago, Waldi said:

Why would 2 bevelled teeth wear out if they “catch” each other? I would like to learn.

Thanks,
Waldi

Me Also Waldi, I would assume both chamfered teeth would mesh perfectly & easily, but I won't argue with a machinist who cuts gears etc. Maybe someone will be along with an explanation.

Richard.

Edited by Richard71
Typo
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A pinion for starter gearing having a radially extending concave face, the concave face being formed so that the teeth of said pinion gear are angularly disposed with respect to the transverse plane of said pinion thus protruding outwardly from the engaging end of said pinion. In order to aid a starter drive pinion into mesh with a rotating ring gear the concave face allows the tips of the teeth to protrude from the face of the pinion and therefore easily engage the teeth of the ring gear, thus, bringing the pinion up to synchronous speed with the ring gear more quickly than face-friction alone would accomplish. Remember on a 6 pot the teeth only wear at three points on the flywheel.

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Hi Neil,
thanks. Stupid I could not think of that myself:)

Looks like you copied text from a US patent, see this link:

https://patents.google.com/patent/US3798977A/en

 I find those patents hard to understand (am involved in them occasionally for my work), especially because they are in a foreign language and written in such a way that is covers “everything the originator wants to protect”, but often is a total mystery to an average engineer like myself.

So can you explain in simple words why the chamfers would or would not need to “match”?

Thanks,

Waldi

 

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