P6B starter motor

D

Duane

Member
I have just received an aftermarket starter motor for my P6b and it is just free spinning. The distance from the mating surface to the flywheel looks correct when the pinion is thrown so I can only assume the gear is the wrong diameter.
Could someone tell me what the diameter of the pinion gear is to the outside of the teeth.
 
Pics are always very useful when asking this type of question.

Are you sure the pinion is being thrown out?
 
After market high torque howling thing, for Rover P6B

IMG_2238.JPG

Original starter motor from a 1972 P6B

IMG_2239.JPG

Both slightly over 25mm

Any help?

Richard
 
Thank you. Now I am confused as that is the same as my new high torque starter that doesn't seem to engage. i I have no idea what is wrong now. The pinion definitely gets thrown on the bench.
 
I don't think 2mm difference in the radius would stop it engaging, it should mesh more than that.

Did the old one work ok?
 
The problem is the car didn't have a starter motor when I bought it. so I have nothing really to compare the new one too that I am certain worked.

I need to get back underneath and have a closer inspection.
 
Hi, Perhaps the pinion is not throwing far enough to reach the ring gear. A couple of questions. How far is the ring gear away from the starter face compared to the starter itself? Is it auto or manual and has it always been that?

Colin
 
Is there any way you can take any pictures Duane, they really do help?

Remove the motor and take a picture of the hole it fits into and the end of the starter.

Where did you get the new starter motor? and is it specifically for the V8?
 
Always been an auto.

40mm from starter face to forward edge of ring gear, and the ring gear is thrown 12mm. That matches the flywheel from the same face, so either the ring gear isn't being thrown at all (unlikely as it certainly does on the bench), or it is hitting the flywheel face on and spinning against it (that could only be the flywheel or the pinion being massively oversize which I can't see), or it isn't meshing with the flywheel (because the pinion is too small). none of these make any sense other than the first one.

Flywheel teeth look fine.

I think I will put some paint on the flywheel where it should mesh, put the starter back in and crank it, then take it back out and see if there is any smearing of the paint.
 

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Starter motor is from RoadRunner Starters here in NZ. They have sold hundreds of these for Rover V8 engines so are scratching their heads too.

The more I think about it the more I'm thinking if I put it back in it is going to work fine second time round.
 
Duane said:
Starter motor is from RoadRunner Starters here in NZ. They have sold hundreds of these for Rover V8 engines so are scratching their heads too.

The more I think about it the more I'm thinking if I put it back in it is going to work fine second time round.
Click to expand...
 
Hi Duane,

I have just taken a couple of photos of a NOS starter motor that I have. On the face of it, the measurements appear the same. The full distance when the pinion gear is thrown out is some 55mm.
20221128_144005 (Large).jpg
20221128_144146 (Large).jpg

Ron.
 
Yep sound about the same. I think something went wrong with my initial try. Or the clutch in the starter is dicky.
 
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