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MG TD TF 1500 - Starter Pinion and Ring Gear not Meshing Properly

Testing our starter on the stand we find that the starter drive does not disengage from the ring gear when the starter is stopped, and the sound does not seem normal (please do not ask me to describe the sound.) Close inspection indicates that the teeth on the ring gear mesh so deeply into the teeth on the pinion gear that there is virtually no play between them and the fit is too tight. It seems as if the starter was a bit further away from the flywheel this problem would not occur. We expect the drive would disengage when the engine is started but would like to get this right.

Reading in Paddy Willmer’s MG T Series in Detail regarding the change to the 8” clutch he states the following: “…8-inch clutch was fitted along with smaller ring gear. Thus it is important when replacing starter motor to ensure that the pinion teeth of the starter will mesh correctly with the ring gear.”

The starter motor was replaced about two years ago. We installed a new ring gear while currently rebuilding the engine. I see only one starter listed for all TD/TF in the Moss and Abingdon catalogues and one ring gear for early TDs and another for later TDs and TFs.

Does anyone have any suggestions?

Thanks in advance,

Robert

Robert
Robert Weinstein

Check that your starter has 9 teeth, and your ring gear has 120 teeth. Put a paint dot on one tooth and then rotate slowly, counting the teeth - the other ring gear has 93 teeth, so the difference should be obvious. If your flywheel is for the 8" clutch, only a 120 tooth ring gear (there were two) will fit.
R A WILSON

R.A.
Are you saying that there were two 120 teeth ring gears? Are they interchangeable with the starter drives?
thanks,
Robert Weinstein

For the TD the early flywheel with the 7.25" clutch, the 120 tooth ring gear had an ID of 10.375". The later TD/TF flywheel with the 8" clutch had a 120 tooth ring gear with an ID of 10.75". The starter motor, with 9 teeth, did not change.
I assume you have the 8" clutch, because if you have the early flywheel with the 7.25" clutch, then the very early 93 tooth ring gear will fit, but it will not mesh with a 9 tooth starter gear.
The combinations are 93/10 and 120/9.
R A WILSON

Make sure the starter drive moves freely in and out. Test it out of the engine- it should move to engage when energized, and the force of it slowing down when power disconnected and the light spring pressure should move the drive back. If it sticks engaged position, then the starter drive is the problem. As above, the 93 tooth TC ring gear will only fit the small flywheel. Did you compare the old and new ring gear? George
George Butz III

Used starter from another XPAG and it sounded fine and had some play. Will compare pinions and wait for replacement Bendix.
Robert Weinstein

Hope it solves the problem. Sorry if I introduced too much complication.
R A WILSON

This thread was discussed between 25/02/2018 and 26/02/2018

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