I am restoring a 3.8s 1967, automatic. The ring gear has 132 teeth, and is worn out. It seems if they only manufacture gears with 104 teeth. Does anybody have advice for me?

 

Typical Auto with uneven wear ~ flex plate out of true. My only suggestion if you definitely can't find then find a starter motor pinion designed to operate with 104 teeth

 

Sorry - wrote a reply relevant to a manual and just noticed your car is an automatic.

 

So finding a starter motor pinion designed to operate with 104 teeth should be easy. Many have uprated to high torque starter motors so lots of spares around or upgrade the starter motor and get a new or good used 104 tooth ring gear. Sorry I have not counted my ring gear teeth.

EDIT: Peter has withdrawn his comment that this addresses. Cass is watching this thread & can give you the right info on starter motors & ring gears for Autos. He has a BW35 & high torque starter motor.

 

Refresh page for edit.

 

Sorry Glyn can't help here. Never counted the teeth on my ring gear when I had my engine and gear box in bits. They came as a set so never had to check them and when I fitted the high torque starter I gave them my car details and they supplied the starter to fit.
Here is a picture of my ring gear which I think has 133 teeth. Mine is a 3.4s with the BW35 auto gearbox.

 

That still helps Rob. The OP should look for a used flex plate with good ring-gear or talk to an Auto specialist.

Would you know the details of your high torque starter motor ~ model etc? Or the company you spoke to?

 

Here. Moss have them on sale. They also have 133 teeth & 104 teeth ring gears on sale. Talk to them. They have others too. Explain what your problem is & let them help you. If you choose to go for a high torque starter motor it doesn't matter. Just match a ring gear that will shrink on & the right motor for it. A high torque motor will spin any number of teeth within reason. It's matching the ring gear to the starter pinion that matters.

https://mossmotors.com/c4809-ring-gear-132-teeth

https://mossmotors.com/c18517-ring-gear-133-teeth

https://mossmotors.com/c13870-ring-gear-104-teeth

 

My high torque starter motor is an RAC408 for the Auto gearbox supplied by a company called Powerlite. https://www.powerlite-units.com/starters/rac408.html
It has nine teeth on the spline.

 

Thanks Rob! I'm still using my original properly rebuilt starter motor on it's 90,000 mile ring gear that is fine & the good old 3.8 XK engine cranks perfectly and springs into life at the first push of the button. Yes I was going for concours once which is now achieved. Now I can change to my 15" wood-rim Nardi steering wheel (one of 4 made) & a few other things & have fun. This is no trailer queen. If I can't drive it I don't want it. Very few minor mods intended. Things like the cooling system are done but you would never know it. My thermostat keeps the engine up to temperature in torrid SA. I have excess cooling.

 

Hi,

thanks for the advice, I will check with Moss Motors, otherwise opt for a new starter motor if needed.

 

Yes ~ just sort out that ring gear with a new one that fits first. And establish whether you have a Borg Warner DG250 or a BW35 transmission. You are at the change point from one to the other. If it has an Aluminium casing its a BW35 but check on the transmission ID plates.

 

Yes they changed from the DG250 to the BW35 in around Sept 1967 on the S Type.
One of the main things to look for as Glyn has said the BW35 had an Alloy casing, DG250 was cast iron.
The ID plate is not easy to get to as it is tucked up on the left side of the gearbox so the only way to see it is with the gearbox out or by sticking a camera phone up the side of the box and tunnel and take a photo of it. You will need to take several to get a clear one. The ID plate actually says "Borg Warner 35" and should have the serial number beginning FG. Obviously you can also find this number on the VIN plate so if your gear box number begins FG it is a BW35. If it begins JBC its a DG250. There is an inspection plate in the left side of the gearbox tunnel that gives you access to the gear change lever and if it is a BW35 the Inhibitor switch located on the side of the gearbox. You could by looking in this hatch see the ID plate. The DG250 has the inhibitor switch under the dash behind the gear selector handle.



Other things to tell the difference.
The BW35 has an oil cooler in the bottom of the radiator and has two pipes running from the right side of the gearbox along the line of the sump joint to the bottom of the water radiator.
The BW35 does not have the "speed hold" switch on the dash which the DG250 has.



Location of the ID plate on the BW35 gearbox.


Oil cooler pipes coming from right side of BW35 gearbox.