The Stovebolt Site Forums The Shop Area Engine Shop Starter Ring Gear Compatibility Question

I have converted my 54 3100 to 12 volt. While I have the engine out I would like to change out the 139 tooth starter ring gear for a 168 tooth starter ring gear. The question I have is: before I order a starter ring gear are the starter ring gears interchangeable meaning will a 168 tooth gear properly fit on a flywheel that currently has a 139 tooth gear.

Thanks in advance
Walt L. Williams
La Verkin, UT

I think you need to find a flywheel from a 12 volt truck or car. The diameter of the flywheel is different to accommodate the change in the tooth count. Make sure that it will match the crankshaft as well. I think that a 235 early and a 235 late would interchange. The early one would be for 6 volt starter and the later one would be for a 12 volt starter. The starter ring won't interchange as far as I know. Maybe some one else can jump in here to correct me if I am wrong.

Steve is correct, the OD of the flywheel changed when the change to 12 volts was done.
Any 1955 2nd through 1962 flywheel will work, it just depends on what clutch size you want to run.

Most knowledgeable Dave,

Can one machine an early 6 volt flywheel down to fit a later 12 volt ring gear or is it the other way around? Which has the larger I.D. and anybody know how much the difference is?

The OD of a 6 volt flywheel where the starter ring fits is about 13 1/16". 12 volt is about 13 1/4".
This is a ruff tape measure measurement.

Sound like this cannot be machined down. I wonder if one could have a machine shop make an adapter "ring"? ???? Could one possible use some shim stock to adapt with? ???

Walt

Is a 12 volt flywheel that hard to find in your area?
You know there is nothing wrong with running your 6 volt starter and flywheel on 12 volts.

Yes indeed. The thing about 6 volt wiring and starter is, its twice as beefy as needed to run 12 volts! Yes, the 6 volt starter will live forever and then some on 12 volts because 6 volts actually requires twice the current than a 12 volt system. So, the 6 volt wiring is twice as large throughout the truck. If the 6 volt starter is still in the truck and all you are doing is changing the battery to 12v, your problem is the other systems, like the coil, generator, fuel gauge, etc.

http://speedprint.com/deves50/flywheel.php

Havent explored this idea, but how about just having your starter shop put the 6 volt gear on your 12v starter?

Won't fit.
I have heard of rewiring a 6 volt starter for 12 volts.

54Belair
Please heed the advice of the REPLY S above! They all KNOW their $hit.
I have been told by my Engine Guru and he is VERY Close to 70 yrs of age with at least 55 years of mechanics experiences, A classmate of mine , That he would heat the old Fly wheel ring gear off that flywheel , Remove it, turn it around (NEW Solenoid to ring gear surface) , Do the same with the new flywheel and then install old on new, NO adapter "ring"needed". Then use the old 6 volt starter on the NEW 12 volt Flywheel. Now you have a NEW 168 tooth Flywheel that will adapt an Old 6 VOLT starter! The VERY best of BOTH worlds! Good LUCK Jerry

I'm going thru a similar problem right now. I have two project cars: the one i'm working on is a 52 tin woody that has an engine casting number that shows it's a 1959 235 engine. I have another '50 tin woody that has an engine with a casting number that says it's a 1953 235 engine.
They had both been converted to 12 volt. Yet, they both have the 139 tooth flywheel with the starter that has the larger gear pitch to match. The 52 has had issues with the bendix engaging since I got it. 90% of the time, the bendix will not engage; just shoots out and "whines" against the ring gear. If I rock the car to move the flywheel a bit, it may engage. If it engages, it cranks the motor fine. I've turned the ring gear around, no help. I've had the starter rebuilt, no help. I've tried the starter from the '50 and it doesn't work either. 90 % of the time it also does not engage, just "clicks". If I rock the car, it will sometimes engage and crank the motor. According to the parts book, the correct ring gear should be the larger diameter 168 tooth with matching starter. Not sure why this 1959 235 has the old 6 volt style with 139 teeth. Anyone have any ideas on what could be causing this?
By the way, the 139 tooth ring gear is a different diameter than the 168 tooth ring gear; the 168 is larger and will not fit on the old flywheel.