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Starters and flywheels

00Dan

Well Known Member
In the course of my engine swap, I was planning to re-use my old Prestolite boat anchor so as not to screw with the ballast setup I have going. However, I discovered that it and my old flywheel are 122 tooth, and the new motor came with a 149 tooth flywheel.

This presents me with a couple options:

1. Hang my old flywheel on the new engine and press with the Prestolite.
2. Find a 149 tooth Bendix to swap into my starter.
3. Use the new flywheel and bite the bullet on a new starter.

Complicating factors: I read that alternator RPM can be an issue with the new larger belt drive support assemblies, and I have an auto alternator. Second, the new engine has 10:1 pistons - will the 122 tooth Prestolite give me trouble over one of the new designs?

Is there a clear way to go here or other factors I’m not considering?
 
I vote for a 149 tooth setup

If for no other reason than logistics, I’d recommend going with the new 149 tooth setup. When your old starter eventually fails,….and it will at the most inopportune time and place, how difficult will it be to find a quick replacement as compared to a 149 tooth? You can beg, borrow, or steal a 149 tooth from just about anywhere.
 
Also, the 122 may be an issue if you wanted to install some brands of electronic ignitions.
 
It is possible to replace just the ring gear (teeth) on the starter ring gear support. The problem is that the 149 tooth and 122 tooth gears are not the same thickness (front to back) and the clearance between the ring gear teeth and starter teeth will be less or they will contact each other when rotating the prop with starter not engaged.

The SkyTec NL starter is the one starter that I know of that can have issues with this. This does not mean that all will have the issue. I have installed a 149 tooth gear on my 122 tooth starter ring gear alternator pulley support 26-years ago and it just clears and has worked for more than 10-years with the NL starter.

A back issue of 'Kitplanes' had an article on how to accomplish the gear change. SkyTec use to have a notice on their website about the NL starter ring gear swap but after they were sold, the notice was removed.
 
I checked both flywheels today and turns out they’re both the old 7-1/2” belt drive, so my auto alternator concerns are moot. In the immediate sense that makes my decision about if I want to re-use my Prestolite starter.

Has anyone ever tried the old Bendix starters with high compression engines? Is torque an issue?
 
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