Thanks Lynn.
Interesting stories as always.
Do you know any sources for 7.25'' (or 5.5") ring gears and lightweight
starters that will mesh?

Cheers
Cary

The numbers are clutch disc diameters. The 7 1/4" is a common size for street and racing. The 5 1/2" is racing only with metal or carbon friction surfaces, and tend to be grabby. More like a switch. Note that many cars spin the wheels on standing starts. With low time drivers stalling the car. A very difficult skill to develop. Plus the clutch pedal has a very short throw with a mechanical stop to prevent the coaxial throw-out bearing from damaging the clutch spring.

A 4 1/2" or 5 1/2" cover has very little movement from fully released to locked up solid.

 

The ring gear is mounted on a special built aluminum plate machined to fit tabs on the button flywheel. Same as the cover diameter, about 6 1/2" diameter. The spare is just the stock automatic trans flex plate. I use the smaller of the two top mounted starters from the 70s. It is too heavy for aircraft use, but is still available from Auto zone, overnight only.  

 

There are a number of very light reduction gear starters that can be mounted, depending on what mounting system you plan to use. Only turning direction must be maintained. A perfect gear match with the ring gear is not required. Tilton has a very large selection. And I would want a piece that is available from Auto zone or another national chain. I would get samples from a scrap yard if you have an unusual layout. This has been done by many already, and on other building sites if you ask about it.  So, for example, a starter from a 99 Toyota Corolla might be a better choice than one from a 51 Fairthorp Electron Minor.  

 

There are two flex plate diameters. The early smaller diameter RX-2 and 3 and the later RX-4 and Cosmo. Which one  is correct I don't know. They are getting very hard to find. If you find one hang on to it. Also there are many American car flex plates that could be modified to work, with very close to the correct diameter. I have a BD-4 kit but am nowhere far enough along to need the data.

 

Lynn E. Hanover