Columbia 2-Speed Rear End Advice

Hi Folks,

We are doing some work to the Kurtis Tommy Lee Special and have some questions about the rear end. First, I realize it's difficult to do much without pictures (I will get those soon) but I've done some research and it looks like it's a '36 Ford because the radius rods are cast and attach to the rear end with brackets welded to the axle tubes.

Some things we do know...

1. We measured the ratio at ~4.10. This is by measuring rotation of wheel vs engine, not just by reading some stamping on the case.
2. The Columbia 2-speed rear end is (apparently) in high range.

The car ran the Colorado Grande last year and the owner had it to 97 mph but said it was pretty much topped out. This car has an Offenhauser 270 c.i. 4 cylinder engine that should rev to 6000. Doing some calculations, with the tire size and 4.10 rear end and a 1:1 top gear, 100 mph should be in the 5000 rpm range. This makes sense...so far.


Here is the issue we are trying to resolve. If the Columbia is in high range and the resulting ratio is 4.10, it would need to have a r&p ratio of something like 5.87:1. From what I can find, these rear ends came with ratios from 3.54 to 4.55.



While it makes no sense, is it possible someone put some truck gearing in this differential? Or, is a truck rear end? I've done a lot of searching and can't seem to find many pictures of early Ford truck rear ends.



Thanks in advance for your expert input...

 

I would change your ***le to "need help with a columbia 2 speed rear". I'm a fan of your car so I looked at the post. The guys that know columbia's may not see this.
Clark

 

Thanks for the advice. Change has been made...

 

Ratios into the 6's* were available from Getz when they were around...but all this is unlikely.
Remove the vac shifter can and shift the thing the other way manually. Betcha it is in standard drive with a 4.11 R&P, which would be a very reasonable choice for Columbia, and also a very common original ratio in the '30's.

*for crazy short dirt tracks, I think

 

Initially this was my thought as well. Both the gentleman with considerable seat time in this car and another with considerable wrench time on the car tell me the car does shift from low to high range but since low range seems pointless, it is left in high range. It's a little tough for me to argue at this point. It's puzzling that someone might put such a short rear end in a car with the torque this one has...

 

In that case...time to get out the wrenches and have a look in there! The 5.87's will be great for running the mud at lattimore next year...

 

Yup...seems like the only way, unless we see something obvious next time we crawl under it...

 

Bruce....that car on the track at latimore!??!!! Might as well lock the gates and never let another car on the track. Doesn't get any better than that.

Then again a Golden sub clone did run the track.
Clark