It has been seven years since rebuilding the gearbox on the '36 FC Standard, once again the bushings are mixed with the lube and the shaft is damaged. I searched the old forums, but couldn't find if anyone has retrofitted the bushings to bearings? Can the gears be bored and bearings inserted? Stock 0.875" shaft? Best bearings?
Surfair You need to be a paid member of the VCCA to be able to post photos on Chatter but by posting a link to a hosting site your photos will show. I have to relearn how to do it each of the rare times I post pictures. Tony
SurfAir, How many miles since you rebuilt 7 years ago? I have about 10,000 miles on my '35 Standard since doing transmission work 40 years ago. Sounds like something besides normal wear and tear. Good luck with your remedy. I have a few spare parts if you need something.
In a word... no. I've got nearly 50 years of experience with modern gear lube from Shell and Esso (GL-5 and GL-6) in the same transmissions we've run for all of those nearly 50 years, and none of them have ever shown any synchronizer or non ferrous bushing problems.
Certainly sounds like your shaft is bent, or severely out of balance. Either way if you have not done so already it should be taken out and checked. JMHO Art
Sorry, I thought by the way you were talking it was the torque tube shaft when I said it could be bent. The way it is worn would indicate it is starved for lubrication. Isn't there a thrust washer on that shaft? Are there oil spinner slots cut into that thrust washer? Are there oil distribution holes drilled into the center of the cluster gear? Just because you found it the way you put it back together does not mean it might not have been assembled wrong in the past, or the cluster gear might not have been finished correctly from the factory. We have all reassembled something in the past "just like we pulled it apart" only to find it wasn't right in the beginning. Interesting problem. Please keep us posted. Art
Wow that's very clever! I'm currently in the process of going through a 3 speed. I noticed that the parts suppliers sell replacement bushings. Hard to tell from their pictures but it doesn't look like they have any oil grooves/ holes like the original bushings. Did your last set of bushings that wore out your shaft have any oil grooves? Also curious to know the results of your new bearings and the vendor that you purchased them from. Thanks for posting that, Nice work!
The reason I was asking about the cluster gear was - going from memory isn't there a hole all the way through the cluster gear on many transmissions? If that is not present on your cluster gear I would be tempted to drill one. Seems like they were 3/8" to 7/16" pretty good sized. It has to get oil somehow otherwise it will fail. Art
This is probably a dumb question/comment but what material and hardness was the shaft that wore out in 10,000 miles? If you're running bronze bushings, rule of thumb is you'll want at least 0.45% carbon content and a minimum shaft hardness of Rc ~35 or so. If you're planning to run roller bearings (which it looks like you are), you'll want a hardness of ~Rc 58 or higher or you'll risk a short lived shaft and bearing.
Personally, on an application like this, given the choice between a bronze plain bearing and a needle bearing, I would stick with the bronze plain bearing. On this application, a good choice would be a shaft made of A2 tool steel, hardened to Rc 50 to 60 and an oilite bronze bushing, this setup would outlast all of us given that there were no other issues such as balance, alignment, etc.
With your roller bearing setup, a shaft made of A2 hardened to Rc 58 would work, though it might be better to use something like D2 tool steel.
