Idler gear bearings

[Bruce2]

One of the locals is working on his own gearbox and was asking about the bearings used for the 4 forward idler gears, so here's some info.

First is the 3rd and 4th gear bearing:

The right one is found in late 60s and early 70s gearboxes. They have 10 pairs, or 20 rollers.
The middle one is found in mid 60s gearboxes. It also has 20 rollers, so it is not much better than the later bearing.
The left one is from the early 60s. It has 23 rollers, so it's the one to use.

Next is for 1st and 2nd gear:

The right one is found in late 60s and early 70s gearboxes. They have 12 pairs, or 24 rollers.
The middle one is found in mid 60s gearboxes. It also has 24 rollers, so it is not much better than the later bearing.
The left one is from the early 60s. It has 28 rollers, so it's the one to use.

Finally, here's the inner race for 1st gear:

The left is from the early 70s, the right is earlier.
Note the large chamfer on the later race. This means that even if you pick the bearings with the long rollers, they aren't supported over their full length by the inner race. You need to find the early race to benefit from the longer rollers.

[Casting Timmy]

Nice write up Bruce. I do think the single rollers are better than the double rollers, as I do listen to teh theory of the double rollers making friction to each other.....although still better than the plastic ones.

A trick I saw from Dave on Facebook is the single roller ones can have two simple dremel cuts to go over the splines of a late model shaft. Pop out a single roller and then cut in at an angle so you leave enough material to touch the roller on 3 sides up top and bottom. I kind of did one from the right up top and then one from the left on the bottom. Slip it over the splines and then pop the roller back in and it's good to go.

[Bruce2]

Can you post a pic of how you cut the cage, Tim?

Here's how I've done it in the past