I am working on rebuilding my gearbox for the E type. The main shaft is worn about .007 where the input shaft connects via a needle bearing. I have a few options that I think would work and I am looking for some input. The measurements should be 1.250 OD and 1.000 ID for the Torrington J1612 needle bearing. I am not sure this is the original bearing as the box has been into before but it seems to be the correct size. I am looking at having the shaft laser welded and turned down and putting in the same size bearing. While flipping through the bearing catalog it looks like a 25mm by 32mm bearing could be made to fit with out welding, but by grinding the shaft to 25mm and increasing the size of the housing by a few thousandths. Lastly whatever bearing I install should it be a needle bearing in a cage (like the one removed) or a full complement needle bearing? There is no pressure lubrication to this area just the gear oil in the box. This box does have an oil pump but no oil port here. This shaft is directly connected to the flywheel so speeds of 6K will be there. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
With a cage IMO. A full complement will have a lot more friction and wear on the rollers (roller-to-roller contact at 2X the roller surface velocity rather than roller-to-cage contact at 1X the roller surface velocity plus the cage material will be softer than a roller) -- full-complement are usually only used in low RPM, very high radial load situations (and typically have a lower RPM rating than the corresponding "with cage" of the same size).
You're welcome -- I'm happy to make a suggestion, and nothing wrong with an E-type You might have some issues grinding the shaft down to the 25mm size: 1. Doesn't seem like you'd be removing much, or any, material if you are already .007" worn, plus 2. Even if it does clean-up visually, it really needs to be a hard surface, and, since they usually only surface harden such areas (in order to keep the bulk of the shaft tough and not brittle), it may be softer (when at a reduced diameter) than it was originally. Just wanted to mention that if you go that way, you should confirm/measure the hardness as well as size and surface finish (i.e., you may need to hassle with doing something to add hard material and regrind whether reducing to 25mm or restoring to 25.4mm -- if so, staying with the stock size bearing will eliminate the need to open up the housing bore.)
