Fixing your Thrust Washers

(For Good and All)

The car I am running this year has no thrust washer problems. The way to fix this is to modify the end bearing cap to use two sets of thrust washers, and pin them in place. This gives a full circle of thrust surface instead of half, so the wear is theoretically cut in half.

( snip ) What one does is take your 1500 (or big bearing 1300) and a couple sets of new thrust washers to a competent machine shop. Finding one of thses may be the most difficult step. What the shop should do is bolt up the rear cap to full torque, and machine a slot in the cap that is the same size and shape as the slot in the block, allowing the use of two thrust washers on that face. They don't need to do the front side, as there is not nearly as much wear in the other direction, the wear almost all comes from reaction to depressing the clutch diaphragm. With a full 360 slot for the thrust washers, they would spin uselessly and then fall out if you didn't so the next step. Have the shop drill some holes, on the order of 1/8 inch, in the block and the bearing cap. If the holes go all the way through to the other side, it will make marking and drilling the thrust washers easier.

So with the slots milled and the holes drilled, offer up the thrust washers and mark the hole locations on the back. The "back" is the side without the slots for oil, and usually has the part number stamped in it, too. Then drill partway into the back of the washers. It may be wise to drill a spare set or two of thrust washers at this point, assuming you have some of the proper thickness.

The next step is to put some roll pins of the proper diameter into the holes in the block, and leave them protruding a bit less than the depth of the holes in the washers. Then tap the washers into place, and you should have full circle, pinned thrust washers that won't spin out and have the clutch work funny and the crank machine itself into the block. If you have an 1147 motor, or a small journal Mark 3 motor, the same procedure can be used. It will take more care on the part of the machine shop and in the assembly of the bottom end, as there is less metal in those bearing caps, and the faces may not be that parallel, so getting the cap and block lined up properly during crank installation can be tricky. But it is a worthwhile modification for Spit (and Midget 1500) lumps. I may try to cobble up some drawings and put them somewhere in the ftp tree. By the way, I still have the remains of the thrust washer I pulled out of the Trailer Queen after that run at VTR, stuck on the wall of the garage as a momento. mjb.