A while back when we had the discussion about shiners and trailer queens
showing up at car meets, I was tempted to reply. Some of you on the lists
may remember the 1993 VTR convention just north of Seattle in Everett, and
the car I had. It was a 1977 Spitfire, maroon in color, gold minilite type
wheels, some gold pinstriping. You may remember that it spent most of the
time on the trailer, and there are some viscious rumors floating about that
I took it off the trailer once just to wash it, while my buddy Pugs was
shining his Mark 1 Spit. During that meet that car was christened "Trailer
Queen" by my illustrious companions.
WHY was it on the trailer for most of the weekend, a behavior quite uncommon
for me and my cars? Thrust washers. You see, I was autocrossing that car
with a motor pulled from yet another $300 parts car, and it had bad thrust
washers. The thrust face of the crank was badly scored, and a fresh set of
washers might last for 3 or 4 autocross runs, or maybe 5 minutes, whichever
came first. Part of the saturday afternoon prep for an event on Sunday was
jacking up the car, dropping the pan and then slipping in a fresh set of
thrust washers.
So at Everett I saved the car for the autocross. I made Pugs drive first so
that if the washers did fall out, at least he'd get a chance to drive it. As
it turns out, we both did fairly well, but the thrust washers did fall out on
my last run, so when I went to downshift at a near 180 degree turn the last
part of the course, I had some trouble with the clutch, costing me a few tenths
and I missed FTD once again by a tenth or two. Drat. At least I still had the
fastest time for a 4 cylinder Triumph!
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. I haven't pulled the pan to
check the bearings yet this year, so I can't say how well it is working. By
the way, that motor will be in the Spitfire I bring to VTR this year, I just
don't know at this point if it will be in the '74 currently housing it or if
we'll make enough pogress on the early car to bring it along. We'll see.
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.
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