The main bearing/rod bearing/thrust washer replacement was the
best/easiest job on a TR6 or TR250. Of course you can tell if
its necessary due to the oil pressure dropping to about 10 psi
at hot idle, should be 50 psi at 1,000 rpm after the replacement.
Seems with the bearings wear that all the oil pressure is used to
drown the mains and cylinder walls with none left for the valve
train... After replacement, my valves were quiet, oil consumption
dropped from a quart/tank to quart/1k miles and the engine "sounded"
better, but it was in terrible shape prior to repair.
1. Drop oil pan (remove bolts and it falls off (raise car on
solid stands as the torque takes some effort)
2. Remove and replace rod bearings one at a time, remember
all MUST go back in the same place, same position. Push
out the bearing with plastic stick (metal will scar the
journal), insert new ones (cover with engine rebuild grease),
careful to keep them lined up as they rotate in and seat the
alignment piece (makes a good spot to tap). Torque (I used
plastic-guage on the first one to make sure the crank hadn't
been ground, before and after... seems it was 3 before 1 after).
3. Same for the mains, only a loosened them all first, a couple are
tough and you don't want to stop this job as leaving the crank
hanging can ruin the front/rear seals.
4. Rear thrust washer should be replaced, I used a stock size, but
it should be measured (end play on crank).
Seal it back up and use the starter to build oil pressure prior to
firing it, break it in like a new motor. You should notice a difference
in the pressure. I have been told that the "Van..." bearings are
best" followed by "E & M"??? from England, everything else is junk.
TRF will get you the right stuff, its only about $75.00 including
gaskets. I of course had to paint the pan, etc. so it took about
8 hours. I would suggest re-checking everything after a nights
sleep prior to replacing the pan.
Roger
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