Hi,
Don't listen to your V-8 bretheren. They want your experiment to fail so
that you'll buy a 'mericun car.
;-)
Seriously and all kidding aside. It is very easy to replace the main
bearings in situ. Pull off one cap at a time, make sure you put the caps
back on the same way they came off - this is very important. To get the
upper shell out/replaced, I merely lubed the thing liberally and then
placed it up against the crank journal and then rotated the new bearing
shell into place. This action forces the old one out quite nicely. Just be
sure that when the old one is out that you use no sharp or hard anything to
pull the old bearing off the crank. The key here is "no scratches" on the
journals.
As for the big end bearings, you probably can do this, but I'll point out
that the lower front frame crossmember is in the way as far as getting a
torque wrench on there when you go to re-torque the thing. This is
especially true for the big end of the number 2 and number 3 rod, if I
recall. Personally, I'd pull the motor if I was replacing the con-rod
bearings, but it's your car.
I would think that at 75K miles you'll have little journal wear as long as
you've been religious about oil changes. I doubt very much that you'd get
any oil pressure at all if you'd worn the crank enough to justify getting
over-size bearings in there. It used to be that you could get .001 (or was
it it .005?) under bearings, but I don't see any listings for them any
more. So that's not an option.
If I were you, I'd replace the main bearings, and then button things up and
see if the OP goes up. If so, great. If not, you should seriously consider
pulling the motor to refresh the rod bearings and oil pump etc. If you are
dead set on replacing the oil pump, then go for it, but I was able to get
my oil pressure up by just replacing the mains and the rod journals a few
years back. I did this with the engine out of the car.
Other than that, this is a pretty simple operation, and Len Renkenburger
does state in Six Tech that he was able to get something like 300k miles
out of a TR6 engine by replacing the bearings every 50k miles or so. I
believe him. The crank material is pretty hard and seems to wear very slowly.
As for bearings, get Vandervell if you can - if not, I've used the AE
Glacier brand parts from TRF/Moss and they seem to work okay. FWIW, I
really beat on my car, so if they hold up for me, they're probably okay for
you.
One more thing. If you cannot displace the upper main bearing shells by the
above method, I've also used a tie-wrap to push the bearing out. This is a
good idea because the tie-wrap is not hard enough to scratch the journals.
The key is that the upper bearing shell has to rotate the full 180 degrees
out of the upper saddle before you can extract it.
As for preferred vendors, call them all. I have several sets now - but the
first time I refreshed mine, TRF and Moss were out of stock so I had to
backorder. I forget which showed up first, but they must have come from the
same source and they showed up at my house within days of each other.
If you get desperate, I'm sure I have at least one set on the shelf
(somewhere) that I could try to track down. They would be STD size.
Good Luck
Bob Lang
TR6's
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