Message text written by "Martin A. Secrest"
>My TR6 has low oil pressure and a bearing knock at hot idle. I've
>undertaken a bearing/oil pump/TW rebuild.
>Q #1: How does one remove the metal bridge on the sump face that
>supercedes the #1 main bearing? Aside from two screws, it's wedged in
>with metal shanks. I'm hesitant to try prying too hard to get this
>piece off so I can get at the #1 main bearing.
This is the single most difficult part of the operation. There are two or
three bolts that screw into this piece from the timing chain cover which
can be removed without removing the crank pully but with some difficulty.
I sacrificed a lower end gasket kit and cut a small piece of the front
plate gasket to replace the part that was destroyed in the removal process.
I also installed new seals between this piece and the engine block. And I
used plenty of Form-a-gasket #2. So far no leaks. (Wish I could say the
same for my transmission)
>Q#2: When I removed the #4 main bearing, I could not find the bottom
>thrustwasher! And it's not sitting in the sump, either. How the hell
>did this happen? Very strange. All I can think is that the PO or his bad
>mechanic had the sump off, saw this washer in there, and tossed it.
There is no lower thrust washer in the TR6. The #4 bearing cap acts as a
anti-rotation device for the thrust washers that reside on the top half of
the crank. If you inspect the cap you will see that there is not enough
clearance for one anyway. Others on the list have talked about a
modification wherein the cap is machined to accept thrust washers and a
double set installed. However they must be pinned or some other technique
must be used to keep them from rotating. In my opinion it is guilding the
lilly and the unless you are making some tremendous horsepower or if you
are looking for super longevity the factory design is just fine.
>Possibly as a result of this condition, the #4 main journal has a very
>slight ridge on it. (All the other journals are in good shape.) My plan
>here is to renew all the shells, and the oil pump, to get the car
>through perhaps another year before I yank the engine for a complete
>rebuild. Am I headed for trouble with this slight ridge on #4 main? Or
>can I get by with it for a while?
Is this ridge from contact with the crankshaft? Check the crank to see if
there are corresponding marks on it. Or take the cap to a machinist and
ask his opinion. I acn't comment without seeing it. The ridges may be
normal factory machining marks and if so all is OK. If there is no crank
damage and you do all this you can run the engine another 10 years before
you yank it. If there is crank damage you should yank it now.
I did this to my car some two or three years ago (see, I have forgotten how
long ago is was and it runs great!) and I have excelent oil pressure and
the engine is only lacking a head overhaul.
>Martin Secrest
Good luck, Martin. It's a fairly easy job and I think the factory had just
this service in mind when the engine was designed. Len Renkenberger (THE
TR6 guru) says that if you change the bearings and rings every 60,000 or so
miles the engine will run 200,000 miles without a major overhaul.
Dave Massey
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