"Ron Webb" wrote in message ...
Hello

Does anyone have any experience getting the bolt pattern off the
transmission side of an auto engine?

I'm building a PSRU, and I need to make the plate that bolts to the engine.
The rest of the pattern is generic, but that is engine specific.

I have tried several ways of measuring the holes in the block, but I'm sure
I can't get accuracy better than 1/10 inch or so. Surly engineering drawings
for these patterns are available somewhere.



In my case I built my own motor since I used to build NASCAR motors in
a previous life. What I did was to fabricate a aluminum shaft that was
the same OD of the crank housing bore in the block, laid it in the
block and lightly tightened the main caps.On the end of this shaft I
machined a smaller size stub that fit my outboard bearing perfectly.
Thats how I got my PSRU centered. Since your motor is all built you
can get your PSRU aligned the same way I double checked mine. Get a
block plate that is used on automatic tranmissins that fits your
motor. This is the thin metal plate that sandwiches between the block
and the bell housing. You can borrow on from a friend, trans shop or
even get one from a Ford dealer, transfer the holes and return it for
credit.The pattern on this plate is pretty close to what you want. The
real critical dimension is the dowel holes and that will be done at
the end of the process. Transfer the holes onto your PSRU block plate,
the one thats getting mounted to the rear of the block. This plate
sould be .375" minimum. You will have to machine a large round circle
in this plate since the flywheel needs a place to reside in. When you
machine this be careful to make it as round as you can since this will
be your indexing surface. Now with this plate built bolt it on the
rear of your motor and lightly tighten the bolts, take a dial
indicator and fasten it to the crank rear flange. Position the
indicator so that it measures the round hole where the flywheel rides
in. Turn the crank andlightly tap the plate around till it reads .001"
or so runout. Tighten the bolts up .Now the trick that makes this
process work perfectly is to got get a bottoming reamer. My block had
..500 dowel holes in and I assume yours does too. I ordered a .562
reamer from MSC tool supply. You can find one at any large tool
supplier. They cost 12 -15 bucks. Ream the existing dowel holes to the
..562 and make two new oversize dowels. Now every time you remove and
re install the PRSU it will mount on perfectly. This sounds like a lot
of work but it is really pretty simple to do. The PSRU does need to be
mounted on the motor as precisly as possible so take your time.

Good Luck.

Ben Haas N801BH