[DeTomaso] This ought to be fun...

[Kirby Schrader]

Personally recovering from major depression and lack of motivation on the
Pantera front in Magnolia...

The Space City guys already know about this and we've discussed it a lot,
but for some reason, I'm in the mood to throw it out to the rest of the
collective.

My new 377 Cleveland engine build with less than 400 miles on it spun the
front main bearing.
I have never seen this happen, ever... and I've run the same combination of
block, crankshaft, rods, etc. for years and beat the crap out of it with no
problems.
Daily driver, track events, etc.

Facts for your consideration follow. I can get more detailed, but I think
the following is enough to start you thinking.

1) Two bolt main iron block, lifter bores bushed, line bored, J&E pistons,
Eagle rods, nodular iron crankshaft from Quella, Moroso restrictors (I
spent a lot of money on this block!)
2) Iron 4V heads, new valves, springs, etc. etc. etc.
3) Comp Cams solid roller cam, lifters, pushrods, rockers
4) Symptoms were that my oil pressure started dropping gradually when I was
driving home from the annual SCP pig roast. By the time I got to the last
stoplight before my house, I was down to 10 psi hot at idle. Oil pressure
is taken from the port just above the filter. You know it was less at the
back of the engine.
5) There were no knocking, banging or otherwise nasty noises. Main bearing
problems make distinctive noises. I know. Been there, done that. Got the
scars. But I did not hear anything this time.
6) I pulled the pan and found bearing material.
7) Pulled the oil pump and it had obviously done some trash pumping.
8) All the other rod bearings and main bearings look just fine.
9) The front one had not only spun (when I pulled the cap, both had rotated
by about 40 degrees), but one half was actually partially canted out of the
web towards the front of the engine. I have pictures if you're desperate.
10) Nothing is blue or shows signs of getting hot.
11) The main cap is worn badly and has to be replaced.
12) The machinist thinks he can salvage the block with another line bore. I
hope so...
13) The crankshaft journal needs turning, obviously, and can be saved.
14) The machine shop put the short block together, I assembled the rest
15) I had an Accusump plumbed into the back of the block where the stock
oil sender usually resides. Accusump was set at 30psi.

Proposed failure modes
a) The main bearing was put in upside down - The machine shop is adamant
that is not the case. 'Hell, no! No way!' was the response to that one...
b) The crankshaft is bent - He's checking this week, but that would have
been very apparent during assembly, so he believes strongly this is not the
case.
c) Not enough oil pressure - On start up and later, 65psi hot at rpm, 30psi
hot at idle.
d) It ran fine while I was tuning the EFI. Other than running rich
initially and some issues with the ECU, I had no problems.

Fortunately, no other damage occurred.

So..... my questions....

Why did it fail?
What do I do to make sure it doesn't happen again?
Why me?

Who am I and why am I here?
:-)

Let the fun begin.
Regards,
Kirby