BBC Oil Pump Recommendations
 

Pulled the motor out after noticing drop in oil pressure and the rear main and one of the other mains were ate up. The rear main looks like it was starved of oil was on the verge of failure. We ran our current pump most of last year without issue but this year we only got about 10 - 15 runs on new bearings before I noticed drop in pressure.

Was hoping you guys could provide some opinions;

What pump do you guys like to run in a BBC?

What pressure range do you like to see?

Any help would be greatly appreciated.

Re: BBC Oil Pump Recommendations
 

Lack of oil has always been up front, last bearings to get oil, in my limited experience. I kinda doubt the pump is your problem.

Re: BBC Oil Pump Recommendations
 

Wet mag the crank, check it for straightness, size, taper, and roundness.

Then check the main bores for size, roundness, and straightness.

Odds are you'll find something .

Re: BBC Oil Pump Recommendations
 

What does the flange on the rear main brg look like?

Have you changed trans or converter?

Might have a thrust bearing problem instead of oil pump.

Re: BBC Oil Pump Recommendations
 

^^^^ More likely.

Re: BBC Oil Pump Recommendations
 

thrust bearing and rod bearins all look fine. One thing is the front of the main bearing (flange) was rubbed down to the copper, like the crank had pushed back toward the converter. Doesnt make sense because I thought typically the crank would push toward the front of the motor if any as a result of converter ballooning. Does this indicate anything in particular? Having crank magged and block checked for proper line hone.

Re: BBC Oil Pump Recommendations
 

also converter and trans are same no change whatsoever.

Re: BBC Oil Pump Recommendations
 

Take it across the "River" and let Jeff Taylor look at it and check it out, you will be head in the long run.

Re: BBC Oil Pump Recommendations
 

I'd say good chance your crank is cracked and flexing,you said had about 15 runs on bearings,what was the old bearings like or was it first build?

Your on the right track checking crank and line bore
Mike Taylor 3601

Re: BBC Oil Pump Recommendations
 

we took the whole thing apart this past winter and replaced the bearings. The bearings we took out looked flawless.

Re: BBC Oil Pump Recommendations
 

You may of cracked crank since you put back. Did you check bearing clearance when you put new bearings in? You need to check all 8 rods and all 5 mains when checking clearance if you did'nt,alot of people will just check a couple,that leaves too much room for error.
The main reason I can think of for front of thrust to wear like you said,is if crank is cracked it's flexing enough to rub thrust,or when bearings went crank bent and has enough run out that is scrubbing thrust.
99% of time when you have bearing go out rod or main the crank will draw from heat and warp mains, you will have run out on mains, if not cracked,crank can be heated to around 575 degrees and straightened in crank straightening press,needs to be within about .003 before regrinding.
What about oil pump mounting bolt ? Does main have pump bolt hole all the way through cap or is blind hole? Either way if bolt is too long can crush rear main bearing and tighten on crank.
Also if have main studs w/6 pt. nuts it can hit oil pump and hold off main cap and create a leak or press leak,ARP's come w/ 12 pt nut that goes on rear main to clear oil pump.
Also if nothing else found would it been possible could had sealer holding cap off block @ rear and cocked rear main cap.
Or had wrong flywheel bolts(too long,Std shift w/flexplate) installed and pushed rear cap forward'
Mike Taylor 3601