BBC oiling issue

On my blown alky BBC after a pass, I can see on my data logger my oil PSI drops to about 60 psi at about 4.5 seconds into a run, we idle at 90psi and at the hit it goes up to about 125psi, I have a 3 quart oil accusump, large Dan Olson oil pan with a kick out on the right side, I have all 4 oil restricters installed and they are only .030 per unit, we run 16 quarts of oil in the pan 50wt racing oil , and if I add any more oil to the pan it just blows it into the puke tank, I know we are stacking to oil on top of the heads (Dart 360's) and a new centrey 10,200 solid block, and we are running it about 8800 rpms at the top end of the track, running a 5.90 tune, and we do not have any bearing troubles

My question is can you install a belt drive pump? to pump the oil from the top of the heads into the pan? and if so, what are you using?

Thanks again

Butch

 

You need lots of drain backs in the valley of the block

 

Also an air hole back of the timing gear. Often thought of reed valves in the valley of a century.

 

Hello Butch,
I ran a New Century block and 18* big Chiefs, similar oil pressure as you, but I only had 2 restrictors (028 each). I know we also used aluminum stacks in the valley and we opened up the drain holes as well as the webbing in the valley to allow the oil to rush to the rear under g force.
Not going to confirm its your issue but if it's stacking oil I feel there there is too much going up there to start with IMO (only worth .02, lol). We kept making the jet smaller until the problem was gone, never got a pushrod tip or anything but that was my concern.
Good luck!

 

BBC oiling

all, Thanks so much for all of the info!!!

Yes, I have machined large openings over the cam in the valley and also above the oil pump. and there is also a large hole behind the cam gear. If you are going to plug 2 of the restricters, what 2 would you plug ? front or back? or does it matter?



thanks again for the help!!!!!

Butch

 

Yes top oiling is an issue. This year I went to an Aviaid external belt drive pump (two suction, one pressure, one scavenge and outlet) and tapped into the head with #6 on each end (close to intake side) and ran those to a manifold with a #8 going to a scavenge section on the pump. Then the pump goes back to the outlet from the where the oil pump used to be (since there is no oil pump in the pan). The #6 does not seem to be enough so we are going to #8's with a #12 scavenge. I am also going to put restrictors in the front-only have in rear now. This is on a 540 KB Olds with twin turbos on a mini rod pulling tractor. John Schwartz at Aviaid was a tremendous help. JW

 

We ran a screw blown Chevy in a 3 second promod. Here is what we had:
-Wet sump with a Titan sportsman pump
-15 qts total oil including a 3 qt. accumulator
-Redline 20W/60 Race oil (the label just calls it 60 weight). We found this to be critical, we had no luck running any type conventional oil.
-We found that restrictors didn't matter. With most lifters, as long as your lifter bores are not loose, your lifter is actually going to be what determines how much oil goes to the top end. With tighter lifter bores we regulated the amount of oil going to the top end by slightly grooving the body of the lifter to get a bit more oil up there.
-The bottom end of a blown engine gets a lot of blow by pressure so you have a high volume of air going up to go out the breather tubes which doesn't let oil drain back down very well. We added tubes from the valve cover to the oil pan and to help equalize this pressure and give the air another path up.


It took a lot of effort but we ended up with a pretty rock solid Chevy engine. Good luck!

Joad