Oil Pressure?

I have 477 cu.in. Arias BBC. Supercharged and running 7.0.
Oil pressure is 80+ at startup and all through warmup in the pits. Start at the line and 80+.
@5.80 it is 80
@5.92 it is 70
@6.08.......60
@6.20.......54
@6.31.......64
@6.66.......51
@6.77.......45
@6.88.......40
@7.10.......30
then 0 @ de acceleration.
System1 pump....Brad Penn 70wt. Dan Olsen funny car pan 14+ qts.

I thought at first the engine maybe pumping the pan dry/low and that was the reason for the drop. I added a qt. after each pass ...approx. 3 more which should put it over 14 qts. and no change.
The oil filter is clean after each pass.
Could the pump be worn and losing pressure as it gets hot during the run?
thanks,
Steve

 

oil pressure

Very simmple the pan is going dry you need more oil when we ran a chevy or olds we needed min. 14 qts. in pan.

 

100% agree Kosky. I run almost the same combo as you Steve with a billet Moroso pump and had the same problem years ago. I didn't have enough ground clearance for a bigger pan so I run a 3 quart Moroso accumulator and the oil problems went away. Also I run Brad Penn 60 wt and 70 wt. I only run the 70 when it's very hot out because it doesn't drain back quick enough when it's cold out. Also drain back hoses from the heads to the pan help allot. How smooth are the cylinder head drain passages?

 

Thanks for the replys......it helps to have people with experience give their advice.
I was adding oil after each pass and have at least 14/15 qts. and it hasn't changed.....hard to believe that much oil is staying up top! So I was worried I had too much and maybe aerating the oil. I had a accumulator on it last year and looking back at that data I had the same problem....the numbers were just about 5 lbs. more. I ran 16 qts. with it.
So I will get the accumulator back on it and add more oil.

 

Any idea what the oil temprature is during this oil pressure drop?

Scott Hall
Sales Engineer
Moroso Performance

 

I have the same problem as the OP. I was up to 15qts with an accumulator. The pressure drops just from a warm up and a few throttle whaps. I am wondering if the oil heating is thinning it enough to cause a pressure drop. I start at 90psi and by the time I'm up to temp its 40psi. I was going to crank up the pressure on my pump to try to compensate for the drop.

I would pull the valve covers right after shutting things down and there was no extra oil up top. I have all the drains and so forth.

Just a theory but its all pointing that way.

Corey

 

Got the same engine..old Arias...System 1 wet...14qt pan...I DID add Oil Returns at the front and rear of the heads! 4 #8s returning to the pan.....and a Morose 3qt Accumulator!! 120psi all day!

 

Open the return holes above the cam. You can cut them into slots if you like. Thats what the Century guys told me. Also 4 oil restrictors, two front two in back.

 

Accumulater will help. I have a 3 quart available if you want to plumb it in and try it. If it works, you can buy it.

 

Might be a silly question but have you got a windage tray in the oil pan?

 

Is the oil being routed externally in any way? And where is the pressure reading from?

 

Static rpm pressure drop from the oil warming up is typical. Pressure drop under load going down the track, as I understand the OP's issue to be, points to a problem in the oiling system.

 

On rare occasion I've seen too much bearing clearance cause this. As the block, etc., warms up the clearances open, too. Like bleeding to death. Likely not your problem, but something to ponder.

 

I'm putting the accumulator back on and adding hose from each valve cover. There is a 12an fitting in the pan that is capped off right now. I made a tee fitting to run #10an lines from each valve cover. I don't think the oil is staying in the heads. I think it is staying in the lifter gallery. The holes above the cam are small and the crankcase pressure coming up and out of those holes is a big contributor to the oil not getting to the pan. I think the hoses I'm installing might be more of a crankcase pressure relief than a drain back system. AND I'm going to add more oil. Can't be worse !!!!! BTW...it does have restrictors front and back and a windage tray.
My problem at this point is the car is in Nashville and I'm home. Our next race is the HHR at BG. So I'm thinking about this without the car here!
Opening the holes in the lifter gallery would be the be a good idea but the engine is together so that will have to wait. The car will be coming home with us after BG and I will have some data then and time to make some other changes if needed.
Thanks again for the help!!!!!!!!!!!
Steve

 

oil pressure

I just had the problem Randy mentioned. tightened up mains. one line from each head in rear as you guys advised me to do. I previously only pulled from driver head. I use through pushrod oiling to limit galling.
The funny part is I street drive mine. farthest is thirteen miles so far. engine gets hotter than most. Starts at 120= psi was ending at 40 psi. before changes. Time will tell.