motor help

[ohlde21]

I got a oil pressure issue on a fresh rebuild motor hold 60-70Psi cold and holds good until 220 degrees then oil pressure drops to 20-40 and bou. es back and forth like the motor starts cavatating and as soon as the motor drops back down to 200 the oil pressure goes right back up to 60psi what would cause this i change the oil and filter incase the filter pluged but the results were the same any ideas?

[dereksehi]

Is this at an idle or more rpm?

[ohlde21]

This is at race rpm which is 6800-7100

[JustAddDirt]

do you have oil restrictors in the rear oil galley?
what type of oil pan?
What type of oil pump?

[ohlde21]

7qt kick out with baffles... high volume pump ..... no on the rear galleys

[dereksehi]

I would run the restrictors if it was mine sbc will pump an awful lot of oil up top if they are not restricted also was your pickup tube to bottom of oil pan clearance within the 1/4" to 3/8" tolerance?

[ohlde21]

Yes the pump is a 1/4 inch off the bottom of the pan .. would windage cause this problem as well?

[JustAddDirt]

Are you running a roller camshaft and lifters, or is it a solid lift?
Just checking, cause you may not want to run restrictors with a solid lift, or hydraulic camshaft.
What happens if you add another quart of oil?
What oil are you running?

[buzz51]

Are you running a roller camshaft and lifters, or is it a solid lift?
Just checking, cause you may not want to run restrictors with a solid lift, or hydraulic camshaft.
What happens if you add another quart of oil?
What oil are you running?

is this on the track when it happens or just in the shop ?

[powerslide]

is this on the track when it happens or just in the shop ?

exactly what i was wondering after re-reading his post a couple times.

[ohlde21]

Solid lift cam ..... this happened on the track

[buzz51]

Solid lift cam ..... this happened on the track

ok thanks. I know on track I have had engine oil psi drop or bounce during the race due to oil being sloshed around and then as soon as the oil gets a chance to settle back in the the pan the psi went right back up.

another question please if you are at 220 and under caution does the oil psi drop or bounce ?

[ohlde21]

Under caution the pressure relaxes at 30 psi which i know is good and i know that 20 psi or lower for a long period of time leads to detination cuz thats what happen to the last motor on a hammer down tacky track

[JustAddDirt]

What brand is the pan, and pickup? I have heard of this with cheap pans, and not many trap doors, and baffeling to control oil slosh.
Does the pan have trap doors around the pickup. if so how many?
How big of an area is the pickup in? If the pickup is a small one, and the area it is in the pan is pretty large, without trap doors or baffles, just wandering if the oil is moving around the pan a lot (as stated above), and sucking a bit of air.
I would try another quart or two and see if it fixes problem.
Of course oil will get hot, and thin out. What weight oil u running.
Remember the oil saying on oil PSI.
10psi for every 1k rpm's

[buzz51]

What brand is the pan, and pickup? I have heard of this with cheap pans, and not many trap doors, and baffeling to control oil slosh.
Does the pan have trap doors around the pickup. if so how many?
How big of an area is the pickup in? If the pickup is a small one, and the area it is in the pan is pretty large, without trap doors or baffles, just wandering if the oil is moving around the pan a lot (as stated above), and sucking a bit of air.
I would try another quart or two and see if it fixes problem.
Of course oil will get hot, and thin out. What weight oil u running.
Remember the oil saying on oil PSI.
10psi for every 1k rpm's


all good stuff, what brand pan are you using.? Also just my two cents but what weight oil are you using..going to a straight 30wt should help psi as well.

[ohlde21]

Morroso pan. Valvoline VR1 50wt racing oil ..... im changing pumps and changing oil to Joe Gibbs 15-50 racing oil

[MM90]

I just had this conversation with my engine builder. My new engine has the block tapped at the camshaft so it reads oil pressure at the last thing to get oil instead of at the pump. He put an adjustable Melling HV oil pump in and cranked up the pressure on it. When I was racing in the middle of the corners the oil pressure would drop below 40 psi. It scared me because I have always read oil pressure at the pump. He said he didn't care if the oil drops below 20 psi cruising through the pits as long as you give it some throttle and the pressure raises right back up.

[JustAddDirt]

15-50 synthetic will probably make problem worse, over he vr1 50wt.

[Egoracing]

If this is happening 1-2 laps into the race I would lean to the fact that you do not have proper crank case ventilation and it is keeping the oil in the top of the engine. Are there breather tubes in the lifter valley and have the drain back holes been opened up?

[ohlde21]

Thanks guys all good stuff and questions....... the problem was cause by my oil pump houseing crackedand one of the trap doors stuck open allowing the oil to move to much the other thing i found is the size of the rings were wrong so some of the oil was blowing by the ring .... what do u guys think about joe gibbs 15-50 oil?

[JustAddDirt]

its good oil, just pricy