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Discussion Starter #1
I had a blast today chasing around cobras and mustangs at the Portland Int. Raceway open track for the NW Shelby club. At around 4500 and up RPM on straightaways my oil pressure gauge gets the hiccups. the needle will bounce down fom 60 psi to 40 or so for a split second. Right back to 60 and bounce down and up. It did it a few times each lap. What the hell is this?
new filter, new oil, Cobra T pan, mechanical gauge High volume melling pump. This happens on straighaways (not corners or curves.
jimbo
 

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It sounds like you need baffles in your oil pan, plus maybe a windage tray. The oil is being displaced away from the oil pick up for your oil pump. In a straight away, under hard accelleration, the oil is being "shoved" to the back of the pan and uncovering the oil pump pickup. Apparently, this is not a whole lot of displacement, just bordline exposing the oil pump pickup. When you are on curves, you are not accellerating as hard so the energy is not pulling the oil to the back of the pan, plus the angle actually might be draining the oil over to where the pick up is. This is just a wild idea on my part, based on my reading. This is why Canton puts baffles in their racing oil pans, to keep the oil over the pump pickup. Is it possible that there is a mismatch between your oil pump pick up and your new pan? When I purchased a large capacity canton pan, I had to ditch the pickup I had and use theirs, which was angled differently. I suppose you could check this on the freeway late at night when there is no traffic by coming from the onramp and treat the car like you are on the straight away - do you get the same result with your oil pressure gauge. Try again with less pedal to the metal. Did that fix the problem? Congrats - sounds like you have a torque monster for a motor and a real good "runner" for a vehicle.
 

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Does it do it when you nail the throttle up to 4500rpm out of gear at a standstill? If not, this could possibly verify 70sportsroof's comment. Try sitting in your garage and ripping it up to 6k or so and watch your oil pressure gauge. Try also holding it in the higher rpm's like you would on a straight - say 5k for 10 seconds and watch for fluctuations. If it NEVER does it, I would say it could be the pan issue. I'm suprised you don't see it in the turns, but then again, when your cornering on a track at high speed I never get chance to look down at my gauges either!

The stresses your car goes through on the track are immense, lots of wierd things start to happen that never did or would on the street! ;) We run the Canton 9qt Road Race pan with the trap door baffles in our track car for this very reason.

Still, glad you had a good day and made it home in one piece. Do I sense another hooked open tracker? ::
 

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Discussion Starter #4
I have a windage tray in there, The pan has baffles. It happens near the top of the shift or when you hold it there at 4 grand about to stomp the brakes to set up a turn. I was thinking something wierd like the overflow valve on the oil pump hanging open. Or maybe the oil pickup was sucking itself to the bottom of the pan.
jimbo
 

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Discussion Starter #5
I don't dare run this thing up to 5 grand in the neighborhood. I could get away with it maybe once every five years. I am Way over quota for other transgressions. I can leave it in 3rd and make it happen on the freeway. It is still risky. The police are ambitious here. We have a law on the books right now that they can confiscate the cars of street racers. AND the cars of the people who are watching the race.
As far as the open track thing I had a blast. Really nice people. I got a driver lesson from Dave, The owner of 003 (gt350-R) and then he rode with me in my car for a session. I must have done OK because he didn't crap in his pants like I did.
jimbo
 
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