low oil pressure sbc 400

I recently had my 400 bored 30 over to make a 406 ci for racing. It has new bearings throughout splayed 4 bolt main caps, steel crank, new cam, valve springs, pushrods, high volume oil pump and new oil pan. I
had great oil pressure at start up around 40 psi at idle 1000 rpm. I raced in a 25 lap race on a 3/8 mile oval track and as the race went on the oil pressure dropped at idle it was 20 psi and while racing only 50 psi at 6300 rpm. I noticed while scrubbing tires going right and left when I would turn right the psi would drop near 0. I haven't checked anything yet it's actually still on the trailer. Does anyone have any suggestions. I have read a few posts that indicate a oil filter bypass, is this something I should look at or am I doomed for new bearings.
Thanks
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The lack of a windage tray comes to mind...
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aka-SBM wrote:

Yeah...and the pump sucking air.
                    NOI
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baffles me too ;-)
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terminal snipped-for-privacy@sand-hill.freeserve.co.uk

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Well I tried a few things with the motor and I believe my transmission was putting strain on the motor and causing the problems. I pulled the trans out, started the motor and I have 50 psi at idle and 80psi at 4000 rpm's. Oil still looks great, no metal shavings or anything. Could the transmission bog down the motor that much? Powerglide with direct drive shaft. Thanks
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Monteracer5 wrote:

No, the transmission is not going to make you lose oil pressure. However as was mentioned by others, a racing engine MUST have a windage tray or baffling system of some sort in the oil pan to keep the oil at the pickup in hard turns and slides. On the slides the oil is slopping up out of the oil pan and leaving the pickup dry. This MIGHT not have caused damage yet, but allowed to continue it WILL cause damage to the engine.
--
Cy Welch
89 Camaro RS 5.0 TBI
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Monteracer5 wrote:

I still think it's the oil moving away from the sump as you take off/make a hard turn/make a hard stop.
As others have mentioned, you should have a windage tray of some sort in the pan that would make sure the oil doesn't run away from the sump under racing conditions. To continue down the present path (no pun intended), you are going to eventually cause damage due to oil starvation.
                    NOI
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Thanks for the reply's. My oil pan is suppose to have a windage tray and baffles but it is something I will look into. Thanks again. I also noticed that I didn't have oil restrictors in the back of the motor. Would this help keep some of the oil in the pan rather than filling up the vavle covers.
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Have you looked into something called a dry sump? Im building a new 426, and its got electric pumps on it..really nice setup...of course, you need a spare motor, but its worth it.
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Our rules don't allow us to use a dry sump system, I wish they did. So, I put oil restrictors in on top of the cam and now I am getting good oil pressure on the track all the time. I must have been filling up my valve covers and draining the pan. Thanks all for the advice.
I now have another problem!
I attempted to put a saginaw three speed stick shift in my car with a 7.25 triple disc clutch and Howe throw out bearing. I could not get the throw out bearing to move at all. Meaning I could not shift the car while it was running. Also to note I have a new Girling clutch master. Anyone have any insight or suggestions.
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Check the obvious...then, recheck it.
Did you measure the clearance on the input shaft, VS the assembly you installed? Its possible you are not able to move the slave enough, OR, the slaves moving fine, but you just dont have the proper clearance, but first thought would be to check for that pesky air pocket that wont leave.
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I checked and rechecked everything several times. I bleed the system again, only this time I ran the bleeder line back into the clutch master using a clear plastic tube then pumped the pedal until there was no more air bubbles. This worked great and now the throw out bearing works wonderful. Must have been air locked before. The clearance on the bearing is right at 1/8". Thanks
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I have acquired a new problem. I replaced my old worn out distributor with a MSD hei one part number 8365. I developed a high rpm miss around 5500-6000 rpm. Checked the timing and it had jumped 3 degrees so I pulled the dist. cap and the rotor was broken. Looked like the screws just backed out because the treads were still in good shape. I replaced the rotor and raced on Sunday and the same thing happened. I now have it on jack stands and with a new rotor I am still getting a slight vibration at 5300 rpm's. I have made sure the new dist. is not longer so thats not the problem. However, when I pulled the old one out it was rather tough to pull it all the way out. Same thing when I put the new one in. It was binding a little towards the bottom. The only thing I think it could be is one of my oil restrictors in the back of the motor is binding the shaft.
If anyone has any suggestions I would appreciate it. Thanks in advance
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If it were binding, i would have expected it to grind itself free at 5500 RPM in a very short time.
Have you checked/cleaned the advance mechanism/springs etc.
Electrical connections? Good Earth & good Voltage and big enough supply cable.
Does it miss in neutral or under load ?
Other stuff to check .. Plugs & leads ok ? gapped right.
Fuel supply & filters.
Thats all I can think of ATM, lets know what else you find.
HTH
--
Mitch - 1995 Z28 LT1 M6 terminal snipped-for-privacy@sand-hill.freeserve.co.uk
Lancashire England http://www.sand-hill.freeserve.co.uk/terminal_crazy /
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I don't think it would grind itself free because the housing does not move in the motor. I did have a transmission fire a couple weeks ago that could have got the wires too hot. I have replaced most of the wiring to the dist. but this problem did not occur with the old dist. I will replace the plug wires and reply back. That might be the problem. btw the plugs are gapped at 35 and timing is set at 36. Thanks
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Hi, Was the previous dizzy non HEI. I 'think' non HEI distributors used a balast or resistor cable to feed it. HEI i think need a 12V supply.
Just a thought.
--
Mitch - 1995 Z28 LT1 M6 terminal snipped-for-privacy@sand-hill.freeserve.co.uk
Lancashire England http://www.sand-hill.freeserve.co.uk/terminal_crazy /
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Bad bearing on the shaft?
wrote:

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Well, I pulled the trans out and backed off the oil restrictor and it worked. I can now set the dist. with ease and at 6000 rpm it's right on.
I still have a hesitation at first throttle but I think the fuel filter is dirty. Does anyone know how to clean the stainless steel filters.
Thanks for all the rely's
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