Ok Guys, I tested the car again today and I have to say that I don't think it's agressive braking. I was only doing 40 and I got the oil pressure to drop down to 0 psi without locking up the brakes. Now because I could'nt really trust my Autogauge oil pressure gauge, I installed my Pro-comp Ultra-lite LQF oil pressure gauge with the same result using new oil pressure line. I have been building engines for years and this is the 1st time I've ever had this problem. I mean when I stop I really have to pay attenion to how fast I'm appling the brake. It's like I have an open container of pop. Thanks for you help guys I appreciate it. I will still be replacing the pan. I just really baffled by this. Also when you go in reverse the oil pressure stays constant.

might wanna double check the pump clearances when you have the pan off.... im assuming under braking the rpms are low(pump not building pressure), along with the oil migration would cause a loss of pressure????


just thinking outloud.... just seems like a good time to check everything when the pan is off.

I appreicate that Race Rodz. I am pretty stumped and any new ideas are not unwelcome. I will replace the pump as well as the pan. But for curiosity will also check the clearnce of the old pump. It is very strange. At idle warm it's 28 psi.

Had the same problem with my 67' Lemans. It was the pan on mine.

Ok well theres one important thing I overlooked to tell you guys. I had lost a distribtor gear about 2 months ago, I had replaced it and throughly flushed the motor. When I put the new gear in I broke it back in again with moly lube and dumped the oil. I just got off the phone with George at Melling. He says that it's probably the spring in the pump more than likely it has some debris left in it. When I described the symtoms to him he said that it causing it to stay close in one position. Making the pressure go to zero. My luck just keeps getting better. Boy I see a big project on the horizon. Thanks for your help Guys I will keep you posted.

Pressure drop
 

Ok well the results are in. The next time someone says they are loosing oil pressure under light braking and it’s a small Chevy; tell them to check the pick up. It appears that the 2 tack welded spots did not penetrate the cast pump. This is really pretty amazing as my friend and I were both in aw as we realized that I had continued to race the engine thinking it was just the oil going up into the timing cover. The engine would not drop pressure when I accelerated, turned left or right, or even in reverse. If someone does suspect that they have lost there pickup I would suggest obviously to open the pan up and check or at least ALWAYS keep it full until you can check. Well I had to replace the gasket anyways and now I am running the pan you guys were talking about I now have a CV Products or Champ Pans 1080 LTRR pan with the 5 trap doors and 3 crank scrapers. Oh yea and most important of all the pick up is now bolted on. Talk to you guys’ later thanks for the help everyone.

something that no one else mentioned that is good insurance is an accusump

I had the same problem, Changed the pan and put in the accusump. Problum solved. Not to scare you Fastbowtie put I changed my pan after I noticed the problum put is was to late. I spun a barring the first time I tracked the car. I think I hurt the motor with the old pan. I would cut open your next couple oil filters and make shure they are clean. Randy

Thanks Randy but all things worked out good. After changing the pan and the pump I actually increase oil pressure. I had taken the caps off to inspect the main bearings and all looked good with no sign of wear. Now with the new HV55 Melling pump I have to actually wait until the car is really warmed up before I start beating on it. The pressure on a 60 degree F day is 100 psi with mobil synth 10w30 at first but later settles down to a comfortable 60 psi at 2000 RPM.