Have a question for you experts out there. I took the race car to the track last night, made 3 runs, everything seemed ok with the car, ran fine. On the third run the oil pressure drop down the 30 psi going through the traps, when it is usually around 60 going through. It goes through the traps at 5800 rpm. As soon as i let off the gas the oil pressure jumped back up to where it should be. Car was running around 180 degrees coming back up the return road and had oil pressure. I run Mobil 1 synthetic oil (10w30) and was wondering if i should switch to a thicker oil or if there are some other things to look at. The car has a deep 9 quart oil pan on it from TA and has 9 quarts in it. The basic motor set up is this: 470 race motor - 596 HP -Block filled -Ported iron heads with stainless valves etc -1.6 roller rockers -Eagle Rods -Ross Pistons -12 to 1 compression -TA SPX intake -Biggs Dominator -Solid Cam -MSD Pro Billet Distributor and Wires -TA / Tilton Mini starter -TA Deep Sump Pan -Rossler turbo 350 tranny- 9 inch coan convertor -12 bolt rear with spool and 3.73 gears Has the new TA timing cover on it to, so should i just try to adjust the pressure up on it or look somewhere else for a problem? Thanks in advance I will be pulling the system one filter today to make sure there is no metal in it to.
are you using a elec gauge or the reg manual gauge. when my buick or vette get warm they go low till rpms are upped. i had a elec gauge and will never use one again. it was not accurate.
If the system one looks ok, then I would try running with 2 qts less oil. You could be aerating the oil. Just because you have an 9 qt. pan doesn't mean you need 9 qt. It makes the pan deeper to get the 5 qts farther away from the rotating assembly and all the windage and splash associated with rpms.
Used to have the same problem with my center-sump pan. Baffling to keep the pickup covered, as well as deepening the sump to keep the oil away from the crank solved the problem. I use an accumulator for backup. Devon
Thanks Guys. We will be finding out what the problem was, going to pull the motor and see. When i pulled the system one filter apart it had metal in it, so we are going to take it down and see what the problem is.
Denny sounnds like you hit a bearing. I like to use an oil temp gauge. If the oil is hotter than normal then you know you have a problem.
Hope you are getting to the bottom of your problem. You have had some good questions asked. First, the oil could be running away from the pickup if it is not baffled. Or as some one said, you could be aerating it. Again do yu have a scrapper and windage tray. Metal in the filter is another matter, if there is a lot and it looks like bearing material. there will most always be a little metal in the filter, its just how much and what type. It's a lot of work to take it apart but might be the safest thing. Good kuck with it and cover all the bases next time if you missed something this time. JIm N.
Bob Yeh, it has the right pickup tube in it. Right now, i drained the oil and it looked good, there was only a very small tint of metal, nothing that would have made me worry about it. I cleaned out the system one filter and filled the engine with 7 quarts of oil, started it back up and ran it for a little while, car has 35 lbs of pressure when warm at an idle and when you rev the motor it goes right up to 70 with no problems, going to look into a few other things before doing anything else right now. The oil looked great in it after having it running this past weekend. Thanks for the help again guys. Great advice.
are the readings from the front or the rear of the motor. I personally read from the rear only its the most important area to me. An oil temp gauge is also very helpful. 200+- degree oil acts alot different than 160 and funny things happen to pressure. But thru the traps with 30lbs is not good. Make sure the bypass piston in the pump is not hanging up or obstructed with a small piece of aluminum or something.
If you got 35 at idle, you should be ok. Mine will go down to 20 at idle after a pass. If it was falling off on the big end, it was because oil was away from the pump pickup or aerated oil. Jim
I find this thread interesting. Of all the comments Ive read, does this expain the low oil pressure at 5800 rpm, then he let off the gas and the oil pressure went back up? Am I reading that correctly?
Wayne You were reading that correctly. When i went through the traps on that last run, the car was at 5800 rpm and went a 10.98 at 122. When i crossed the line i looked down at the guage and it was down to 30, as soon as i let off the gas the pressure went back up to 60, coasted through to the return road and coming back up the return road it had 30-35 on the guage and that was at no more than 2000 rpm.
The reading is from the front of the motor on mine. I think i will be putting a oil temp. gauge in the car after this to. All the temps. i posted and have are water temps.
what oil are you running? hopefully is not the rotella stuff while racing. PM me if you want to know why. Air bubbles in oil is very possible and the pick up could be cavetating like Jim N. says. If you are sucking the pan dry then you need to address more oil return lines from the back of the head and drilling the front of the block with larger holes for decelerating. I've been thru this!
I was running Mobil 1 10/30 synthetic in the car when this happen. I am looking at everthing we can before moving forward right now, I want to make sure this doesnt happen again. Thanks
