slick1hunting

Ok I got my mechanical oil pressure guage installed this weekend and unfortunately the factory guage wasnt off by much. I am very aware of the low oil pressure syndrome with lt1 owners as well as the factory minimums.

My oil pressure meets the 10psi per 1000rpm until probably 3500rpm. I am not seeing any greater psi than 35(warm). My motor is whats in my sig and should be 375-400 to the wheels on motor with the potential to spray a 200 shot of n2o. I wont spin above 6200 rpm. What pressure should I consider a minimum for that?

I have a 8qt pan and the oil pump was new and provided with motor and I put the correct pick-up on(it bolts to pump so doubtful it came loose). I did notice the one time i gassed it that pressure climbed and dropped and climbed and no were near matched the rpm. It also seems very sluggish.

I believe the pump was melling 55 and dont know if it was the high volume one or not.

Please give me any suggestions of possible causes or solutions as well as what pressure would be safe around 6000rpm. If I have to drop the pan I would just assume put a new pump in or at least have one on hand so please advise what pump would be suitable for my build with the occational nitrous runs.

Thanks

RUDEDOG

This is the one I run even with a stock pan and have never had a problem. 80 psi cold and 35 psi hot.Melling M55HV Oil Pump : Amazon.com : Automotive

RamAir95TA

Honestly I don't see a problem with your oil pressure. I would install a higher pressure GM white spring (or Melling pink spring, same thing), run a slightly thicker oil, and see if that helps. Perhaps the relief valve on the oil pump is stuck open.

Running a high volume pump comes with it more potential problems than benefits so in MOST cases they are ill-advised.

slick1hunting

Thanks guys. The drop in pressure is what concerned me the most as ive never seen any do that nor be so sluggish.

I will trust your advice Joe and stick with a regular volume pump and use the spring. Is there an advantage either way with the 3/4 pickup or the 5/8 ????? If so what should i choose?????

Im tempted to pay a few extra bucks and get one of these as the thought of it being gone through and matched up and bench tested (plus the deburring and polishing) is worth some piece of mind as I dont look forward to dropping the pan and only want to do it once. Precision Oil Pumps

RamAir95TA

There's not much of a difference but I am fairly sure the stock pick-up is 3/4". A bigger pickup is easier on the pump.

Truth be told I would use a Melling 10554. They are a MUCH more robust casting than the typical M155 pump, which has been known to crack in higher HP applications.

slick1hunting

Thanks Joe, thats what I ordered. I had heard about the breakage and that they supply many of the other manufacturers. I read they changed the casting at some point and never heard if it was the old or the new castings that were prone to breakage. The pump I.ordered comes with the higher pressure spring installed as well as a metal sleeve and the intermediate drive. Ill spend a little extra time this time and check my pickup to pan clearance as well. Im wondering if its not a little close right now and thats the sluggishness and the drop when I floored it. Thanks again I am feeling pretty good about this pump.

slick1hunting

update. I got the pump in this weekend and have better pressure and less motor noise. It still is a little low for what I would like to see so I will probably run a heavier oil. I have 10- 30 in it now. I was still getting the drop when flooring it. I took a quart out and no longer had that problem. When I ordered my pan they said I would probably want to run 7 qt rather than the 8. Any reccomendations on a heavier oil. It idles at 12 and at 1500rpm its 22 and looks like 45-50 over 5000.


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ACE1252

Has the pressure always been like this or has it slowly dropped over time? How long has it been like this?

The nuts and bolts of the situation boils down to bearing clearances. They are either a little on the loose side or one more of them are wearing for some reason.

10-40 will help bring it up a little...I run 10-40.

My issue was dropping oil pressure around 3500, but it would come back at 5000 on max acceleration from low speed..
http://www.youtube.com/watch?v=IjclVu1HYYM

The fix involved a Moroso pan(20185) and a canton pickup(20-013). I feel the pickup was the "fix" but since I did both at the same time I can't say for certain. Results....
http://www.youtube.com/watch?v=a6iKOaJ6XK0

Sounds like you have low pressure all the time, so the above will not fix that....but if you have dipping on acceleration, the above will certainly fix it.

slick1hunting

thanks ace. I had actualy read the thread you were commenting on and several others prior to posting and deciding to put a new pump in. The pressure has been low from first start. I have less than 2000 miles on motor. I have champ pan and pick-up on it. Running the seven quarts took care of the drop when accelerating and that was good news to me as that was my greater concern. I am considering 10-40 or 15-40 and possibly 20-50 in summer. Im in the research phase lol. I guess my concern is being sure I get good oiling because perhaps its only one bearing clearance thats loose or what. I really dont know enough and want to protect the motor the best I can. I also wonder if any additives would be worth while in using.


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bw_hunter

What did your builder say about the correct oil to use? Low oil pressure from the first start probably indicates larger than stock clearances. That's not necessarily a problem, just a preference that your builder has.

I'm old school and believe that the additives available aren't worth much more than spit. I believe a good quality oil, at the right viscosity and changed regularly is the best way to preserve you engine.

slick1hunting

im pretty much of the same mindset but I know there are advances in technology and I sure dont know everything lol. I know most things are gimmiks or just biased claims to make sales pitches. Some of the racing teams that really moniter things may be using things and getting results though. I know thats were the advancement often show up first. I am on the fence with using conventional oil and changing more often or using synthetic. I put synthetic in this time as I lean towards it. Builder recomended 10-30 and I have mobil 1 full synthetic 10-30 in it. I am not really the builders biggest fan lol. I had to pull the motor to seal my head studs because he used teflon tape and several were seaping water before even starting motor.


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bw_hunter

I'm thinking that any advances in oil technologies will end up coming from the oil companies and not the additive guys...but, again, I'm old school.

I use synthetic oils exclusively in our LT, LS and LQ engines and change them at the normal interval in the owners manual. Granted, I don't do a million miles a year so it's not a wallet breaker. I've read everything I can find on oils...and no, not everyone agrees with what's best...and decided to use synthetics. I don't use any additives as I expect the antioxidants and detergents in the oil will do their job. I also stay far away from Fram filters and use only Moroso racing filters. If you care, thhe part numbers are 22459 for the short (stock length) filter or 22460 for the long one.

Just to show how contrary I can be, I use conventional oil in our Land Rover...a heavy duty 15W-40 rated for diesel engines. The owners manual calls for 10W-30 but all the Rover websites agree on this...even on the brand! Those old design engines need thick oil and lots of oil changes or they rattle and gunk up....what a beautiful design!

slick1hunting

thanks for the info. ive been using wix filters on the car as ive heard some bad things on others and since some manufacturers supply other brands I dont know who supplies whom(same with fuels lol). one my truck I run amsoil filters as I have a dual bipass setup with big monster filters. it does a nice job. I would probably have to run the short one as I cant run the standard wife I have to get one about a half inch shorter. what is it you like about the moroso filter?


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slick1hunting

lol stupid autocorrect. I can run the standard wife and dont need a shorter one haha but I do need the shorter filter than the one wix lists for our cars.


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bw_hunter

I basically like the higher flow rate, the anti drainback valve and the nonporous end caps on the filter. fram uses cardboard (my company supplies it).

The filter media itself is pretty much the same specification on all the brands. Low priced filters get paper, more expensive ones get synthetic fibers blended with the paper fibers.

I'm not saying my choice is the only right one...read up and make your own call...