High Oil Pressure >.<

-
70DusterDev

70DusterDev

Well-Known Member
Joined
Jul 22, 2008
Messages
416
Reaction score
319
Location
Bethel, Vermont
So this is an issue i still need to address from when i rebuilt my 340. When I got the car it had a recent piston ring job so I was told and when i ran it, there was no smoke or anything so I went about giving her some attitude. I put a big cam, long tube headers, high rise intake, 750 carb, heads re-machined and valve job etc and she runs awesome! And the response is just rediculis. But when she runs at like 1200rpms the mechanical oil pressure gauge is pegged at 100. Once she warms up and is idling at 700ish its at about 70-75 but as soon as I tap the gas its pegged back at 100 :angry7:. My uncle (who i bought the car from) changed some springs or something (nooo idea) in the oil pump making it either high volume or high pressure I cant remember. But still this cant be right can it? Will I be blowing seals?
 
I would check the gauge, IMO gauges unless they are liquid filled are not very reliable, and if you really are getting 100 psi yes that i do beleve is waay to high, I have a 360 stroked brand new, like 30 miles on it with a melling HV pump and it runs 60psi cold, with Shell 15w-40 Rotella, what make is your gauge?? Auto Meter, etc??
 
I thought it might be the gauge because its a manual that was installed years ago so i went and baught a brand new one from Bond Auto and put her in and had the same results... I did however use the same oil line but you can clearly see the oil move through it fine so i wasnt worried about it.
 
I use stock pumps with the MP spring. I had one that I installed the cupped plug too deeply on. There was like 1/8" behind the plug to the reatining cotter pin... It had 120psi and climbing at 4K. Sounds like the relief valve might be stuck or the relief spring installation isn't right. You should not leave it like that.
 
When I rebuilt my motor I installed a Melling HV pump. With the tight clearences of a fresh motor I switched to 10w-30 brad penn instead of 20-50 because of high oil pressure.
 
people sometimes don't warm up the engine/'oil' and thats when you start seeing 90psi as you shift at 5500 with the engine/'oil' still cold....

Yes more pressure is more parasitic drag/hp loss [lil].

I personally like seeing 35psi or so psi fully warmed up, it just makes me feel good and I think to a point keeps a certain amount of transfer of heat dissipation at the lower rpm where there is not much air moving by....
on the other hand...compressing oil/fulids makes heat, the more you compress...the more heat AND hp loss.

pondering again...
 
but mine idles at 75.. and as soon as i TOUCH the gas its pegged at 100. And if i just lift the motor up some can i get the oil pan off?
 
Man, really? I think my engines have so much oil flowing through them I couldn't ever get 100 pounds.....

Warm, they have to be at like 4K to hit the 75psi mark. Moper is right, the relief must be stuck.
 
Ok, so if i take that centerlink or k member? same thing? off then what do i do to the oil pump once i take it out or to know if the relief is stuck?
 
I am going to reccomend getting a book. Besides the advice here, "How To Rebuild A Small Block Mopar" would be a good one, wat better than a Chiltons, without the Hi PO Spin like Lawrence Sheepherders "How to Hotrod" series.......
 
Alright, well i have a Hanes manual for the motor. I'll have to look through it and most likely it will have the steps to rebuild the pump then. Also will it hurt anything having such a high oil pressure?
 
When you get to the pump itself it's easy. It will have a tag on it that has the part number on it, or it may be cast into the body. If it ends in "HP" it has the higher pressure relief, but stock volume. If it ends with "HY" it's a high volume which automaticvally has the higher relief pressure. If it was me, I'd order teh MP high pressure spring kit, because to get the relief valve out, you have to pull the cupped plug that's part of the package. After you remove the pump cover make sure you scribe accross the rotors and body so you can return them to the original positions. Take it completely apart and clean everything with solvent, including the pick up. I always tap the pickup on the bench and blow air/solvent backwards thru it to loosen up and wash away anythign that might be stuck in it.
 
moper, thats exactly what my uncle did, i saw him do it a few years ago. He got some kit, and put it all in the stock housing. Now its very possible that he messed something up because when i got it, i just put it in the car. Just dreading lifting the motor up to get the pan off.
 
I've messed it up too. It happens. The kit's like under $10 so I'd just get it to have on hand when you pull the pump. When you re-assemble it, just drive the new plug in enough to get the cotter pin behind it. Any further and you may have high oil pressure. It places stress on the oil pump drive and robs a bit of power, not to mention adding heat to the oil for no reason at all.
 
Alright will do. The high pressure kit right? not volume? er the high volume. And was your motor already in and all set as well?
 
If it's a street car or even a mild race car you need neither a high pressure nor a high volume oil pump. Oil pressure as high as you describe will pump the pan dry in no time and start spinning crank bearings because the oil doesn't have a chance to drain back into the pan. I'm actually surprised you haven't blown an oil fiter off the side of the engine. I've seen it happen. I wouldn't even run pressure that high with an 8 quart oil pan. All an engine needs is 10 PSI per thousand RPM. 10 PSI at 1000, 20 PSI at 2000, 30 PSI at 3000 and so on. That's IT. In fact, if the oil pressure gauge is even off the peg at ALL at idle, guess what? That's enough. Most stock oil pressure sending units cut the oil light on at 3 PSI. The parasitic drag is the absolute LAST thing you need to worry about. If you have a stock oil pan on it, I sure wouldn't even run that engine at all until you replace that pump with a stock pressure/volume unit. Opinions vary, but that's mine.
 
dodge... You really need to raise your standards dude....lol (thank you in any event...)

The engine I did it on was built, assembled, but was on my running stand when I noticed the issue. The oil presssure was climbing with rpm and at 4500 was pegging the gage at 120psi (love the Wix filters!!)

As far as the pumps neeeds... I agree the vast majority of engines that are not destined for sustained rpms beyond 6K are fine with a stock pump. However, I have noticed the stock pumps without the high pressure spring sometimes limit the oil pressure to 45psi which IMO is not enough. I subscribe to the 10psi/1000 rpm. After repairing, and it was my fault... there was 1/8" between the cap and the pin... The engine now has 25psi hot at idle (15/40 oil) and 70 at 3K and up. The "HP" siffix means standard volume, but has the high pressure relief valve. HV means it has both the extra volume and the high relief pressure. The high volume draws a ton of power and as stated can leave a lot of oil trapped in the crankcase rather than the pan. The HP pump draws slightly more than a stock pump due to the higher relief pressure. But nothing near the HV units.
 
Mopar, they always go back in the same place, I just always faced the impeller this way, and you turn the pump facing this way, and thats the way it goes..... Way too complicated. Why a paint marker never even came to mind........ Guess I was too worried about putting it back together in the wrong place..... LOL
 
You must log in or register to reply here.
-

Back
Top