Oil pressure concern

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mistreta

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I just had a local Mopar engine builder do a 360 to 408 stroker for my Duster.
Using all good parts from Mancini racing. The motor seems strong, I have not drivin to too hard yet, it has about 200 miles on it. My concern is low oil pressure on idle, when its in gear, at about 6 to 800 RPM's, the pressure is between 10 to 15 lbs. Above that it holds around 50lbs when driving. It has a mopar hv pump with a windage tray and stock pan. I'm using a autometer mechanical gauge with copper tubing, there is a tee on the block so my factory guage still works, it stays just about in the middle all the time. The 340 that was in the car before seems to have a little more pressure on the factory gauge, I added the autometer for a more accurate reading. We plan on droping the pan next week to replace the gasket, it drips in the rear of the pan only after I drive it. I wipe the pan dry, no more drips. Would that have anything to do with oil pressure?
Any input on this?

Thanks
 
i dont think that small of a leak would affect oil pressure, my car is about 20-40 on idle and around 80 when driving,and has small oil leak, but my last engine was around 10 on idle and 60 while driving drove it for half a summer thinking it was ok and i ended up ruining engine it fused my bearings together and did a lot of damage.
 
Sounds low to me my worn out 318 with a hv pump carries 15 @ idle and 50-60 when running.
 
that is plenty of pressure. I assume you mean at idle when hot? all a small block mopar needs at idle is around 6-8 lbs. if you have 10-15 that's nothing to worry about. I put a 4 in. crank in a 360 to and run valvoline 10-40 on the street, drive ot hard and every day and no problems. I have tore into it once after about 5000 miles and the bearings were just as new as the day I put them in there.
 
Are you running the 90 degree adapter? I've ran my 360 with and without the adapter and noticed my oil pressure drops 5-8 psi without the adapter. Probably due to less restriction. I think when my engine is nice and warm it runs right around 15 psi. Have about 5k on the motor with no issues except I can't keep my head out of the hood area for too long. Every time I stick my head in there it adds up to $$$.
 
That kind of oil pressuree is good.But if you have a high volume pump and a stock oil pan you need to change the oil pan to a deep pan.What happens when you turn your engine hard the high volume pump will suck the pan dry.When that happens you will wipe out your rod and main bearings.This is a common mistake.
Jim
 
63dartman said:
Are you running the 90 degree adapter? I've ran my 360 with and without the adapter and noticed my oil pressure drops 5-8 psi without the adapter. Probably due to less restriction. I think when my engine is nice and warm it runs right around 15 psi. Have about 5k on the motor with no issues except I can't keep my head out of the hood area for too long. Every time I stick my head in there it adds up to $$$.
Click to expand...

Yes I am running a 90 degree adaptor, and VR1
 
one thing that could be both issues is that oil plug that goes under the rear main bearing cap. 10psi sounds low to me for a rebuilt motor. my 318 i just did sits around mid 20's even on a hot day in cali.
 
Yes Camd64 is right .Now that I think about it.That would be good Pressure for a stock pump.I have a high volume in mine.When mine is warm idle is around 30-35 lbs and going down the road at 65 mph it runs 70 lbs.
Jim
 
What rpm does your engine idle at? I've seen low pressure due to low idle speed too. Nevermind just went back and read your original post. If it's running consistantly at 600 rpm I would try bumping it up to a steady 850 and see what the pressue does. Have you talked to the builder about your concerns? I would see what they have to say. Are you sure the pickup is placed correctly?
 
Did your engine builder run the engine on a test stand or dyno before it was delivered to you? If not, was it full of oil with the pump primed?? If not, what did you do before starting it up? Small block pump can suck air if the pump is not fully seated on the rear main cap. There is also a oil gallery plug inside the cam valley facing backwards next to the intermediate shaft bushing that must be installed tightly. Ask him also about the little welsh plug by the rear main cap. There is a certain depth that it must be driven in to. Did it take long for the engine to start up? You should have better idle pressure than what you state. That would be low even in a clearanced race engine, so there might be one of the issues I mentioned, or a bearing problem. Good luck.
 
Tuff to say what could be amiss. If anything. It's nice to know clearances when the engine went together. Especially in the main/rod bearings. How were the lifter bores/lifters. The type of pump has a large bearing on pressure. If you take the pan off, check the pickup for tightness. They are sometimes loose and pressure will be lost there. Oil filters can affect pressure, at least in my experience.
I recently went with 5W50 full synthetic in my Super Bee, (10W40 is no longer available here) and that picked up pressure at idle (hot), and down the road.
If it was a stock type pump, with typical clearances for a freshened block, I don't think your pressures are a concern.
 
The pump is a high volume pump, that doesn't necessarily mean it's a high pressure pump. My pressure ga reads ~20 at idle and 60 at cruising speeds
 
72dustyer said:
The pump is a high volume pump, that doesn't necessarily mean it's a high pressure pump. My pressure ga reads ~20 at idle and 60 at cruising speeds
Click to expand...

That's right. A few yrs. ago I rebuilt a 360 and it had low pressure (exactly what you say yours is) even with a new HV pump so I pulled it back apart after about 750 miles and checked it over and all the bearings looked just like the day I put it together so I made a test jig to test the oil pump relief and found it relieved at 60 lbs. I also had another HV pump and put it on the jig and tested it and it relieved at 78 lbs. Quite a difference between some pumps.
 
I had the same problem, 10-15 at hot idle, 40-45 while driving. I switched from 10w-40 to 20w-50 and now it hot idles at 20-25 and gets 60-70 while driving.
 
mistreta said:
I just had a local Mopar engine builder do a 360 to 408 stroker for my Duster.
Using all good parts from Mancini racing. The motor seems strong, I have not drivin to too hard yet, it has about 200 miles on it. My concern is low oil pressure on idle, when its in gear, at about 6 to 800 RPM's, the pressure is between 10 to 15 lbs. Above that it holds around 50lbs when driving. It has a mopar hv pump with a windage tray and stock pan. I'm using a autometer mechanical gauge with copper tubing, there is a tee on the block so my factory guage still works, it stays just about in the middle all the time. The 340 that was in the car before seems to have a little more pressure on the factory gauge, I added the autometer for a more accurate reading. We plan on droping the pan next week to replace the gasket, it drips in the rear of the pan only after I drive it. I wipe the pan dry, no more drips. Would that have anything to do with oil pressure?
Any input on this?

Thanks
Click to expand...
Did you figure out what the problem was? I am having the same issue
 
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