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rwirtzfeld1
06-19-2006, 02:44 AM
I have a 1963 OHV 170, that I rebuilt last year. I have a question in regards to oil pressure.

When my engine is cold, after setting the whole night, it starts with 70 psi of oil pressure at idle! At 3000 rpm is will be around 80-85 psi. After 10 minutes or a short drive, when engine temps. are at operating temperature, it drops to a normal 15 psi at idle and 50 psi at 3000 rpm. I'm happy with those hot numbers, but the cold seems way too high. I disassembled the oil pressure relief valve and all was in order, but I cleaned it anyway. I also checked the oil pressure numbers with a new gauge. Shouldn't the oil pressure relief valve handle the duties of controlling oil pressure when the oil is cold and thicker?

I run 10W30 oil. These numbers have been the same since I rebuilt it. I was wondering if I could have gotten the wrong spring with my oil pump rebuild kit or something? I have been looking in to the high cold oil pressure, due to seeing some leaks showing up externally, and I'm thinking the high cold pressure is not helping the leaks? What else would be a problem with this intial cold start oil pressure? I have worked on other engines and they do a much better job of regulating cold oil pressure, but they are generally regulated at the oil pump, by a bypass in the pump, so maybe they are just more efficient at controlling it, or do I have some kinda problem?

gordr
06-19-2006, 04:09 AM
quote:Originally posted by rwirtzfeld1

I have a 1963 OHV 170, that I rebuilt last year. I have a question in regards to oil pressure.

When my engine is cold, after setting the whole night, it starts with 70 psi of oil pressure at idle! At 3000 rpm is will be around 80-85 psi. After 10 minutes or a short drive, when engine temps. are at operating temperature, it drops to a normal 15 psi at idle and 50 psi at 3000 rpm. I'm happy with those hot numbers, but the cold seems way too high. I disassembled the oil pressure relief valve and all was in order, but I cleaned it anyway. I also checked the oil pressure numbers with a new gauge. Shouldn't the oil pressure relief valve handle the duties of controlling oil pressure when the oil is cold and thicker?

I run 10W30 oil. These numbers have been the same since I rebuilt it. I was wondering if I could have gotten the wrong spring with my oil pump rebuild kit or something? I have been looking in to the high cold oil pressure, due to seeing some leaks showing up externally, and I'm thinking the high cold pressure is not helping the leaks? What else would be a problem with this intial cold start oil pressure? I have worked on other engines and they do a much better job of regulating cold oil pressure, but they are generally regulated at the oil pump, by a bypass in the pump, so maybe they are just more efficient at controlling it, or do I have some kinda problem?


This leads me to wonder if, sometime in the car's prior life, perhaps somebody stretched the spring on the oil pressure relief valve in an effort to improve the oil pressure in a tired engine. Or maybe there is a buildup of varnish in the relief valve bore that prevents the plunger from retracting as far as it should? Seeing as you cleaned the valve, I doubt if that would be the case, though. But a stretched or incorrect spring might go unrecognized if you have only a single example to look at.

I imagine that if new springs are available, that they cost only a couple of bucks. Might be worthwhile to try one?

Gord Richmond, within Weasel range of the Alberta Badlands

r1lark
06-19-2006, 12:32 PM
quote:Originally posted by rwirtzfeld1

I have a 1963 OHV 170, that I rebuilt last year. I have a question in regards to oil pressure.

When my engine is cold, after setting the whole night, it starts with 70 psi of oil pressure at idle! At 3000 rpm is will be around 80-85 psi. After 10 minutes or a short drive, when engine temps. are at operating temperature, it drops to a normal 15 psi at idle and 50 psi at 3000 rpm. I'm happy with those hot numbers, but the cold seems way too high. I disassembled the oil pressure relief valve and all was in order, but I cleaned it anyway. I also checked the oil pressure numbers with a new gauge. Shouldn't the oil pressure relief valve handle the duties of controlling oil pressure when the oil is cold and thicker?

I run 10W30 oil. These numbers have been the same since I rebuilt it. I was wondering if I could have gotten the wrong spring with my oil pump rebuild kit or something? I have been looking in to the high cold oil pressure, due to seeing some leaks showing up externally, and I'm thinking the high cold pressure is not helping the leaks? What else would be a problem with this intial cold start oil pressure? I have worked on other engines and they do a much better job of regulating cold oil pressure, but they are generally regulated at the oil pump, by a bypass in the pump, so maybe they are just more efficient at controlling it, or do I have some kinda problem?


Except for your hot idle pressure, these are the same pressures I see on my '64 OHV six. I use the Shell Rotella which I think is a 15W oil. My hot idle pressure is around 25 psig. This is a 45000 mile engine, with original bearings, lifters, oil pump, etc. My oil pressure relief is clean and working.

Hope this helps.

Paul

Visit The Studebaker Skytop Registry website at: http://hometown.aol.com/r1skytop/myhomepage/index.html

64R1
06-20-2006, 01:45 AM
That is about what I see on both my OHV 6s with 15w40 oil. They have bigger oil pumps than the flatheads do. The high oil pressure cold is ok just don't rev it too high cold.

rwirtzfeld1
06-21-2006, 08:28 AM
Isn't the bottom line that the oil pressure relief valve does not control oil pressure to below 55 psi? My initial thought was maybe I got the wrong spring with my oil pressure relief valve kit, but if you guys also see the same thing with yours, than that's not the case.

If the oil pump is bigger than the flatheads, why is the oil pressure relief valve not designed to handle it? I run my Stude everyday, it get's me to work. I can't imagine letting it running 15 minutes in July, to warm up before hitting the interstate to work. Not to mention it get's cold here, so the winter temps. would just magnify the cold start oil pressure. I can't imagine running 15w-40, that's why I run 10w30. I wish I had x-ray vision to see just how much oil the oil pressure relief valve is dumping back to the timing cover when the cold oil pressure is 80 psi?

Thanks for the replies