Oil pressure - How much,is too much ?

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oldhead
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Oil pressure - How much,is too much ?

Post by oldhead » Sun Oct 29, 2017 2:08 pm

That oil pressure that is. My new engine oil pressure when cold at 7000 is 95# (70 degrees},It never goes this high because I don,t race it cold, except one to see how high it would go. When warm it goes 70# at 7000, How bad is this? I was thinking (I think once and a while) that I could make a "Blow off valve" for the outside of the engine. What you think :D :D :D :D Oldhead
Last edited by speedtalk on Mon Oct 30, 2017 9:47 am, edited 1 time in total.
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Re: How much,is to much ?

Post by oldhead » Sun Oct 29, 2017 2:12 pm

That with 5/30 oil,I have made 5 runs at the 1/4 the other day. with no problem :D :D :D :D Oldhead
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Re: How much,is to much ?

Post by engineguyBill » Sun Oct 29, 2017 2:14 pm

Used to be that the recommended formula was 10 lbs of oil pressure per 1000 RPM when the engine is at normal operating temperature. But this thinking has gone out the window with the availability of better parts and machining abilities. In actuality, 70 lbs of oil pressure is wasting valuable horsepower in a race engine. High oil pressure won't necessarily hurt anything, just wastes horsepower.
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Re: How much,is to much ?

Post by mark_follweiler » Sun Oct 29, 2017 3:14 pm

yeah, it doesn't NEED that much. but would not mess with lowering it now.

oldhead
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Re: How much,is to much ?

Post by oldhead » Sun Oct 29, 2017 4:51 pm

How bad would it be if I HAD to run it cold at 95# Oldhead
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Re: How much,is to much ?

Post by cgarb » Sun Oct 29, 2017 5:10 pm

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Re: How much,is to much ?

Post by plovett » Sun Oct 29, 2017 5:36 pm

I would never run an engine at 7000 rpm with cold oil, regardless of the oil pressure. Let the oil warm up before beating on it.

JMO,

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Re: How much,is to much ?

Post by Zmechanic » Sun Oct 29, 2017 8:08 pm

95lbs cold at 7krpm is no surprise at all if you have any sort of improved oil pump and/or higher viscosity race oil. I agree it's way too much pressure for an engine, but the consideration there should be warmed up pressure not cold. Horsepower is proportional to flow and pressure. Increase either and the power to spin the pump goes up. Biggest risk I wound suspect is to your pump, pump drive shaft, and distributor gear.

As for a black and white "will it hurt anything"? I don't know..

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Re: How much,is to much ?

Post by swampbuggy » Sun Oct 29, 2017 8:10 pm

:wink: Plovett, i agree 100 percent, i am a firm believer in preheating oil and then getting the oil to 200 deg. after starting before applying max. RPM, fanatical Mark !!

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Re: How much,is to much ?

Post by GARY C » Sun Oct 29, 2017 8:37 pm

swampbuggy wrote:
Sun Oct 29, 2017 8:10 pm
:wink: Plovett, i agree 100 percent, i am a firm believer in preheating oil and then getting the oil to 200 deg. after starting before applying max. RPM, fanatical Mark !!
Yes, until I put an oil temp gauge on my car I had no idea how long it takes to get oil up to temp, most people think it is once the water reaches 180 but it's not.

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Re: How much,is to much ?

Post by MadBill » Sun Oct 29, 2017 8:40 pm

Oil temperature is very load sensitive; absent an oil to water cooler you can idle a car with no fan until the water hits 240° and the oil temp still willbe barely off the peg...
Last edited by MadBill on Sun Oct 29, 2017 8:42 pm, edited 1 time in total.
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Re: How much,is to much ?

Post by GARY C » Sun Oct 29, 2017 8:42 pm

oldhead wrote:
Sun Oct 29, 2017 2:08 pm
That oil pressure that is. My new engine oil pressure when cold at 7000 is 95# (70 degrees},It never goes this high because I don,t race it cold, except one to see how high it would go. When warm it goes 70# at 7000, How bad is this? I was thinking (I think once and a while) that I could make a "Blow off valve" for the outside of the engine. What you think :D :D :D :D Oldhead
I don't like it that high but 65 to 70 is fairly common unless you design everything for less, I have run between 48 and and 70 with no issues. one thing for sure is if it's to low you wont have to wonder because your bearings will tell you for sure. :D

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Re: How much,is to much ?

Post by superpursuit » Sun Oct 29, 2017 8:48 pm

swampbuggy wrote:
Sun Oct 29, 2017 8:10 pm
:wink: Plovett, i agree 100 percent, i am a firm believer in preheating oil and then getting the oil to 200 deg. after starting before applying max. RPM, fanatical Mark !!
I agree with swampbuggy. The extreme pressure additives in the oil do not start to work until your oil is up to temperature so you will probably see excessive engine wear if you race on cold oil. The other thing I would be concerned about racing with 95lb oil pressure is blowing the o ring out of the oil filter. At the least that will be a big mess. At worst a blown up engine. Just my 2c.

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