High oil pressure?

[Ed Wright]

Yes, I mis-spoke about the bypass. I was trying to get my point across. That, there is no need for a high volume oil pump in a SBC. Cleveland Fords? probably so. Why more oil at idle? absolutely no reason. If somebody has better bearing life with 10% or more pump volume, they need to seriously take a look at what they are doing. The old "big block-style" +25% pumps? Are you kidding??
A few of my old roundy-round customers seemed to worry about their oil pressure dropping to 15 psi at idle after running 25 to 35 laps WOT in Oklahoma summer heat (no oil coolers). Thought they needed high volume pumps to "cure" that. They just didn't know better, but you still have to waste time trying to explain something that was evidently over their heads. GM says 10 psi per 1000 RPM, I have found that to be VERY safe, to say the least. All this was before synthetic oil, btw.

[Charles Rainey]

Originally Posted by Ed Wright

But, those were Fords. And sbc = Small Block Chevy, which has a great oiling system, unlike the early Fords. Myself, and many others building small block Chevys use the STD volume pump, modified for LESS volume. I also limit mine to 40 psi @ 8500 RPM. Bearings always look like new. Just replace them when I start to feel guilty about running them so long. If you ever build a sbc, call Larry Stewart Sr about buying an oil pump.

Ed
I didnt mean to step on your toes, but I havent seen people use 10 psi for 1000rpm and apparently you dont either by your posting as above. Carl and I was just saying there is several ways to get to the oil issues of motors. I have found that a SBC only needs 4.5 gpm and a ford needs 6.5 gpm but every once in a while you get an engine that is an anomaly and for what ever reason needs slightly more. I have always felt that Melling and several oil pump companies are pretty good business people. I have no idea why they built a HV pump but I am pretty sure they knew what they were doing. I can purchase a HV pump for about the same price as a Std pump on my WD account and I lower the spring pressure even more so I dont bang on the unloader all the time. I have always felt that oil is as much a coolant as water and you can get clearances so tight that you do not get volume or at least not enough to carry off the heat and also I feel you want enough pressure to create the hydrodynamic wedge that you need. Many factors go into how much oil you need etc, width of bearing, compression ratio, normally aspirated or not. I have found turbo motors with boost like volume but it doesnt mean you have to flood, just carry the heat off.
Sorry didnt mean to toe step Ed. Just expressing an opinion

[carl hinkson]

We build a lot of circle track engines for the last 35 years or so and we use a lot of 10552 and 10553 pumps, Plus we building alot of engines with .903 lifter bores which will bleed off a little more oil. But the 10% more volume pumps seem to work very well.

On our Honda rod and 283 main engines we use the standard volume pump and still have to drill another bypass hole to keep the oil pressure under control.

I also use the drve pump which is a low volume drag race pump onn some of my build with zero problems.

[Charles Rainey]

Hello Carl
Havent talked to you in many years. People as old as me and you should have already retired but------. I too use more select pumps now than I did in the past. I also have found the .903 requires more oil than the .842. Big Blocks shows the same requirements. As Ed has said, he is running 40 psi thru the lights. I have several motors running 5 gpm and running less pressure than even that. I look for volume and not pressure and I watch temp coming out of bearings to see if I need more flow.

[Ed Wright]

Charles, I have Honda rod bearings, std 350" mains and .904 lifters (bushed bores) in mine, and use a pump with shortened gears with a "stuffer" plate to cut volume. With zero wt oil it idles about 15 psi hot, goes to 40 by 2500 RPM. Cold it idles close to 40. Idle speed is 1600.

I don't think sharing what we have learned is stepping on toes.

Take care, Ed

[carl hinkson]

Originally Posted by Charles Rainey

Hello Carl
Havent talked to you in many years. People as old as me and you should have already retired but------. I too use more select pumps now than I did in the past. I also have found the .903 requires more oil than the .842. Big Blocks shows the same requirements. As Ed has said, he is running 40 psi thru the lights. I have several motors running 5 gpm and running less pressure than even that. I look for volume and not pressure and I watch temp coming out of bearings to see if I need more flow.

I am only 51 years old and still have a few miles to go before I retire LOL

[Ed Wright]

Originally Posted by carl hinkson

I am only 51 years old and still have a few miles to go before I retire LOL

Must be nice! :-)

[carl hinkson]

Originally Posted by ed wright

must be nice! :-)

lol

[Pvt Parts]

Originally Posted by Ed Wright

Charles, I have Honda rod bearings, std 350" mains and .904 lifters (bushed bores) in mine, and use a pump with shortened gears with a "stuffer" plate to cut volume. With zero wt oil it idles about 15 psi hot, goes to 40 by 2500 RPM. Cold it idles close to 40. Idle speed is 1600.

I don't think sharing what we have learned is stepping on toes.

Take care, Ed

What is it at the finish line?? My Corvette was dancing between 40 and 60 at 1000 feet when the car was on kill. Clutch it and kill it at the finish line or it would go to zero.

[Ed Wright]

Originally Posted by Pvt Parts

What is it at the finish line?? My Corvette was dancing between 40 and 60 at 1000 feet when the car was on kill. Clutch it and kill it at the finish line or it would go to zero.

40 psi at the finish line, drops to 25 or so when I put it in neutral (clean neutral Rossler) unless it has zero wt oil, then drops to about 15. 10W30 cold idles at 40. I can't tell much difference watching the gauge between this pump and my old Moroso pump with the 40 psi spring.