High oil pressure?

[Ed Wright]

Originally Posted by BlueOval Ralph

Ed:
I know for a fact that Fadely & Edwards ran HV + HP Fadely had a supply of the old trans-am oil pump springs with a .125 shim = 85 to 90 hot and Pennzoil 20-50, I had the deep rotor (from 534 Ford Truck engine) covers machined at one of the Ford Machine shops. The 351-Cs need alot of pressure.

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.

[BlueOval Ralph]

There where some SBC out there that had wrong crank drillings and would shut off oil at Habove 7500 rpms you would show pressure but could not feed rods

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 Wright]

"Many smart engine builders use HV pumps so as to have enough volume later in life of the engine as clearances begin to get larger from wear."

I would have to debate the "smart" part of that statement. SBCs typically run well over 200,000 miles with no oiling issues, way more than a race engine will ever see. The factory pump has plenty of reserve capacity to compensate for wear. Pumping the pan dry? There are other problems if that happens. What actually happens is the pump bypass stays open, peeing un-needed oil right back into the pan. Heats up the oil, wears the dist & cam gears, and wears the thrust areas on the back of the cam sprocket and front of the block, wastes power. I've seen those areas really chewed up over high volume pumps in local roundy-round engines. Absolutely no need for them.

Raph, I've been doing this for fifty years now, I have never seen a crank drilled like that. But, old as I am I haven't seen everything yet. :-)
Don't think a bigger pump would be the correct fix for that.

[BlueOval Ralph]

Nope it has to do with the angle of drilling vs Stroke> It will just flat shut the oil off, the SBC cranks I am talking about were made by BRC when they were doing cranks in TNN. Had a small block Ford that Crower did from a Ford Forging same way it was something to do with the cross drilling and if you put a plug in the one side it would crutch it but not totaly fix it thing go wrong about 7500 to 8000 if you stayed below that RPM they would last, but above it would shut oil off and spin bearings. There is a article some where on the Internet but cna not Find it FJ Smith might come in on this, I thinkd he had a couple of these cranks.

Originally Posted by Ed Wright

"Many smart engine builders use HV pumps so as to have enough volume later in life of the engine as clearances begin to get larger from wear."

I would have to debate the "smart" part of that statement. SBCs typically run well over 200,000 miles with no oiling issues, way more than a race engine will ever see. The factory pump has plenty of reserve capacity to compensate for wear. Pumping the pan dry? There are other problems if that happens. What actually happens is the pump bypass stays open, peeing un-needed oil right back into the pan. Heats up the oil, wears the dist & cam gears, and wears the thrust areas on the back of the cam sprocket and front of the block, wastes power. I've seen those areas really chewed up over high volume pumps in local roundy-round engines. Absolutely no need for them.

Raph, I've been doing this for fifty years now, I have never seen a crank drilled like that. But, old as I am I haven't seen everything yet. :-)
Don't think a bigger pump would be the correct fix for that.

[Ed Wright]

Thankfully I never used one of those. lol

[carl hinkson]

Originally Posted by Ed Wright

"Many smart engine builders use HV pumps so as to have enough volume later in life of the engine as clearances begin to get larger from wear."

What actually happens is the pump bypass stays open, peeing un-needed oil right back into the pan.

.

On a EOM or Mellings pump when the oil is bypassed and peeing back to the pan how does this happen as there is no orface in the pump cover to do this.

That being said on those HV pumps years ago we use to drill another bypass hole in the cover and bleed off the extra oil pressure when the oil was cold but when we did this we never saw pressure go over on the average 72 pounds.

Since Melling has come out with the 10% more volume pumps years ago we have never used a 25% higher volume pump.

That intersting pumping pans dry as where are you going to put 5 quarts of oil in that engines when the pan is dry.

[Charles Rainey]

I wasnt going to post on this subject any more until Carl posted, but I thought why not just one more. Carl is correct, the SBC does not bypass too the pan. It bypasses within itself, that is one reason you dont want the bypass valve to continually open. It by passes withion itself and builds heat. I, just like Carl, have drilled my on relief hole in the pump so that it will bleed back to the pump. Smokey unit showed me that several, several years ago. The reason, from what I understand, that Melling and other companies came out with HV pumps was to move more oil at the low rpm ban. If you go thru their catalog, you will notice that their HV pump does not make as much pressure. They have a pump called HP to do that. Several years ago, I mounted a remote oil filter with a flow meter mounted in the line. I changed the pumps from standard to HP to HV to Select. If the clearances were ok, There was no more oil going thru the engine, UNLESS you change the pressure. If you up the pressure, then it did flow more oil. It only had more capacity to do so if need. The pulsations WAS slightly lower on the HV. I, just as Carl, now use the 10% HV. Oh yes ED, I, like you, have been doing this since the early 60's. And I think I am too old to see something new, but damn I learn something every time I fire the dyno every day. So Ed, you and I are on the right path to still learn. If you learn something new today, call me. I dont want to miss out on anything. I have to keep notes now though. Book is getting full. I crashed my PC other day and I thought I was really screwed, cause my notes was on it. Then my grandson said, dont worry pops, I backed it up in the sky. So guess he has a direct line to the man upstairs or something like that. I told him to write him a letter and get my notes back. He said I would have them this week end. Now that is service my man.
charles

[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.

[Pvt Parts]

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.

Takes a while for the newbies to catch on Ed. I was doing the same thing to my pumps back in the late 70's and 80's. And we're not talking about changing the bypass spring.

[Ed Wright]

Originally Posted by Pvt Parts

Takes a while for the newbies to catch on Ed. I was doing the same thing to my pumps back in the late 70's and 80's. And we're not talking about changing the bypass spring.

Wish I could think of the guy's name that got me thinking correctly about sbc's oil pumps. He was a Modified & Comp engine builder from New Mexico in the '70s. Wish I could think of his name now. (I’m old) Had the pick up tube fall out of the oil pump in my ’56 Chevy at Albuquerque NM. Too much blowing sand & dirt to pull the pan there! I just loaded up. He was asking what happened, and told me I should be pulling the spring and braze the pick up in place, then ask how much oil pressure I had? I proudly announced “65 psi!” He said, “And a high volume pump?” I said “Yes!” He then screwed my head on straight about pumps and pressure. I have an old rear main cap, tapped for a fitting, flexible hose and oil pressure gauge. I bolt the pump to it, drop in the parts washer and spin it up with a ½” drill. What I see there, I see in the car. Been doing it this way since that day. Before synthetic oil too. <G>