If you are having problems "sucking the pan dry" then you should look at oil drainback first, cause that's probably where your problems are..... fine mesh screens and thick oil or perhaps screens clogged with metal fragments. Oil gets to the top of the engine via the pushrods and all lifters have a metering valve inside them. You're only going to get so much oil to the top of the motor. I chalk the "pan sucking dry" arguement up as one of those MYTHS people have come to accept over the years without really thinking through it in much depth.

I'd be willing to bet my house that if you see a pressure loss spike (oil pump pickup becoming "uncovered") then your problem, 99% of the time, lies in the oil pan design or is a combination of poor drainback & bad pan design. So I'd 1st ask myself.... what safeguards are incorporated into the oil pan? Does the oil pan use a one-way gate to insure oil stays where you want it during hard braking and accleration?

I do agree with these comments:

1) A hi-volume isn't necessary with stock bearing clearances
2) Stock pump and higher pressure spring is ideal for modified stock-clearance engines

But disagree with these:

1) A HV will suck the pan dry
2) A HV requires a higher capacity oil pan

What an HV does require is a better pan design with better oil control. Whichever route you take, more pan capacity is a good thing. Keeps the oil cooler and may lessen the chances of uncovering the pickup.

I wouldn't run an oil cooler or accusump without an HV pump though.

-Mindgame

 

Mindgame, well put, as usual. But a SBC with a stock oil pan and no mods that decrease the amount of oil going to the top of the motor or that increase the drainback rate WILL potentially suffer oil starvation if an HV pump is used and the car is run at relatively high revs for more than a few minutes. Combine this with an oil level that is at the lower end of "full" and the likelihood is that much greater.

I know this, 'cause I have seen it on more than one occasion. Is it common? I don't know. But since there is no benefit to an HV pump when it isin't needed and the potential for loss of a motor and also a couple of extra hp to drive the pump and more oil heating from it, I fail to understand why people continue to use them.

Rich

 

It is incorrect to put HV and HP in the same breath. They are NOT necessarily the same.As I noted earlir, that includes 99.4% of the engines driven on the street.It is a major effort to get the oil back in the pan, in an OEM oiling circuit.

 

I have a hard time believing that a .080 diameter hole through a pushrod (16 of them) could possible move more oil than could be drained back by four 1/2" return holes in the lifter valley. Then consider the lifter metering valve regulating (to some degree) just how much oil the top will get. Just doesn't compute.

Low oil levels are just plain stupid. I know guys who do it in search of a little more but yeah... just plain ol' redneck. Some people just have to learn the hard way.

Rich, how did you monitor oil levels in these examples where the pan was "run dry". Was this dyno testing or track related? How do you know the pickup wasn't uncovered for any amount of time due to poor oil control?

I do agree that HV pumps are over-used but I also feel that they have their place. Maybe not the most popular belief these days but I have my own experiences to back my "feelings".

-Mindgame

 

AFAIC, the oil does not become cooler. It just takes longer to get up to a stabilized temp. Also, there is great effort taken to modify the bypass circuit in an OEM style pump the allow more effective hi perf use. This tells me the OEM style pump has more than adequate reserve.

 

I also have a hard time believing that you will have oiling problems with a stock pan and HV pump. There are some Mustang guys running a HV pump on a stock pan and turning some rpms without a problem.

My question is if you run a HV pump that has a 25% increase in volume, can you increase your bearing clearences by the same 25% and still not have a bearing problem?

 

I'm with you on this one, SBC's are not known to have any problems getting oil back to the pan. I've been running a HV pump and stock pan for a while on my 385 with no issues and spin it to 7K on occasion. I think more problems with oil pressure are do to the pump pick-up not being the proper clearance from the bottom of the pan like being to close to the bottom.

 

I fail to understand how the above would add to the oil requirement. I don't see it affecting it.It IS difficult to not agree with that logic.

 

"AFAIC" is not required arnie... it's implied that since you're the one writing it... well, you know.

Oil pans serve a number of different functions and to some extent, they do act as heatsinks. All things the same, larger volume pans are better heatsinks. I feel it's a minor thing in the scheme of this but I think it's relevent to this discussion. I know a number of guys using heat dispersent coatings on oil pans to help in this regard. The differences in temperature are measurable. Just like the differences in going from a 5 quart capacity steel pan to a 7 quart aluminum. I personally have seen temperature differences of ~10º F with no other changes.

Two... more sump volume also means more time in the sump for oil to lose the heat before cycling through the system again.

We have two SBC engines with different oil pans... one is a 1 quart capacity and the other is 5 quart. Which one do you think has the higher oil temperatures?

arnie, lay off the capuccinos... you seem a bit hyperactive as of late.

Fluid flow 101.

Anytime you add more passage length to a flow system you will have more pressure loss. Been a while since I've had to run any calculations but I believe the official term is "head loss". You have to recoup the loss in some way or just accept it.
If an accusump discharges, we'd like to have more pump capacity to keep up with the system during recharge.

JMO of course.

Now I'm going fly fishing arnie... if you want to throw more questions at me they'll just have to wait a week. I'll deal with you then.

I'm now officially in tarpon hunt mode and care nothing for oil pans or engines.

-Mindgame

 

Now why do I not find that comparo appropriate?
Yes, a pressure loss is common/expected. You're stating you can overcome a pressure loss (actually pressure differential) with volume? It is a pressure issue, not a leak issue that would require a volume recoup/makeup. Either I accept the pressure differential (as you noted), or I'd increase the pressure at it's origin.That accusump is not a constant drain on the oil supply. IOW, someone did not forget to put the plug in. Once it is filled, it is a non issue. If you are draining it constantly, I'd look for the real problem."AFAIC" is not required arnie... it's implied that since you're the one writing it... well, you know.
Watch out for that fly coming up from the rear.

Maybe we can agree on THIS much..... There IS a limit to the number you can take home. Don't get the shoes/boots full (of water).

 

I wonder what bait you use to catch flies?

As far as oil pans go, it seems to me that the level in the pan will be lower with a HV pump and that the level will be lower the higher you rev the motor, especially if it is for a prolonged period. This increases the chance of uncovering the pickup, as does accelerating/braking/cornering - which of these being the worst depending on the precise design of the pan/pickup. Combine these things with an oil level that is marginal to start with and the possibility of disaster is even greater.

Mindgame: the two specific LT1 examples I know of were track related in cars with automatic transmissions+race converters, where the revs are high for the whole pass. Your elequence and experience non-withstanding I still say it is stupid to run a HV pump with a stock pan. If you "need" an HV pump, you "need" an aftermarket pan with better oil control and perhaps with more capacity.

Hope you catch a lot of flies on your trip.

Rich

 

Rich, as someone noted earlier, I agree, a 'vortex' generated/caused from an improperly positioned pickup can be an issue. This coupled with the higher suction of a HV pump, could easily result in the pickup sucking air even though there is an adequate oil level in the pan

Examples you related Rich, was evidenced by a drop in pressure, I take it. A drop in pressure could easily be caused by the above. Some FFT.

 

This is a hell of a talk....

How about a couple of other thoughts about this, I got a little oil pump study crazy after Mindgame mentioned that he always puts anti-chatter grooves in his oil pumps and a lot of looking into what is really needed in a oil system for a high performance street/strip motor and what you really need.

One of the problems that we really don't have to deal with in our SBC based design LT1 is the connection of iginition timing and the oil pumps effect on that. Thank god, because that rear mounted distributor I still feel is a big mistake in the SBC. This was the main reason that the big block pump with more teeth on it's oil pump gears was preffered over the small block design... also the same reason for the anti-chatter grooves, and probably the same reason for the HV pump to be made.

So on to the HV pump deal, and what about pressure? IMHO you don't need a HV pump on anything making under 650hp unless you have some big clearances in the bearings. That I think is the first rule to look at. In a blown, or turbo application you can use a HV pump and it's not going to hurt, but I don't see the point in a NA application (mostly due to the differences in power and clearances). The other thing is oil pressure. Everyone wants to worry about having a bunch of pressure at high RPM, thing is you don't need it. 55psi is more than enough pressure in a SBC to hold up about all the power you can throw at it. I don't really see the need for a 80psi pressure relief spring. A stock pump, blueprinted with a stock relief spring is actually a perfectly AWESOME pump for a motor, be it a stock motor or a super-stroker. The problem with the stock oil setup in the LT1/SBC is the oil pressure at LOW RPM not HIGH. If I can get 40psi at 800rpm in a motor (like a LS1) and then hold it to about 55-60psi at high RPM with a standard pressure relief spring that's about the optimum for me in a motor. The lack of oil at idle and low cruising RPM to me is the big deal not the 10 lbs per 1000rpm thing, making sure the oils path thru the pump, main cap and back to the pan is as easy as possible is the key to making the oil system work well for you along with the proper clearances.

As for the HV pump in a stock pan... only question I have is what was the windage tray setup like in the pan? A windage tray or lack there of can cause more problems than you know what to do with, doing things like adding oil, or adding a higher volume pump makes the situation worse. Again I still don't think you need a HV pump unless your oil passage size and bearing clearances warrant it, and if they do then if you are running a stock pan you are doing the wrong thing in the total package.

One other thing to add, at the Engine Masters contest being a spectator has it's advantages of seeing things that they don't tell you about. It was normal to see the oil pressures on those motors at 40-60psi with the good ones getting to 50psi and maybe seeing 52psi max and this was with the oil temps hot for the contest, not as hot as I would like to see them compared to being in the car thats being BEAT on but hot 190°ish.

BTW I just put a blueprinted STOCK GM oil pump in a pretty high tech, well done motor because it was the best choice for the job. There is about 5 hours of work in the pump to get it where I wanted it, but if the motor goes to 40psi at low RPM and stays there climbing to about 50psi max I will be happy as a clam.

Bret

 

Maybe we already beat this one to death, but another thought occurred to me. AFAIK, GM never installed a "HV" pump in any production or crate small block. Now, I understand something of how decisions get made in a big corporation like GM. If they did everything "right" for us performance nuts, I guess there wouldn't be much of an aftermarket and the 4th gen wouldn't have the 10-bolt rear, among many other compromises. Nonetheless, their choice of something as basic as an oil pump probably tells you something.

Rich

 

That 'stretch', I don't agree with.IF you are referring the the 'white' spring from GM, I have yet to see it described as anything over a 70# spring. From my experience do not even consider it at an honest 70# either. As such, I subscibe to it's use. I agree, I'm happy with 60# pressure, in regards to a requirement.