Help Solve the Myth!

[Jerryl]

High Volume Oil Pumps have been used for some sometime with very mixed results. Alleged results of the HVOP include anything from;
1. Smoking problems due to over-oiling the heads
2. Premature main and rod bearing erosion
3. Premature cam bearing failure
4. Premature cam gear failure
5. Etc

The idea behind the poll is to pool the results and data determine if you have some actual data pertaining to the questions in the poll. Multiple answers are allowed. If you are speculating, I would ask you not vote as this will skew the results and not solve the myth.





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[Razor]

Wont know until I tear apart the motor next time. So far no issues with mine on new build.

Next time "happens".. just hasnt happened yet

 

[TurboTnZ06]

No problems with mine.

 

[Mad_Trbo]

Opinion

Everything I have learned indicates there is no need for high volume pumps or put another way the benefit is nill.

#1 - for those looking to increase oil pressure with a high volume pump, it isn't the pump that generates or creates pressure. You can think of the oiling system as a controlled leak. Pressure is controlled through the rate of the leaks, in other words bearing clearances.

#2 - If you are looking for that last little bit of HP, high volume pumps are HP robbers. Bottom line they require more HP to turn.

#3 - They will generate excessive wear on your friction bearings, no doubt about it. Take it up with any professional engine builder worth their weight in salt and they will tell you this.

Just my .02 cents as the saying goes.

 

[Pronto]

My understanding is on race engines they leave the clearances on the wide side for extra hp so the high volume pump makes up the difference for the oil pressure. It stands to reason if you have stock clearances the need for a high volume pump is not as critical or may actually cause problems. On my 403 T/A that I had a preformance rebuild on, I had a high volume/pressure oil pump and my distributor gear got all chewed up in 2 years.

 

[Ormand]

for those looking to increase oil pressure with a high volume pump, it isn't the pump that generates or creates pressure. You can think of the oiling system as a controlled leak. Pressure is controlled through the rate of the leaks, in other words bearing clearances.

Well, sort of. The oil pumps have a spring, that provides internal relief if the pressure goes too high. This is different from the spring that bypasses the filter. An oil pump is a positive displacement pump. Every rev of the pump passes a certain amount of oil. This oil WILL go somewhere. That's why the pump needs the relief spring. If the clearances are loose, that oil will flow with low pressure. It the clearances are tight, the same amount of oil will need more pressure. The oil carries away heat as it flows, and you need a certain volume to maintain the surfaces at the right temp. If you don't have enough flow, you can "burn" a bearing. And you need enough pressure to get the oil into the crank against centrifugal force at high rpm. That's why you hear things like "10psi for every 1000 rpm". So, pressure is controlled by the balance of clearances and pump volume and oil viscosity. And you need to have "enough", whatever that is.

 

[Mad_Trbo]

Well, sort of. The oil pumps have a spring, that provides internal relief if the pressure goes too high. This is different from the spring that bypasses the filter. An oil pump is a positive displacement pump. Every rev of the pump passes a certain amount of oil. This oil WILL go somewhere. That's why the pump needs the relief spring. If the clearances are loose, that oil will flow with low pressure. It the clearances are tight, the same amount of oil will need more pressure. The oil carries away heat as it flows, and you need a certain volume to maintain the surfaces at the right temp. If you don't have enough flow, you can "burn" a bearing. And you need enough pressure to get the oil into the crank against centrifugal force at high rpm. That's why you hear things like "10psi for every 1000 rpm". So, pressure is controlled by the balance of clearances and pump volume and oil viscosity. And you need to have "enough", whatever that is.

I think we are on the same page sort of for the most part. I don't necessarily think close clearances need more pressure. Instead they create more pressure because the same amount of oil can't pass through the smaller bearing clearance. I am no physicist, I can't even spell the word. But if you had spicket spewing into an open container the water pressure wouldn't change as you opened or closed the spicket at least not on the side the water was coming, but the volume would.

Pressure would not change until you created a restriction, so on the other side of the spicket right before the water coming out would be pressure.

Another way of looking at it is to take the bearing clearances out of the picture and move from a higher volume pump to a lower volume pump or vice versa. Would oil pressure change?

 

[TurboDave]

No problem with mine. Been in there over 10 years now.

 

[VadersV6]

But if you had spicket spewing into an open container the water pressure wouldn't change as you opened or closed the spicket at least not on the side the water was coming, .

This isnt pouring water into a bucket. Its moving water through a hose. Open the knob, backpressure increases, and more water comes out of the hose. If you try to move more volume through the same size hole, the backpressure will increase.
Its also not a controlled leak like you were saying. You're making it sound like the pump is just a controlled leak or restriction. The pump is the pump. Nothing else is going to push that oil through the galleys.

 

[Ormand]

The pump is the pump

Exactly. The pump is the pump, and oil galleries, bearing clearances, and passages are the "restriction". With larger clearances, the same pump, pressure will go down, due to less restriction. So, close clearances don't "need more pressure", but instead, they CAUSE it, for a given volume of flow. But this is not answering Jerryl's question.
Why would a high volume pump cause smoking? That one is a mystery to me. Pressure would go up, from pushing more oil through all the passages. But why would that cause smoking? Maybe oil could pool up in the heads, and there would be more on the valve stems?
The higher oil flow is not likely to "erode" the bearings. Erosion by a clean fluid is not something that happens often. Not in my experience, anyway.
The one thing that is a given, is that more pump=more load on the drive gear and the timing set. So I can understand that the life of those parts might be shortened. But by how much? That would have to be a guess, and my first guess would be that wear is proportional to load. If you double the load, pump drive gear my last only half as long. But that would still be a long time, relative to other parts on these cars.
Results of the survey will be interesting.

 

[buickpower]

I think I should point out that I did have the smoking problem, but in no way blame it on the hv pump. I know pretty much for a fact that it was a piss poor valve guide job.. so yes i did have smoking but after thinking about it I don't want to give the wrong impression that I thought it was the pump's fault entirely, guess I should have picked another choice.

 

[Jerryl]

Keep em comming folks.
Some good data for future use already.
YES, you can post without voting. :tongue:

 

[Blown&Injected]

Maybe the high volume oil pump is good for those of us that have over .002" on the mains and rods?

http://www.turbobuick.com/forums/showthread.php?t=192887&referrerid=1527

I am going to try one out if my engine is still OK as it is right now.

 

[Alky V6]

There are only two normal ways for oil to get into a combustion chamber. I'm leaving out obvious problems like bad intake gaskets, turbo oil seals, etc. The valve guides and past the piston rings. Obviously, good valve guide clearance and seals will help control the oil getting past valve guides. Oil getting past the piston rings is another story. The oil rings and second ring on the piston help control oil. It is possible to over oil the cylinder walls and make oil control harder for the rings. We must remember that the main concern with a proper oiling system is to keep the crank from seizing. How much oil pressure and volume you need from the system is directly dependant on the planned load that will be put on the bearings. Top fuel for instance, 70 wt. oil at 120 psi and the engine revs to 7800. The general rule of 10 psi per 1000 rpm is good, but in some cases it's not. A well layed out oiling system will require less oil pressure than a poorly designed (passage restrictive) oiling system. The volume required will be one that is needed to maintain the target pressure. No more (wasted HP to recirculate heated oil, from pressurizing it, through the pressure regulator valve), no less (undue engine wear). So now that we have the proper pressure and volume in our oiling system, what can we do to help control over oiling the cylinder walls. A high performance engine demands a certain amount of bearing clearance for proper oiling and cooling of the bearing surfaces. The trick is to find that fine line and keep it on the tight side. Excessive bearing clearances will cause oil control problems as far as the piston rings go. Watch your crankcase pressure too. Higher crankcase pressure means oil control problems.

Keep in mind the turbo seals too. If there is no restrictor in the turbo oil feed line, you could over power the seals in the turbo and get oil into the intake or exhaust or both. I use a .060" restrictor in mine with a prefilter so that the orifice does not get plugged.

 

[Alky V6]

One way the OEMs managed to increase gas mileage numbers was to use a variable volume oil pump in some automatic transmissions. The 200-4R included. As pressure needs increase, higher loads, pump volume also increases. Under cruising situations, pump pressure is low and pump volume is minimal. This saves horsepower by not having to pump an excess volume of oil that's just going to be dumped by the pressure regulator valve anyway. This helps oil temps too. When you pressurize a fluid, you also heat it up. If your pressurizing a smaller volume of fluid, you are generating less heat and the transmission has an easier time staying cool.

 

[obrut]

I've been working on this for a very long time. My car had 92,000 miles and ran fine. Before i had the motor rebuilt i had about 5 psi of oil pressure warm. I had the motor rebuilt and installed a 210/210 roller, ported and polished the heads and intake and had the HV pump added. When i got the motor running after the rebuild i had smoke on start up and a little at idle. The oil pressure after rebuild was 50 psi cold and 30 warm at idle. I had the turbo rebuild twice changed the intake gasket twice added the pvc check valve and the catch can and none of these helped. When i did a compression test all the cylinders were about 160. I never had any oil on the plugs but always let a big puff off smoke out everytime i started it. Then at idle it would smoke a little out of exhaust. I never did a leak down test and i never tried changing back to a stock oil pump. I recently pulled the engine and right now i have the heads off and pulled the valves. When i measured the guides i got .342 and the valves are .340 so that would seem fine. But looking at the bowl with the exhaust valves removed you can see oil accumulated around the bottom of the guides and on the valves. So there is something wrong, its either the guides or the head is getting flooded. But this is were the oil is getting into my exhaust. If the machine shop measure and get the same results that i did then i'm going to have to look towards the HV oil pump. Here is the link to my current post http://www.turbobuick.com/forums/showthread.php?t=191466

 

[Red Regal T]

All I can say is I always run a HV Melling oil pump, for hundreds of thousands of miles. I've never had a problem. If you have low oil pressure with a HV pump, you know you have a problem and it ain't the oil pump. I'm not mr. Super mechanic, so I'd rather have the HV oil pump take up my margin of error. If I put it all together right, and I feel the oil pressure is too high, I can always just run thinner oil. As far as I'm concerned, you can have the stock pump. I'm not going to go through all the work of putting an engine together and have 50 psi at WOT because I didn't use a $32 HV pump. You're never going to pump all the oil out of the pan and into the heads either. MYTH!

 

[Alky V6]

Obrut, I would be looking elsewhere for your problem. I can't imagine it being the oil pump.

 

[Ormand]

The general rule of 10 psi per 1000 rpm is good, but in some cases it's not

The 10 psi per 1000 rpm is from the Buick "folklore". It actually depends on the diameter of the crank, since the centrifugal force varies with the radius. Bigger cranks may require more than 10 psi per 1000 rpm. The journal bearings are "hydrodynamic", in that the turning crank provides the pressure once the oil actually gets where it is needed- oil pump pressure is no longer involved. That's true in top fuel, and in an econobox.
One issue with higher pressure on the Buicks can be side clearance between the rods. That dimension, along with rod bearing clearance, controls flow that splashes onto the cylinder walls. Years ago, you could get new rods that were "thicker" than stock, to let you set that clearance tight, if you wanted to. Now, that dimension may be too big, and with a high volume pump, you might get more oil on the cyldinder walls than the rings can handle. Seems possible, anyway.

 

[Alky V6]

The 10 psi per 1000 rpm is from the Buick "folklore". It actually depends on the diameter of the crank, since the centrifugal force varies with the radius. Bigger cranks may require more than 10 psi per 1000 rpm. The journal bearings are "hydrodynamic", in that the turning crank provides the pressure once the oil actually gets where it is needed- oil pump pressure is no longer involved. That's true in top fuel, and in an econobox.
One issue with higher pressure on the Buicks can be side clearance between the rods. That dimension, along with rod bearing clearance, controls flow that splashes onto the cylinder walls. Years ago, you could get new rods that were "thicker" than stock, to let you set that clearance tight, if you wanted to. Now, that dimension may be too big, and with a high volume pump, you might get more oil on the cyldinder walls than the rings can handle. Seems possible, anyway.

Excellent point, Ormand. The weight oil that is used should also be considered in regards to bearing clearances. I have witnessed HP engines built with big clearances actually lose oil pressure at high rpm when the owner thought it would be a good idea to go to a lighter oil. A big block Ford with a monster single turbo in a red Lightening. I know. A truck? This particular fella came by the shop and was explaining the problem to me. He also mentioned that he was not having the problem with the heavier oil that his engine builder recommended. Oh my gosh! I about flipped my lid. I told him to get that thing home, just cruise it and get the thicker oil back in it. As Ormand brought up, the thinner oil was escaping the bearing journals quicker and the oil supply couldn't keep up with it. All because of centrifugal force. And yes, as Ormand brought up. Rod side clearance has a big part in oil control. Too large, oil control problems, Too small, and the rod journals can overheat do to the lack of circulating, cooling oil. Everything is a balancing act.