Please school me on dry sump systems

[lorax]

Kevin,

It was explained to me that the linear line before 2000 engine rpm is the volume displacement of the pump, above 2000 rpm in that graph the bypass seems to kick in (graph going flatter). If you take the gpm at say 600 engine rpm and you multiply by 10 for 6000 rpm, it would be a fair assesment, since the teeth displace the same volume but they turn faster (all other variables ignoring). However, even with 22 gpm the pump output should be sufficient against the backpressure in the system to reach the bypass setting. I cannot believe the engine would warrant 22 gpm not even on high rpm.

We're getting a bit off topic, but there is a possibility that this would not provide the solution. If that's the case I think the only viable option would be dry sump. Right ?

You still seem to be trying to tie pump speed and volume to pressure that activates the relief.

I don't know if the cooler is still in line, but consider this, If the cooler and all its lines and fittings, plus the pressure drop across the filter have a fixed volume they can pass at a given pressure, say 75 psi. and your engine requirements EXCEED that volume, the pressure relief in the pump side can activate even though the oil pressure in the block is dropping like a rock. The pump is pushing as hard as the relief will allow, but the engines volume requirement climb with RPM, and the cooler line and everything else are acting as a volume restriction between the two.

If the cooler is suitable for a go cart, the pump can only do so much to push oil thru it because it has a pressure regulator.

[Kevin Johnson]

Kevin,

It was explained to me that the linear line before 2000 engine rpm is the volume displacement of the pump,

The chart is labeled, "MTC 10555 Orifice Fixed at 2000RPM to 70PSI".

Yes, I calculated the slope of the initial line to be ~.00675 gpm per rpm. That yields 20.25 gpm at 3000 pump rpm (6000 engine rpm). I also made a comparison estimate to cross check this by extending the chart physically and that produced a 3000 rpm intercept of about 21.5 gpm.

[Kevin Johnson]

Kevin,

It was explained to me that the linear line before 2000 engine rpm is the volume displacement of the pump, above 2000 rpm in that graph the bypass seems to kick in (graph going flatter). If you take the gpm at say 600 engine rpm and you multiply by 10 for 6000 rpm, it would be a fair assesment, since the teeth displace the same volume but they turn faster (all other variables ignoring). However, even with 22 gpm the pump output should be sufficient against the backpressure in the system to reach the bypass setting. I cannot believe the engine would warrant 22 gpm not even on high rpm.

We're getting a bit off topic, but there is a possibility that this would not provide the solution. If that's the case I think the only viable option would be dry sump. Right ?

You still seem to be trying to tie pump speed and volume to pressure that activates the relief.

I don't know if the cooler is still in line, but consider this, If the cooler and all its lines and fittings, plus the pressure drop across the filter have a fixed volume they can pass at a given pressure, say 75 psi. and your engine requirements EXCEED that volume, the pressure relief in the pump side can activate even though the oil pressure in the block is dropping like a rock. The pump is pushing as hard as the relief will allow, but the engines volume requirement climb with RPM, and the cooler line and everything else are acting as a volume restriction between the two.

If the cooler is suitable for a go cart, the pump can only do so much to push oil thru it because it has a pressure regulator.

Yes, remember that your pressure gauge is located at the block after this portion of the circuit. You proposed earlier to add a second pressure gauge earlier in the circuit. That was a good idea. Cosworth used a variation of this to make an aeration level check (SAE paper).

[Kevin Johnson]

It appears the confusion in the pump chart is partially the fault of Melling for not distinguishing pump rpm and engine rpm more explicitly.

[Kevin Johnson]

We're getting a bit off topic, but there is a possibility that this would not provide the solution. If that's the case I think the only viable option would be dry sump. Right ?

What about attaching the small piece of screening that I sent to you to the underside of the windage tray ...

?

I know that would involve dropping the pan. If you try the pump mod at the same time and do not achieve success you will not know if one source of aeration was replaced by another. Being methodical in your experimentation is time consuming, yes.

[Belgian1979]

Kevin,

When I take off the pan I will certainly install the screen. No issue on that. But I would like to rule out certain things first.

As for the gpm the pump puts out : I stand correct. Drawing the lines further seems to imply the gpm the pump puts out is somewhere around 22-24 gpm at 6000 engine rpm. The question remains how many gpm the engine needs at that rpm. If that would be near 22 gpm I agree the pump cannot supply enough and the bypass is not in play (maybe inlet cavitation). So far, what i've found on the subject seems to suggest a Chevy in standard form, uses between 8-10 gpm at 8000 rpm ( Smokey Yunnick). Let's assume it needs 50% more because of the valve spring oilers, pressurized lifter bearings and loss in the accessoires which means 15 gpm. It would still have more flow available (7-9 gpm) than needed.

My reasoning with the bypass was among other aspects based on what was written here about the bypass :

http://nutterracingengines.com/racing_o ... pumps.html

What still has me wondering was that the lower viscosity oil improved the pressure drop. I would think that if pump maximum output would have been reached (22 gpm) with a thinner oil that can be expelled from the bearings and lifters faster.( higher rate of leakage) the pressure drop would have still been there but a lower rpm
Then again other people pointed out that oil temps may have been significantly lower in the bearings due to the lower viscosity.

http://www.bobistheoilguy.com/forums/ub ... ost3093226

It would seem that it is difficult to isolate one thing from another. This is one of the reasons that using an external bypass might put the bypass out of the equasion interely. Can we agree on that ?

I apologize to everyone giving advice about dry sumps that this thread seems to go in different directions, but I found out that this seems to happen all the time when discussing this type of thing.

PS : this was also discussed with Canton, who do sell oil pumps as well and even they finally said not to be able to provide a clear answer. I think even they were not aware of the pump graph.

[Belgian1979]

Kevin,

It was explained to me that the linear line before 2000 engine rpm is the volume displacement of the pump, above 2000 rpm in that graph the bypass seems to kick in (graph going flatter). If you take the gpm at say 600 engine rpm and you multiply by 10 for 6000 rpm, it would be a fair assesment, since the teeth displace the same volume but they turn faster (all other variables ignoring). However, even with 22 gpm the pump output should be sufficient against the backpressure in the system to reach the bypass setting. I cannot believe the engine would warrant 22 gpm not even on high rpm.

We're getting a bit off topic, but there is a possibility that this would not provide the solution. If that's the case I think the only viable option would be dry sump. Right ?

You still seem to be trying to tie pump speed and volume to pressure that activates the relief.

I don't know if the cooler is still in line, but consider this, If the cooler and all its lines and fittings, plus the pressure drop across the filter have a fixed volume they can pass at a given pressure, say 75 psi. and your engine requirements EXCEED that volume, the pressure relief in the pump side can activate even though the oil pressure in the block is dropping like a rock. The pump is pushing as hard as the relief will allow, but the engines volume requirement climb with RPM, and the cooler line and everything else are acting as a volume restriction between the two.

If the cooler is suitable for a go cart, the pump can only do so much to push oil thru it because it has a pressure regulator.

I could actually rule out the oil lines and everything that sits in between fairly quickly. The remote oil filter is on the side of the block. If I order a couple of male -10 plugs plug the lines to the cooler and the return and connect the block exit directly to the filter inlet I'm there.
I would even be a no brainer since the line I need to fab for the external bypass can be used for that as well.

[Kevin Johnson]

What still has me wondering was that the lower viscosity oil improved the pressure drop.

You held the filter as a constant when you changed the oil being tested. There was an explanation of this in another thread.

[Belgian1979]

Yes, the filter was not changed during the change to a lower wt. Comments about the filter were regarding the higher idle oil pressure I was seeing as well.

[Kevin Johnson]

My reasoning with the bypass was among other aspects based on what was written here about the bypass :

http://nutterracingengines.com/racing_o ... pumps.html

Be sure to be very clear in your mind what you mean by "bypass". And where you propose to put it... And whether you propose to remove or alter the existing bypass somehow...

After reading the link, I am suspecting this is a bit jumbled.

[Belgian1979]

My reasoning with the bypass was among other aspects based on what was written here about the bypass :

http://nutterracingengines.com/racing_o ... pumps.html

Be sure to be very clear in your mind what you mean by "bypass". And where you propose to put it... And whether you propose to remove or alter the existing bypass somehow...

After reading the link, I am suspecting this is a bit jumbled.

jumbled as in not correct ?

Bypass : I have only the bypass integrated in the oil pump, which opens when pressure reaches at certain point and opens a passage towards the inlet of het pump. The spring acting on the plunger is a pink 75 psi spring.

The external bypass is here :

http://www.petersonfluidsys.com/pump_acc.html

What I'm thinking of doing is installing a bypass on the exit of the oil from the block with a setting of 70 psi. Oil pressure in the system would then stop at 70 psi (point before the internal bypass opens) and return excess oil (pressure) to the sump. The internal bypass setting of 75 psi would not be reached and the internal bypass would not start working.

[Kevin Johnson]

Yes, the filter was not changed during the change to a lower wt. Comments about the filter were regarding the higher idle oil pressure I was seeing as well.

In general a hot 10W30 oil has a higher air release rate than 10W40 because of the decreased viscosity. This would have to be balanced against possible deeper-injection/greater-splashing.

That could lower the amount of air that gets sucked up by the pump so the net drop is lower (even if the overall pressure is lower as well).

[Belgian1979]

Yes, the filter was not changed during the change to a lower wt. Comments about the filter were regarding the higher idle oil pressure I was seeing as well.

In general a hot 10W30 oil has a higher air release rate than 10W40 because of the decreased viscosity. This would have to be balanced against possible deeper-injection/greater-splashing.

That could lower the amount of air that gets sucked up by the pump so the net drop is lower (even if the overall pressure is lower as well).

There is something else to consider I believe : a thicker oil doesn't flow out of the bearing as easy, thereby getting hotter because it stays in the bearings longer and total oil temps are higher with thicker oil. Thinner oils flow out more easily and do not absorb as much heat which would keep viscosity more stable...A thicker oil has more resistance to shear, which would cause also more heat being introduced in the oil

Overall : a thinner oil would stay at the right temp more easily and therefor keep it's intended viscosity more easily
.
I did notice the 5W30 being a whole lot less hot.

[Kevin Johnson]

My reasoning with the bypass was among other aspects based on what was written here about the bypass :

http://nutterracingengines.com/racing_o ... pumps.html

Be sure to be very clear in your mind what you mean by "bypass". And where you propose to put it... And whether you propose to remove or alter the existing bypass somehow...

After reading the link, I am suspecting this is a bit jumbled.

jumbled as in not correct ?

Bypass : I have only the bypass integrated in the oil pump, which opens when pressure reaches at certain point and opens a passage towards the inlet of het pump. The spring acting on the plunger is a pink 75 psi spring.

The external bypass is here :

http://www.petersonfluidsys.com/pump_acc.html

What I'm thinking of doing is installing a bypass on the exit of the oil from the block with a setting of 70 psi. Oil pressure in the system would then stop at 70 psi (point before the internal bypass opens) and return excess oil (pressure) to the sump. The internal bypass setting of 75 psi would not be reached and the internal bypass would not start working.

You need to install the second oil pressure gauge to confirm your assumption that the internal 75psi bypass is never in operation with the first oil gauge showing 70psi. A danger is that flow through the secondary bypass itself (without bypass activation) can cause a pressure drop and this would allow dissolved air to evolve following it in the circuit = bad.

[Belgian1979]

That's something I can agree upon. I can try it out before I put on the external bypass.

What are the ways to reduce the introduction of air in the mentioned relief ?