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Oil Drainback/Windage Issues

General engine tech -- Drag Racing to Circle Track

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BILL-C
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Re: Oil Drainback/Windage Issues

Post by BILL-C »

A nasty Procharged engine with appropriate ring endgap is likely to have some significant blowby even when done properly. It is very difficult for oil to drain back down through the same holes that blowby gasses are coming up through at the same time. I've fixed similar problems by opening vent holes to timing cover area in front bulkhead of block and installing a -16 vent hose from mechanical fuel pump boss to valve cover. Running the oil pump with a drill with the valve covers off will give you a good idea if head drains are getting overwhelmed.
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Re: Oil Drainback/Windage Issues

Post by RDY4WAR »

matt69nova wrote: Fri Aug 27, 2021 1:04 pmThe mains are 0.0030-0.0031 and the rods are 0.0026-0.0027 (steel rods). The recommendation for 20W50 oil came from Brad Penn.
I don't agree with their recommendation. Those bearing clearances and your power level dictate a 40 grade at most, a 30 grade if oil temps are kept <180*F. The boost doesn't dictate a higher viscosity oil unless you're really pouring it to it. Boost works well with an oil with great thermal and shear stability. If it was my engine, I'd be running a PAO-based 5W-40 with a good bit of ester for thermal and shear stability, solvency, and friction reduction. High Performance Lubricants Bad Ass Racing 5W-40 and Redline HP series 5W-40 would be good oils for this. Penngrade (haven't been Brad Penn since 2014) syn-blend oils are decent oils for classic street cars with flat tappet cams and some mild nitrous applications. I have ethical issues with Penngrade as a business, but their oils aren't bad in certain applications.
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Re: Oil Drainback/Windage Issues

Post by Kevin Johnson »

How do you have your accumulator set up? (Pressure switch etc. You can use a remote pressurized reservoir to allow a high gas pressure to drive the piston throughout its stroke.)

Does the car remain level throughout the run?

How many Gs are you pulling during the run?

Did you test your pan by filling it with water and tilting it to simulate actual and apparent G forces?
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Re: Oil Drainback/Windage Issues

Post by matt69nova »

Kevin Johnson wrote: Mon Aug 30, 2021 10:40 pm How do you have your accumulator set up? (Pressure switch etc. You can use a remote pressurized reservoir to allow a high gas pressure to drive the piston throughout its stroke.)

Does the car remain level throughout the run?

How many Gs are you pulling during the run?

Did you test your pan by filling it with water and tilting it to simulate actual and apparent G forces?
The accumulator is set up on a 35-40psi pressure switch. One thought was that if the oil pressure at idle after the burnout is less than the threshold pressure and the accumulator is empty when I stage, it probably doesn't have enough time to fill for the brief second I bring the RPM up before I leave, and throughout the run, some portion of the oil pump output is being used to refill the accumulator, thus lowering pressure. Next trip to the track, I will shut and leave off the accumulator to eliminate this possibility. I shut the car off at the stripe anyway, so as mentioned before, the accumulator may not be of any benefit anyways.

For now, the car does remain fairly level throughout the run. I've got wheelie bars on it set relatively low. I would have to go back and look at the Racepak to find the Accel G's. Unfortunately I did not test the pan with water, but maybe that's something I could do over the winter.

For this last outing of the year, I'll try:

1.) Shut off accumulator, remove excess oil
2.) Use thinner viscosity oil
3.) Lower oil level in pan
4.) Change from 160 deg. to 180 deg. thermostat

Over the winter:

5.) Add Ishihara crankshaft scraper
6.) Add rear sump baffle
7.) Re-Verify pump-to-pan clearance
8.) Add oil pre-heater
9.) Look at adding cylinder head drainback lines
10.) Investigate switching oil pans

Does anyone have experience with the Moroso 21017 pan? I wanted to use the 21234 pan, but it only works with 168T flywheels, and mine is 153T. Switching flywheels isn't an option. I looked at the Canton pan 13-104 as well as the Milodon 31167. Any feedback on these either?
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Re: Oil Drainback/Windage Issues

Post by PRH »

I’ve had good results from that Canton pan with a 3.75” stroke.
Somewhat handy with a die grinder.
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Re: Oil Drainback/Windage Issues

Post by ClassAct »

matt69nova wrote: Tue Aug 31, 2021 10:36 am
Kevin Johnson wrote: Mon Aug 30, 2021 10:40 pm How do you have your accumulator set up? (Pressure switch etc. You can use a remote pressurized reservoir to allow a high gas pressure to drive the piston throughout its stroke.)

Does the car remain level throughout the run?

How many Gs are you pulling during the run?

Did you test your pan by filling it with water and tilting it to simulate actual and apparent G forces?
The accumulator is set up on a 35-40psi pressure switch. One thought was that if the oil pressure at idle after the burnout is less than the threshold pressure and the accumulator is empty when I stage, it probably doesn't have enough time to fill for the brief second I bring the RPM up before I leave, and throughout the run, some portion of the oil pump output is being used to refill the accumulator, thus lowering pressure. Next trip to the track, I will shut and leave off the accumulator to eliminate this possibility. I shut the car off at the stripe anyway, so as mentioned before, the accumulator may not be of any benefit anyways.

For now, the car does remain fairly level throughout the run. I've got wheelie bars on it set relatively low. I would have to go back and look at the Racepak to find the Accel G's. Unfortunately I did not test the pan with water, but maybe that's something I could do over the winter.

For this last outing of the year, I'll try:

1.) Shut off accumulator, remove excess oil
2.) Use thinner viscosity oil
3.) Lower oil level in pan
4.) Change from 160 deg. to 180 deg. thermostat

Over the winter:

5.) Add Ishihara crankshaft scraper
6.) Add rear sump baffle
7.) Re-Verify pump-to-pan clearance
8.) Add oil pre-heater
9.) Look at adding cylinder head drainback lines
10.) Investigate switching oil pans

Does anyone have experience with the Moroso 21017 pan? I wanted to use the 21234 pan, but it only works with 168T flywheels, and mine is 153T. Switching flywheels isn't an option. I looked at the Canton pan 13-104 as well as the Milodon 31167. Any feedback on these either?


Why would you go to a 180 thermostat? That is going backwards IMO.
matt69nova
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Re: Oil Drainback/Windage Issues

Post by matt69nova »

[/quote]
Why would you go to a 180 thermostat? That is going backwards IMO.
[/quote]

Thinking, at least in the short term, it would allow the oil to get a little warmer and allow easier drainback. Maybe not needed though with a thinner weight oil?
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Re: Oil Drainback/Windage Issues

Post by ClassAct »

matt69nova wrote: Tue Aug 31, 2021 9:04 pm
Why would you go to a 180 thermostat? That is going backwards IMO.
[/quote]

Thinking, at least in the short term, it would allow the oil to get a little warmer and allow easier drainback. Maybe not needed though with a thinner weight oil?
[/quote]

I’d rather keep the coolant temperature at 160 degrees and run thinner oil rather than have a higher coolant temperature and run thicker oil. There isn’t much good about A thick oil.
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Re: Oil Drainback/Windage Issues

Post by smeg »

I had this exact same problem many years ago although I was reving it higher than you 9000 rpm. I did fix it after lots of head scratching. Do you have a HV oil pump on this engine?
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Re: Oil Drainback/Windage Issues

Post by matt69nova »

smeg wrote: Wed Sep 01, 2021 7:49 pm I had this exact same problem many years ago although I was reving it higher than you 9000 rpm. I did fix it after lots of head scratching. Do you have a HV oil pump on this engine?
Yes, the pump is a Moroso billet unit, P/N 22171.
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Re: Oil Drainback/Windage Issues

Post by smeg »

matt69nova wrote: Thu Sep 02, 2021 12:02 am
smeg wrote: Wed Sep 01, 2021 7:49 pm I had this exact same problem many years ago although I was reving it higher than you 9000 rpm. I did fix it after lots of head scratching. Do you have a HV oil pump on this engine?
Yes, the pump is a Moroso billet unit, P/N 22171.
Do yourself a favour and fit a good quality std volume pump with the large pick up pipe. Investigate cavitation and the quantity of oil needed at X pressure. The HV pump is by passing the oil even at 1500 revs. I have tested this on an oil pump testing machine, the higher you rev it the oil becomes saturated with air and the pressure drops. My engine was worse than yours untill i fixed it.
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Re: Oil Drainback/Windage Issues

Post by rustbucket79 »

What was the pump screen to pan floor clearance number?

Accumulator isn’t necessary and as the pressure falls it fills up the pan, creating a windage issue.

I’ve run both the wide sump Moroso pan and the narrow sump power pan from Milodon 31167. Used both the M55 and M55HV with the Z 28 spring. Both had excellent oil pressure during the run, the difference was the Milodon pan has excellent pressure AFTER the finish line slowing down. Currently running the M55 pump I bought back in the early 90’s before Melling “improved “ the pump body and used sintered gears. I use either 10W 30 or 5W 20 oil, and warm the engine up in the morning to 180 and let it sit for qualifying. Burn out at 120, stage between 130 to 140, seldom above 150 on the return road. Bearings always look like new. 7700 shift points.

Disable the accumulator, verify the correct oil volume and test.
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Re: Oil Drainback/Windage Issues

Post by Kevin Johnson »

When you warm the engine up to 180 and let it sit before qualifying/racing, do you do this by running the engine or heating the oil and coolant?

If the latter, that could help to degas the lubricant (remove dissolved air).

If the former, that would probably stabilize the amount of dissolved air to some unknown level. Resting would allow entrained air bubbles to rise to the surface and break, Dissolved air and entrained air are two different things but entraining air will help ensure dissolved air.

Just data for analysis and further understanding of the successful technique.

https://chempedia.info/info/bunsen_s_ab ... efficient/




rustbucket79 wrote: Thu Sep 02, 2021 11:05 pm What was the pump screen to pan floor clearance number?

Accumulator isn’t necessary and as the pressure falls it fills up the pan, creating a windage issue.

I’ve run both the wide sump Moroso pan and the narrow sump power pan from Milodon 31167. Used both the M55 and M55HV with the Z 28 spring. Both had excellent oil pressure during the run, the difference was the Milodon pan has excellent pressure AFTER the finish line slowing down. Currently running the M55 pump I bought back in the early 90’s before Melling “improved “ the pump body and used sintered gears. I use either 10W 30 or 5W 20 oil, and warm the engine up in the morning to 180 and let it sit for qualifying. Burn out at 120, stage between 130 to 140, seldom above 150 on the return road. Bearings always look like new. 7700 shift points.

Disable the accumulator, verify the correct oil volume and test.
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Re: Oil Drainback/Windage Issues

Post by matt69nova »

rustbucket79 wrote: Thu Sep 02, 2021 11:05 pm What was the pump screen to pan floor clearance number?

Accumulator isn’t necessary and as the pressure falls it fills up the pan, creating a windage issue.

I’ve run both the wide sump Moroso pan and the narrow sump power pan from Milodon 31167. Used both the M55 and M55HV with the Z 28 spring. Both had excellent oil pressure during the run, the difference was the Milodon pan has excellent pressure AFTER the finish line slowing down. Currently running the M55 pump I bought back in the early 90’s before Melling “improved “ the pump body and used sintered gears. I use either 10W 30 or 5W 20 oil, and warm the engine up in the morning to 180 and let it sit for qualifying. Burn out at 120, stage between 130 to 140, seldom above 150 on the return road. Bearings always look like new. 7700 shift points.

Disable the accumulator, verify the correct oil volume and test.
I don't remember the exact pickup to pan clearance, but the Moroso instructions state 0.250" - 0.375", so I'm sure it's within that range.

I'm guessing reduced oil level, lower oil viscosity, and disabling of the accumulator will make a significant difference, and there are easy things to try without having to dig deeper into the engine before the season is over.
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Re: Oil Drainback/Windage Issues

Post by rebelyell »

smeg wrote: Thu Sep 02, 2021 7:48 pm
matt69nova wrote: Thu Sep 02, 2021 12:02 am
smeg wrote: Wed Sep 01, 2021 7:49 pm I had this exact same problem many years ago although I was reving it higher than you 9000 rpm. I did fix it after lots of head scratching. Do you have a HV oil pump on this engine?
Yes, the pump is a Moroso billet unit, P/N 22171.
Do yourself a favour and fit a good quality std volume pump with the large pick up pipe. Investigate cavitation and the quantity of oil needed at X pressure. The HV pump is by passing the oil even at 1500 revs. I have tested this on an oil pump testing machine, the higher you rev it the oil becomes saturated with air and the pressure drops. My engine was worse than yours untill i fixed it.
x2
in lieu of old-fashioned M55, beginning ~ 1993 GM-Melling redesigned it and began with M155; has a larger 3/4" pickup but M155 otherwise same as M55.
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