(2ZZ) dry sump?

[MikeW]

so I'm not sure why MikeW refers to the accusump as a bandaid solution. The HP boost would be a nice benefit though not to mention improved spousal relations :UO[/quote]

With the Accusump, you get oil delivered at a pressure that is based upon the the static pressure in the unit at that time. As the piston moves during it's operation, the pressure decreases. You get what it's able to give you, but not what a well designed oiling system is capable of. When your engine recovers from whatever caused the Accusump to to activate, you now have another situation. You may have an extra quart or more in your engine sump. That in itself may not be desirable. In addition, you oil pump will be trying to pump oil through the engine and back into the Accusump at the same time. That takes time. Your engine may have less than desirable oiling while the pump is possibly trying to supply more oil than it effectively can. While an Accusump is better than a pan with no oil in the bottom, it's not perfect. Some race clasees will not allow a dry dump. In that case, a well designed pan and Accusump might get you by. Certainly the 2zz pan is not designed for any cornering. There are no baffles at all.

[Boosted2.0]

Originally Posted by choi0706

http://www.komo-tec.com/index.php/cPath/109_110

Thats not for a 2ZZ Jay - maybe for a rover motor?

[mikelr]

Originally Posted by Boosted2.0

Thats not for a 2ZZ Jay - maybe for a rover motor?

Sure looks like one

[codymac]

Originally Posted by mikelr

Sure looks like one

Hey, wait... grrrrrr.

[choi0706]

whoops, Komotec says its for the 111R..

[mikelr]

Originally Posted by choi0706

whoops, Komotec says its for the 111R..

They still use the K-series Rover in the UK in some of the S2 models.

[Patricko]

Originally Posted by mikelr

They still use the K-series Rover in the UK in some of the S2 models.

All Lotus Elise 111R use the 2ZZ world wide...

[TimMullen]

Originally Posted by MikeW

With the Accusump, you get oil delivered at a pressure that is based upon the the static pressure in the unit at that time. As the piston moves during it's operation, the pressure decreases. You get what it's able to give you, but not what a well designed oiling system is capable of. When your engine recovers from whatever caused the Accusump to to activate, you now have another situation. You may have an extra quart or more in your engine sump. That in itself may not be desirable. In addition, you oil pump will be trying to pump oil through the engine and back into the Accusump at the same time. That takes time. Your engine may have less than desirable oiling while the pump is possibly trying to supply more oil than it effectively can.

I think you are taking an extreme look at the operating conditions - looking at the limit of the capability range.

In reality, when the Accusump "discharges", it's not a big "whoosh" and all the oil is suddenly used up. The oil system itself is rather restrictive, that's what gives you oil pressure in the first place - the pump trying to force oil through the various passages. When the pump "runs dry" the oil is simply sourced from the Accusump - they can provide pressure for several seconds depending on the size. Although an Accusump can be configured so that it doesn't open until the pressure drops below a pre-set point, usually they are "open" - they are always part of the oil system, with oil capacity (and pressure) fluctuating with the regular oil pressure of the engine. Basically they act as a large buffer.

When the Accusump has supplied oil to the engine when the pump runs "dry" the oil is not getting down to the engine's pan, while you are cornering (the reason the pump went dry). As the Accusump supplies the oil, yes, the total internal volume of oil in the engine has gone up, but only by the amount the Accusump has discharged. That oil now has to travel back into the pan, along with the existing oil in the engine. That will, again, take some time - it doesn't all just go "whoosh" and suddenly get to the pan. Once the pump is "wet" it can start pumping oil again, and supply the oil flow and indirectly, the pressure. As the oil is pumped, pressure builds - some of the oil flow is into the engine's oil passages, and some into the Accusump - but the pressure is balanced. The Accusump is not suddenly filled back up with oil, it "bleeds in" with the raise in the oil pressure - that same oil pressure that the engine internals sees. The biggest difference in the oil system operation will be that the oil pump pressure bypass will not have to open as soon during high RPM operation as the pump will be filling a larger volume (the engine and the Accusump), but still at the normal operating pressure.


As an example, your engine is pumping 50 PSI of oil pressure. The Accusump also holds 50 PSI of pressure (and a volume of oil). Now you hit a corner - the pump is making 50 PSI and no flow is coming in or out of the Accusump. As the corner continues the pump goes "dry" and the oil pressure starts to drop. At this point, the oil is supplied from the Accusump at the "current" 50 PSI. As the oil slowly flows out of the Accusump, it provides 49, 48, 47... 20 PSI. The oil will flow from the Accusump until the pressure in the Accusump reaches the same level as the engine. Hopefully before it gets too low, you are done with the corner, and the pump is "wet". It's now picking up oil from the sump and the oil pressure is raising - it gets to 25, 30, 35... 50 PSI. While the pressure was raising, the oil was flowing throughout the engine and also back into the Accusump. Also while that oil pressure was raising, the oil was flowing back into the sump, so by the time the pressure is back up to normal, the volume in the sump, and the volume in the Accusump are back to normal too. It will be highly unlikely that there will ever be too much volume of oil in the sump (if there was, the pump would have been able to pump it out quicker and build up pressure faster, which in turn would have filled the Accusump faster).

It's not like all the oil is diverted to the Accusump once the pump starts pumping again - the oil goes to the engine and the Accusump in balance.

Although pretty much everyone will agree that a dry sump is probably a better deal, an Accusump is far from a band-aide. They are a proven design and have been used in racing from many years. An Accusump also provides one thing that a dry sump cannot - pre-oiling. An Accusump can "dump" oil just prior to starting the car, such that you always start the car with oil pressure already in the engine (and turbo if equipped).

Although I don't expect to need either a pan or an Accusump, I believe I'd opt for the Accusump first.

Finally, you can always add a pressure warning buzzer to the Accusump that "tells" you when it's being used - something that you can't do with a pan. In the case of the Accusump, if you are dropping pressure/"running on reserve" the buzzer can let you know. With a pan, when you run out of reserve, it's too late...

[codymac]

Originally Posted by TimMullen

Although I don't expect to need either a pan or an Accusump, I believe I'd opt for the Accusump first.

Ahhh... but some of us do. Looking into my crystal ball, I see tires without tread.

[Viva]

I got this kit from Pace Products early this year.
Kit includes oil tank and all the hardware except the oil lines.
Fitting the engine into the chassis will be this winter's project.

[MikeW]

Originally Posted by TimMullen

I think you are taking an extreme look at the operating conditions - looking at the limit of the capability range.

In reality, when the Accusump "discharges", it's not a big "whoosh" and all the oil is suddenly used up. The oil system itself is rather restrictive, that's what gives you oil pressure in the first place - the pump trying to force oil through the various passages. When the pump "runs dry" the oil is simply sourced from the Accusump - they can provide pressure for several seconds depending on the size. Although an Accusump can be configured so that it doesn't open until the pressure drops below a pre-set point, usually they are "open" - they are always part of the oil system, with oil capacity (and pressure) fluctuating with the regular oil pressure of the engine. Basically they act as a large buffer.

When the Accusump has supplied oil to the engine when the pump runs "dry" the oil is not getting down to the engine's pan, while you are cornering (the reason the pump went dry). As the Accusump supplies the oil, yes, the total internal volume of oil in the engine has gone up, but only by the amount the Accusump has discharged. That oil now has to travel back into the pan, along with the existing oil in the engine. That will, again, take some time - it doesn't all just go "whoosh" and suddenly get to the pan. Once the pump is "wet" it can start pumping oil again, and supply the oil flow and indirectly, the pressure. As the oil is pumped, pressure builds - some of the oil flow is into the engine's oil passages, and some into the Accusump - but the pressure is balanced. The Accusump is not suddenly filled back up with oil, it "bleeds in" with the raise in the oil pressure - that same oil pressure that the engine internals sees. The biggest difference in the oil system operation will be that the oil pump pressure bypass will not have to open as soon during high RPM operation as the pump will be filling a larger volume (the engine and the Accusump), but still at the normal operating pressure.


As an example, your engine is pumping 50 PSI of oil pressure. The Accusump also holds 50 PSI of pressure (and a volume of oil). Now you hit a corner - the pump is making 50 PSI and no flow is coming in or out of the Accusump. As the corner continues the pump goes "dry" and the oil pressure starts to drop. At this point, the oil is supplied from the Accusump at the "current" 50 PSI. As the oil slowly flows out of the Accusump, it provides 49, 48, 47... 20 PSI. The oil will flow from the Accusump until the pressure in the Accusump reaches the same level as the engine. Hopefully before it gets too low, you are done with the corner, and the pump is "wet". It's now picking up oil from the sump and the oil pressure is raising - it gets to 25, 30, 35... 50 PSI. While the pressure was raising, the oil was flowing throughout the engine and also back into the Accusump. Also while that oil pressure was raising, the oil was flowing back into the sump, so by the time the pressure is back up to normal, the volume in the sump, and the volume in the Accusump are back to normal too. It will be highly unlikely that there will ever be too much volume of oil in the sump (if there was, the pump would have been able to pump it out quicker and build up pressure faster, which in turn would have filled the Accusump faster).

It's not like all the oil is diverted to the Accusump once the pump starts pumping again - the oil goes to the engine and the Accusump in balance.

Although pretty much everyone will agree that a dry sump is probably a better deal, an Accusump is far from a band-aide. They are a proven design and have been used in racing from many years. An Accusump also provides one thing that a dry sump cannot - pre-oiling. An Accusump can "dump" oil just prior to starting the car, such that you always start the car with oil pressure already in the engine (and turbo if equipped).

Although I don't expect to need either a pan or an Accusump, I believe I'd opt for the Accusump first.

Finally, you can always add a pressure warning buzzer to the Accusump that "tells" you when it's being used - something that you can't do with a pan. In the case of the Accusump, if you are dropping pressure/"running on reserve" the buzzer can let you know. With a pan, when you run out of reserve, it's too late...

I'll give you an example of what I was referring to. Take an engine that has a bad sump design and subject it to a continous high G force for a extended period of time. The oil may slosh out of the bottom of the pan and climb the walls of the pan and even the walls of the crankcase. Braking while nose diving a car and rev matching and/or letting it wind at high rpms for several seconds can do it. I've had it happen myself. This was with a Corvette road race pan. In the case of an Accusump, it would discharge a quart or whatever needed and when the attitude of the car returns to normal and the G force decreases, the pan will indeed have extra oil in it. That's assuming there is no reason for an extra amount of oil to be trapped temporarily in the top end of the motor. It was down in the lower end of the motor all along, just wasn't covering the pickup. For a short time, that extra quart or 2 will be there to deal with. Bad news? Depend on the specific engine and the specific pan. I've seen test where people added 1 quart and 2 quarts to Z28 oil pans and had issues with oil temp increase, power loss and frothing. This was on a dyno, not on a road coarse. After decade of everyone accepting it was ok to do this, someone finally ded the proper research. I'm say that having extra oil in a badly designed pan without proper baffling is an invitation to have it find its way on the crank throws and be slung on the cylinder walls. I realize the 2zz has a tray, although it's a partial one.

You are correct that during oil pressure loss the engine will be supplied oil from the Accusump starting out at the pressure that the Accusump was maintaining. And as you said and I believe I stated, there will be less pressure as it empties itself. Some engines oil themselves with the upper end as a priority. the mains and rods get fed last. A Ford Cleveland is one. Feeding any engine less than the desired oil pressure for a given load is detrimental to bearings. But even those with "priority main" feeding, you have to maintain a proper film of oil to avoid metal to metal contact as well as overheating the bearing. So while you are feeding an engine solely from Accusump, you had better hope the regular oiling system recovers soon.

As far as refilling the Accusump when the oil pickup gets covered with oil and the pump operates on its own, the pump does have to fill the Accusump and lube the engine at the same time. Again, the bearings and other vitals aren't likely to see the oil pressure the engine was designed to see until the Accusump starts getting pretty full. Yes, I understand about the pump's bypass valve being shut. That doesn't necessarily mean that the pump will automatically have enough volume to simultaneously fill the Accusmp and maintain the proper oil pressure for the engine. While there are larger pumps for various engines that can do this, (I have plenty) most oem pumps handle their normal chores well enough, but don't have capacity for dual duty.

I won't say that I would never have an Accusump. They can and do save engines with bad oil pan designs. The're better than nothing. I would never put one on without fixing the problem that could cause you to have to rely on one in the first place, that being the pan. If I'm not mistaken, Canton was in the business of making pans before they made the Accusump. Our use of the term "bandaid' may differ. However, I certainly would not call an Accusump a "cure" either.

[codymac]

Originally Posted by Viva

I got this kit from Pace Products early this year.
Kit includes oil tank and all the hardware except the oil lines.
Fitting the engine into the chassis will be this winter's project.

Suddenly I vaguely recall seeing this photo.
Care to share any more details?

[Viva]

Here is another photograph.

[sleepe]

anyone familiar with these?
What is a crank scraper

[luxige]

Originally Posted by sleepe

anyone familiar with these?
What is a crank scraper

There is a brief discussion of the I-J scraper/windage tray for 2zz here:
Oil Control

[dmh]

I have one for sale...
Crank scraper

[Monkeywrench]

We have a complete dry sump kit that will be available for sale very soon. Parts are on the shelf we're just holding off until we complete testing. We have plans to spin the modified 2ZZ in our Drag / LSR celica to 10,500 rpm or more this year so the dry sump is a must.

I'll post pics of the pan by Monday.

[Chococar]

I look forward to seeing it. Thanks!

[Monkeywrench]

[darkSol]

But Matt... it's almost a mee-lion dollars