dry oil sump systems

[Doof]

is anybody running one of these and what would be pro's and con's to running a system like this?

i know they are supposed to be used on race cars and what not, but would there be any problems with it on a DD?


im just doing some research for a future motor and i figure that if im going to be upgrading my motor i might as well pull out some stops and make it

[93tonkatoy]

http://en.wikipedia.org/wiki/Dry_sump

"A dry sump is a lubricating oil management method for four-stroke and large two-stroke piston internal combustion engines that uses a secondary external reservoir for oil, as compared to a conventional wet sump system.

Four-stroke engines are lubricated by oil which is pumped into various bearings and thereafter allowed to drain to the base of the engine. In most production cars, which use a wet sump system, this oil is simply collected in a three to seven litre capacity pan at the base of the engine, known as the oil pan, where it is pumped back up to the bearings by the oil pump, internal to the engine. In a dry sump, the oil still falls to the base of the engine, but rather than being collected into an oil pan, it is pumped into another reservoir by one or more scavenger pumps, run by belts from the front or back of the crankshaft. Oil is then pumped from this reservoir to the bearings of the engine by the pressure pump. Typical dry sump systems have the pressure pump and scavenger pumps "stacked up", so that one pulley at the front of the system can run as many pumps as desired, just by adding another to the back of the stack.

A dry sump affords many advantages, namely increased oil capacity, decreased parasitic loss and a lower center of gravity for the engine. Because the reservoir is external, the oil pan can be much smaller in a dry sump system, allowing the engine to be placed lower in the vehicle; in addition, the external reservoir can be as large as desired, whereas a larger oil pan raises the engine even further. Increased oil capacity by using a larger external reservoir leads to cooler oil. Furthermore, dry sump designs are not susceptible to the oil starvation problems wet sump systems suffer from if the oil sloshes in the oil pan, temporarily uncovering the oil pump pickup tube. Having the pumps external to the engine allows them to be maintained or replaced more easily, as well.

Dry sumps are common on larger diesel engines such as those used for ship propulsion. Many race cars, supercars, and aerobatic aircraft also utilize dry-sump equipped engines because they prevent oil-starvation at high g loads and because their lower center of gravity positively affects performance.

On the downside, dry sump systems add cost and complexity, and the extra pumps and lines require more oil, so maintenance costs go up as well."

For a full-time dedicated OFF road vehicle that severe demands are made on, I would say it would be a good idea. For a split duty DD/play vehicle, it would be a very large chunk of money, and more stuff to maintain/repair.

[Goose]

Nicely said tonka...

[jimbo74]

if you think it means you can run the truck upside down or at extreme angles all day it doesnt... it cannot supply oil to everything all the time

[93tonkatoy]

True, Jimbo. The scavenging pump still has to be able to pump the oil back to the reservoir, and if the engine is upside down, the oil will not drain to the pan. You'd have an upside down engine FULL of oil, and no lubrication.

[Doof]

thanks for that bit of info

how long of a time would you be able to run if you flopped on the lid or just a regular flop?

[WHITE_TRASH]

thanks for that bit of info

how long of a time would you be able to run if you flopped on the lid or just a regular flop?

Depending on your oil pan pickups and tank pickup indefinitely but you'd have to waste a couple of engines to recoup the cash dropped on a dry sump setup....  For me, tight clearances and rod bearings once a year is cheap and easy.

[REG535]

i will be running one soon i hope!

[jimbo74]

thanks for that bit of info

how long of a time would you be able to run if you flopped on the lid or just a regular flop?

i would honestly not think that long... lets say your engine capacity is 5 qts... and lets say your system is 5 qts, and you are on your lid... will that system pump another 5 qts into the engine? what good is 10 qts of oil going to do on your rocker arms? that crank needs the oil.... the rocker arms, not so much....

[Rockcrawlintoy]

if you are worried about that why not run an accumulator. it will help on starts and give you a few more seconds of you flop.

[unclejpl4x4]

finally some one explained it so I can understand it

No how about some 22r set ups ?

[93tonkatoy]

The length of time an engine could run without the oil actually being pumped BACK to the reservoir would depend on several factors.

1. The length of time it takes to pump a quart of oil through the engine. Bearing tolerances would be the biggest factor in this. Any pressure relief could be returned to the supply line, or returned to the reservoir instead of to the oil pan, as the stock pump does, but not sure of the workings of specific systems.

2. The capacity of the reservoir. While the capacity of a 22r(-e) pan is 4 quarts (plus filter), a reservoir can be as large as you need. I believe race engines use an 8 - 9 quart reservoir.

3. Engine speed. The faster an engine is turned (the higher the maintained pressure of the oil), increases the amount of oil that will be forced through a given bearing clearance.

While the engine is at an angle which does not allow the scavenging pump to return the oil, it WILL pool in the lower part of the engine. If you are flopped on the side, the oil will pool into the cylinders (under the pistons). If you are upside down, the oil will pool in the valve cover. In the latter case, the oil will be drawn, by the breather tube and the pcv valve into the intake, meaning you will still need to shut the engine off as quickly as possible. Uphill runs will not effect the performance of this system (or the stock system), but long, steep downhill grades could cause oil starvation with a stock system. With a dry sump and downhill, the oil would pool at the front of the pan until the level was relatively high enough for the scavenging pump to again start returning it to the reservoir.

In addition to the performance improvement limitations, you also have to consider the additional plumbing, fittings, multi-stage pump (running on an external drive belt), and the reservoir (and where to put it). The extra plumbing, reservoir, pump and belt could also be an additional failure from rocks or other trail hazards.

Baja and prerunning could possibly have better benefits, because of higher engine speed and jumps, that may cause temporary starvation with normal oil systems.

I am not downing the system, but I don't believe that for the benefits, it would be worth the expense for crawlers. With that said, if I was GIVEN one, I would seriously consider using it.