Board logo

Whats with a dry sump?
Chaz - 25/6/05 at 10:56 AM

Its probably a very noddy question to lots here. Whats the difference between a dry and wet sump? Well i know how a wet sump works, so whats with a dry sump? What are its adv and disadv?

flak monkey - 25/6/05 at 11:01 AM

Dry sump lets you mount the engine lower to get the COG down. Not sure about any other advantages though...

dmottaway - 25/6/05 at 11:18 AM

dry sump has at least one pump that evacuates the oil from the sump to a remote tank and a pressure pump to take it from the tank to the engine.

advantages are larger oil capacity, oil-air separation, lower engine mounting.

high RPM engines enjoy a small HP increase by not having the crank churn the oil in the sump.

disadvantages are cost and complexity, need to mount tank somewhere nearby, and they nearly always leak.

mounting the tank will offset a portion of the CG movement gained by lowering the engine.


or so I have heard.

dave

MikeRJ - 25/6/05 at 12:14 PM

Probably the most important use of dry sumping is to eliminate oil surge.

Surrey Dave - 25/6/05 at 12:45 PM

Thats what I thought MikeRJ....

James - 25/6/05 at 01:45 PM

Me too!

Chaz,
Hi speed cornering will mean the oil can all slop (for want of a better word) to one side of the sump and therefore not get picked up by the pump- eventual result engine goes bang!

Hicost recently fitted one to his Cossie engine. The tank sits in the boot area.

Cheers,
James

Chaz - 25/6/05 at 07:10 PM

Thats got to increase weight, with his oil tank right at the back with all the wiring for both pumps and the oil lines!?

Where do most people put them/ rig them up?

Simon - 25/6/05 at 09:01 PM

quote:
Originally posted by Chaz
Thats got to increase weight, with his oil tank right at the back with all the wiring for both pumps and the oil lines!?

Where do most people put them/ rig them up?


Chaz,

There is no wiring - the pump is "usually" mounted very near the sump and driven by a crank pulley. Oil is fed by usual oil hoses. So discard heavy steel sump and replace with lightweight ally one, and lose weight saved on extra hosing. Gain huge benefits from surge protection and churning (which in itseld should release the odd horse or two)

ATB

Simon

andylancaster3000 - 25/6/05 at 10:07 PM

IMHO the main purpose of a dry sump is to prevent oil surge and the eventual oil starvation and expensive clean operations! Any other advantage is only second to that. Therefore it is not hugely cost worthy for a road based car but any serious track car does usually require one.
They can be built at a very reasonable cost with a bit of thought. The original pump can be re-plumbed as a pressure pump, a seperate pump can is then used as a scavenge pump (this is generally the bit requiring the most thought!) A sump can be made from an original sump re-worked into a shallow trough with a length of RHS as the collector tube.
Or.... you could just go and buy a bolt on kit from Pace for a couple of thousand!

Andy

[Edited on 25/6/05 by andylancaster3000]

phelpsa - 25/6/05 at 10:30 PM

Remember that not all engines react well with a dry sump! For example GSXR 1100 engines don't react too well to a difference in oil level in the sump.

Adam

gazza285 - 25/6/05 at 11:22 PM

quote:
Originally posted by dmottaway
and they nearly always leak.


or so I have heard.

dave



Who told you that? Why should they leak "nearly always"?

gazza285 - 25/6/05 at 11:24 PM

quote:
Originally posted by phelpsa
Remember that not all engines react well with a dry sump! For example GSXR 1100 engines don't react too well to a difference in oil level in the sump.

Adam


Why? Dry sump systems don't have a sump.
Explain why a GSXR 1100 needs a sump filled with oil instead of a dry sump system.

ned - 26/6/05 at 09:50 AM

i will be bold and say that people don't know what they're talking about re the above gazza

It's a simple enough concept, how can people be getting it that wrong!

Ned.

Bart Vangampelaere - 26/6/05 at 06:31 PM

If a GSX-R engine is anywhere near the type of motorcycle-engine I know, it is not comparable with a car engine. Sumps of motorcycle engines are not like car engines. They are a part of the engine block casting (usually split somewhere in the midle) and therefor can't be removed.
Since all that cast metal stays in place, drysumping seems useless.
As for car engines, dry sumpsetups are indeed mainly there to eliminate surge, but the lowering of the engine can be a very important factor too.
There's no more reason for a dry-sump setup to leak then any other oilline to leak.
I'd say: for track cars: go dry sump. For road cars: depends on how much money you want to spend.

JoelP - 26/6/05 at 07:06 PM

in my limited understanding, its done in some cases to prevent oil starvation, and in some to reduce the sump. I had no idea how it worked until i read this thread, i always wondered how you collect all the oil as it drops back out the bottom - i guess a couple of pumps would do that nicely.

Bike engines are more likely to need dry sumping as, when used in cars, they will suffer more sloshing of the oil in the sump - as bikes lean through corners, the engine feels a lot less sideways forces than it would in a car being held level. Some engines are dry sumped cos they need it for reliability, and some because its to valuable an engine to risk without one. Hence zx9s and blades are rarely dry sumped, cos they are cheap, but zx12s and busas will often be, as they are damned expensive.

Dale - 26/6/05 at 07:10 PM

What about something like this-
http://www.accusump.com/acc_products/acc_units.html
It was sugested to me by the guys at the turboford site when I inquired about drysumping the 2.3 or if it was nessesary for oil surg on that particular engine.

Dale

Rorty - 28/6/05 at 06:24 AM

Blimey! What an eye-opener!
Anyway, I've had several engines that were dry sumped and none of them leaked. I've seen some that do, but it's usually a reflection on the car's owner.

Bart, have you actually seen a bike engine since you got out?
I don't think there has been a vertically split sports bike engine for 20 or 30 years, though throwing down a gauntlet like that, someone will no doubt rush forward with an example or two.
All the bike engines I've seen and worked on in recent years have all had detachable sumps, like car engines.

Peteff - 28/6/05 at 09:08 AM

Time warp

gazza285 - 28/6/05 at 09:57 AM

I thought that everybody talked like that in Australia?

Bart Vangampelaere - 28/6/05 at 05:29 PM

quote:
Originally posted by Rorty
Blimey! What an eye-opener!
Anyway, I've had several engines that were dry sumped and none of them leaked. I've seen some that do, but it's usually a reflection on the car's owner.

Bart, have you actually seen a bike engine since you got out?
I don't think there has been a vertically split sports bike engine for 20 or 30 years, though throwing down a gauntlet like that, someone will no doubt rush forward with an example or two.
All the bike engines I've seen and worked on in recent years have all had detachable sumps, like car engines.



got me there...
Well, I've been out of bike-stuff for not that long, like 8 years ago I had my final year of car-mechanics, and we had traing for two days a week, full school year. I did mine in a bike shop, and can tell most engines had split casings, but not vertically. The castings were horizontally split, if I remember right. Then again, it's been a while since I looked at a bike engine up close...
Bike engines could indeed use a external pump, and tank, but then again, if the system works on a bike, where cornering speeds are way higher, and the engines are almost tilted to the side, why should they have a problem in a car??? Show me the car that has that much body roll!

gazza285 - 28/6/05 at 06:06 PM

That's the problem with putting bike engines in a car. In a bike you lean into the corner and the centripital force keeps the oil on the centre of the sump. In a BEC the oil is thrown to the side of the sump as the engine does not lean into the corner like it does on a bike and oil starvation is the result.

Liam - 28/6/05 at 06:15 PM

And cornering speeds (or forces at least) are certainly not way higher on a bike!

Liam

Bart Vangampelaere - 28/6/05 at 08:30 PM

http://www.mcnews.com.au/NewBikeCatalogue/2001/Suzuki/GSXRimages/6_donk_600p.jpg

just have a look... oil is kept in the housings, not in a seperate sump as in a car engine.

The Shootist - 28/6/05 at 08:38 PM

Take a gander at the bottom of the engine. It's got a sump pan bolted on.

stevebubs - 28/6/05 at 08:40 PM

quote:
Originally posted by Bart Vangampelaere
http://www.mcnews.com.au/NewBikeCatalogue/2001/Suzuki/GSXRimages/6_donk_600p.jpg

just have a look... oil is kept in the housings, not in a seperate sump as in a car engine.


Not meaning to be rude, but what's the sump-like plate at the bottom of the engine? A typical car engine has the sump integral to the engine, too.

When running a bike engine may well (as standard) keep a lot less oil in the sump than a car engine, but the oil *will* eventually drain back down.

As mentioned before, this low capacity isn't usually an issue in a bike because cornering forces etc hold it in the right location.

In a car, this isn't the case because
a) the engine doesn't lean like it does in a bike
b) more often than not, the BEC has the engine N-S rather than E-W as in a bike.

Both these mean the precision bike engineering in the shallow oil sump dept stops working and the pickup is often in danger of being uncovered and air being sucked up into the whirry bits instead of oil.

3 answers to this

1) Overfilling is popular with the more robust engines (R1, Blade, ZX9) etc. Not enough to cause churn on the crank, but enough to ensure a constant supply

2) Baffling to prevent oil moving away from the pickup

3) Dry Sump. Suck all oil out of the bottom of the engine into the top of a separate tall (and 99% of the time larger capacity) tank using scavenge pumps. Take a feed from the bottom of that tank (which should never have the pickup uncovered) and use that feed to supply the oil pressure to the whirry bits

Does that help or confuse?

[Edited on 28/6/05 by stevebubs]

Bart Vangampelaere - 28/6/05 at 09:13 PM

quote:
Originally posted by stevebubs
quote:
Originally posted by Bart Vangampelaere
http://www.mcnews.com.au/NewBikeCatalogue/2001/Suzuki/GSXRimages/6_donk_600p.jpg

just have a look... oil is kept in the housings, not in a seperate sump as in a car engine.


Not meaning to be rude, but what's the sump-like plate at the bottom of the engine? A typical car engine has the sump integral to the engine, too.


[Edited on 28/6/05 by stevebubs]



The plate under the engine can hardly be called a sump. It's not there to contain the oil, merely to cover the hole, yet be able to remove it for inspections. A sump on a car is ONLY there for holding oil, it doesn't have any other purpose. But if you'd replace it by a flat piece of steel, you're in problems. Replace that bike-engine cover by a flat piece and you wouldn't notice (if clearance allows, of course)
Actually the plate is under the (integral cast) gearbox anyway.
But you're right about the the fact that because most BEC having the engine in the "wrong" direction in comparison with the original bike.
Nevertheless drysumping can end surge here too, it just won't help to mount the engine any lower.
Oh, and about car engines having integral sumps too: sorry, I just remembered I haven't looked at a normal piston engine for let's say 10 years. That's what happens when you are into rotary engines: sooner or later you forget piston engines exist

stevebubs - 28/6/05 at 09:18 PM

quote:
Originally posted by Bart Vangampelaere
quote:
Originally posted by stevebubs
quote:
Originally posted by Bart Vangampelaere
http://www.mcnews.com.au/NewBikeCatalogue/2001/Suzuki/GSXRimages/6_donk_600p.jpg

just have a look... oil is kept in the housings, not in a seperate sump as in a car engine.


Not meaning to be rude, but what's the sump-like plate at the bottom of the engine? A typical car engine has the sump integral to the engine, too.


[Edited on 28/6/05 by stevebubs]



The plate under the engine can hardly be called a sump. It's not there to contain the oil, merely to cover the hole, yet be able to remove it for inspections. A sump on a car is ONLY there for holding oil, it doesn't have any other purpose. But if you'd replace it by a flat piece of steel, you're in problems. Replace that bike-engine cover by a flat piece and you wouldn't notice (if clearance allows, of course)
Actually the plate is under the (integral cast) gearbox anyway.
But you're right about the the fact that because most BEC having the engine in the "wrong" direction in comparison with the original bike.
Nevertheless drysumping can end surge here too, it just won't help to mount the engine any lower.
Oh, and about car engines having integral sumps too: sorry, I just remembered I haven't looked at a normal piston engine for let's say 10 years. That's what happens when you are into rotary engines: sooner or later you forget piston engines exist




I quite agree that dry sumping won't normally help you mount a Bike Engine any lower. Once running, there's not a lot of oil held in the bottom of the engine at all - it's normally sucked back up in double quick time due to fancy bike-driven design.

PS Most Porkers are dry sumped, too

[Edited on 28/6/05 by stevebubs]

madman280 - 28/6/05 at 11:15 PM

With regards to oil level in a bike engine, it should be remembered that the many use a wet clutch. It's imersed in and cooled by the oil. So, low oil level would mean a toasted or inoperable clutch. Not all bike engines have wet clutches, just the majority. It needs to be taken in to consideration when modifying the oiling system. I may be wrong in my thinking, but I do know what happens to the clutch if the oil level is low, before the engine self disassmbles.

Bart Vangampelaere - 29/6/05 at 09:34 AM

quote:
Originally posted by madman280
With regards to oil level in a bike engine, it should be remembered that the many use a wet clutch. It's imersed in and cooled by the oil. So, low oil level would mean a toasted or inoperable clutch. Not all bike engines have wet clutches, just the majority. It needs to be taken in to consideration when modifying the oiling system. I may be wrong in my thinking, but I do know what happens to the clutch if the oil level is low, before the engine self disassmbles.

Bart Vangampelaere - 29/6/05 at 09:37 AM

eh seems my post didn't get through???
Anyway, I wanted to say I agree. Most bike engines use wet clutches. If you'd dry sup these, the clutch might run dry.
But I'm not so sure it's needed anyway.

gazza285 - 29/6/05 at 11:22 AM

http://www.allensperformance.co.uk/dry-sump-kit-suzuki-hayabusa.htm


Quote:

"enables engines to be fitted 75mm lower in the chassis. Stops oil surge and improves reliability."

Hellfire - 29/6/05 at 11:45 AM

The total cost of installing a dry sump is almost - if not more than - the cost of majority of motorcycle engines. If a wet sump on a motorbike can cope with wheelies and heavy braking, then I'm sure there can't be a great deal of difference between that and cornering hard in a BEC. To my mind, installing a baffle plate to prevent excessive oil surge should be sufficient. I guess only time will tell................