Why do we have oil tanks?

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Diablouph

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Feb 9, 2009
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Why do we have oil tanks? Why not a sump, separated by a plate so the crank does not hit the oil. Is the tank, which is higher than the oil pump, put there to have column pressure? Seems to me, autos have had oil pans for years, with the pump immersed in the oil.

Just curious (which killed the cat).
 
Dry sump with external tank keeps the engine/crankshaft low in the frame. Ground clearance.
To prevent oil starvation on long wheelies :lol:
I wondered about running wet sump but power loss due to drag, oil foaming, and crankcase breathing.... it wasn't designed with that in mind.
 
Diablouph said:
Seems to me, autos have had oil pans for years, with the pump immersed in the oil.

Just curious (which killed the cat).
Click to expand...

For example regular Corvettes have a wet sump but the ZR1 has a dry sump. As do most race cars.

As mentioned it's about drag, you only want enough oil in the crankcase to do it's job and then get it out.
 
Its exactly as Will has reviewed and newest cycle wonders are trying
to get back to Brit Iron dry sumps for same reasons.

Its common knowlege now from hard lesions with seized modern engines
by stunters ridding wheelies a ways.
You'd have to go about vertical or more to starve oil tank Commando
but the Combats would wet sump their diapers d/t the front
sump oil drain, heck they do any way when their trust
sloshes and slings oil to the rear, but then the secondary
flywheel oil pump and rear breather tube oil return system
kicks in.

In my Ms Peel special I provided for this in oil plumbing, nose
high flow but also hose low flow times in the Ozarks
where only level places are roofed over.

hobot
 
hobot said:
Its exactly as Will has reviewed and newest cycle wonders are trying
to get back to Brit Iron dry sumps for same reasons.

Its common knowlege now from hard lesions with seized modern engines
by stunters ridding wheelies a ways.

hobot
Click to expand...

My "modern " is dry sump.
Why do we have oil tanks?

Oil tank wraps around the front cylinder, black tank under rad shroud.

Will
 
Oh yeah Will, got ya one of them colorful bait fish Ms Peel
loved to tease with.
Be careful if you ain't yet had scary recovery events,
them squaty wheeled hi CoG rigid rigs don't give much warning how
close to crashing they get just to feel a bit extra G's in turns.

I seek a Commando like bike that can stunt with the best of
em, expect for the stoppies, as Commando's just stop or
slide front but can't seem to lift rear enough to count.

My SV650 is wheelie prone if I just got off Ms Peel in past,
but its a wet sump and famous example of taboo to wheelie long.
Was Blue but many crashes/major parts, just white boat paint now.

hobot only like much a wheelie when leaned way over
Why do we have oil tanks?
 
Diablouph said:
Why do we have oil tanks? Why not a sump, separated by a plate so the crank does not hit the oil. Is the tank, which is higher than the oil pump, put there to have column pressure? Seems to me, autos have had oil pans for years, with the pump immersed in the oil.

Just curious (which killed the cat).
Click to expand...

...erm, because then it would be a Royal Enfield twin. The Enfield system of a cast in oil tank behind the crankcase was not much liked, other than by Enfield enthusiasts.
 
Why didn't people like the Royal Enfield twin System? BTW, I'm not talking about going to a wet sump, with the crank hitting the oil. I was thinking of a tank/sump at or below the bottom of the crank. Obviously, I am thinking about (dare I say it?) WET SUMPING.
 
hobot said:
Oh yeah Will, got ya one of them colorful bait fish Ms Peel
loved to tease with.
Be careful if you ain't yet had scary recovery events,
them squaty wheeled hi CoG rigid rigs don't give much warning how
close to crashing they get just to feel a bit extra G's in turns.
Click to expand...
You've got it all wrong. Low CoG, the battery, lightweight engine, oil tank, are close to ground. Ti exhaust ways nothing. Built by dirt bike company. Hooligan Machine with sub 400lb dry weight. Tons of feedback. Name of the game is control, for without control, power is useless.
 
You've got it all wrong. Low CoG, the battery, lightweight engine, oil tank, are close to ground. Ti exhaust ways nothing. Built by dirt bike company. Hooligan Machine with sub 400lb dry weight. Tons of feedback. Name of the game is control, for without control, power is useless.
Click to expand...

Hehe, not a wasted review on me Will,
but I've been lightening rod stuck and know for a fact ya
don't know what ya missing out on w/o a triple linked Cdo
to define new orbits of control and power application.

Its funny to me - I'm the only one who preaching Commando
as supreme handler and tool of choice in tough riding loads.
Maybe just maybe I know something only one other does so far.

Arrive safe and watch this space for objective data someday.

hobot -
 
...erm said:
Well ...I have an Enfield 750 mk2 and a Commando and I do prefer the oil positioning of the Enfied as I think that the more weight on the bottom the better handling...Enfield have a lot of strange " things" (individual cylinders & heads just to mention a few) but the oil tank was not one of them!
Philippe
Click to expand...
 
A lot of the reason is the evolution similarities to the DeDion-Bouton single, one of the early 4-cycle success stories. Also, a separate tank was deemed necessary to give the oil a chance to cool before being pumped to its various points of service. Air-cooled motors are, after all, air- AND oil-cooled and oil in a sump tends to heat up and not be able to slough off the excess temperature. The air-cooled multis of the 70s and 80s made up for this with nearly a gallon of oil in the sump and huge, finned cases for heat sink. British vertical twins, especially the 180 degree firing ones like Dominators are really like big singles and with ancillaries like timing drives, alternators and clutches outboard of the crank ends, a dry sump makes for a more compact motor.
 
by Danno A lot of the reason is the evolution similarities to the DeDion-Bouton single, one of the early 4-cycle success stories. Also, a separate tank was deemed necessary to give the oil a chance to cool before being pumped to its various points of service. Air-cooled motors are, after all, air- AND oil-cooled and oil in a sump tends to heat up and not be able to slough off the excess temperature. The air-cooled multis of the 70s and 80s made up for this with nearly a gallon of oil in the sump and huge, finned cases for heat sink. British vertical twins, especially the 180 degree firing ones like Dominators are really like big singles and with ancillaries like timing drives, alternators and clutches outboard of the crank ends, a dry sump makes for a more compact motor.
Click to expand...

But, why did BSA, Triumph, Norton, etc. elect to place the tank ABOVE the sump? Is there a reason, maybe column height? Why not put the tank at the level, or slightly lower then the sump? If they were concerned about immediate oil pressure upon startup, couldn't there be a small amount left in the bottom of the sump, around the pump? If heat was a major consideration, why didn't the engineers make the tank out of aluminum and put fins on it? There must be valid reasons for putting the tank up high. I am just very curious as to why. It seems to me that, with some design changes to the center stand, there would be room.
 
Diablouph said:
by Danno A lot of the reason is the evolution similarities to the DeDion-Bouton single, one of the early 4-cycle success stories. Also, a separate tank was deemed necessary to give the oil a chance to cool before being pumped to its various points of service. Air-cooled motors are, after all, air- AND oil-cooled and oil in a sump tends to heat up and not be able to slough off the excess temperature. The air-cooled multis of the 70s and 80s made up for this with nearly a gallon of oil in the sump and huge, finned cases for heat sink. British vertical twins, especially the 180 degree firing ones like Dominators are really like big singles and with ancillaries like timing drives, alternators and clutches outboard of the crank ends, a dry sump makes for a more compact motor.
Click to expand...

But, why did BSA, Triumph, Norton, etc. elect to place the tank ABOVE the sump? Is there a reason, maybe column height? Why not put the tank at the level, or slightly lower then the sump? If they were concerned about immediate oil pressure upon startup, couldn't there be a small amount left in the bottom of the sump, around the pump? If heat was a major consideration, why didn't the engineers make the tank out of aluminum and put fins on it? There must be valid reasons for putting the tank up high. I am just very curious as to why. It seems to me that, with some design changes to the center stand, there would be room.
Click to expand...

Simple, they put it where there's otherwise unoccupied space. Oil tanks have been and still are made out of aluminum but they tend to fail if not isolated from vibration, and steel is cheaper. Ease of use. Ease of manufacturing. How complex would a tank have to be to hold a suitable amount of oil and fit behind/underneath/between gearbox/crankcase/swingarm/frame and how much heat is already present in those areas.
 
Most alloy parts were cast or forged. I can't think of any that were made of extruded, gas-welded aluminum. Now, of course, there are more alloys to choose from thanks to the technology that advances by leaps mand bounds eery time there's a war. By the time there were suitable alloys that could be used to make tanks, oil coolers were around. Only a few alloy fuel tanks made it onto production machines, so cost was likely a big consideration also.
 
Hi,
There is no reason that a clever fellow could not build and install a low/lower oil tank (oil bag to some). I believe Jean has a home built alternatively mounted aluminum oil tank on his Atlas thats pictured along with his postings.
I could imagine an elongated upside down triangle shaped tank mounted to the bottom of the cradle (think Buell mufflers). If your bike was fully faired it would be an even easier task.
Although, if one were taking on such a project to cure a wet sumping problem there are already easier and proven ways.

GB
 
Well, it's obvious that, like most things in life, it comes down to money. Tanks were put where they were because it was less expensive.
 
Danno said:
Most alloy parts were cast or forged. I can't think of any that were made of extruded, gas-welded aluminum. Now, of course, there are more alloys to choose from thanks to the technology that advances by leaps mand bounds eery time there's a war. By the time there were suitable alloys that could be used to make tanks, oil coolers were around. Only a few alloy fuel tanks made it onto production machines, so cost was likely a big consideration also.
Click to expand...

The first P11s came with stamped and welded aluminum oil tanks.
 
Diablouph said:
Why didn't people like the Royal Enfield twin System? BTW, I'm not talking about going to a wet sump, with the crank hitting the oil. I was thinking of a tank/sump at or below the bottom of the crank. Obviously, I am thinking about (dare I say it?) WET SUMPING.
Click to expand...

An oil tank below the sump has been done, my last featherbed racer originally had an oil tank below the frame, like the Seymour Velocetes!!! Also, look at the late John Player Norton (the works racers!!!) they had the ol tank low, just behind the front wheel, asdid the works Triumph Daytonas!!
 
Seeley920 said:
Diablouph said:
Why didn't people like the Royal Enfield twin System? BTW, I'm not talking about going to a wet sump, with the crank hitting the oil. I was thinking of a tank/sump at or below the bottom of the crank. Obviously, I am thinking about (dare I say it?) WET SUMPING.
Click to expand...

An oil tank below the sump has been done, my last featherbed racer originally had an oil tank below the frame, like the Seymour Velocetes!!! Also, look at the late John Player Norton (the works racers!!!) they had the ol tank low, just behind the front wheel, asdid the works Triumph Daytonas!!
Click to expand...

Absolutely! bikes built for tracks, putting the tank in the wind where it cools best. Not a good Idea for average street going bikes though. KTM 990 SM use the space directly in front of the engine, behind the front wheel but have a cast and welded tank and ground clearance to help keep it from harm.

You have a Seeley, I'm envious.
 
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