Dry-sump construction

[oldcorollas]

does the oil in the accusump circulate? ie it is full flow? or it pressurises once and then hold the cold oil until it is needed?
if it stays (relatively) cold, does it make any difference to the emergency situation, since it is trying to force cold oil in? or any is better than none?

would it be worth combining the accusump with a cheap single stage sump evacuator, ie for priming and extra 'just in case'? or with the reservoir/air remover, it is not needed at all?

[YLD-16L]

This may be a stupid question but how do you determine the oil volume once you have built one of the drysump setups mentioned? (I don't think I saw this detailed anywhere).

[Mr Ed]

I guess you could start off with the tank filled up to 20mm below the fill pipe (or wateva Bill said before), then run the engine and keep slowly pouring more oil in as it runs keeping it at that same level until oil starts coming out the fill tube.

[kingmick]

This may be a stupid question but how do you determine the oil volume once you have built one of the drysump setups mentioned? (I don't think I saw this detailed anywhere).

Easy mate, you fill it up 3/4{dry sump tank} and prime the system with a pulley on a drill with a belt to the pump etc, then start the engine and get the oil tank to a level that it isnt spitting it out the {god platting my two girls hair half way through this}
top of tank and filling the breather!
when the engines running 3/4 is about the level if its a properly made tank!

[kingmick]

I guess you could start off with the tank filled up to 20mm below the fill pipe (or wateva Bill said before), then run the engine and keep slowly pouring more oil in as it runs keeping it at that same level until oil starts coming out the fill tube.

or you could just answer if you know

[YLD-16L]

Thanks guys, the question just crossed my mind.

[Mr Ed]

I was under the impression things are discussed on the forums. Perhaps I should have added prime the pump but if I expected him to unquestionably follow my suggestion I wouldnt have said "I guess".

I agree, running the system with a drill is a much better way of doing things though. I would have thought these pumps might require a reasonable amount of torque to turn them that is all. (Especially a multi-stage one)

I wasnt try to just make shit up though, twas just a suggestion. Sheesh!

[ed]

does the oil in the accusump circulate? ie it is full flow? or it pressurises once and then hold the cold oil until it is needed?
if it stays (relatively) cold, does it make any difference to the emergency situation, since it is trying to force cold oil in? or any is better than none?

i think that as the accusump is an continual active buffer, with its volume flutuating at all time with engine pressure, it will see a continuing, if not small/moderate turn over of oil throughout a driving session. it will be cooler than the cic fluid, but i certainly doubt cold and useless

[kingmick]

I was under the impression things are discussed on the forums. Perhaps I should have added prime the pump but if I expected him to unquestionably follow my suggestion I wouldnt have said "I guess".

I agree, running the system with a drill is a much better way of doing things though. I would have thought these pumps might require a reasonable amount of torque to turn them that is all. (Especially a multi-stage one)

I wasnt try to just make shit up though, twas just a suggestion. Sheesh!

sorry mate, was ment as a ribbing!

no the drill works fine on 5 stage pumps, the only problem is holding it straight! Dry sump pumps sap a very small amount of power for the work they do!

[kingmick]

i think that as the accusump is an continual active buffer, with its volume flutuating at all time with engine pressure, it will see a continuing, if not small/moderate turn over of oil throughout a driving session. it will be cooler than the cic fluid, but i certainly doubt cold and useless

in short, any oil is good oil!

[roadsailing]

so another stupid question, what stops the oil draining back into the "dry" sump?

i can see this as a potential problem as the sump no longer has any great volume, and oil could flood the crankshaft etc.

i would gues that you don;t get drainback as both the pumps are positive displacement, but bill mentioned drainback happening.

is it not a problem as all the oil gets sucked out pretty quick and the crank flings all the oil off?

[Billzilla]

Back again guys, sorry for going for a few days but I do occasionally have to work.

the question is what happens if the scavenge pump runs dry, does it not happen or not matter?

Doesn't matter, as there's SO much oil running around in the engine that it'll pick up more very quickly.

This may be a stupid question but how do you determine the oil volume once you have built one of the drysump setups mentioned? (I don't think I saw this detailed anywhere).

Open the top of the tank and look down the hole - The oil level should be about 30mm or so below the middle plate.

I guess you could start off with the tank filled up to 20mm below the fill pipe (or wateva Bill said before), then run the engine and keep slowly pouring more oil in as it runs keeping it at that same level until oil starts coming out the fill tube.

Nah there's that much oil spashing around, you can't really see a level you can use.

so another stupid question, what stops the oil draining back into the "dry" sump?

i can see this as a potential problem as the sump no longer has any great volume, and oil could flood the crankshaft etc.

i would gues that you don;t get drainback as both the pumps are positive displacement, but bill mentioned drainback happening.

is it not a problem as all the oil gets sucked out pretty quick and the crank flings all the oil off?

It often does, on some installations. On the racer it doesn't, but on the Fraser if I leave it for a few hours the oil level in the tank goes way down, as the dry sump turns into a wet one.
I figure as long as there's no puddle of oil under the engine and there's a bit of oil in the tank then I'll start it, then check the oil level again shortly after shutting down.
The extra oil in the sump as it starts isn't a problem. (Well, I haven't heard it being so for anyone yet)

[kingmick]

use a stick to check oil level! check it after being cranked with no ignition and then when its going, but you soon get used to eyeballing it!

No it cranks to low an rpm for the oil to be a problem!

Hint, the tanks from aviaid and barnes etc that are split{join in the middle} make life easy to clean theam and to mega clean them after a blowup and are designed as a swirl pot!

[Billzilla]

Hint, the tanks from aviaid and barnes etc that are split{join in the middle} make life easy to clean theam and to mega clean them after a blowup and are designed as a swirl pot!

Yeah, excellent tanks they are.

[clubagreenie]

The accusump is a hydraulic pressure accumulator.

It has a piston inside that has oil pressure on the engine side and air pressure on the other. This pressure can be adjusted to suit the engines opersting pressure and anticipated requirements for reoiling (bearing in mind that it will only push as quickly as the return line OD allows). When engine pressure drops below the pressure behind the piston it will push oil into the system. When normal operating pressure is re-established in the engine it overcomes the pressure behind the piston (hence the need to set the piston pressure correctly or it won't refill) and refill.

Most modern hydraulic devics on trucks etc (cherry pickers, concrete booms etc) run accumulator systems, it eliminates the need to run all the heavy pressure lines to the control point and back to the device to be operated (thats 1 pressure line and usually 2 lines per device). Instead running low pressure (lighter, less chance of blowing) pilot controls that return to the base and operate valves that have the accumulator pressure running to them, which is periodically restored by to PTO pump. It reduces the ned to have the pressure pump running constantly, Difference is the size of the accumulator, from 20 to 200lt.