NS Dev
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| posted on 18/12/06 at 03:41 PM |
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Dry sump - not filling crankcase up with oil??
Simple question, but I've only ever dealt with 3 dry sumped engines, and certainly no bike engines with dry sumps!
On the new grasser, I plan to run 1 7 or 8 litre oil tank to feed the two dry sumped engines........
What stops the head of oil filling the crankcases of the engines up when they are not running? I'm just worried that while it is stood for some
time, I could end up with a serious problem if a crankcase full of oil on both engines!!!
Any thoughts, or anybody got a dry sump bike engine and tell me what happens on theirs?
edit to add the "when not running bit" !!!!!
[Edited on 18/12/06 by NS Dev]
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ecosse
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| posted on 18/12/06 at 03:49 PM |
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The return feed sucks (literally  ) so the oil circulates rather than accumulates 
Cheers
Alex
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NS Dev
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| posted on 18/12/06 at 03:56 PM |
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I know that!!!!
I meant when the engine is stood and not running, I'm guessing the only seal between tank and crankcase is the pump rotor, in which case there
will be some leakage, which over time will surely fill the crankcase?
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
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zzr1100rick2
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| posted on 18/12/06 at 03:59 PM |
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is there not an anti syphon valve fitted in the oil line
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mookaloid
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| posted on 18/12/06 at 04:00 PM |
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I know a couple of people with old brit bikes who fit a tap in the pipe at the bottom of the tank so it doesn't drain back into the sump.
The tricky bit is remembering to turn the tap back on before starting the engine.!
Also some have fitted a one way valve (simple ball bearing and a light spring type thingy) for the same reason. Some don't trust this in case
the valve sticks and so they go with the tap method above.
Cheers
Mark
"That thing you're thinking - it wont be that."
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ecosse
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| posted on 18/12/06 at 04:02 PM |
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Ooops  LOL
Well I only know them from harleys, and the oil pickup from the tank is higher than the oil level in the tank (if that makes sense) so you get whats
in the pipe running back to the crackcase/sump if left lying for any time, I think the oil is too thick for much more than that to draw by
syphoning.
Hope thats more helpful than my last
Cheers
Alex
Just read that back and realised it doesn't make sense (not having a good day!) but I meant that the pickup goes in higher but obviously is then
piped to the bottom (or near) for collecting the oil.
Does that sound better or should I just give up now 
[Edited on 18/12/06 by ecosse]
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NS Dev
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| posted on 18/12/06 at 04:16 PM |
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quote:
Originally posted by mookaloid
I know a couple of people with old brit bikes who fit a tap in the pipe at the bottom of the tank so it doesn't drain back into the sump.
The tricky bit is remembering to turn the tap back on before starting the engine.!
Also some have fitted a one way valve (simple ball bearing and a light spring type thingy) for the same reason. Some don't trust this in case
the valve sticks and so they go with the tap method above.
Cheers
Mark
bit confused on the one way valve idea, as the oil needs to flow to the engine down the line, but only when its running.
The return line is fine as that goes to the top of the tank.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Nick Skidmore
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| posted on 18/12/06 at 04:19 PM |
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I ran a dry sumped hayabusa and the oil does drain from the tank to the sump until they are both at the same level (like a hydrometer).
When starting the engine after standing, remove the plugs first and prime the system with the starter motor until the oil light goes out / gauge
registers pressure. Then crack it up.
Whilst the engine is cold it will appear that there is very little oil in the tank as the viscosity makes it slower to return, the level will however
return to normal as the oil warms up. Install a sight gauge in the tank to keep and eye on the levels. I made mine from John Guest push fit plastic
fittings for 8mm nylon pipe.
[Edited on 18/12/06 by Nick Skidmore]
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NS Dev
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| posted on 18/12/06 at 04:20 PM |
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quote:
Originally posted by ecosse
Ooops LOL
Well I only know them from harleys, and the oil pickup from the tank is higher than the oil level in the tank (if that makes sense) so you get whats
in the pipe running back to the crackcase/sump if left lying for any time, I think the oil is too thick for much more than that to draw by
syphoning.
Hope thats more helpful than my last
Cheers
Alex
Just read that back and realised it doesn't make sense (not having a good day!) but I meant that the pickup goes in higher but obviously is then
piped to the bottom (or near) for collecting the oil.
Does that sound better or should I just give up now
[Edited on 18/12/06 by ecosse]
Ah, now that might be the trick, that just makes me nervous about getting a pipe full of air every time I start up, but I guess no different to most
engines filling filters etc.
Thinking about it logically, the oil from the tank will have to force its way through the pump, filter, bearing clearances etc etc to get into the
sump, so maybe short term the leakage will be very slight, and long term a tap and a sign on the steering wheel will do the trick!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ned
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| posted on 18/12/06 at 04:27 PM |
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Nat,
Aren't you better off running seperate dry sump tanks for each engine? If one engine goes bang and contaminates the oil or you lose a
hose/fitting on one engine you risk rogering both engines surely?
Ned.
beware, I've got yellow skin
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Nick Skidmore
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| posted on 18/12/06 at 04:33 PM |
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Just make sure that the outlet from the tank isn't too high as all that can happen then is that you will have the same level in sump as you do
in the tank.
It takes about a week for the oil to drain level sump to tank
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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tks
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| posted on 18/12/06 at 05:36 PM |
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quote:
Originally posted by ned
Nat,
Aren't you better off running seperate dry sump tanks for each engine? If one engine goes bang and contaminates the oil or you lose a
hose/fitting on one engine you risk rogering both engines surely?
Ned.
Good point NED!!
Would also mount 2 resv..
Tks
The above comments are always meant to be from the above persons perspective.
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Phil.J
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| posted on 18/12/06 at 07:04 PM |
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You need to run a tank for each engine to secure each has a known quantity of oil. On my GSXR engined racer the oil drains from the tank into the
engine overnight. I always remove the belt from the scavenge pump and manually turn the pump to refill the tank before the engine is turned to get
oil pressure up before firing.
Scavenge pumps are obviously designed to shift oil and air mixed back to the tank. If you start the engine cold with it full of oil, the scavenge pump
drive mechanism is put under tremendous load trying to move large quantities of thick cold oil, and can fail in extreme circumstances. You may have
noticed drivers of big single seaters at hillclimbs rev the engine hard for a few second before switching off. This is to empty the sump of oil for
this very reason.
ATB
Phil
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NS Dev
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| posted on 18/12/06 at 07:12 PM |
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Ok, so it sounds like my concern was founded, and like a tap will prevent the startup hassle (as long as I don't forget to open it!!!!! )
I had hoped to run one bigger tank rather than two smaller ones to save weight and complication etc.........is this not wise, and why not?
I get the blowup point Ned, and I suppose that alone probably makes a good case for one tank per engine.
In terms of "enough oil for each engine", I know the size of the original tanks as fitted by aprilia, and I was going to just double
that.
Any further comments (all being taken on board even if it doesn't sound that way, as I've never run two engines in one car either before!
)
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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dmottaway
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| posted on 18/12/06 at 07:34 PM |
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Accususump make an electrically controlled oil valve for their devices. could put it in line and wire it to the ignition. Ignition off, valve
closes.
Only concern, then, is wiring failure to the valve while engine is running!!!
dave
Somewhere, in Texas, a village is missing its idiot.
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Stu16v
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| posted on 18/12/06 at 07:34 PM |
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quote:
You may have noticed drivers of big single seaters at hillclimbs rev the engine hard for a few second before switching off. This is to empty the sump
of oil for this very reason.
Why? The scavenge side always clears oil quicker than the pump delivers. Revving the engine merely speeds the cycle of events up...
Re sump drain: If the oil tank return is at the highest point of the tank, the only way oil can reach the engine is through the supply side. Keep the
mounting of the tank(s) as low as sensibly possible, and the oil can only 'siphon' as low as the crankshaft...
Dont just build it.....make it!
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NS Dev
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| posted on 18/12/06 at 07:53 PM |
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very good point Stu, only worry then is that I assumed the feed side of the pump liked to see some pressure head form the oil in the tank? Maybe not I
suppose as you don't get much from the tank in the boot of a mk2 escort rally car when its piped all the way to the front! ?
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Phil.J
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| posted on 18/12/06 at 08:50 PM |
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Iwas trying to make two points. The first is that scavenge pump drivest under a lot of load when pumping just cold oil and not an oil and air mix. The
second is that your pressure pump will run out of oil before the scavenge pump can replenish the empty tank unless you prime it in ome way. To keep
the weight down on my car my tank has a running capacity of about 3 litres, the whole oil system comprises about 6 litres (Two oil coolers and big
pipework). That 3 litres in the tank is almost all retained in the engine when it is cold because of the viscocity,it tends to 'stick'
inside the engine onthe walls, the head, gearbox,clutch etc, so I find it important to get the tank as full as possible before the engine is started.
Once the engine is warm that 3 litres is all returned to the tank when running.
Assuming that the oil pumps in both engines are well balanced, and there is a lot of spare capacity in the dry sump tank, it is probably okay to run
just the one tank, albeit at the expense of some possible extra weight and the risk of damaging both engines should one of them get damaged and the
oil system gets contaminated.
ATB
Phil
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Stu16v
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| posted on 18/12/06 at 10:53 PM |
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quote:
Originally posted by NS Dev
very good point Stu, only worry then is that I assumed the feed side of the pump liked to see some pressure head form the oil in the tank? Maybe not I
suppose as you don't get much from the tank in the boot of a mk2 escort rally car when its piped all the way to the front! ?
In an ideal world, it would be best for the pump to have a 'head' of oil, but if you can keep the tank *around* sump level, it will have
the same, if not more head than a standard oil pump would have pulling from a sump pan...
Dont just build it.....make it!
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Peteff
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| posted on 19/12/06 at 12:53 AM |
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I'm not familiar with dry sumps.
Does the scavenge pump return unfiltered oil to the tank? If both engines are same they should both take a similar amount from the tank and only have
what they need in circulation at any time shouldn't they?
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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ned
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| posted on 19/12/06 at 08:34 AM |
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Pete,
typical/generic Pace 3 stage dry sump setup/connections (albeit on a vauxhall engine) here:
http://www.sbdev.co.uk/Info_sheets/Oil_systems/Connections%20for%20the%20SBD%20dry%20sump%20system%202.0L.htm
Ned.
[Edited on 19/12/06 by ned]
beware, I've got yellow skin
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NS Dev
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| posted on 19/12/06 at 09:34 AM |
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On the aprilia its a very simple setup, there are two connections on the engine, one that returns "used" oil to the tank via the cooler,
and one that supplies the internal oil pump from the tank. The filter housing is integral with the engine case and withdraws via two allen screws and
is a cartridge type paper filter.
My only concern was overfilling the crankcase with oil from the tank when the car was stood, bearing in mind I will have a taller tank (thus more
static oil head over the pump inlet) than that used on the bike.
Thanks for all the help, and particularly nick skidmore who has made some suggestions via u2u, including the obvious but clever point that I can make
a "double" tank which will still save most of the weight of a second tank, whilst keeping the oil seperate, which as ned pointed out is a
good idea if one engine lets go.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ned
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| posted on 19/12/06 at 09:51 AM |
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so just make a single tank with dual inlets/outlets with a large baffle/divider down the middle inside?
Effectively a single tank installation/situation/weight with seperate oil systems then?
Ned.
beware, I've got yellow skin
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NS Dev
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| posted on 19/12/06 at 10:01 AM |
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Exactly, funny how the obvious doesn't spring to mind when you are doing it yourself!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ned
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| posted on 19/12/06 at 10:46 AM |
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quote:
Originally posted by NS Dev
Exactly, funny how the obvious doesn't spring to mind when you are doing it yourself!
Story of my life
beware, I've got yellow skin
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