accusump with drysump

[spatz]

Does anybody know if it is still necessary to have an accusump when using a dry sump system.
I understand the accusump is providing addtional oil under the circumstances that the oil pressure
of a wetsump systems cracks down because the oil pump is not able to suck oil which actually is
what you prevent with a drysump system ?

thanks

[Steve_D]

An Accusump will provide oil pressure when the oil pump fails to keep up possibly because you are cornering and the oil is away from the pickup. The drysump system is pumping from a storage tank so an Accusump is not required.

The other thing the Accusump does is supply oil under pressure before you start the engine which will reduce engine wear but I have not seen anyone use it with drysump but you could.

Steve

[spatz]

got confused, because he did

http://www.craig-ultima.com/

and it resulted in a very complicated oil system with lots of "cheap" goodridge hosery

thanks

[CanAm Dave]

spatz said:

got confused, because he did

http://www.craig-ultima.com/

and it resulted in a very complicated oil system with lots of "cheap" goodridge hosery

thanks

The accusump in Craigs situation is only being used as a pre-oiling device.

Regards Dave

[spatz]

Thanks Dave, still do not understand what is so unique about his setup, drysump and accusump,
from your website I can tell that you have been digging deep into this and maybe can tell me
why his setup is done this way.
The only thing that makes sense to me is that in that few seconds before the oil pump builds up the
pressure the accusump empties out and maintains engine pressure which would also means an oil system
with accusump is always pressurized ?

thanks

Edited by spatz on Thursday 26th February 15:23

[Steve_D]

When an engine is off all pressure in the oil system will be lost.
When you start the engine it will run without oil to the bearings for a few seconds before the pump comes up to pressure.

With an Accusump pressure is retained when the engine is switched off. When you next turn the ignition on it will release and start flowing oil through the bearings. If you don't start the engine but just leave it sitting with the ignition on it will take about 20 minutes for the Accusump to empty.
When I start up I turn on the ignition and wait a few seconds before pressing the start button so that oil pressure comes up. My dash also shows the pressure rising.

Steve

[spatz]

ok got it that is what the valve is for, with ignotion on it is open and closes and with ignition off
closes so the full pressure and oil is staying in the accusump.
I always had the opiniom there is always a minimum film staying everywhere and a static
pressure of an accusump would not help much unless the bits in the engine are moving ?
But I am a novice just my thoughts, there is sure reasons for using accusumps.

[rdodger]

My thoughts on these have always been they are a good idea for a wet sump but why bother when you have a dry sump since damage on start up will be tiny as modern oils do stay put to a degree.

Having said that, if I had just spent 10k + on an engine and the car may spend weeks on end not being used, for the extra few hundred quid it seems daft not to.

It's always nice to have a bit more goodridge hose too

[738 driver]

Start and warm up are when most wear occurs, irrespective of residual 'oil film'.
Pressure needs to be established to provide minimal lubrication.
In a pure race motor on dry sump only, start ups are less of a consideration as usually the motor is rebuilt after every endurance race.
Accusump is not bad insurance particularly if your car may experience long periods of lay-up (during winter etc)!
Or you could always go the other route for a high output pushrod engine. Remove the rocker covers and pushrods on switch off, then reassemble and prime via the distributor drive prior to the next run out!

Edited by 738 driver on Thursday 26th February 21:35

[LuckyP]

Would good insurance for a dry sump - no accusump system to spin the engine over with the plugs out (no ignition ) for a few secs???

[738 driver]

IMHO Pete, thats a lot better than nowt!
Even with an oil accumulator, the clearances are not ideal until all the engine bits have reached operating temps. However the accumulator does go a long way to protecting things initially. Obviously in a high performance/ optimized engine, maintaining optimal operating clearances can be even more of a concern, depending on your engine builder and choice of parts.
Problem is there are now soooooooo many variants of SBC blocks, lubrication systems and build methods that it would be difficult to come up with one answer. In a performance pushrod motor, particularly a V configuartion, oil is your best friend.

Many years ago when the local BIB ran 3.0s Capri's their cars would come in for service with their Essex V6's having covered 150000-175000 miles. Still purring along like new. But they were always warm and usually ran for most of their 24hr shift cover, operating in their optimal condition!
Even then I thought hmm..... there must be something in this ideal operating temperature thing!

Edited by 738 driver on Thursday 26th February 22:12

Edited by 738 driver on Thursday 26th February 22:15