ACCUSUMP question...

[wilf leek]

Craig - you guys down under sure do know how to complicate things. The Accusump is just another shiny piece of good techy stuff to fit and gaze at. Period.

Actually, being sensible about it (I do have to try hard) - the 3qt (or 2) moniker is a tad misleading. All the thing is, is a cylinder with a sealed piston running up and down it internally. Air one side, oil the other. You can "preload" the air side to whatever level you like (Accusump recommend something like 5 psi remaining even when the piston has expelled all oil).
So....... when the engine generates oil pressure, oil flows into the Accusump until the air pressure on one side of the piston equals the oil pressure on the other. This may be 3 qts, it may also be a lot less, depending on how you "preload" the air side.

If your engine runs, in the cruise, at 60 psi, and then you come down to, say 50psi at tickover, oil will flow OUT of the Accusump (assuming an open mechanical valve) until the pressure on the air side equals 50psi. But not all 3qts - just enough to drop the pressure and equalise it both sides of the piston. So you will not flood the sump with all 3 qts of oil in that situation.

As to how long the thing takes to recharge - I dump pretty much ALL of the oil in the Accusump through my engine before cold starts. I then don't rev the cold engine, but let it tickover, and in this condition the engine oil pressure takes about 10 seconds to come up to full "normal" levels - i.e. to refill the Accusump. If I rev'd it a bit, it would take a shorter time.

Once the oil is warmed up and considerably "runnier", this cycle takes a lot less time. The time taken will also vary from engine to engine, for example a high volume oil pump would probably refill the Accusump quicker.

You are going to owe us all a beer at DVSFIII!