Slalom4me

What steps are folks with accumulators like the Accusump or
Moroso units taking over the course of a season to ensure
these continue to fill completely and that there is no air in
the cylinder or lines?

Assuming that the device is set up properly during installation,
it seems there is still the reality that it can discharge and possibly
be susceptible to air in the oil, too. I've read of some creative
mounting locations in C4's - the hose runs and mounting positions
these entail seem like there'd be some potential for air to find
a home

Do you rely on the reading displayed by the indicator gauge or
do you periodically bleed the lines and/or reset the cylinder?
Does anyone add a bleed line from a fitting at the valve to create
circulation?

Also, does anyone plumb a line from the cylinder and mount the
gauge remotely in the cabin where it can be monitored while on
the track? Or perhaps use an electric sensor in the cylinder to
drive a cabin-mounted gauge?

63Corvette

I've been racing with my original Accusump continuously since 1983.

Slalom4me

I bought this Accusump and the Mecca filter down on the frame
rail from Canton in the late '80's. The configuration as shown was
completed in '95. There is perhaps a 3' run of hose down to where
it 'T's into the one-way valve, low pressure switch and return line
from the cooler located under the rad.



.

Slalom4me

Can you describe how you maintain it, how you know it is charged and
free of air prior to going on track, any provisions you've added for
determining when/how long it activates and perhaps how it is mounted/plumbed?

Thanks,
Ken R.

.

63Corvette

I have used several configurations on several diffenent engines over the years. when the engine is running it fills the accumulator, so you want to turn off (close) the accumulator valve prior to shutting down the engine. Then OPEN the accumulator valve prior to starting the engine, which primes the engine with oil pressure. Any time the oil pickup is out of the oil pool for any reason resulting in oil pressure falling, the oil in the accumulator, under pressure from the air bladder, pressureizes your engine (slowly fallling pressure). I use the 3 quart accumulator. That guaraqntees that I will not lose oil pressure on the highest G turns on tracks that I personally run on.

Slalom4me

I have a rocker switch at the instrument panel on the car above
and use the procedure you mention.

What about when the switch gets left open on shutdown
and this isn't noticed until after returning to the
shop or come next race day? If an accumulator is mounted
high and the contents siphon out, will hydraulic action
evacuate air or does the plumbing need to be cracked open
at the valve to bleed the system?

With the valve open and the car on the track, the accumulator
is likely to be cycling, releasing oil into the system and
refilling as required. Over time, it will acquire particulate
matter that will settle to the low point in the cylinder.
How does the owner purge the accumulator of these dregs during
oil changes? Should the accumulator periodically be removed,
drained and cleaned?

Also, is the following math on target? The large 3 qt
accumulator holds 3/4 gallon. A good OEM SBC pump delivers,
say, 8 gallons per minute at red line. So, the big accumulator
contains about 9.4% of the volume a SBC pump can flow in one
minute at speed [(0.75*100)/8], or about 5.6 seconds worth of
pressure safety margin. (And because air on the other side of
the cylinder moves the piston, I think this means the pressure
delivery is non-linear.)

If so, then in say a 1.25 G corner where the oil climbs up the
wall away from the pickup, then there would be a margin of
however long the pump takes to consume any oil (1/2 qt?) trapped
around the pickup by baffles plus the time offered by the
accumulator (5.6+ secs). Then the accumulator will compete
with the engine's requirements after the high load because
the accumulator needs to fill up again after discharge.

Without some kind of indication of the state of the available
charge a driver is unlikely to realize the need to get off the throttle
to give things a chance to catch up. If there is a succession of
corners, is it likely that the unit gets progressively depleted to the
point that by the third corner, it has no available reserve? Here
is where I am thinking that a cockpit gauge displaying the air
pressure on the back of the cylinder would be helpful.

.

63Corvette

Um, Can't disagree with you. Just referencing what works for me. Assuming 144fps @ 100mph, 5 seconds of accumulator pressure equals about 1/8th of a mile of hi-Gee turn. No one disagrees that a full dry sump lubrication is the best (and $$$), but the tracks I run on don't offer Daytona hi-banking type hi-G turns. Use your Accusump with a race type (Canton?) pan of course. Remember, I'm running Vintage, so you may be pulling more Gee than I, but race pan +Accusump is what all of my competition runs. I can't say I've never lost an engine, so you may be right about the sediment collecting in the Accusump, but it simply works better than NOT using an Accusump.
When you forget your Accusump, it just fills the Accusump when you start the car. I've never had a problem with that. A properly baffled sump will only "occasionally" need the reserve of the Accusump, and you can wire up an indicator (tail light?) to light whenever oil pressure drops below a preset level.....so you'll know to ease off (but damage may already have occurred....your results may vary

ZR1 MK

The accumulator is overrated and relied on too much. A proper and superior design oil system is key. Most cars dont have enough oil volume. The accumulator is just a little extra protection. The accumulator does have maintenance issues due to wear that many dont realize.

Mike P

When you change your oil, you should remember to open the Accusump valve and let it discharge into the engine, that way you'll get fresh oil into the cylinder. Granted, without purging the lines you won't get every bit of old oil out, but it's better than having 3 qts of dirty oil come pouring into the system the first time the piston cycles.

When the cylinder is empty, just double check the air pre-charge on the cylinder.

After changing the oil, close the valve, start the engine and crack the valve back open to refill the Accusump. Then set the pan oil level to your preferred level.

Mike P