sza

Hi Guys,

While I haven't narrowed down the actual cause of my recent on-track engine failure, it's gotten me thinking about oil starvation, especially when I inevitably upgrade to "real" tires (to date I've been running on street tires in a deliberate attempt to keep the g-loads down in order to avoid starvation problems).

I happen to have a 3qt Accusump lying around my garage which was formerly on my '69 Firebird, which doesn't need it any more because it's getting a dry sump system when it's put back together. It seems like a shame to waste it.

This brings me to my questions. Hopefully someone here is running an Accusump on a late C4 'vette and can lend some experience. For the record my car is a '95 6spd.

1. Mounting location for the Accusump itself: any suggestions? I'd prefer to keep it out of the interior for the normal hot-fluid-leak reasons, but also because the car is still street driven and does frequently see passengers (namely, my wife) who would rather not step over a hot tube filled with oil.

2. Plumbing: Sandwich adapter on the oil filter? Is it neccessary (or desirable) to use a check valve (I have one)? I'm also considering adding an external oil cooler, so my dream solution would involve some sort of 3-port filter adapter that allows easy hookup of both.

3. Valving: On the Firebird I used their conventional electronic valve with a manual switch. I've heard criticism about the fill/dump rates of the electronic valve. Should I consider a manual valve? The EPC valve? Or just run the one I've got with a manual switch in the cockpit like I did on the Firebird? Is there any real disadvantage to mounting the valve slightly away from the Accusump (which would reduce the overall length by 3" or so, making mounting easier)?

Finally, if anyone has any pictures of C4 Accusump installs it would be extra useful (even on racecars).

Speaking of pictures, here's what I'm trying to avoid in the future:



-Jon

TRACKMAN2

i ran an adapter beween the oilfilter and block then ran lines to an oil cooler the one of the lines had a "t" in it which ran to the accusump i used a manual valve and it was mounted to the roll cage inside..

ScaryFast

Mine's in the passenger footwell, so not much help I'll have to look around and see where else it might fit. Do you still have AC and all those unecessary creature comforts?

As trackman says, you need a T-adaptor. You want the oil system to be able to run independantly of the sump. I run a T before the filter. My oil cooler is on that side also, so cool oil goes into the sump. I have a manual valve so I can shut off the sump and run the car normally for simple things like loading and unloading from the trailer, tooling around the street, etc. There are other ways (read: street car friendly) to do that. There is also a valve you should add that maintains a certain pressure in the sump cannister at all times. I used the manual valve solution because I want to be able to purge the sump fully. But I have to remember to shut the valve with the car running, or it purges the extra 3 qts into the pan...not good.

Put the valve anywhere. In fact, the longer your oil lines the more cooling your system has (but the more oil it takes in a change...I'm at 10 qts ) I like the manual valve better, but for a street car it adds maintenance at every start. However, if I were you, I'd leave it out of the system entirely for most driving, then just open the valve when you go to the track.

I have pics at home I can post.

Slalom4me

For mounting, several members have resorted to placing
the Accusump in the rear where the spare tire formerly
resided. A 3 qt accumulator requires a bit of real
estate (as you will already know) - a precious commodity
in a C4 engine compartment. For a dual purpose car, I
am considering the use of quick disconnects on accumulator(s)
in the spare wheel well, rather than discarding the spare
entirely.

For simple access to the lubrication circuit, a Moroso oil
filter adapter p/n #23690 (sandwich adapter) does the job.
Unfortunately for me, it means removing the OEM heat
exchanger.

The Moroso and the equivalent Canton adapters have two ports.
Both are used when a cooler is in the circuit, otherwise one
is plugged for use with an accumulator. Typically, an accumulator
is plumbed into a cooler circuit via a tee fitting. However,
if you don't like the flow restriction imposed by a 90º fitting
then take a look at the Barry Grant Billet Y-block p/n #170027
with 1/2" NPT ports. This is what I will use to plumb two
accumulators into a single line to a Moroso adapter.

IMO, a check valve is essential for a system with a remote
Canton/Mecca (CM) oil filter because these units do/did not
have built-in anti-drain back devices. BUT, conventional
spin-on oil filters DO have anti-drain back built into them
so I vote that such a system could do without the added
expense of the low-cracking check valve.

My vote is that mounting a control valve away from the
accumulator instead of right beside it does not matter.

Incidently, did you see the threads about C4 wet sump oil control
and about WNDOPDLR's dry sump from earlier this year?

.

Slalom4me

.

About the control valve and fill/discharge issues. Can you elaborate
about the issues you have heard about.

I posted about the EPC a day or so ago. You already have the
electric valve, by adding Canton's adapter and pressure switch
or fabricating your own, you could update to an E.P.C. setup

As mentioned in my recent thread, the EPC is just a pressure
switch added in series with the electric valve for the accumulator.
It keeps the valve closed by interrupting power to the valve. When
pressure in the system falls below the target range (3 ranges offered
by Canton) the pressure switch closes, powering the accumulator
valve and releasing pressure into the circuit.

If you choose the appropriate pressure range, the EPC approach
keeps oil level in the sump from fluctuating as the accumulator
cycles in response to system pressure and adds/removes oil the
way it does with just an electric or manual valve.

.

BrianCunningham

That's the best idea I've heard all day!

Slalom4me

Thanks

The trick would be leak-free fittings and a procedure for
bleeding air out of the lines each time the accumulator(s)
are installed. I imagine actuating the valve after installing
the cylinders and watching for pressure to rise on the
instrument panel.

This together with a bracket arrangement where the
cylinder is held in place with positive locking, quick release
Pip Pins and the electrics are hooked together via Weatherpak
or similar connectors could produce a set-up you could install
or remove in seconds.

(I don't imagine anyone is interested in my idea for a swappable
base for the passenger seat on which fire bottles, data logger,
radio and other debris could be mounted on?)

.

Sidney004

By the way, what brand and weight of oil were you using when you had the mishap? What oil temps were you running? Was it overfilled or normal capacity?

DREGSZ

[QUOTE=sza]Hi Guys,
1. Mounting location for the Accusump itself:

We put it on a verticle brace behind the panel behind the front tires

2. Plumbing: Sandwich adapter on the oil filter?

I plumbed it into the gallery through a fitting on the back of the block, (but it is a Dart sportsman block)
We used a sandwhich plate to run the lines out to the cooler/remote filter, but I think it's prudent to plumb the accusump into the block to get the oil into the block when and if it's needed.

3. Valving:
I used a manual valve on the console, pull open/push close

Were you using a Hi volume oil pump on the blowed up motor?

sza

On Canton's website they say:

From my own experience on the Firebird it would actually take 5-10 seconds for the reservoir to fill completely after using it for prelubing, which was visible as a drop in pressure on the oil pressure gauge.

I've also seen drag race guys complain that they use up all the accumulated oil idling during staging, and on a fast car (8-9 seconds) there isn't enough time for the accumulator to refill before hitting the brakes at the top of the track.

All this being said, Canton themselves recommended the electric valve, and I specifically told them I was using the car for open track events.

Thanks for the good advice, BTW. I don't drag the spare tire around (even on the street) so mounting the accumulator back there is a heluva good idea. Also, no, I didn't see the older threads--care to link me to them?

sza

Mobil 1 10-30 oil, 1qt overfilled, and oil temperatures were near, but under 300degF (most likely 295degF or so).

Hot, I agree, which is why I'm most likely going to plumb in an oil cooler. I also happen to have a decent-sized spare stacked plate cooler from the Firebird with -10AN inlet/outlet.

No. The motor was 100% stock with nearly 90,000 miles. Quite frankly, I was expecting to have to rebuild it sometime in the near future. Would have been nice to make it through the end of the year though.

Slalom4me

This is not my idea, the credit belongs to others.

IIRC, Vetracr and ???

.

Slalom4me

How do your headgaskets look?

Colour is often inaccurate in pictures but I wonder if your
engine suffered 'Death by Chocolate' - coolant in the oil?

Was there white smoke at the time of expiry? If you retain any
of the oil, you could have it tested if there is any question.

.

Slalom4me

I have some opinions and people can make their own evaluation of
these. I welcome critical review of my opinions.

First, I make an assumption that a good SBC oil pump might pump
8 gallons per minute at max RPM. (This will vary according to
which specific pump is used, how the pressure relief is configured,
engine clearances & ect.) 8 gpm is equal to 32 quarts in 60 seconds
which is roughly equal to 3 quarts in 6 seconds.

In other words, at full RPM my hypothetical SBC pump needs six
seconds to fill a 3 qt accumulator under ideal conditions. Note
that during this six seconds all oil goes to the accumulator, the
fill will take longer if volume is going elsewhere (like to the
bearings.)

Next, the pressure and volume within the accumulator is dynamic
and varys with the pressure in the engine circuit (unless something
controls the accumulator contents.) If the pump loses pressure
at full RPM, a 3 qt accumulator theoretically offers 6 seconds
of lubrication, but if pressure is lost at 3000 rpm there will
be less stored volume and pressure and hence less reserve time.

IMO, adding a manual ball valve or valve electrically operated
by a solonoid does not change the situation described above.

(Incidently, because of the convoluted design of the passageway
in electric valves, I suspect that flow through this style is more
restrictive than through a ball valve - but I have nothing other
than appearance to support this prejudice.)

If the drag race guys are opening the accumulator valve prior
to or during staging, then any time that their engines are
operating below, say 60 PSI, the accumulator is dumping some
portion of its charge into the system and raising the level in
the sump.

Can you say "more windage, less reserve protection time and oil
pump pressure/volume lost to refilling the accumulator during the
critical moments of launch and acceleration"?

My vote is that Canton's remarks about refill rates has to do
with the characteristics of the solonoid actuator on the electric
valve. The same valve is provided as part of the E.P.C. unit.

These valves are one-way in operation - the lubrication system
can fill the accumulator regardless of whether the valve is
actuated or not. Apparently the fill rate is higher when the
valve is NOT actuated.

My take on this is that the powerful solonoid may open the valve
a certain distance and hold it there. However when the solonoid
is not energized, perhaps the valve can open a greater distance
and permit more flow/faster filling of the accumulator.

As mentioned, the E.P.C. unit comes with the same electric valve.

What is added is a pressure switch in an adapter coupling. My
vote is that it works by maintaining the accumulator in a fully
charged state until system pressure falls below the range chosen
for the EPC pressure switch. Then the pressure switch closes
providing power to open the electric valve. If the pressure drop
is momentary, the switch opens and deactivates the electric valve when
pressure rises above the EPC target range. With the valve closed
again, this permits faster fill rates.

Still with me?

Frankly, I think that the statement by Canton is bafflegab, driven
by marketing rather than by engineering. My vote is that the refill
issue is due to how much of the contents of the accumulator is being
unnecessarily discharged at reduced RPM (with all the consequences
this has for raised oil levels in the sump.) Keep the oil in the
cylinder until it is needed and I believe much of the refill rate issue
will go away.

Canton putting the EPC and manual valve on par may be appropriate for
engines continually operating in the upper RPM range, but for other
applications where RPM vary widely, I feel the EPC arrangement is
superior.

Incidently, I need to give some thought to whether quick refill is always
desirable. If I spin and the accumulator discharges and then I immediately
go to full power to regain position, is this the time to divert pressure
and volume to refilling the accumulator?

.

sza

I haven't gotten the motor out of the car yet, so I'm not 100% sure on the headgaskets. There was no water in the oil, no smoke, no oil lost, etc...

To my eye, the oil looks like it held up pretty well. The actual oil is still a nice amber color. In the photo the oil in the bottom of the filter is absolutely full of babbitt and copper shavings which throws the color off quite a bit.

I'll have the engine out and disassembled this weekend--I've been working on it after work but I have limited time during the week.

sza

Yes, and after thinking about it, I agree with you on the behaviour (faster fill when "closed"), although one of us will probably have to disassemble a valve and see exactly what the mechanics of the situation are.

I also wonder if the EPC valve allows the Accusump to discharge more slowly--meaning that it will open the valve to allow outflow, but when the system pressure rises above the switch pressure it shuts the flow off (as opposed to allowing the two pressure systems to reach equilibrium). This would be good for the oil level in the pan as well as providing a faster fill rate because the Accusump isn't completely empty.

DREGSZ

I really only considered my accusump as a preoiler with the dry sump. With a wet sump it may prevent momentary drops in pressure if you race with the valve open as it will fill or remain full w high RPM/oil pressure and then dump w momentary drops in pressure like sweeping turns. It won't much prevent more then a momentary drop in pressure or give you about an extra 3 second window to shut it down if something goes really wrong.
If you mount it in the way back like the spare tire carrier area, your volume in the lines will greatly exceed the 3 quarts in the bottle, but I wonder if the distance will temper the function. I don't know

Slalom4me

While I do not have the reference in mind or at hand, I will see
if I can track down the source. It may be Canton's own literature,
but someone more knowledgable than me made the statement.

The valve design is commonly used in fluid control - we have similar
valves with 120V AC solonoids in the walls of the laundry room that
control water to the washing machine. I will see if I come across
cross-sectional drawings on line. I intend to open my new valve at
some point to blend in & radius the end of the pipe threads and I
will take photos.

More slowly?

No, the EPC is just the addition of a switch that senses pressure
outboard of the electric valve. It is binary - on/off, there is no
intermediate modulation by the electric valve.

Exactly how it works, IMO.

In my other EPC thread I write about how the lowest EPC range of
20-25 PSI is too high for my idle pressure of 16 PSI and would open
the valve unnecessarily. The pressure switch appears to be
user-adjustable and I intend to test this.

Additionally, I am considering adding a throttle-actuated switch to
bypass the EPC pressure switch and power/open the accumulator
valve directly above a certain throttle opening (say 50%?). While
I don't want the accumulator dumping into the sump at idle I do
want it to be online if the car loops under power or if cornering or
poor drainback causes there to be no oil at the pickup at high load.

.

ScaryFast

Those temps are fine. I ran my stock C4 LT1 for 6 years without a cooler under the same logic you have - when it goes I get to rebuild and add more HP. Not that it's wise, but I regularly hit 330* with Mobil 1. It's listed as good to 400* (although it seems like a bad thing to test ).

My engine finally went last year, but I only spun a rod bearing (or 3), nothing catastrophic (meaning no parts in the pan). The only solution at the time was to make the block into a 383 . However, I have added a huge cooler, Accusump, RR pan, etc. I don't want to rebuild again for a long time.

ScaryFast

I would absolutely agree with this assessment. Adding a wet sump to a RR car is primarily to improve longevity of your motor by keeping pressures high enough to lubricate. When I change the oil and open the sump it completely discharges in about 3-5 seconds, surely not long enough to for you to notice and react to save your motor while racing. It will help regulate pressure and avoid extra wear during momentary (and regular) drops in pressure under cornering and braking, but it will NOT save you if you have a major failure due to overrevving, a broken line, etc.