Dry Sump for Street Car?

[Clatter]

Sitting ruminating upon the location for a dry sump in a car that needs use of the back seat...
Car in question being a type 3 fastback with type 4 motor.

While many competition cars have room for a pony keg standing upright where the back seat used to be,
There has to be a more practical location...

The 911 has a large dry sump tank that doesn't take up interior room, right?

How about building a low, rectangular box to sit below the back seat?
Like the battery; only on the other side.
It would be easy enough to run a vent line out back through to the trans area, and into a breather box located as normal.
This way it might be low enough to not siphon all the oil out of the tank during long storage?

Or, perhaps run the tank all the way up front?
The type 3 has a dandy large area in front of the spare tire.
Could run a couple of -8AN (-10AN?) lines through the tunnel pretty easily, as it's open right now.
Might make it easy to run a front-mounted cooler as well.
Plus, putting the weight up front would be good.

No matter where, some creative fabrication for a tank is likely to be part of this.
Such is my idea of fun..

Anybody ever do something like this?

[Piledriver]

A t3 has a bit of room in the engine compartment, passenger side by the bellows,(some on both sides actually) if you can fab a custom tank.
(admittedly the exhaust gets all in the way with the original motor, but with a t4 it just restricts access to the alternator )
The 911 DS ank or even a bug has room/lives under the rear fenders (autostick tank, for example), a t3 has a big cooling air channel everywhere you might think to put the DS tank.
The t3 does have a bit of room in the front fenders though, similar to a 911.

I would be inclined to keep the lines as short as possible, and the return line at least as large as possible.
IIRC 911s used 18mm ID line.

I would try for around the engine somewhere or by the trans, with a sealed flap in the deck for the filler.
(OK, not sure how to do the filler on a fasty, have a square)

I was going to finish welding the under-the-trans exhaust but it rained on me, maybe tomorrow.
(I'm outside, no garage. Yet.) This is to make room out back of the engine for... Stuff.

[Steve Arndt]

Opposite the battery under the seat is hidden and safe (oil lines covered and hidden). It also places the tank level close to the sump level so drain back after shut down isn't an issue.

I still don't like the idea of a hot oil tank in the interior for a true nice street car. The tank will be hot, noisy, and bulky. Hiding it near the transaxle would be best.

[FJCamper]

Hi Clatter,

It might help your options to know that there are small, square dry sump tanks, most of them by Butlerbuilt and hold three gallons. Try EBay.

We run one in our Chump/LeMons Super Bug, but it is in the passenger seat location. Ours is great but with one minor problem ... the oil-out fittting is on one side, no problem for a circle track car, but in high-rpm high-G sweepers it is possible to force oil on the other side of the tank and for a few seconds suck foam. We have a big low-pressure warning light that tells us when this happens. This is not likely to happen to you on the street. With us, it is rare enough to keep us from applying the fix, which would be to relocate the oil-out fitting to face the rear of the car.

The cylindrical tanks are designed that way to allow swirling circulation of the oil to defoam it.

Be aware if you live in a colder climate, you'll need a tank heater for freezing weather, and if in a moderate climate, at least an oil thermostat to divert from the oil cooler.

I recommend a dry sump tank for racing. for the street, it's just nice to have.

FJC

[buildabiggerboxer]

My thoughts are I would use the needs must rule for a street car, do you NEED Dry sump, if you spend hours in the car just cruising to a destination, it's probably not worth the added cost work and complexity for most purposes away from serious race track work, then as its a road car, I would site it outside the cabin, the oil tanks belch pretty acrid smelling fumes, we have to vent ours to catch tanks for racing, I don't smell mine during eventing until the cooling down lap, but you won't miss its stink then, being front mounted, I presume the racing air speed vents the fumes away until i slow, also, there's the 100* cabin heater effect to consider you won't notice it racing, but you will stuck in traffic jams in summer, careful what you wish for. ..

[Clatter]

Tanks for the replies, guys...
So sorry for that...


The car in question is completely disemboweled, and all mounts and hangers are TBD at the moment.
Now is this time, if i'm going to do it..

This info helps a lot for sure!

Maybe a large, shallow, cylindrical tank beside the trans...?
Maybe two small ones, even?

I'll be up under there to make some measurements shortly.
A fastback is, for all intents, identical to a square in that area, FWIW.
A filler up through the deck would be do-able, with maybe some S-bend..

A 915 and frame horns doesn't leave a lot of room!

Any chance someone has a pic of either an auto-stick tank,
Or one of those front-mounted 911 tanks for me?
Been groping around for pics, and it's frustrating finding these....

[FJCamper]

Hi Clatter,

I forgot to mention something really important that relates to dry sump use on a street car.

The oil-out fitting on the tank and the oil-in fitting on the pump need to be as level with each other as possible. When the tank is mounted higher than the engine, the oil in the tank tends to flow downhill until the oil level in both tank and engine are the same. Our "little" square tank sits low enough (right on the passenger side floor) so that all we had to do was create a slight up-curve in the oil line to the engine and we have little to no drain-back.

Guys who mount their bigger tanks higher typically have to use shut-off valves to keep from slowly flooding the engines. That means one day, someone will start the engine with the valve shut!

Even the 911 had a little drain-back problem on some models, and on a morning startup, you'd see some oil smoke.

Something to plan for -- FJC

[turbobaja]

Make sure the tank is "easy" to access and fill/drain as well. You need a method of measuring the oil level in the system as well. The only 911 I've had my hands on had the oil tank in the right side of the engine compartment and a gauge on the dash displaying the tank level ( to be read at idle). I run my DS tank high in my interior, behind my back seat. It's vented back out to the engine evac system and there's no smell whatsoever. I made a simple dipstick calibrated to the oil level in my tank shortly after shut down. Do it right after an oil change and you'll know how full the tanks is with X qts of oil in the system. I do have to run a ball valve in the feed line to the pump inlet from the tank, but I also believe the tank being above the pump inlet helps feed the pump. The valve also makes it possible to disconnect the tank from the engine and NOT drain the tank. That being said, I'd definitely try to design a tank that sits ~level with the engine's oil level for all the right reasons (simplicity) just keep access and service in mind.

[FJCamper]

Gentlemen,

Yesterday, we were stripping the tinware off our LeMons dry sump Superbug (engine in place) to check the head torque. When Jamie popped off the a valve cover, out flooded an immense amount of oil.

A dipstick check showed the case was entirely full of oil up above the cylinders!

This is the first time we've had our sump drain back this way. We have that nearly perfect level plane between the oil tank out and the engine oil pump. Of course, I do know the oil level in the tank is higher than the oil level in the engine, and oil drainback is possible, but it's never happened to us this way. I have read that drainback can be increased if the oil pump gears stop in a certain alignment, but that's second hand knowledge.

The car has been setting level for a few months before being pushed into the shop to be made ready for Barber in February. I have to confirm that the front end wasn't set on jackstands above the rear as our crew has been working on it, but as of yesterday, both front and rear of the car was up on jack stands.

FJC

[andy198712]

I guess maybe how hot the oil was when shut down may contribute??

[Piledriver]

Adding a sight glass setup of some flavor should be pretty easy, and a good idea.

A lot of tanks are set up for it already, all it has to be is some translucent or clear teflon tubing, 1/2" would probably work best.

You could just as easily put a simple one in the case, rocker box, or valve cover.
Metal screw in ones start at ~$5, although you may want to remove the visual "reflector" so its easy to clean off the window inside.

[FJCamper]

Hi Piledriver,

The Blitzwagn's oil tank actually does have a sight glass, being a plastic tube with brass end fittings. The tube was hard to see with the tank cover in place (LeMons insisted on an exterior metal housing) so we provided a Lexan window to see the tube, and a push-button batter-powered LED inside the tank to illuminate the tube.

Even with all this, the visibility and line of sight was awkward, so we drilled a hole for a throttle cable guide tube in the top of the tank, tapped it in, and installed a standard dipstick.

That worked! No more guessing about oil levels.

It appears our oil drainback occured because for a day the car's front was up on jackstands, and rear tires on the ground, while a new CSP 20.6mm master cylinder was being installed. The mechanic wasn't thinking about drainback., but we will all be looking out for it now.

FJC

[Clatter]

FWIW,

I have seen a buzzer rigged up to the ball-valve lever.
So, should someone turn the key on with the valve closed, they get buzzed at...

Would be redundant if it there was already a buzzer on the oil light circuit!

Will be measuring how much room is up under the deck of the type 3.
A fill and dipstick up through the deck, vented to the regular breather box in the compartment.
Hhmmm....

It would keep the tank out of the compartment, and low(er), and a little bit further forward...

[Piledriver]

One could also easily put an ignition kill on the ball valve handle.