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Bob: IM S6 posted:

As one who has 11 or 12 liters of oil in my engine, I get it changed each Spring, and if I have put more miles than usual on it during the Summer, I get it changed before Winter storage.  As Stan says, it's the age and acidity of the oil you need to be concerned with.  Two filters need to be changed each time, also.

And an oil change for my car ain't cheap...

And Stan, you forgot me..."I now know of 3 guys who are dry-sumped-- you, Danny, and me. I'll never go back."  

Add in my compatriot David Stroud, and we have at least five members of the Dry Sump Society.

Everything cost more when your in the stratosphere of IM ownership   Good for you. 

Having a dry sump system is great.  Depending on where your dry sump tank is located as to level with motor or above over a period of time the oil level will rise in the crankcase.

Where am I going with this? 

If you store or park your car for the winter you may want to have a shut off valve or remove the inlet line to the pump to prevent oil seeping into the crankcase.

I known people to have a dry sump system store a vehicle for months and go to start it and when checking the oil level they add a few quarts/liters only to hydro the engine when firing or once the pump begins to scavenge they have excess oil in the tank.

Will it start if the oil crancase is full?  If it does would'nt a note to self be a better way.  While a shut off valve is a good idea, I can see someone forgetting to turn it on and smoking the engine ...

I think I would make myself a note to not add any oil how long would it take to pump the sump dry?  

Just a thought.  

Hand brakes are forgotten on all the time etc etc. An oil shutoff would scare me. 

Anthony posted:

 

If you store or park your car for the winter you may want to have a shut off valve or remove the inlet line to the pump to prevent oil seeping into the crankcase.

I known people to have a dry sump system store a vehicle for months and go to start it and when checking the oil level they add a few quarts/liters only to hydro the engine when firing or once the pump begins to scavenge they have excess oil in the tank.

I've discovered that my engine / dry sump system will allow some seepage as Anthony mentions above. I think that may be called wet sumping. Older British bikes were famous for it.

My last Roadster run before today was in Florida about a month ago. Oil level was perfect. I checked the dipstick on the motor today before startup and it was about a litre over. No big deal but some smoke on startup too. I checked the oil level in the remote sump when all was warmed up after a 20 km drive and all was correct. I then checked the dipstick in the engine and it was back to normal = full. 

Radial aircraft engines are famous for this and Jim Kimball down in Florida came up with a electric shutoff valve that was switched in such a way that the engine's starter would not work if the oil valve was still shut off.  If you hydro lock a radial aircraft engine various things can go very bad quickly...like bent connecting rods etc. My small 5 cylinder radial engine has two cylinders below the center of the crankshaft. After shutdown, on number four cylinder there is a little tin can hanging under the downward facing exhaust pipe to collect oil that might drip out of the exhaust valve and on number five cylinder there is a small valve you open to let any errant oil hanging around the low spot on the intake runner. 

 

Last edited by David Stroud IM Roadster D

@David Stroud IM Roadster D wrote- "...about a month ago. Oil level was perfect. I checked the dipstick on the motor today before startup and it was about a litre over. No big deal but some smoke on startup too. I checked the oil level in the remote sump when all was warmed up after a 20 km drive and all was correct. I then checked the dipstick in the engine and it was back to normal = full..."  

I'm confused, David- I thought that with a dry sump system there was almost no oil in the crankase. Why would you have a full 2½ quarts of oil in the engine- the wet sump would be full? The whole idea of a dry sump system is that there is no appreciable amount of oil in the crankcase area to be whipped around- correct? Doesn't the scavenge stage suck it out into the remote tank as fast as it's pumped in?

Last edited by ALB
ALB posted:

@David Stroud IM Roadster D wrote- "...about a month ago. Oil level was perfect. I checked the dipstick on the motor today before startup and it was about a litre over. No big deal but some smoke on startup too. I checked the oil level in the remote sump when all was warmed up after a 20 km drive and all was correct. I then checked the dipstick in the engine and it was back to normal = full..."  

I'm confused, David- I thought that with a dry sump system there was almost no oil in the crankase. Why would you have a full 2½ quarts of oil in the engine- the wet sump would be full? The whole idea of a dry sump system is that there is no appreciable amount of oil in the crankcase area to be whipped around- correct? Doesn't the scavenge stage suck it out into the remote tank as fast as it's pumped in?

Interesting point, Al and it's quite possible that I don't know exactly what I have. I didn't build the system, don't have a diagram for it and have never seen one before. Is it possible that I have an " auxiliary" type remote oil system rather than a true dry sump system ?  My engine does have it's stock type dipstick and there is oil showing on it from the stock VW sump. 

Edit:   I just checked Henry's website and my car is still in the "sold" section of used IM's for sale. It does mention there that the engine is high performance 2332 cc with dry sump and 911 reservoir. I just went out to check the engine's dipstick again and it's still at the full mark. Something amiss ? 

Last edited by David Stroud IM Roadster D

David,

It's a dry-sump system-- but I think it's got a CB oil pump, which isn't as nice as a Bugpack or AutoCraft.

Regardless, you don't ever check a dry-sump system in the crankcase. It's dry when running, and the only thing you have in it when not running is what bleeds back.

You want to check is in the tank, on level ground, with the engine running and warmed up. The tank is your sump. You carry oil in the tank, not in the engine.

Last edited by Stan Galat

David:

Where is the oil dipstick on your set up?  With a dry sump, the only dipstick is the one in the oil tank, which in my car is in the back right, accessible from the engine compartment.  There is no oil dipstick as part of the engine itself.

The oil filler is is also remote from the engine.  I have to remove the oil cap, and inside is a dipstick.

I have to check the oil while the engine is running, warmed up, on level ground.  That gives me a true measure of what oil is in the system.

 

Last edited by Bob: IM S6
Bob: IM S6 posted:

David:

Where is the oil dipstick on your set up?  With a dry sump, the only dipstick is the one in the oil tank, which in my car is in the back right, accessible from the engine compartment.  There is no oil dipstick as part of the engine itself.

The oil filler is is also remote from the engine.  I have to remove the oil cap, and inside is a dipstick.

I have to check the oil while the engine is running, warmed up, on level ground.  That gives me a true measure of what oil is in the system.

 

His engine is a converted T1, and therefore has a dipstick tube on the engine. This is the confusion. I've got mine capped and plugged, but if the last guy just left it in there to keep oil from spewing out, I can understand the confusion.

Regardless-- don't look at that one, David-- it's meaningless.

Stan:  Here is a shot of David's set up.

https://www.flickr.com/photos/...m-72157697419866162/

https://www.flickr.com/photos/...62/with/43551363524/

David:  Use the dipstick under the silver oil filler cap at the side, to check your oil level, car warm, engine running, on level ground.  There is a dipstick under the filler cap.

Last edited by Bob: IM S6
Stan Galat posted:

David,

It's a dry-sump system-- but I think it's got a CB oil pump, which isn't as nice as a Bugpack or AutoCraft.

Regardless, you don't ever check a dry-sump system in the crankcase. It's dry when running, and the only thing you have in it when not running is what bleeds back.

You want to check is in the tank, on level ground, with the engine running and warmed up. The tank is your sump. You carry oil in the tank, not in the engine.

Yes, checking the oil dipstick under the filler cap on the oil tank is what I was taught to do and that is what I do. Everything level and everything running and warmed up. Someone noticed that I do still have the original oil dipstick on the crankcase so me being me, I look at that sometimes too. 

Thank you all for your advice and concern. Motor on, eh  ? 

Bob: IM S6 posted:

Stan:  Here is a shot of David's set up.

https://www.flickr.com/photos/...m-72157697419866162/

https://www.flickr.com/photos/...62/with/43551363524/

David:  Use the dipstick under the silver oil filler cap at the side, to check your oil level, car warm, engine running, on level ground.  There is a dipstick under the filler cap.

Shyt, Bob....that's a nice looking car, eh ? About $19,000 USD and the Bride and I got a nice cross Canada tour to boot. Thanks again for the info / confirmation.

I know, Ray...it's got patina which you're not so fond of...but hey, I've got it too. Trademark windshield treatment too. 

You guys are funny, dry sump society....

David, two things control oil seep into the crankcase. The first is the height of the tank, if it is appreciably higher than the pump inlet, the height can exert some pressure(measured in inches of water, or in this case, oil) on the pump gears. The second is the closeness of fitment in the pump gears. You could put a solenoid in the line or a valve, but I wouldn't. Too much chance of forgetting the valve or failure of a solenoid valve.

I don't know about the CB pump, but I do know that the Autocraft and Bugpack pumps have suction gears that are about 2x the length of the pressure side. Just like the 911 pump.....so any oil that may be in the crankcase is gone in a second or two of startup.

It is easier to control the height of the tank in a Spyder, there is more room in front of the engine. I have zero oil migration into my old "wet sump", even after the winter of sitting. What is funny is my dipstick is still in the engine to cap the tube. But I still use it. Just not in the normal location. I modified and installed a Vanagon dipstick tube, it is much longer and made it easier to check the oil with the old system and the 911 shroud. It's about a foot long, so it allows me to use it in the dry sump tank, then store it in the engine. I know it's weird, but it works well.

FYI, there is no crying in the DSS. HA!

Last edited by DannyP
Meade posted:

I'm having some issues with temperature in my Subie in my Beck.  My VDO oil gauge indicates about 220, and it ain't even summer yet!  I noticed that they only installed a large single fan on the radiator but Cary said that it was sufficient. I'm thinking of puling my clock out of the dash and installing a water gauge.  I'm wondering what the WATER temperature will be... Also, I need to find out where the sending unit is located on the engine.

Meade

The coolant temp sensor is on the coolant manifold on top of the engine, Meade. Image search Subaru coolant temp sender location and you'll see many examples.

That will give you the temperature of the coolant coming right out of the engine as it heads to the rad. Remember that the Soob coolant system has it's thermostat located where the rad cooled coolant enters the engine. 

Last edited by David Stroud IM Roadster D

Some of you guys may be able to give me some info concerning something this thread made me think of. Years ago I bought a type 1 engine built for road racing and it had an Accusump thing hooked to it. It was a tube like thing that as it was explained to me pushed additional oil into the system when and if the engine saw a low to zero oil pressure reading. This wasn't a traditional dry sump setup. Has anyone have any knowledge or experience to what this was exactly?  I have enjoyed reading this thread, thanks to all for the educational and entertaining posts.

I do, and I run one in addition to the dry-sump. They serve two functions:

1) as a safety to supply oil in the event that the oil pressure supplied to the galleys drops below a certain point (5 psi, generally)

2) as a prelube device-- pressurized oil can be supplied to the bearings before start-up

I put mine in pre- dry-sump, but am only using it for pre-lube now, as there's really no chance of exposing the oil pick-up to air or foam any more.

The principle is exactly like that of a diaphram pressure vessel for a well pump. The Accusump is a vessel with an oil chamber and an air chamber. There is a piston with a seal dividing the two sides. When oil pressure exceeds the pressure on the air side, the vessel begins to fill with oil. As the vessel fills, it pushes the piston into the air side, thereby increasing the air pressure. When the two pressures find equilibrium, oil stops flowing. If the oil pressure in a galley drops below this pressure, oil starts to flow back to the engine. This can all be controlled even more precisely with a  solenoid valve arrangement and pressure switch. It's really the cat's meow.

I can't for the life of me figure out why more guys don't run them.

Last edited by Stan Galat

Thanks Stan ! You gave a well worded easy to understand answer. You are right I would think anyone with a high dollar engine would have one of these things but I have only seen one of them in use. The dry sumps are a must for hard road course driving. I had a couple track experiences with loss of oil pressure during long hard turns and having valve covers flooded with oil and also oil coming from unfamiliar places on the engine. Things I wasn't prepared for or understood well. I can see how a dry sumped engine is the way to go. The new vette's have dry sumped engines. I cant wait to see more of those on the streets and in the used market 5 or 6 years from now(maybe 10-15 for my budget).

Stan Galat posted:
Gordon Nichols posted:

IIRC, George Brown had one on his engine, too.

An Accusump? Yes, he did. That's where I got the idea. I'm pretty sure it was the only thing GB and Jake Raby ever agreed on. I figured it had to be worthwhile if neither felt the need to sling mud on the other one for it.

Stan--I didn't know you knew about George B.  Those emails were the best entertainment since  Vince was around here.  Glad you brought GB up.  Goes back what---10 years?

Last edited by Jack Crosby
barncobob posted:

i believe that if the engine is running and it shows full then its full..U might be trying to outhink the system..

Bob, Danny Pip said this a couple of posts earlier....

"  I don't know about the CB pump, but I do know that the Autocraft and Bugpack pumps have suction gears that are about 2x the length of the pressure side. Just like the 911 pump.....so any oil that may be in the crankcase is gone in a second or two of startup. "

This implies to me that there should be very little to no oil in the crankcase if the dry sump system is working properly. I'm just curious to know what's going on with my system. 

David,

I know that your have a dry sump system-- converted from a wet-sump system, and I'm 99.9% sure that the conversion was done by Ron L. after he had the engine built, installed, and running. That's why there's a dipstick on the engine-- because the dipstick tube was already there, and putting a dipstick in it is a decent way to keep from puking oil out the hole. Here's what I did with mine:

Blank-off

I think I finally understand the confusion. I believe you want to know why there's a level in the sump, as it can't bleed backwards that quickly (it's not overnight, it's "right now").

I've got one big question-- does your oil pump look like this?

CB Dry Sump

^^^ A CB dry-sump pump is only about 1-1/2" thick. ^^^

Or does it look more like this:

AutoCraft Dry Sump

^^^ An AutoCraft or Buck-Pack pump ^^^ sticks much further away from the case-- like about 3- 4" out to the face of the pump.

The pumps we are talking about are "2-stage" pumps-- they are 2 separate pumps in the same housing*. With both of the pumps above, there is a "scavenge" pump, and a "pressure" pump. The scavenge pump sucks the oil out of the engine and puts it into the reservoir, the pressure pump sucks it out of the reservoir and puts it back in the engine bearings. The oil can be filtered and cooled in either system, but almost everybody (except me) does it in the scavenge circuit.

The scavenge pump will always be bigger than the pressure pump, because the whole goal is to keep the sump dry ("dry sump", get it?).

As you can see from the thickness of the pumps, the impellers on the AutoCraft pump are a lot bigger than those on the CB pump. A LOT bigger.

Why? Well... packaging. The big drawback to a nice, big dry-sump pump is two things

  1. The crank pulley gets in the way.  
  2. The header collector almost always gets in the way (unless you have a Spyder).

My crank pulley is small enough to clear, but that means it's way smaller than a power pulley even-- small enough that in order for the fan to spin at the right speed, I need a much smaller alternator pulley. That's why I've got a serpentine set-up. Mine was one of the first ones, before everybody was making them-- it was just a guy in his machine shop doing them after work. He (and only he) offered a dry-sump set-up that replicated the stock fan ratio using smaller pulleys that would clear the pump. When everybody in China started copying the systems, he moved on the other things, and the dry-sump pulley set-up became unobtainium.

The other thing is the header, and I had to wait 6 months for Tiger at A1 to build me a custom sidewinder (2 actually, one was 1-3/4" when I had the 2332) that would clear the pump. It was less than awesome trying to do it two time-zones away.

Anyhow-- that's why CB does it the way they do: to allow the use of a 6" power pulley, since the pump doesn't stick out super-far, and the cover plate can sneak behind a 6" pulley, and to allow you to run any exhaust you want. It's slick, except that it may not pump fast enough to keep the crankcase empty of oil.

There's the trade-off. It sounds like yours isn't doing everything it could be doing, and I'd suspect it's because you have a CB pump.

OTOH, it isn't hurting anything either. You aren't carrying any more oil in the crankcase than you would be with a wet-sump, and you are pumping out of the tank. It'll probably run just fine with that, but I'd definitely want an oil pressure gauge in the pressure side of the system to see what kind of oil pressure the pump is producing. I'd guess it's less than you'd think, because the pressure pump on the CB dry-sump pump is pretty small as well. It's hard to fit two nice sized pumps under a pulley. 

*FWIW, AutoCraft (and Moroso, and a lot of other people) make multi-stage pumps with many scavenge circuits pulling from a lot of different places (valve-covers, etc.), all dumping back in the reservoir. They're really, really funky looking and are typically belt-driven.

The deeper you go into this stuff, the cooler it gets. Good luck. If you decide to go to a bigger pump, get out your wallet-- it's goes pretty sideways, pretty fast.

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  • CB Dry Sump
  • AutoCraft Dry Sump
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Last edited by Stan Galat
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