Oil Tank question

[Uwon]

My original oil tank for my turbo motor was destroyed in a crash. It had a third oil line connection just to the right of the filler cap which was fed by a hose connected to the scavenger pump attached to the cam at cylinder #3:



I have a replacement oil tank from (I think) a '78 SC which does not have the third oil line connection so I am wondering how I can use this to dump the oil from the scavenger pump:




I have found a couple of threads that address this issue to some degree but I still have some questions that I need to clear up in my mind.

1. Can I T-in the oil line from the scavenger pump directly to the lower oil line connection on the tank (right beside the base of the filler neck), and, if so, what mods do I have to consider to prevent oil from flowing back into the top of the motor;

2. My understanding is that the third oil line on the turbo oil tank (shown here in the first pic) has an internal tube that flows to the bottom of the oil tank. Is this correct? and,

3. If my assumption in #2 above is correct, can I not simply weld in a connection to the bottom of the SC oil tank to one of the two indentations on the tank for the scavenger pump? See pic below...



For those of you that may be interested, you can see the progress of my build in the 911 tech forum.

Evolution of a Carrera RST

Thanks in advance.

[cole930]

Uwon:

An alternative that is easy, safe, and simple !!!

There is a thread on this here on the turbo forum.




Cole

[Uwon]

Cole,
Doesn't this mod require a filter before dumping the oil into the top of the motor?

[cole930]

Uwon:

No !!!! I installed the in line filter just to filter any coke ( burnt oil )
granules out of the scavenge line before it got in the main oil tank.
The filter comes apart and has a cleanable screen in it. I just clean
the screen while I'm doing a normal oil change.

I dumped the scavenge oil through the sump plate because
it was very easy to do. The oil is then picked up by the engine sump
system and sent back through the oil filter before entering the oil tank.

Cole

[fredmeister]

Originally Posted by Uwon

My original oil tank for my turbo motor was destroyed in a crash. It had a third oil line connection just to the right of the filler cap which was fed by a hose connected to the scavenger pump attached to the cam at cylinder #3:



I have a replacement oil tank from (I think) a '78 SC which does not have the third oil line connection so I am wondering how I can use this to dump the oil from the scavenger pump:




I have found a couple of threads that address this issue to some degree but I still have some questions that I need to clear up in my mind.

1. Can I T-in the oil line from the scavenger pump directly to the lower oil line connection on the tank (right beside the base of the filler neck), and, if so, what mods do I have to consider to prevent oil from flowing back into the top of the motor;

2. My understanding is that the third oil line on the turbo oil tank (shown here in the first pic) has an internal tube that flows to the bottom of the oil tank. Is this correct? and,

3. If my assumption in #2 above is correct, can I not simply weld in a connection to the bottom of the SC oil tank to one of the two indentations on the tank for the scavenger pump? See pic below...



For those of you that may be interested, you can see the progress of my build in the 911 tech forum.

Evolution of a Carrera RST

Thanks in advance.

You really want to get a hold of a sportomatic oil tank. I'm 90 percent sure this is the same one used in the turbo. It has a fitting port on the bottom of the tank near the large diameter S-hose port that receives feed from the turbo scavenge pump line. The turbo adopted this tank since it was inventory Porsche had from the days of the 911 sportomatic transmission.

I know this is easier said than done, but maybe you could source or trade the SC tank for the correct one. Thats if you want to replicate OEM.

Check out the Parts exploded diagrams on this website and maybe it shows the turbo specific oil tank and you can see if the tank is the same as for the sportomatic 911 models.

Fred

[fredmeister]

http://www.pelicanparts.com/911/911_parts/1974-75/1-6-2.JPG

Here is the link to the Parts diagram off Pelican's technical pages.

Fred

[TurboKraft]

What year is that tank supposed to be from?
The 1978-89 Turbo tanks do not have that.

You can filter scavenged oil before returning it to the engine case, but the factory did not filter it on the 993 Turbos.

[Flat6pac]

Thats a Carrera tank from 84 to 89. Connects to a vacuum line to the throttle body.
Bruce

[spuggy]

Originally Posted by fredmeister

You really want to get a hold of a sportomatic oil tank. I'm 90 percent sure this is the same one used in the turbo. It has a fitting port on the bottom of the tank near the large diameter S-hose port that receives feed from the turbo scavenge pump line. The turbo adopted this tank since it was inventory Porsche had from the days of the 911 sportomatic transmission.

Yup. PO told me that, and I checked; same part # in PET for the Sporto and 930 oil tanks.

I have a sporto/930 oil tank listed for sale in the Classifiieds; I picked up another one, had Fabcar extend/baffle it and used that instead.

[Uncle]

Originally Posted by cole930

Uwon:

An alternative that is easy, safe, and simple !!!

There is a thread on this here on the turbo forum.




Cole

Yep that's how I did it more or less. I must of been using my inner "Cole" when I thought of it.
That SOB has gotten into my head! Now how to make up a 934 rear engine bar...

[cole930]

Uncle:

Just mock it up out of cardboard.



Cut it out:




Reinforce the end hangers:




Bolt her up:




Done Deal:






By the way !!! It;s actually that " Old SOB "

Cole

[Uncle]

LMAO. Nice one Cole.

[Uwon]

Originally Posted by cole930

Uwon:
I dumped the scavenge oil through the sump plate because
it was very easy to do. The oil is then picked up by the engine sump
system and sent back through the oil filter before entering the oil tank.

Cole

Cole, forgive my ignorance but isn't this sump plate an oil fumes breather mechanism leading to the oil tank? If so, am I correct to assume that in your setup the dirty oil that has gone through the turbo finds its way internally into the bottom of the engine and directly out to the oil tank without being used by or splashed to any other area in the motor?

[Uwon]

Fred, Chris and Bruce, the original damaged tank is from my wrecked '86. I have looked at the PET pages for several of the model years but it sure is difficult to decipher the various tanks and where all the hoses go per the factory. My motor being a converted 3.2 to a 3.4 turbo with no emissions, etc. whatsoever has fewer boxes, tubes, etc.
Anyway, I am considering Cole's idea but at this point I think that I will attempt to pull the damaged tank out of the wreck and cut it open to see the layout of the internal tubing. It's pretty squished between the fender and the engine bay. That may sway me to graft a nipple to the bottom of the new tank. Cost would be the same as I would have to either pay for tapping or welding.

[cole930]

Uwon:


The turbo oil tank has an additional fitting at the bottom right side of the tank. I you were to cut the tank open you will find that the fitting internally is an additional tube that runs about 3/4 of the way up the inside of the oil tank. This was done to make sure scavenge pump return
oil could not siphon back to the pump when the engine was shut off.

Chris ( The Horsepoew God ) at TurboKraft actually suggested dumping it into the crankcase vent. By discharging it there it gets screened again and picked up by the crankcase sump and pumped through oil return line to the tank where it is filtered again.

I had a bent up scavenge return line and would have had to replace the old discharge line so I cut the fitting off the end of the discharge line, cleaned up a penny and soldered it inside the old fitting and used that to plug the scavenge inlet at the oil tank.

Putting the fitting in the sump cover was a piece or cake. I used a 1/2 npt tap and then bought a 1/2 npt to 6an adapter for
the line back to the scavenge pump outlet. Send me your address and I'll send you the tap if you don't have one.

Hope this helps clarify things.


Cole

[cole930]

Uwon:

Run a 6an line from the scavenge pump outlet to the crankcase
vent cover on the top of the engine.











Cole

[fredmeister]

Originally Posted by Uwon

Fred, Chris and Bruce, the original damaged tank is from my wrecked '86. I have looked at the PET pages for several of the model years but it sure is difficult to decipher the various tanks and where all the hoses go per the factory. My motor being a converted 3.2 to a 3.4 turbo with no emissions, etc. whatsoever has fewer boxes, tubes, etc.
Anyway, I am considering Cole's idea but at this point I think that I will attempt to pull the damaged tank out of the wreck and cut it open to see the layout of the internal tubing. It's pretty squished between the fender and the engine bay. That may sway me to graft a nipple to the bottom of the new tank. Cost would be the same as I would have to either pay for tapping or welding.

I understand. If you do cut open the tank please post pictures for us to see what it looks like inside there. This would be valuable info, to me at least.

Cole pointed out an important feature in that you would need the internal anti-siphon tube to prevent backfeeding into the turbo pump from the oil level in the sump tank. He is a smart dude to point this out.

Coles solution is probably alot easier. The only thing I would do is add a small inilne filter to the discharge line from the turbo pump so that filtered oil gets dumped back into the vent breather cover or the engine oil tank. Without a filter little bits of coke from the turbo are allowed to run through the engine oil pump back into the oil sump (Coles method) or through the pressure side and into the oil galleries (OEM method).

I still cant believe Porsche never compensated for this some way. There are a few posts in here on this topic if you search as well. Some guys show how they added an inline filter to help alleviate this issue.

Fred

[Uwon]

Cole,
Those are very helpful pics for the modification. You are very kind to offer to lend me your tap, however, I have today been able to borrow a metric tap locally (after all we are supposed to be metric in Canada). So thank you on both counts. In any event, Canadian postage costs being what they are, its probably cheaper to buy the tap in the U.S. and have it sent to Canada rather than sending yours up to me and then mailing it back to you.
My curiosity is getting the better of me so I will try to dissect the damaged oil tank this weekend, If, I can get it out of the wreck.

Fred,
I will post pics if the tank comes out and I can do the dissection.

Cheers....

[cole930]

Mr. Fred :

My method does have an in-line filter.







Cole

[fredmeister]

Originally Posted by cole930

Mr. Fred :

My method does have an in-line filter.







Cole

Yes because you are a smart dude.

I re-read my post and the wording does make it sound like you neglected the filter....sorry about that. I meant to say that tapping the cover was your way versus the OEM sump tank solution.
I just really wanted to make the original poster aware of adding the filter in case he did not realize it.
No harm no foul.

have a good weekend,
Fred