Magnus, I may have missed your description of your oil tank setup...

Is it a stock tank? Stock location? Stock oil lines?

Do you have the ability to measure Blow-by?

69 shell, 964 engine, SC Oil tank (stock location) , pre 75 oil lines, front mounted oil cooler.

I dont have any equipment to meassure blowby. What would I need to do that?
But I havent seen this oil issues on the dyno sessions I've had the car on, the last was just a week ago.

Under heavy braking, the oil will run up the tank. There is potential that you can also starve the engine for oil during this event.

The RSR tank had an extended area as well as a plate to prevent the oil from running up.


Blow-by is measured with a blow-by meter. They are not very common.

I'm not sure how your tank is plumbed but here is my catch can on a Carrera tank with my 3,0 carbed motor. I run with my oil level at the bottom line. Never had any oil spill into the catch can.
http://forums.pelicanparts.com/uploa...1587501914.jpg

Braking, now that would make sense!

I searched here for rsr oil tank, I found some pictures where the tanks are extended 2 inches in the bottom. Is that what you mean?
Did they have some horizontal baffle plates too? I have a stock 69 tank cut open and there is just some mesh "baffle" inside.

Like that. But with higher oil level. It could be that with the oil level at MIN it would be fine, but if oil starvation could be an issue I don't like that option. Maybe extending the oil tank and running att MIN could be a good way to fix it?

I've never had this problem in my other 911, but that has a 3.2 instead of a 3.6 and not the same amount of grip either.

Correct. They extended the tanks for added capacity and a horizontal plate.

I can't imagine one quart less in a 3 gallon tank would cause starvation, but I will defer to others that may have experienced it.

I have read that the issue was with '71 and older tanks. The newer '73 on tanks are larger and the pickup is different. But maybe racers have modded the newer tanks as well?

ATTN: Bill Verburg

I know he has tracked 3.6s in older cars for years, maybe he will chime in.

:)

I have this in stock.....

http://forums.pelicanparts.com/uploa...1587567754.jpg

http://forums.pelicanparts.com/uploa...1587567809.jpg

It has the factory design lower baffle and the extended sump. I may be able to help with custom M30 plumbing as well.

Please email me for info.

Len.Cummings at verizon.net

:)

What year is that tank? Looks like the older style with the smaller filter mount, in the pre-72 position.

Nice looking tank! Details?

The oil breather catch can and running at Min will help you . . . that's what we do with 3.8L 964 engine in 1978SC 911 body and stock oil tank . . . our 3 cooler system holds 15 quarts but oil changes are only 11 qts . . .

photo of engine and catch can with drain valve to empty below . . .

Regards,
Roy
http://forums.pelicanparts.com/uploa...1587569261.jpg

:)

Its a repro 73 RSR with BIG Filler neck. Cannot find the cap but will look further over the weekend.

Bought it for a project that is still waiting, and don't know if it ever will get done.

Too many distractions.

My move to NH really put me behind, but at least now I am doing Hoses once more.

Len

:)

It would totally depend on scavenge efficiency, duration of WOT and the amount of G's applied at the end of the straight. Our engines do not scavenge that well above idle, and it gets progressively worse as RPM's climb

The factory made some trick oil return tubes for the 3.8RSR to help prevent oil from running up into the 1-2-3 heads

There is no question that the problem is instigated by g forces based on what you report … but something else must be going on. Lots of people use stock tanks on track cars and aren't blowing oil into the overflow / catch tank.

Is it possible that the level is wrong in your tank? Earlier in the thread you questioned whether you have the correct dipstick for your tank. I think you also mentioned that you put 11.5 liters of oil in, which seems high. Also, you're checking oil level hot, correct?

Done some testing. It definitely pushes out less oil with lower oil level, like on minimum (when hot, idle level ground and all that.), but I'm not sure I'm cool with running such low levels when I also know how the oil is being pushed around in the tank.

One solution would be to let it push it out and just let it drain back from the catch tank.

I got a second oil tank (a 930 in this case) cut it up made an extension and welded it back up.
Welded by a pro, not the prettiest mod ever but that is on me and not the welder. The tank material is very thin and my fitment of the extension piece a bit sketchy.

http://forums.pelicanparts.com/uploa...1593415763.jpg

I also made a horisontal baffle an the front edge to keep the oil from not riding up the front so easily. That makes the oil level sender non usable, but I don't have a gauge for it anyway...

Not fitted it to the car yet.

Question about the 930 oil tank:
There is 2 extra connections, one larger that is a return from the turbo return scavenge pump. The other (smaller one that I have capped) is a source for oil. Is the turbo also feed oil by a second pump or what is this??

I believe Porsche used the sporto oil tanks on the turbo. So one of the ports is not used for that application.

Yes, you are right!
https://www.mecatechnic.com/en-GB/oil-tank-for-porsche-911-and-930-1978-1989_RS10139.htm

You learn something everyday. My tank is stamped 930 in the middle of the tank, nothing else.