toofast928

Under boost oil is being wipped into the oil beather cover. 1 QT every few times engine RPM goes above 4000. My current set up goes like this:
Both valve covers vented
Two baffles in the block oil breather cover
3/4 hose from block breather cover to valve cover (to drain oil) then to oil separator.
Just using the OEM oil fill can as an oil fill, not using the OEM oil separator (so oil in the pan can't creep up the oil drain hose and flood the fill can)
Oil level 1 qt low.

The crankcase pressure is minimal but I can't separate the oil wipped up. Should I add a gasket to the oil pan to lower it from the rotating crank? AND/OR install crank scrapers? It's a street engine so I don't want to dry sump.

Read all the threads on this subject but has it ever been resoved?
Thanks

toofast928

Forgot to add using 20w-50w synthetic oil.

toofast928

Ok has anyone tried just venting the left and right valve cover?
Or how about cutting short the metal portion of the oil drian tube (tube submerged in engine oil sump) That way the I could vent crankase from the tube without the crank oil whip.

Brett928S2

Hi

You have the same problem that I have with my Nitrous when producing high hp it also produces enormous amounts of oil blowby...
The ONLY answer I found was to run the breather pipes to an oil catch tank....then no big clouds of smoke from exhaust...

All the best Brett

PORSCHE 928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS, KICKDOWN SWITCH, K&N, WIZARDS OF NOS - NITROUS KIT 150 HP JETTING - 505 BHP / 500 FT LBS TORQUE
PCGB UK 928 FORUM MODERATOR - Email managingdirector@pchealthcare.co.uk

toofast928

Yea but the catch can "floods"..........

Brett928S2

Hi

Well mine is a 1 1/2 ltr shampoo bottle I get about half a litr every couple of hundred miles in normal driving (using Nitrous occasionally) ...when using Nitrous more...maybe a half litre every 50 miles...

You need a bigger tank....

All the best Brett

918-S

I had an oil consuption issue. I disconnected the drain back tube thinking that was the problem. Not the case.
I tried a vent tube from the cam carrier. I used a clear tube so I could see what was moving through it. It acted like a big fat drinking straw! I was freaked out! I took that thing off fast!.

I just discovered my excess crank case pressure was coming from stuck rings in # 5 & 6 cylinders.

toofast928

The drain tube is problem #1. Crankcase pressure pushes the oil up the tube, into the sep and intake. The lower metal portion is bolted to the oil pan. The tube continues into the sump, covered by oil. So if I cut the tub flush with the top of the oil pan. Blowby gasses can excape and little oil mist. Double ck me, could this work?

918-S the valve covers become flooded with oil whan the blowby can't escape from the crankcase. The oil can't drain quick enough. Was that your situation?

918-S

The stock vent running from the fill canister to the intake plenium couldn't handle the amount of crank case pressure developed by stuck rings. But I didn't know that was the problem at the time. In addition the cam carrier drain back path became the "path of least resistance" This slowed the drain back giving the vent enough added suction to drink the oil. Very bad idea in my case. I only figured this out today as I just pulled the pistons and discovered the rings were stuck in the pistons causing the compression loss. My engine was a salvage yard purchase. I never ran a leak down on the engine. I will next time.

marton

There is a little oil/air seperator under the oil filler cap; it looks like a little basket. Try filling it with stainless steel gauze; like pan scrubbers. That will improve the oil condensation and so reduce the oil blow by

Marton

Brett928S2

Hi MARTON

I tried the steel gauze....helped a little but not much...maybe 10% better...only

I did think the theory was good though...and even had thoughts about something better than the gauze...like a sponge...but sponges although they would absorb the oil perfectly...would break up...and I didnt fancy bits of sponges in my oilways or bearings....

Now if we could find a steel sponge lol.....

All the best Brett

PORSCHE 928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS, KICKDOWN SWITCH, K&N, WIZARDS OF NOS - NITROUS KIT 150 HP JETTING - 505 BHP / 500 FT LBS TORQUE
PCGB UK 928 FORUM MODERATOR - Email managingdirector@pchealthcare.co.uk