Oil scavenging question

BBAY1 · 01-15-2007, 07:02 AM

As a collector of nearly every time of car on the planet over the years, I have recently added a 911 to the mix. Though I've owned air colling VWs and a load of motorcycles, applying my knowledge of air cooling engines is not enough here, so I may be a fequent poster.

BBAY1 · 01-15-2007, 07:08 AM

OK, don't hit enter for carriage return. So, I recently acquired a 1977 with a 1982 3.0 engine. It had been setting for 3 years. PO stated that is suddenly started blowing cloud of smoke and he just parked it. On checking in out for a recommissioning, I drained the sump and tank. I found 12 quarts in the sump and one quart in the tank. Applying standard M/C knowledge, I would just assume that it wet sumped from sitting. Otherwise I must assume that the scavenger pump failed to return oil to the tank 3 years ago, thus causing the smoking engine. Where do I start in diagnosing this problem? Thanks

MBEngineering · 01-15-2007, 10:14 AM

HI put 9lt of oil in the tank and fire it up, check the oil press' and run it ti'l warm , check for oil leaks and your smoky engine?? , poss' valve guides or rings, mileage on the engine??. Post some pictures of the car and the engine, then we can see/help you sort the car with you .

regards mike

BBAY1 · 01-15-2007, 11:48 AM

Thanks Mike: I was hoping to determine if the 9 litres in the sump was a result of gravity and time or a failed scavenger before donating more oil
to the recycling centre.
BB

BBAY1 · 01-15-2007, 11:54 AM

A few pics

Eagledriver · 01-15-2007, 05:29 PM

The tank generally drains into the sump over time. This is normal although annoying.

-Andy

MBEngineering · 01-16-2007, 02:15 AM

HI BB just looking at the photo of the engine and I would like you to check some thing for me, On the back of the black trunking/armadillo on the top of the engine, is there a pipe blanked off?? if so it requires to be connected to the oil filler neck, the pipe also has a re stricter in it for oil vapors, it could be that the PO could have over filled the oil tank and the oil could have got in to the intake, The pipes should look like this,

with a blanking plug in the air box, like this,

do know the mileage of the engine??

regards mike

BBAY1 · 01-16-2007, 07:38 AM

Thanks, Mike. I'll check it out. Regarding mileage, there is no way to know as the car's a bitsa, with a '77 chassis, supposedly an '82 3.0 engine and a rebody done some years ago. Clock show 100k, but who knows what that means? I will throw some oil in it and add some fresh fuel to the one inch of old varnished stuff in the tank. We'll see what it says. Thanks again for the help. I'll keep you posted. BB

BBAY1 · 01-29-2007, 06:47 AM

Well, back on topic. Sorry for the digression to the ignition questions. I did a compression check and found 150# across all six. I was able to start the car for the first time yesterday. Before starting I , once again, drained 8 quarts from the sump and return it to the tank. As expected, it smoked very aggressively, particularly while revving. Oil pressure remained good (two gradations at idle and 5 at 5000 rpm). The smoking continued, abating slightly for the 20 minutes I ran it. The oil tanks gauge fluctuated quite a bit but finally settled at neat full. It showed no signs of overheating. Here is where it gets curiouser and curiouser. I needed to run some errands, so left the car to cool for about and hour. When I returned, I resarted it and there was NO SMOKE. Whether at idle or full tick, it just did not smoke. I was feeling pretty cocky that I had 'fixed' it somehow and took it for a test drive. Smoke free for about a mile, then, slowly at first, then a full blown con trail formed behind me. I dash back before collared and parked it. An hour later I started it to move it to its parking spot and, again, NO SMOKE. What gives? Thanks again. And not to beat this to death, but it it really normal for the tank to drain into the sump? It seems that start up with 3 gallons of oil in the flat sump would make for interesting churning scenarios.
BB

BBAY1 · 01-29-2007, 07:31 AM

I just returned from checking on the sick kid. It immediately fired and settled to a nice idle. Good oil pressure. Tank level deep in the red. No smoke. Let it run for 20 minutes. No smoke, even when revving. Tank level slowly returned to 3/4 after 20 minutes. It isn't fixed till I know what's going on. Thanks. BB

MBEngineering · 01-29-2007, 08:56 AM

HI bb please fill in the gap,= 8 US quarts = Lt, have you have drained and re-filled the engine with the same amount ?? if so drain the engine and the tank and ONLY put back in the tank 9Lt, not 8 or 9 US Lt/quarts , have you changed the breather pipes??

regards mike

BBAY1 · 01-29-2007, 10:51 AM

Hi Mike: When I first started working on the car after recovering it from 3 years storage, I drained 12 U.S. quarts (11.353 liters) from the sump and 1 quart (.942 liter) from the tank. I understand that the car takes 12 quarts of oil or 13 quarts (12.3 liters) if the oil filter is replaced. I refilled the empty tank with 12 quarts of oil. The dip stick and the oil level guage indicated full. Yesterday, before I tried starting it for the first time, I drained 8 quarts from the sump. I assume that the other 4 quarts (3.8 liters) were still in the tank. What is total oil capacity of a 1982 3.0 engine? Is there a dip stick to measure oil in the sump? I have not replaced any pipes or hoses. The car does have an oil cooler in the right front wheel well which some have suggested is not stock. Thanks BB

BBAY1 · 01-29-2007, 11:41 AM

I checked the oil with engine running. After 10-15 minutes, the gage is showing 'full' and the tank dipstick is about 1/2 inch below the max mark. Thanks again. BB

rlane · 01-29-2007, 05:58 PM

Do NOT put any trust in the oil gauge, trust only the dipstick, the level should be at halfway between the marks when the car is on a flat surface with engine temp at least 180 F

Mike is giving you the scoop, start with 8-9 quarts total in the oil tank, there will be 2-3-4 in the lines going to the front cooler, these won't drain (quantity varies depending on the cooler)

Overfilling is a real problem, underfilling is not bad as you monitor and top off based ONLY on the dipstick

Hope this helps

Eagledriver · 01-29-2007, 06:11 PM

It sounds like your engine is fine. The oil in the tank varies dramatically based on RPM and temperature. If you have a good level in the tank (somewhere between the marks on the dipstick) when the engine is fully warmed up and at idle or right after shutdown, then you are good.

It sounds to me like the oil system is over full. After the engine warms up it will dump the excess oil into the intake system.

Pay no attention to the tank level guage except at idle when fully warmed up. It will go to the bottom when driving and this is normal. Also the guage is notorious for inaccurate readings.

-Andy

cstreit · cstreit's Garage

Quote:

drained 8 quarts from the sump and return it to the tank

To reiterate what these guys said... Drain ALL the oil from the car, both the sump and the tank. Then add 8-9 quarts/liters to the tank only. Then once the engine is at operating temperature, check the level using the dipstick.

javadog · 01-30-2007, 05:50 AM

And to beat this completely to death, you are checking the oil level in the tank WITH THE ENGINE RUNNING, on flat ground, at 180 degrees oil temperature and at idle speed?

There is nothing to keep the oil from draining back into the sump when not running, so don't worry about this.

JR

BBAY1 · 01-31-2007, 06:29 AM

Good Morning, Team: Well, after draining 12 qts and refilling with 8, the smoking seems to have abated. Unfortunately I got a no oil reading on the tank dip stick. I had to add two qts to even get the stick wet wet idling at temp on level ground. Hmmm.. In a related question, it seems that the exhaust system is full of oil. It was literally blowing globs of oil when first started. Are the muffler or cats at risk by way of this oil contamination? Some of the visible smoke may now just be oil cooking off in the exhaust system, I suppose.
I can now begin to address other issues, such as a God-awful pre-ignition pinging. I notice that the distributer has two air lines going to the vacuum advance. I thought this was for the turbo engine (suction and pressure).
Thanks again for your patient help. BB

MBEngineering · 01-31-2007, 07:46 AM

HI BBAY1 have you changed the breather pipe to the air box?? or is the photo the same as before.

regards mike

BBAY1 · 01-31-2007, 08:05 AM

Hi Mike:
Actually I thought that the pic showed the hoses going to the vacuum advance, but I now see that it was not showing that. What hoses should be replace? I am going to see that the static timing is close (Z1 mark = TDC#1) I will verify that the advance mechanism is free to rotate and that the vacuum advance works properly. That should address the 'pinging" issue.
PO mentioned that for several weeks prior to the smoking problem that took it off the road 3 years ago, it seemed to be running on 5 cylinders. As spark seems ample and compression seem adequate, I am thinking that I may have a blocked fuel injector. Unless advised to the contrary, I intend to pump 100% Chevron fuel injector cleaner into the fuel distributer and force a bit to/through the injectors. Then I'll let set for a while and see if that does not free things up. I am loathe to take it to a local Porsche 'expert' as they usually aren't and seem to resent you demonstrating any knowledge of your own car. It would just be easier to put some diagnostic equipment on it and ID the problems quickly.
I don't know if you suffer from the same emissions testing nightmares we have here, particularly in Ca., but one of the things about this particular car is that, while it has all the appearance of a 993, it registered as a 1977. Rules here dictate that after 30 years, cars are no longer required to get the bi-annual smog test in order to get regisration renewed.
So, I feel very close to getting this thing back on the road. When it's finally finished with a new top and proper tidy-up, I'll send some better pics.
Thanks again, guys. If your ever in Los Angeles, let me know and I'll set out a few beers to warm up for you.
Regards'
BB