911 3.2 Crankcase pressure

[dave99]

Hi, I am new to here but already have a problem
My normally aspirated 3.2 litre 911 has developed a problem. Last year I fitted a breather to the oil tank to reduce crankcase pressure. The engine ran smoother at first and besides the fumes, all was good.
The car has only been used a handful of times over the winter, but when I took her out last week, I left a trail of oil from the local town to my house. The oil appeared to come out of the aforementioned breather.
I changed the pipework back to the original spec and ran the car for five minutes. The car stalled and there was a gurgling noise and oil poured out of the air intake.

Am I wrong in thinking that there should be little or no crankcase pressure on idle?
My head thinks piston ring wear. Should I do a compression test? Are there any other areas I should look at before a strip down?

Sorry it's a bit heavy for a first post

Dave

[aston@ultrasw.c]

Does you breather include a catch tank, or a loop in the hose where oil can accumulate?

Maybe you just filled up the breather with oil and it puked out.

A catch can needs to be emptied occasionally.

[Porsche84]

How is your oil level? It might have too much oil. The earlier cars had a brass "orifice" piece in the breather hose to keep oil from sloshing into the hose, not sure they used it on the 964. With the engine running take the oil fill cap off and see if air is pushing out of the pipe

[kuehl]

Across The Pond:

1) How many miles on the OD?
2) What is the oil level on the dip stick when the engine is up to operating temperature?

[dave99]

Originally Posted by aston@ultrasw.c

Does you breather include a catch tank, or a loop in the hose where oil can accumulate?

Maybe you just filled up the breather with oil and it puked out.

A catch can needs to be emptied occasionally.

Hi, the breather had no catch tank. I just blanked the pipe from the tank at the air intake and fitted a gauze filter at the top of the neck of the tank where the breather pipe originally was. It ran most of last Summer like that with the only adverse thing being the fumes.
You are correct in saying that the oil 'puked'() out of the breather....

[dave99]

Originally Posted by Porsche84

How is your oil level? It might have too much oil. The earlier cars had a brass "orifice" piece in the breather hose to keep oil from sloshing into the hose, not sure they used it on the 964. With the engine running take the oil fill cap off and see if air is pushing out of the pipe

Hi Porsche 84,
After the oil leaking from the breather, I drained the oil, changed the filter and reverted back to the original pipework. There is a brass piece in the breather hose at the tank neck. The car is not a 964, just a 911 with a 964 kit. The 3.2 was retro fitted also...

I put 10 litres of oil in the tank, not sure what that is in quarts but I will look it up!

With the oil fill cap on and the engine running, the oil found its way into the airbox
After cleaning the mess up, I decided the best thing to do was to have a beer and think about the next step....

[dave99]

Originally Posted by kuehl

Across The Pond:

1) How many miles on the OD?
2) What is the oil level on the dip stick when the engine is up to operating temperature?

Hi Kuehl,
Excuse my ignorance, but what is the OD?
I didn't check the oil on the dipstick as it had only ran for one minute when the air intake drank the oil...
I got a bit disheartened then and left it for a while.
I fully drained the oil from the plug at the bottom of the oil tank. I was told the car takes 10 litres of oil from empty. Unless there is a blockage somewhere and it didn't fully drain and then added 10 litres on top ? I let it drain overnight so that is unlikely...
Thanks,
Dave

[kidrock]

Kuehl is referring to the odometer (OD).

Also, it sounds as if you overfilled your crankcase....a common error by newbies. You must drain the oil from the tank above the right rear wheel well, and also a few quarts must be drained from the case itself (there is a plug under the engine for that purpose).

Oil can only be checked when the engine is at full operating temperature, AND running. While warm and running, oil level on dipstick must be at mid-range. You will probably need to drain some oil.

[dave99]

Thanks Kidrock,
I will do that and see what happens. I had visions of stripping the engine out for piston rings etc.....
I will let you know how it goes,
Dave

[dave99]

Hi All,
I just drained the oil from thee engine and the tank and I reckon there is about 15 - 16 litres or the same in quarts!!
No wonder there have been problems....
I am going to let it drain overnight and fill tomorrow...
Fingers crossed that this will solve the problem.
Thanks again to all for your help
I will let you know how it goes.
Dave

[kidrock]

Dave, fill it up with 9 quarts after emptying. After filling, drive car for awhile until engine temps reach full operating temperature (first click on your oil temp gauge, approximately 194 degrees Fahrenheit). Seeing that you're in Ireland, hopefully it is warm enough over the pond to get your temps up. Check your oil with the motor running and warm. Add enough oil to get the level towards the middle of your dipstick.

It's a newbie thing, we've all done it. No big deal. Sure beats the heck out of re-ringing your pistons, eh?

[dave99]

Thanks for that Kidrock.
I filled it with 9 litres or quarts and started her up......
I expected a bit of smoke but there was so much smoke I had to turn it off for fear that the neighbours would call the fire brigade!!
I think the oil must have found its way into the exhaust system and was burning off. I think it will take a bit of time to clear. I will wait 'til the neighbours are out 'til I fire her up again.

Just one worry, I ran her with the oil cap off but there was a bit of pressure in the crankcase and if I put the cap back on the RPM would lower and sometimes cut out.

I keep thinking about crankcase pressure and piston rings..........

Anyway, I hope the neighbours go out tomorrow so I can run her again and check levels.

I will keep you posted of the results.

Thanks for all the information, it's been very helpful.

Dave

[kidrock]

Dave, 2 things:

1) Since you overfilled it, it will naturally smoke. To get rid of the smoke, you will need to drive it. Drive it somewhat gently (keep your shifts in the 3K-3.5K range) until warmed, then really give her a go. The smoke will burn off, and these cars really like to be driven hard and regularly.

2) It is natural for the idle on these cars to dip when the oil cap is removed, as the oiling system is tied into the vehicle's vacuum....explaining why you probably have a bit of oil in your intake, which is causing your temporary smoking issue. The fact that your idle is cutting with the cap off is generally a good sign that you have little, if any, vacuum issues...which are common on this vintage. If your idle doesn't drop with the cap removed, then you would be spending more time tracking the numerous vacuum issues these cars occasionally develop.

In other words: go out and drive her like you stole her.

[A horse with no name]

Hi...Dave, you may already know this - but if not - when you change the oil and filter in a 3.2 it will take 10.5 US quarts which is 10 litres (9.9367 actually) so you are spot on at 9 litres for the moment ...I have found that our 3.2 consistently takes 10 litres with a filter.

It's a bit of a pain, but I would think that with the amount of oil you had in it, you just may have to pull the spark plugs and give them a bath - (in some petrol) _ I guess you'll soon find out in the morning...Which I see is right now ->8:00 am

[Canada Kev]

You might want to clean out the airbox and possibly change your air filter for a new one because of oil and residue in the intake.

[dave99]

Thanks Kidrock , Michael and Kevin for your help.
I will take your advice and give her a careful roasting today. I have ordered a new air filter but it will take a few days. I will fit it and clean out the air box at the same time.

The engine is not the original one and I'm not sure if the vacuum system is piped correctly. there is a pipe at the back which comes out and back into the throttle body. As Kidrock said, there should be vacuum, but I'm not sure if it is piped right.

I will let you know how I get on later....

Thanks,
Dave

I also have a new set of plugs to fit but I might wait til I burn off the oil....

[dave99]

:
Hi All,
I am just back from a drive of about 20 miles. The car performed well once the smoke cleared. I'm really happy now I can drive her for the Summer without having to rebuild the engine
I checked for oil leaks but all looks ok for now. Would you believe there was 18 quarts or litres of oil in the engine?? I can't believe it actually started and ran with that amount of oil!!
The only problem is the car sometimes cuts out on tick over. It idles around 800rpm and just suddenly dies. It starts easy enough afterwards though...

I am delighted the car is back running. It is all thanks to you all and I really appreciate it.

Kind regards,
Dave

[kidrock]

if your engine is idling and suddenly quits, it may be a sign of a pending DME relay or fuel pump issue. Get a good quality DME relay and carry it in your glovebox, it is a necessity with the 3.2.

[msterling]

One or two more notes on checking the oil level. Do not rely on the oil level gauge on the dash and check the oil with engine FULLY warmed up, idling and on a level surface. The last condition is important to get an accurate reading. 18 quarts of oil! Wow! If there were any mosquitos in Ireland, they are now dead.

Cutting out at idle could be DME relay, CHT connection or sensor, bad ground or other less likely woes.

[dave99]

Thanks to you both, I think the DME is the way to go and see what happens.
Msterling;- I drained the excess oil so the mosquitos are safe!!

cheers,
Dave