kaelijos

Hi All: Has anyone had or heard of this problem? When my 77 911s sits in the garage for long periods of time, the oil in the tank empties into the engine and overfills the sump. Upon start-up the car will smoke excessively for about ten minutes. I've been able to minimize the condition somewhat by driving the car on to ramps thereby raising the front , which keeps the oil in the tank. I've been advised that the car probably has a worn oil pump allowing the oil to bypass the pump and seep into the case. I'm trying to avoid removing the engine and cracking the case to replace the pump. Any ideas would be appreciated. Thanks, Joe

theiceman

hi joe and welcome

do you know for a fact this is the case or are you assuming this is the case about te oil draining down.

Steve Weiner-Rennsport Systems

Joe,

Thats normal for these dry-sump engines after sitting for awhile and nobody should ever tell you differently. You do not need another oil pump; you need competent and more honest advice,....

Keep the oil level mid-way on the dipstick when hot and that will minimize excess oil from getting into the airbox.

theiceman

ok now im confused ..

Steve you are saying it is normal for the oil to drain down into the crankcase ?
Further are you stating that this has something to do with his car smoking at startup ?
and if the oil draining down is normal why would keeping it between min and max help it from getting into the airbox ?

or are you talking about 2 different issues

Thanks

Steve Weiner-Rennsport Systems

Heck yes,...

Liquid, oil in this example, always seeks its own level and if it sits for a week or so, will run back through the pump and fill the case to equalize its level with the tank.

Remember now, the cylinders lie in some oil when the car sits for a few weeks. There are several reasons for smoking at startup that include:

1) Siphoning (see above)

2) High oil levels (causes flooded bores and excess oil in the airbox)

3) Worn rings/cylinders (poor sealing)

4) Excess fuel (dark smoke)

Maintaining HOT oil level at or below the middle of the dipstick range reduces the amount of oil the pistons rest in and less the chance of oil getting pushed into the airbox by worn rings, however,......there can be a little smoke at startup after its been sitting for awhile.

kaelijos

Hi Guys: I appreciate your input re my problem. If this is normal for a dry sump system, I find it hard to believe that no one else has had this problem. Many owners leave their cars sitting for long periods of time. It's not just mild smoking on startup, it is severe smoking for at least ten minutes. This can't be normal. As I said, if I elevate the front wheels, thereby keeping the oil from running forward into the cooler, I can leave the car for several weeks without so much as a puff of smoke. Thanks, Joe

race911

That doesn't have anything to do with anything. The thermostat shuts off flow forward, period. Until you're at operating temperature. It's on the scavenge side, anyway.

Can't add anything else to what Steve has said above, other than to say that when I had my shops going it was right in the wheelhouse of total POS 2.7L cars hanging on by a thread. So I saw a lot of junk engines that still ran. Somehow. Never have seen that much of an excessive-smoke-on-startup issue, absent an internal failure like a bad valve stem seal or broken oil control ring.

Steve Weiner-Rennsport Systems

Joe,

If you are seeing big clouds of smoke on startup, my suggestion is to perform a leakdown test as a start. This won't tell you anything about the oil control rings, but gives a general idea about engine condition.

FWIW,.....my own carbureted 2.7 sits for YEARS and starts right up without any puff of smoke. Its oil level is perfect and the ring sealing is in the 1-2% range. I attribute this to my use of Total Seal rings.

theiceman

interesting stuff all round to be sure .... mine sits all winter and has absolutely nothing the first start up of spring .. but after a long hot run .. the next time a start it .. cough cough ..

not to worried though as it uses allmost zilch in oil and runs great ..

kaelijos

Thanks All: I guess it's time for a nice 3.0 conversion, and get away from this magnesium 2.7, which should never had been manufactured by Porsche. Shame on them. Joe

race911

Why not? Worked fine up through the 2.4L era. Even the non-thermal reactor 2.7s that didn't get overheated. I think the highest mileage 2.7 I ever took apart had over 180K original, one-owner, religiously maintained miles. Was pretty cool to take apart a factory assembled engine with that many miles. How it had never puked a tensioner, I have no idea......

Peter Zimmermann

The oil back-filling into the engine is precisely why the oil return tubes will leak after a car has been sitting a week or longer, but not leak during daily use. Believe me, this problem is common, but is it really a problem?

Trust Steve, your car does not need a new oil pump. But it might need the oil level set correctly, and it might need new piston/cylinders, or rings.

HarryD

I think you mean DECADES

Steve Weiner-Rennsport Systems

OW OW OW,......oh man,..you are cruel.

That was a cheap shot, but I cannot blame you for taking it (I would have done the very same thing).

If I get time, I'm going to start it this weekend after a 3 yr hibernation.

HarryD

Steve,

Not cruel, just want to have your car see the sun.

Your car will be happy for the love. Go out and have some fun! If you do it saturday morning stop by cars and coffee (Tigard). Hopefully I will be there for the first time this summer.