Why is 1000 mi per qt oil considered great for 3.0 sc engine

[robert walsh]

I've spoken with several mechanics as well as original owners of 911 sc's that all consider that getting 1000 miles per quart of oil usage to be excellent, I don't understand that comment. They tell me since new that was the case and rebuilt with the same is great. WHY?? I'm concerned only getting 1000 miles out of a quart (synthetic) Should I be??

[lfot]

My car is well maintained, and runs great. I get about 300, maybe 400 miles. 1000 miles seems amazing by comparison.

[RWebb]

do not be concerned - that is well within the factory spec.

911 motors are unlike most others - they are horizontal for one thing

[widgeon13]

I think a lot depends on how it's driven. Go to a track day and you might well be adding oil before the end of the day, drive conservatively on the street and you might get over 1000 before drop in oil level.

[BZ911SC]

Originally Posted by lfot

My car is well maintained, and runs great. I get about 300, maybe 400 miles. 1000 miles seems amazing by comparison.

The SC's use approx. 1.5L (~ 1.5 quart) per 1,000km (~600miles) as per Porsche's specs.

I seem to add a litre of oil about every 5 to 600 miles.

[lfot]

Originally Posted by BZ911SC

The SC's use approx. 1.5L (~ 1.5 quart) per 1,000km (~600miles) as per Porsche's specs.

I seem to add a litre of oil about every 5 to 600 miles.

Maybe it says more about how I drive.

[gamin]

Just for comparison, from the tech spec book for 69,70,71 911 all models, oil consumption is listed as 1.5-2.0 qts/600 miles. 1.0 qt/1000 miles doesn't seem so bad.

[ossiblue]

Originally Posted by RWebb

do not be concerned - that is well within the factory spec.

911 motors are unlike most others - they are horizontal for one thing

Interesting point. I know there are some pilots that frequent the fourm, maybe one of them can comment about oil consumption on horizontal aircraft engines--especially since those engines are meticulously maintained. I'd bet the oil consumption (in hours) is a bit high by automotive standards. Anyone...?

[Rod Schneider]

Airplane engines do use a fair amount of oil, especially compared to most auto engines. The average Lycoming or Continental engine in a small plane shares two design similarities to the Porsche--they are horizontally opposed and they are air cooled. Air cooled engines experience a wider range of temperatures than a water cooled engine and are designed with wider clearances to compensate. That leads to higher oil consumption than in a similar sized water cooled engine. I don't think the cylinder layout has as much to do with it--I've got a Subaru flat six on my airplane, and others who use the same engine report little or no oil usage between oil changes.

[billybek]

3000 miles, 1 litre of oil. Most of that after a DE.

[jerhic]

Toyota Motors says that one quart every 750 is within limits. they all use oil.

[Miguel Antonett]

500 miles/quart you're doing good = normal

[Buckterrier]

Man, mine must be tighter than a tic in a teddie bear. I literally don't use any after the initial fill from doing an oil change. Every 4,500 miles or so.

[gshase]

78 SC less than a half a quart in 3000 miles

[craigyirush]

This is an issue I (perhaps) obsess about too much.

I can understand the 'this is just the way they are' argument.

But then why the variation among Pelicans, given that most of us have engines in relatively good condition?

I get about 6-700 miles/quart in my '86 (and think that's too high). I've heard that Bruce Anderson says that 500 miles a quart on a 3.2 and you should be thinking about a rebuild.

[Miguel Antonett]

Good point.

Why not to start a survey thread (I don't know how...) asking for oil consumption, let's say 80 and older 911's... , 80-90's...90 - 2000... by quart every 1000 miles or so...

[KNS]

About 1300-1500 miles per quart on my '80.

[craigyirush]

I am all for a survey.

Re the factory oil consumption figures - I once asked Bruce Anderson why they were so high (my Carrera manual says something like a liter/1000 kms!).

He said it was probably a worst case scenario - e.g., 150 mph on the Autobahn mile after mile.

[Embraer]

I used to get around 2500 miles per quart in my '80sc

[Zef]

Originally Posted by Buckterrier

Man, mine must be tighter than a tic in a teddie bear. I literally don't use any after the initial fill from doing an oil change. Every 4,500 miles or so.

Same for me...Driving season is about 7 months/4K miles....I just check the oil once a month and never add. But it's a 3.2.......