theiceman

Not to belabour the point if you dont think it is dripping out and you insist it is not burning oil .. er where do you think it is going ? and this opinion of guys bragging about burning oil and poluting ? i have been on the forum for about 10 years in one form or another and have yet to see any Bragging .. only some concern and questions over such things.

Also to Eds point those numbers Porsche puts out are ridiculously low to save Porsche warrant repairs.

You are on to soemthing though and I think would make for a great poll if you are really interested as it seems you are .

Why not set up a poll how much oil do you use between 3K oil changes for example and people can calculae out if they use diferent intervals. Will give you an idea of realy where you lie in the big scheme of things. I bet not many cars use the oil in your numbers, but the facts will be interesting.

Reiver

I've seen the polls on the Pelican site on their oil threads...lots of cars are in the same catagory.
Why do you think Porsche published that 600 number....because many of their (70's early 80's) low mileage cars pulled those kind of numbers.
Oh, it is burning oil all right, no question, they are designed to do so...and higher than I wish it did actually but it isn't smoking so a Porsche can actually use up oil at that level without a cloud of smoke.
The bragging comment was tongue in cheek ref your 'polluting' comment....all Porsches pollute at a much higher level than most cars.

Ed Hughes

Well, in my opinion, there are a lot of 911's going the way of the 944's, with deferred maintenance getting ready to hit the next owner, and to greatly diminish the value of the cars.

Reiver

Ed you're right about the value.
I'll do the maint not the rebuild because the vehicle does not warrant that kind of investment unless you don't care about being totally upside down in the thing.
If the 911sc market improves then it may be worth the expediture.....it's not an emotional issue with me.

Peter Zimmermann

Absolutely incorrect if I read this comment correctly. My '82 SC has 204K unopened miles, and runs so clean that the smog shop that I take it to (he's been doing my car since 2002) for my every two-year inspection (on dyno rollers) tells me that the car has better numbers than a 5-year-old Honda. My consumption rate is about 1 qt/800 miles, my injection CO% is set to the middle of the factory spec range, my plug wires are in very good condition, I use Chevron Premium, and copper core Bosch plugs provide the spark.

Pollution is far more common with pre-CIS cars, such as those fitted with MFI or carbs, or are modified for track use. If the car has properly tuned CIS, and is still fitted with its original equipment smog pump, catalytic converter, and/or Lambda system (depending on year/model), it will be a very clean running car.

It is true that Porsche states that consumption rates are normal at 600 miles/qt, and many have assumed that the figure was that "bad" because of warranty issues. In reality, my shop found our average customer 911 consumed between 1,000 and 1,200 miles per qt, with a handful of rare ones that used less than one quart between 5K mile oil changes. We serviced a large number of cars that consumed between 600 and 1,000 miles per qt. These numbers are for cars maintained by my shop, were driven in the Los Angeles area, and used Kendall 20w/50 GT1 oil.

My shop's "make or break" mileage for top end repairs came at the 300 mile mark, or on cars that had valve clatter, at hot idle, that could not be corrected with a routine valve adjustment. We heard tell-tale clatter in a few engines that consumed about 400 miles/qt, but really never more than that. We also insisted that a handful of customers keep written records of consumption when a valve adjustment would not produce a smooth, quiet engine, and in those cases we discovered, almost to the car, that their consumption rate was about 300 miles/qt.

BTW; on cars with high consumption we did NOT note higher than usual HC specs at tune up/major service/15K mile service intervals. Obviously, my above statements primarily concern SC models, and more valve guide "rules of thumb" must be applied to models such as the '73.5 to '76 models, the 3.2 liter Carreras, etc., and everything changes if a particular engine has already been apart for either partial or complete repairs.

MUSSBERGER

For what it's worth I may add a half quart during a race weekend.
But I baby it.
Change of VR1 after every event whether its a DE or Race.

Reiver

I defer to your expertise on the pollution deal. I should have said they just use oil period. Actually just a reaction to being called a 'polluter' for the oil consumption.
I do appreciate your comments though as I've heard exactly the same thing from the two specialty Porsche shops in the Phoenix area.
I have no valve clatter and the car runs very well other than the oil use.
You would expect a car using that kind of oil to 'smoke' but mine does not...how does that work btw?
Glad to hear I'm not crazy or lowering the values of Porsche's worldwide...

It is true that Porsche states that consumption rates are normal at 600 miles/qt, and many have assumed that the figure was that "bad" because of warranty issues. In reality, my shop found our average customer 911 consumed between 1,000 and 1,200 miles per qt, with a handful of rare ones that used less than one quart between 5K mile oil changes. We serviced a large number of cars that consumed between 600 and 1,000 miles per qt. These numbers are for cars maintained by my shop, were driven in the Los Angeles area, and used Kendall 20w/50 GT1 oil.

My shop's "make or break" mileage for top end repairs came at the 300 mile mark, or on cars that had valve clatter, at hot idle, that could not be corrected with a routine valve adjustment. We heard tell-tale clatter in a few engines that consumed about 400 miles/qt, but really never more than that. We also insisted that a handful of customers keep written records of consumption when a valve adjustment would not produce a smooth, quiet engine, and in those cases we discovered, almost to the car, that their consumption rate was about 300 miles/qt.

BTW; on cars with high consumption we did NOT note higher than usual HC specs at tune up/major service/15K mile service intervals. Obviously, my above statements primarily concern SC models, and more valve guide "rules of thumb" must be applied to models such as the '73.5 to '76 models, the 3.2 liter Carreras, etc., and everything changes if a particular engine has already been apart for either partial or complete repairs.


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Reiver

Peter,
Back to my original question then. I'm getting +/- 600 miles a qt depending upon how aggressively I drive so am adding quite a bit of fresh oil regularly. Brad Penn 20/50.
What interval do you/would you rec for a change with those factors?

Reiver

You need an engine rebuild

Ed Hughes

I used to change mine after every track weekend too. Brake flush done prior to each.

A track weekend was a great time to run injector cleaner thru the tank as well.

Peter Zimmermann

I have no problem doing 3K miles or one year (whichever comes first), nor do I have a problem stretching a 5K miles interval to 18 months. That said, aggressive driving can mean different things to different people. In some cases aggressive can actually be abusive (use of high revs, 4,000+, with a cold engine, cruising at a steady speed at 5,000 revs, etc.), but I consider aggressive driving to be more in line with attacking corners using good lines, using precise braking points, and hitting an apex correctly. All of that can be done inside a power band, can be done without abusing the engine or transmission, and can be done only with a fully warm engine. What this all means is that I need far more info than the word aggressive to help you decide on a service interval.

With your car you also must decide on a good valve adjustment interval. 15K miles is the factory recommended interval for major service/valve adjustment/tune up, but depending on what aggressive means, that interval might be shortened to 12K, even 10K in some cases.

gruppe75

Here is another thought, if you are consistently adding oil why not just replace the oil filter and never do an oil change. If the oil filter is doing what it should be doing, then your oil should be within the acceptable range?

Reiver

Peter,
I always drive conservatively until fully warm...at the 195 deg mark. Aggressively is using the below redline in attacking corners etc not buzzing high rpms on straights. I know it is a high mileage car so give it a safety margin when cold.
The car gets little to no heavy traffic stop/go stuff as I live in a small town. When I leave my street it is 65 mph, low rpm, warm up time.
Not abuse just spirited driving when she is fully warmed up. Mostly highway miles and hardly any idling.

911 Crazy

Peter,

I noticed that I bought Kendall 20/50 GTX oil. Do I need to change out for GT1? Thanks.

Peter Zimmermann

Sounds like Porsche heaven! Change your oil at 5K miles, or 18 months, whichever happens first. Address problems (battery, fuel pump, oil leaks, brake m/cyl, etc.) as they happen, and have fun with the car.

BTW; is your engine fitted with Carrera, oil-fed, timing chain tensioners? Do you have quality P-car service near you (for valve adjustments, CO% set up, filter replacement, etc.)?