Should I go synthetic?
 

I have a 83 911SC with 122k. It is due for a oil change and was wondering if I should go with synthetic oil. The car runs well and does not leak. What is the difference? What brand is a good brand?
Any help would be great!

Thanks, John

In general all fully synthetic brands are "good brands". The main differences are in the additive package they use. Porsche is currently partnered with Mobile 1 and so in some ways that might be considered the "best brand" because it comes recommended by Porsche.

Synthetics generally offer better protection, better heat dissipation, and better operating range.

If your car isn't a daily driver and you don't take it to events then its mostly a personal choice. The people who will see the most benefits are heavy drivers.

There is a ton of information available about synthetics and plenty of oil discussions have appeared on this board. Start with the synthetic FAQ here on Pelican and if you still want more information use the search button above!

http://www.pelicanparts.com/techarticles/mult_gas_and_oil/mult_synthetic_faq.htm

almost too much info here.

I run Synthetic; and agree that it generally offer better protection, and better operating range. . . .but better heat dissipation? I dont think so. There is a dino or two, which have a fairly high zinc content. I think syth would have a hard time competing w/ those in the heat dissipation race.

Yup, you're right. I apparently pulled that out of my tail pipe. Should have checked first. I was under the impression that it had better theromdynamic characteristics, but I can't find any mention of that anywhere.

Also, if you aren't overloaded yet, Mobil has an entire site dedicated to Mobile 1. http://www.mobil1.com/

Do it.....You'll love it.

Don

dO YOU CHANGE OIL EVERY 3K? wHAT ARE THE RULES?

Be prepared for engine oil leaks if you move to synthetic. Jim

No - too risky. Very good chance your dry motor will start to leave little tears on the garage floor.
Nothing wrong with Dino oil - just change it regularly.

No, unless you want more oil leaks.

GO FOR IT. how is your compression? leak down results?

If you have good compression and great leak down test results, go for it. you should be ok.

I put Synthetic in my 83SC @ 160,000 miles. I was using
Valvoline VR-1 20/50 and had NO leaks. I went with Redline
20/50 and had NO leaks ! I did notice my engine ran cooler
and I got better milage.

This gets debated over and over and over again. There have been tests and tests and tests and there is never a clear reason to switch to synthetic, except that you can go more miles before an oil change. I change my oil about every 1500 miles so that is not a reason for me. In my simple mind, if my car didnt leak with Mobil 1, which it does, I would use it becauase it can't hurt anything. In fact, maybe, when the weather is cold, on startup, it provides better protection. Otherwise, the dino oils listed above will do just fine. There are a lot of other things that will go wrong with a 911SC engine before it is damaged because of using Castrol GTX instead of Mobil 1.

The silicone ones are firm but just don't look real. I say stick with natural... Oh, wait, this isn't the OT forum. Sorry.

Synthetic oil almost always has the ability to go twice as far, often 3 times as far as conventional oil between changes. Every car is different so there are no steadfast rules to go by. Used oil analysis (www.oaitesting.com) is the right tool to use to determine how far you can go on the oil (any oil for that matter)

If you do a little studying you'll find that 3000 mile drain intervals are a farce, even with conventional oils. https://www.amsoil.com/usa.aspx

Don
www.lubedealer.com/dstevens

I was just thinking..

The drain interval debate usually circles around the quality and brand of oil. Some people argue that synthetic oil keep its properties longer than dino oil and because of that can be used with longer intervals.

But what about all the small metal parts and dirt that is suspended in the oil posing a threat to the internal engine parts ? Would the accumulation of such debris not be the same with any kind of oil and hence make an important factor for drain intervals ?

Please correct a newbie as you gents see fit ! :)

Don't you think any metal bits or any debris would be caught by the oil filter?

Yes if they are big enough, but I figure there are debris in all sizes and a lot of it so small it passes threw the filter.

Well, it was just a thought...:rolleyes:

What about on a fresh rebuild? Will the same "drip" rule apply to the older type engines with brand new seals and tolerances when/if switching to the synthetics? :confused:

Dont mess with a good thing...stick to dino and avoid oil leaks

Thanks. It does sound like an easier solution.

I was a quart low the other day out with the 930 and I went in to the auto store, picked up a quart of Castrol. I felt like I was cheating a bit since I run it in my other cars/motorcycle. :)

A full synth oil change compared to dino would be marginally noticeable.

This is a valid concern but anthony is right, they will get caught by the filter up to 10000-12000 miles. The pieces that are too small for the filter are relatively inconsequential to wear. We are talking about wear metal in parts per million here. Sure a car that goes 10000 miles on oil might have 30 ppm of iron in the oil where a car that goes 3000 miles may have 10 ppm. Most oil analysis labs don't even flinch at 100ppm so the extra wear from 10 - 30 ppm in the example is not significant relative to the longevity of the engine.

Long drain intervals have been proven safe (as supported by oil analysis data) in thousands of vehicles over millions of miles based on cars with 5 qt sump capacities. Many of these are large V-8s with much piston/cylinder area than our cars have and 1/2 the oil capapcity. Our 10 qt plus oil capacity and realtively small friction areas in the engine arguably allow the oil to disperse even more microscopic metals.

This is another reason for used oil analysis. This will reveal how much additional wear YOU get in YOUR car based on YOUR oil and YOUR driving style/conditions. It absolutely eliminates guess work and speculation.

Don

This is a high mileage street engine, right?
Sure, go ahead and throw money down the drain by using synthetic oil. If you're lucky you might even be able to rationalize it with some reason, no matter how irrational or how much of a stretch it is. Lots of others have managed to justify it.

BTW, i run synthetic just because i have a turbocharger, otherwise i would keep my money in my wallet where it belongs.

turbocharger! . . .on a high mileage street engine? ....

(Now what was that about "justify & rationalize"?) ;)

LOL my engine is no longer a high mileage street engine, it was gone through about 3000 miles ago so now i can rationalize that it is a new engine (not really, that was humor) ;)
And yes, there was quite a bit of rationalization involved in the decision to install a turbo. the easiest argument with myself was hp per $.

I figure a set of SSIs and a good muffler would set me back a grand and get me an increase of somewhere in the 10 hp range after deducting all the exaggerations. That's $100 per hp gained.

My turbo has netted me somewhere between 70 and 100 hp increase (no dyno yet so i leave a lot of room in that range) for around $1200. That's about 9 times more economical and effective than headers. Being a cheap SOB, that made more sense to me :)

Plus the results of the turbo install are real, obvious, and measureable. Changing to synthetic may or may not have benefits that justify the extra money, if it does they would be very hard to measure.

Each to his own but I have used Amsoil racing synthetic on all my vehicles since 1987. Some of them I bought new and others used. I never had any leaks that weren't already there. The syns all now have additives that theoretically prevent this. I change oil filters between 1500 and 3000 miles depending on the vehicle and driving manner. Syn will help save you in the case of catastrophic failure of the cooling system (syn won't coke at temps that fry dino) and I have experienced this on several occasions but not with the Porsche. The miles on all of my vehicles is extremely high with 587K on my Toyota PU but I am sure some of that is due to good engines. In the end it is your choice with lots of advice on both sides of the issue. Good luck.

Best regards,
Gerry