Synthetic or non-synthetic oil poll

[rsr808]

I'm not looking to start a debate here... I've done the research in the forum archives and have an idea about the two religions.

I just wanted to see how both sides stacked up... from my search it doesn't look like anyone has done a poll yet. Let me know if you think otherwise.

If you would like to identify your specific type of oil then please do so with posts.

Mahalo,
Steve

[CHILI]

Dyno oil in the P-car, but Synthetic in the Accord. Both Castrol. I've heard (not starting a debate, but giving an idea as to why I don't run synthetic in the P-car) that Synthetic can make an older car leak. Besides, it's about $4.50 a qt and the dang things take 11 qts!

[masraum]

$50 is cheap insurance.

[arerrac]

castrol 20w-50.
My wrench says that he only put synthetic oil in cars that originally came with it from the factory. He's put it in older p-cars and experiences leaks.

[dmac]

I use Mobil 1 15-50 in the 911. Synthetics hold up better under high temps - and air cooled engines have locally high temps. I don't drive many miles so I change oil/filter annually. No leak problems.

[fred cook]

I have used ex-dinosaurs, syn-blend and full synthetic in my
Porsches over the years. Several years ago, I got stuck in 5:00pm Atlanta traffic on a 100 degree day and SERIOUSLY overheated the engine in my '88 924S. I am convinced that the only thing that kept the engine from being ruined was the Mobile1 in the crankcase. I prefer to use the 15-50 Mobile1 in my 911, but have used other quality 20-50 wt oils when I could not find a "deal" on the Mobile1. Of late, Wal-Mart has started carrying the 15-50 Mobile1 in the 5 quart jugs for about $18-19.
$3.60 per quart is bearable! I put about 9-10,000 miles per year on the 911 and change the oil and filter every 6 months, in the spring and fall so that the oil will be fresh for the hottest and coldest months. I guess that about $100.00 per year for oil and filters is ok.

Fred Cook
'80 911SC coupe

[silverc4s]

Mobil One in the Porsches, I want the added margin at temperature provided, rebuilds are waaaaaay too costly to pinch pennies on oil ;-)

[Kevin Stewart]

Mobile one in the porsche, i took my stock car motor down to the engine shop, the first thing the mext morning i get a call from the speed shop, i look on the caller id and say sh?t, something musty be bad in the motor shop to call me this early, when i answer hes says what the heck kind of oil do you run, i say mobile one, hes says the motor looks like brand new inside, i told him i change it every 4 races, he ask me to come down and look, the motor was spottless in side, my car runs at least 20 degrees cooler, idles better, revs smoother then any other oils i have used in a motor before, to me its worth a few oil wet spots on the engine, if it runs a little cooler because of oil alone, Kevin

Besides Porsche puts it in, and they have more knowledge about thier motor then most of us

[mr.bch]

I used to be an Amsoil freak, but my buddy is Newman's crew chief so now it is Mobil1 in everything for me. The 911 gets 15w-50. No complaints, no issues, no leaks with my Mobil1 synthetics.

I recommend Mobil1 for EVERYONE (shameless plug) !

[Lothar]

Synthetic for me. IF the car sits for a while, it can find its way out of the motor. Otherwise no leaks. Mobil 1 or Kendall synthetic have both worked well for me.

[1982911sc]

I believe in Wayne's 101 book he sites a test that was done on two equal cars (same engines etc...), one had dino one had synthetic. They drove the ***** out of both cars for an extended period of time. They then pulled the engines and inspected the crankcase and could find no diffrences at all between the two engines. He recomends dino for older engines with old seals and synthetics for newer cars. I personally use Castrol 20-50. I used this in my old 912 and my 82 SC. My SC has always used this from as far back as the records go (20 years) and my car with 74,000 miles runs like new (no smoke-ever).

[kepperly]

Bruce Anderson's recommendation is Kendal 20w50 gt-1
no syn. Thats my choice.

Keith Epperly

[BoogieOnSkis]

I heard Bruce Anderson also doesn't like Castrol.

He says whatever they put into Castrol to get it to coat the engine also turns the inside of the engine a funky gold color.

He said this during his engine rebuild class when my Dad attended a couple of years ago.

[chrisreale]

Originally posted by kepperly
Bruce Anderson's recommendation is Kendal 20w50 gt-1
no syn. Thats my choice.

Keith Epperly

On page 190 in the second edition of the 911 perf. hand book he recommends Kendall, Q. State, Valvoline, and Pennzoil for petrolium, or Mobil 1 for synthetic. He does not say he recommends one over the other.

[mr.bch]

I am going to dig for an excellent article I once had on the contents of popular motor oils and what they do. Molybdenum, zinc, all kinds of funky stuff. Turns out, the stuff you use for high G, severe applications, isn't the best for constant running. Slick 50 is great for start up because it has high molybdenum content and coats and sticks to your cylinder rings and such, but $0.79 pep boys oil has less abrasive additives while running. So what do you want to prtect your engine against??? Start-up, normal runnng wear, heat, etc....

[Jadams1]

I just switched from dino to synthetic and I have no leaks. I'm running 10W30 Mobil 1. Next time I'll use a slightly heavier weight.

[RickM]

Mobil 1 in 4 cars and a Harley.

[1fastredsc]

Either amsoil or mobil. With this topend rebuild that i'm almost done with, the seals and gaskets should be no problem. I'd also like to say that heat wise the mobil and ams were the same. Only difference i noticed in my old 944 was that the mobil would be very dark after 3k-4k miles. I let the ams run for 5k and when i drained it still looked far from dark. I don't know if that can be considered a scientific test or not, just an observation i guess.

[jlkline]

My experience with Mobil 1:

I had 11K miles on a one year old rebuild of my daily driver. (no DE ever) Up to that point, I ran dino (Castrol 20-50) changing it every 3000 miles with no engine leaks. After reading a lot of tech articles and forum threads, I decided to bite the bullet and switch to Mobil 1. After 2 months I observed leaks developing in multiple engine locations...case halves, valve covers (930's), etc. which got increasingly worse over the next several months.

I switched back at my 1st valve adjustment interval after the rebuild (15K miles) and the engine leaks completely stopped and have not reappeared after 1 year.

Until someone comes up with a synthetic that behaves the same as dino from a leak perpective...I'll stay with nature's lubricant.

[Jocke]

From a start i used Castrol RS syntetic oil, but after spoken with my mecanic i went to Castrol GTX3 non-syntetic oil, and i must say that the engine runs much better with the non-syntetic oil, not one leak, barely dont take any oil at all.

Same guy who said to me "dont use that synteticstuff" has worked with 911's sins 1965 and been mecanic for some 911 racecars and he told me they always drive with the Castrol GTX in their cars..

Not trying to start a debate only sharing...

/Jocke