Edward

As said in many a thread, if an engine has had no leaks with dino over many years/miles, don't swap to synth. Ok, any thoughts (especially from yous folks who have seen the guts of these engines more than I have seen their sparkplugs ): how much mileage, or how many years, of dino oil usage is the tipping point not to go to synth?

FWIW, my 3.0SC engine was impeccably rebuilt (replete with records down to machine work) maybe 5 years ago, but since it's a tracker, has acumulated maybe only about 25k miles (30k miles max). Always frequent oil changes, has never leaked, and bone dry (except for the pesky VC gasket which I don't consider a "real" leak as that dang gasket is a pest anyway you look at it ...maybe will go to billet here). Your thoughts on whether I should go synth for track is "safe" at my age and mileage would be very much appreciated. Thanks!!

Edward

JackOlsen

Try it. You can always change back.

Synthetic doesn't cause leaks -- it just sometimes finds its way through seals that dyno oil won't.

Auto_Werks 3.6

+1 to what Jack said.... I know what the other thread said, people who experienced new leaks that won't go away completely, but I have never personally seen that. I'm not trying to argue that it doesn't happen, but if your engine is in good shape it shouldn't. My opinion is that I would rather have a few small drops of oil on my floor, and get the benefits of the synthetic oil. I changed my old SC to mobile 1 at ~100k, and I did notice one small new leak. It was not enough to make me regret my decision though.

Edgy01

When I had an SC it was the driest 911 I had owned to that point. But that was in the days when Porsche AG's position (really!) on synthetics was, "have your friend put that oil in his $5,000 Mustang engine, not your Porsche." (They told us this during one of many Warbonnet Region Tech sessions with Porsche AG engineering contributing).

Today's 911s are designed around synthetic oil because the belief now is that 80% of engine wear is during the first 30 seconds of engine start up. This stuff is so slick it is virtually impossible to even BREAK IN an engine!

Having been inside my SC engine with many miles on it I have to say that regular oil, if changed regularly, does a very good job at keeping the internals in excellent shape. I ultimately switched to synthetic Mobil 1 on that engine (after break in) because I was running it modified with a Rayjay turbocharger,--and I needed an oil that wouldn't coke up on the turbo bearings. That engine remained dry.

Edward

Cool, thanks for the feedback. My Trackmeister sees maybe 5-10% street use, and a lot of sitting around. I would think that synth would be beneficial not only for the rigors of track use, but also for those few occasions that I fire her up for "to keep her exercised" in between track use. Any recommendations for a good synth in the 10w/40 range?

Edward

Auto_Werks 3.6

That's a subject of heated debate.....
I run Redline 10w40. You will probably get at least 5 different answers.

Edward

Redline, of course ...one of the stand bys ...I'll check out their numbers. Thanks, Ryan!

Edward

MDL

If you search this site you will find enough info to make your head cave in...

Streetfighter

Not with the new search function what a joke!

911vet

I'll admit my ignorance now, but there has been discussion of the zinc content of the modern oils. Don't know if it's a real issue or not, but I run Brad Penn Racing oil partly for that reason.

Ed Hughes

I don't know a lot about much, but I'd either stick with what you're doing now, or try a semi-syn like BP. I ran Valvoline Durablend up until my rebuild and now I'm running BP which has been one of the rave oils the last couple of years. If I hadn't missed a shift at the track, I'd still be on a 135K engine that was clean as a whistle inside with no evidence of bearing wear or any other issues.

There was just a recent thread where someone put syn in an other wise dry SC, and voila, leaks galore.

salukijac

My story is similar. I took my car (prior to buying it) for a PPI. The only leaks noted were from the valve covers gasket (which the owner had warned me because he had not driven the car enough) and from the shift shaft seal. The PO had always used Castrol non-synthetic and was adamant that I should continue to use it, but never said why.

Upon me buying the car I took the car back to the shop to get the two leaks taken care of. The shop replaced the valve cover gaskets but not the other and told me to keep an eye on it. At the same time they changed to Brad Penn semi-synthetic.

After driving the car home I found that I had a leak from what it seems the lower valve cover on to the right heat exchanger. I took the car back and the shop changed the gaskets (they found one that the bead on the gasket itself was broke) and also told me that they found a leak from the oil breather area and they think the oil was making its way down to the lower valve covers.

So is it coincidence? I don't know. I don't remember seeing any smoke after I test drove the car the first time. As a matter of fact I don't remember any smoke either when I drove the car to the mechanic from the PO's house. It would be pretty hard to miss oil falling on the heat exchanger as it smokes.

As soon as I get a chance I'm going back to Castrol and see what happens...who knows?

old man neri

I use something called 'Total oil'. It's a synth, I forget what group but one of the better ones I think. It was called 'efl oil' until it was bought out and the named changed. No issues so far but I don't measure every surface with a micrometer on a weekly basis.

rusnak

I've been using Mobil 1 Synthetic in the 911s for about 10 years now, but what with all of the ZDDP talk and stuff, I bought a bunch of Valvoline racing somethingrather. It says it has more ZDDP than their regular dino oil. I know that I will be changing oil this summer, and I'm doing a valve adjust either this weekend or next. I'm curious as to whether I will notice more or less sludge under the valve covers.

I have also not had any leaks in the 3.2 911 for eight years, all with Mobil 1 synthetic. Supposedly, the synthetic oil has superior "cold flow" properties, but it is not thinner per se than dino oil.

All of the oil stuff is so mysterious, I can't claim to know anything definitively about it, and just end up buying what is commonly available in most auto parts stores because I like to travel with my 911s, and I sometimes forget to take a spare quart when I leave home.

Edward

The "problem" is that there is too much to read on this subject ...and I have read too much of it

So I want a synth for protection, low viscosity for start up and fast-flow to vitals when cold, high zddp, but don't want to spend a mint, but prefer to make annual oil changes as I run few annual miles (as a 90%+ track car). See, I don't really want it all

Edward