Peter Zimmermann

rnln: In addition to monitoring your mileage, also pay very close attention to your oil consumption! Castrol has lousy detergent properties, and a switch to Valvoline, a superior oil, will undoubtedly begine to clean away crud that has built up on internal parts. The oil rings are really susceptible to build up, and as the crud melts away from the rings they will lose some of their ability to seal to the cylinder wall. I saw this on many cars that my shop converted from Castrol to Kendall - before we fully realized what was going on! (After that we (1) gave our customer the option of changing, or (2) on cars with more than 75K miles we put a small amount of GTX in stock). I found, over time, that most cars eventually returned to something close to their Castrol "consumption" range (as the oil rings regained some measure of sealing ability), but some didn't, ending with about a 25% increase in consumption. We also noticed that the first couple of oil changes after switching that the Kendall came out absolutely black, contrasted to the Castrol, which came out almost clean. I never dreamed such a significant gain in fuel economy could be had by switching to a much better oil - it will be fascinating to hear your next results!
Pete

Jay H

I've got a newly acquired '84 Carrera. Almost 92,000 miles. It's getting anywhere from 21 to 24 mpg in mixed driving. I maybe get 26 mpg on the freeway.

I'm due for an oil change. The previous owner has Castrol GTX 20W 50 in it which has been in it since about 90,000 miles. I'm going to dump in Valvoline Racing 20W 50 (my favorite dino oil anyway) and then keep a close watch on gas mileage and report back. I won't change anything else.

The car runs reasonably well when warmed up, is stock except for a Dansk cat bypass and Dansk sport muffler.

I'm curious now...

Jay
90 964 & 84 3.2

holtjv

Pete--I've read you recommending Kendall in the past? What's the primary difference/benefit? And which Kendall oil do you recommend for street/DE use?

Thanks...Jack

btw, bought the 79 SC you helped with on the PPI

rnln

Peter Zimmermann,
First I have to say that I really admire your knowledge on P car technical.

On your previous reply, several of your comments made me confused. You said "Castrol has lousy detergent properties"... "Valvoline, a superior oil". I am not an expert therefore most of my knowledge/choice are from friends, internet, and personal life experience.

Let me start from the begining of my "oil life". When I start learning to do maintenant on my cars, I decided to use either Castrol or Vavoline and has been using them since then, for many years. The reason was because the local dealers were using them, include BMW and Toyata. Once I switched to Mobile1 Synthetic on my 6-7 years old BMW and found more oil leak. From there, I found "Synthetic enhance leak" comments all over the place; therfore switched back to Castrol/Vavoline. In my mind, I always thought Castrol and Vavoline are equal in quality.

Years back, while talking about things related to oil, similar topic came up and there were several people comments that Castrol is way better, and laught at Vavoline. This is the number one reason for me to use Castrol at my first choice and Vavoline at second choice.

Now I am confused.

Further on your reponse, let me conclude to see if I understand you well. Basically Vavoline is better oil compare to Castrol but switching from Castrol to Vavoline will make the oil come out darker since Vavoline clean the mess from Castrol. And also the car will consume more oil with Vavoline since Castrol oil has detergent and such to seal cylinders wall. Did I get it correct?
If I do, I'm also thinking about oil leak. This means Castrol will make the engine has "less oil leak" compare to Vavoline, Kendall, and other better oil?

I definitely will pay closed attention and will post results.
-------------------

I also just read your comments and suggestions on the transmission G50 noise on the other thread. I definitely would bring my car to your shop on major problem, if you are somewhere closed, but we are couple hundred miles away

Thanks.

Peter Zimmermann

Jack: Hello and I hope that '79 is working out well for you! Regarding Kendall, over the years my shop had the honor of doing a ton of engine repairs and rebuilds - both on 911s and 356/912 models. During that time we found some amazing differences on engines that we could trace oil manufacturer usage. For instance, Kendall engines, after disassembly, were ridiculously easy to clean. A couple of hours in the cold tank and the case halves and cam boxes looked like new. No caked on residue on the connecting rods or other internal parts. On the other hand, Castrol and Pennzoil engines were ugly, really ugly, inside. Three DAYS in the cold tank, followed by two hours of hand scrubbing, and the parts were still not "clean" - bad stains, caked on crud, etc. Connecting rods always required bead blasting, etc. Jumping back to the Kendall engine, the cylinder walls were always in good visual condition, although in very high mileage applications were worn outside of wear tolerances. In Castrol/Pennzoil engines the same was true in much younger engines - accelerated cylinder and ring land wear was the norm. Oil rings clearly suffered from build up (I've seen oil rings completely plugged) in the Castrol/Pennzoil engines. Camshaft and rocker arm wear really told a story. Many times we were able to number each rocker and reuse the rockers and cams in the Kendall engine. That rarely happened in Castrol/Pennzoil engines, cam lobe pitting and rocker face arc wear were the norm. Chain "stretch" seemed to be unaffected by oil, and was primarily caused by abusive driving following cold starts, or frequent use of high revs in first gear. 911 connecting rod and main bearings did not seem to be affected by oil type, but 356 bearings (subject to more vibration and other stresses, did show accelerated wear with Castrol/Pennzoil. For some reason Valvoline never really caught on with my customer base, but we found it to have wonderful lubricant and detergent qualities on cars that we maintained where owners provided the oil. Regarding street/DE use, Kendall GT1 20/50 is an excellent choice, but as I posted above, if the car has a Castrol history really watch consumption. Permit me a short story. Back in the late '70s we changed a 50K + mile Porsche from Castrol to Kendall. Our customer called me from somewhere in the desert, on his way to Las Vegas, a few days later. After yelling at me (loudly!) for not topping up his oil, things calmed down and he added three quarts to the car. I was pretty shaken, we talked about it in the shop, and my mechanic who did that car remembered clearly that he topped it up. Well, the customer called again the next morning. It turned out that after arriving in Vegas he had to add two more quarts! He was no longer mad, but we were all scratching our heads. On the trip back to L.A. the customer added one more quart in the Palm Springs area, and consumption, after that, returned to almost normal. That's really when we figured out that Kendall cleaned the oil rings so thoroughly that it rendered them temporarily ineffective. Of course, other factors play into this discussion, such as how many short trips vs long trips does the car do, how often was the Castrol changed (3K miles? 5K miles?, etc.), and how is the car driven when the engine is cold). Every car will/can be a little different, but, on average, I've found Kendall to be a superior product.

rnln: I hope that my reply to Jack clarifies why I feel the way that I do about oil. My shop has found pitted cams in 911 engines with 200K miles, we replaced the cams and rockers, did nothing else, and those engines are still out there driving around. We've seen cam wear and unusually high oil consumption (usually valve guide wear) in much younger Castrol/Pennzoil engines. We were also able to identify poor detergent action by how "clean" some oils still looked at oil changes, while Kendall came out of the engine almost black. I'm sorry, but I can't address what other manufacturers do, and how their cars respond to different products. I have repaired 911s for almost all of my adult life, and have not worked on other makes of cars. That said, I own a 2004 VW Touareg with V8. It already has 32K miles, I've used Mobil 1 its entire life. There is no consumption issue and the oil comes out a few shades darker than when it went in. What I can see inside of the oil filler cap is sparkling clean, and the engine does not leak. For now all is well with that car.
Pete

Jay H

Pete,

It's always a treat to read your posts based on real world, pro shop experiences. Thanks for writing!

Jay
90 964
84 3.2

rnln

Peter,
Valuable to me. Since I don't have any knowledge on these except personal visual and guessing. After reading your several responses, I decide to not to use Castrol or Penzoil oil anymore unless there is an urgent situation. Too bad, I still have several cases of Castrol at home.

On my car's oil issue we were talking about, I have not replace any oil yet so can't tell if Vavoline is darker than Castrol or not but I found another thing changed in the oil cap. My cap usually has several water drops sticking on the inside. They would come back several days after cleaned. If I don't clean it for a while, there will be a little milky-like on the cap. Also, at every oil change, I can find that milky on the drain plug edges.
Now, I don't know about the drain plug yet, but the oil cap is dry and clean. I've read that this has nothing to do with the oil type/manufacture. It's casue by air leak in the intake system. But that is what I am seeing now. I will keep watching.

Peter Zimmermann

rnln: Your milky stuff on the oil cap is only condensation residue. No big deal, the cars that it usually appears on are city driven, often short distances. No need to worry...
Pete

holtjv

Thanks Pete--and the SC is most excellent--exactly what I was looking for after the 993 experience.

You have me convinced about kendall--now I just have to find some...J

Charles Navarro

It is worth noting that today's Kendal GT-1 is not the same as the stuff of yester year. The new stuff is junk, some of the worst oil I have ever tested. If you want the true green stuff, you can buy it under the Brad-Penn/Penn-Grade brand. They make a 20w50 semi-synthetic that is excellent and has good levels of Zn and P. If I'm not using a true synthetic, I put in the Brad-Penn product. It's worth cross posting that we're having a discussion on oils over on pelican, and thought that some of you might enjoy our discussion here as well.

http://forums.pelicanparts.com/showt...hreadid=288931

r911

I'd like to know how Castrol got a good rep.?

Was it superior back in the 1930s or something?

thrasher

I've been following the Pelican thread, but Pete Z's experiences have made me rethink my choice of Castrol 20w-50 in my air-cooled 911. When I got the car 2 years ago, it was running M1, but leaked several drops after shutdown and my tranny case was covered in residue. So, I switched to conventional Castrol 20w-50 and now the engine is dry again. I suspect my rear mainseal is the culprit, but the oil was a much easier resolution.

With all due respect to Pete's experience and knowledge, is this not an invalid comparison of today's Castrol with yesteryear's? Certainly the formulation has been updated to use newer additive and refinement technology. His anecodotal findings are pertinent, but perhaps only looking backwards.

I have 10 qt's of Castrol 20w-50 in my garage ready for my next change. I'll promptly exchange those for Valvoline or Kendall if some empirical evidence using today's oils can show a reason to do so.

Peter Zimmermann

thrasher: Your points are well taken! My hands-on daily experience dates to the year 2000, from that point my experience is limited to a group of privately-held collector cars that I worked on until I destroyed my shoulder near the end of 2002. Since then my first hand experience involves two cars: (1) my personal 1982 SC with 203K miles, and (2) my just sold '02 BMW 325 Ci with 66K miles. The SC, still running Kendall (the new version lighter colored GT-1 20/50) has shown no changes in oil-related performance. The BMW was scary. Records proved it had used only BMW-labeled Castrol Syntec, which, by agreement, BMW has chosen as "their" oil. I was urged by people who I know well to "get that stuff out of there" and use Mobil 1, but I didn't dare. From what I could see through the oil filler cap opening the inside of that engine was already ugly. And that's with Castrol's "finest," changed every 4K - 5K miles it's entire life. If Syntec can't keep a little, in-line six clean, I don't hold out much hope that GTX has been changed and now works much better than it used to.
Pete

thrasher

thanks Pete. I'm only on my first "tankfull" of GTX in the 911, so I doubt I've gotten much buildup. I don't want to go back to M1 (or other syn) for a few reasons - drips and cost. I use the 911 infrequently, so I change my oil by time passage (annual oil/filter change before winter downtime), not mileage. In a 911 it's enough $$ to consider for 11 qts.

I'll take your word for it on the Castrol, though. So, you would recommend even the newer formulation of Kendall Dino oil over Valvoline? Also are the hight mileage formulations a good option (syn blends, right?)

Thanks,

Craig

Steve Weiner-Rennsport Systems

Hi:

Pete has, (as usual) offered some sound advice here,.... There was a discussion about this on Pelican several days ago and I've taken the liberty of inserting an edited version of what I wrote in that thread.

You cannot go wrong with the dino oils; Kendall GT-1 20w-50 or Valvoline VR-1 20w-50. Personally speaking, I'd not use Castrol GTX in anything. I've not tested some of the others such as Brad Penn so I cannot comment on that. There are some Castrol products sold overseas that we cannot get that I've heard are better that what is made in or shipped in North America. Of the synthetics, I'm a fan of Mobil 1 & Redline oils. I have no experience with Royal Purple or Amsoil since I cannot afford to experiment with my customer's engines.

All this said, be aware that since the EPA mandated 100K catalytic converter life, this forced some MAJOR changes in oil chemistries & formulations. The oil companies were forced to reduce and/or eliminate the critical EP additives (ZDDP, sulfur and phosphorus) that significantly reduce camshaft, rocker arm, and ring wear since these compounds contaminated and reduced cat life. Diesel oils such as Rotella & Delo still contain the critical EP additive ZDDP although that may change as the EPA ramps up the stricter regulations for diesels.

We've been seeing a LOT more rocker arm and cam wear issues so now we use some oil additives containing those EP additives that protect all these parts. In addition, some of the newest cars require clutch disengagement before starting and that really places big loads on crankshaft thrust bearings. We've been seeing much higher rates of wear on these parts due to manufacturers specifying ultra-thin oils, as well.

Do your homework, talk to some knowledgeable people, and you'll find some appropriate products for these cars to aleviate these problems.

Now,....oil is like a religion, one is not going to truly change anyone's mind and that isn't my intention here,... Like Pete, all I can offer is the result of personal experiences over the past 30+ years, but if someone has had good luck with a particular product that makes them happy, thats what they should stick with. No harm, no foul,.......LOL.

My point is twofold: (1) To point out two dino oils that have worked very well for me and (2), make people aware that current changes in oil compositions are making any comparisons with past products somewhat invalid. Things have changed and people need to do some research,...

If someone is willing to change their oil every 2K-3K, then you'll have good luck with almost anything and thats THE most important aspect of proper vehicle maintenance. I'd also mention that oil temperature management is critical to good engine life in the 911 and it behooves every owner to do what is necessary to maintain oil temps below 220 deg F.