Do you believe in oil additives?

Normy;12519 wrote: "Just put Castrol in it"

A mechanic in Michigan that I knew well. His diesel VW pickup ran 400,000 miles before it needed an overhaul.

N

Ya-but a VW diesel will run 400,000 on sowing machine oil

"Ya-but a VW diesel will run 400,000 on sowing machine oil"

That's not exactly true. They need some sort of kerosene to run. The diesel injection pump on that car is actually quite sensitive to sulfur content. People put Jet-A in these and don't understand why they start running rough after a few thousand miles.

-I was a flight instructor at one time, earning about $10k per year. One of my students was a former chemical/petroleum engineer from South Korea. We had a talk about the Shell ashless dispersant oil used in the 6.0 liter 180 hp air cooled four cylinder engines on the Piper Seminole we were flying, and he told me that unless I was running extremely high compression and/or a high boost turbo, basically race cars...then anything other than simple dino oil was a WASTE.

"You...don't...need it. Just change oil"

The rare properties of synthetic oil simply are NOT needed in any sort of street car. He told me to "pick" a brand, and always use it. DON'T mix oil brands! This might cause "kudos", or tar-like oil deposits to come loose and plug up the oil filter.

I follow his advice to this day, and put Castrol in all my engines. I suspect that all the other brands are about the same.

N!

Normy;12653 wrote: "Ya-but a VW diesel will run 400,000 on sowing machine oil"

That's not exactly true. They need some sort of kerosene to run. The diesel injection pump on that car is actually quite sensitive to sulfur content. People put Jet-A in these and don't understand why they start running rough after a few thousand miles.
I agree but that is the fuel (injection pump)
-I was a flight instructor at one time, earning about $10k per year. One of my students was a former chemical/petroleum engineer from South Korea. We had a talk about the Shell ashless dispersant oil used in the 6.0 liter 180 hp air cooled four cylinder engines on the Piper Seminole we were flying, and he told me that unless I was running extremely high compression and/or a high boost turbo, basically race cars...then anything other than simple dino oil was a WASTE.

If he is saying that low ash is not a requirement then well ya, your oil just gets dirtier faster.
Not something I would take lightly.
If he is saying that you can run normal oil in anything but a race car, then he needs to go back to korea

"You...don't...need it. Just change oil"

The rare properties of synthetic oil simply are NOT needed in any sort of street car. He told me to "pick" a brand, and always use it. DON'T mix oil brands! This might cause "kudos", or tar-like oil deposits to come loose and plug up the oil filter.

I follow his advice to this day, and put Castrol in all my engines. I suspect that all the other brands are about the same.

N!

I am sorry to disagree Normy but not all oils are created equal. If you want to listen to him, then good luck.

I am being blunt for a reason, not to be an ass, (Because I know this stuff and I do not want 928 engines failing because of hear say)

You are right that normal oil under normal conditions will normally suffice.

but

Dealers dont just recommend synthetic oils because they think they need it or because it might help,
it is because they need the protection from the severe heat or severe cold climate or extreme internal engine pressures.

My earlier comment was complimenting the VW diesel (jetta) for its durability, but it also requires heavy oil with high zinc (common in diesel oil)
for its flat tappet cams.

I dont think our engines care what brand you buy, as long as it has a high zinc content (1200 recommended) and that the viscosity is correct for the conditions, pressures and cooling

here are some other threads
forums.pelicanparts.com/porsche-914-914-...-zinc-additives.html

forums.rennlist.com/rennforums/928-forum...sity-do-you-use.html

www.lindseyracing.com/LR/Parts/GENZDDPLUS.html

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I generally keep my comments to myself but since I have spent 25 years designing and building oil refining and proceesing plants all over the world for most of the major oil companies I consider myself qualified to comment. Without exception aftermarketoil additives are ineffective. The same can be said of some oil additives included in the oil you buy from the store. It is marketing and giving the consumer ''something extra''. What does the work? The actual hydrocarbon lubricant. If you want to keep your engine alive longer, have a system that gives you oil pressure before the engine starts. That is when most engine wear happens, by far!
Follow the recomended viscosities for the temperature you are operating in and you should be fine. I have run straight 50 and 60 weight in my hot rods and motorcycles during the summers in Houston without failure. As far as mixing different oils, don't mix synthetic with hydrocarbon. If you want to change brands at your next oil change by all means change. It won't make any difference to your engine.
Oil is much better and consistent today than it was 30 or 20 even 15 years ago. If it gives you a warm fuzzy feeling to spend extra money on additives, spend away. If you operate your 928 to the extreme that ZDDP or PTFE is going to make any difference, you are going to replace worn parts regularly anyway.

I would have to agree with Chuck. All my life I have been changing my oil and prior customer's vehicle oil at 3-5000miles regularly.With synthetics now 7500 miles and I have never blown or had customers vehicle blow up or suffer any lubrication related damage. Some would bring me Slick 50 and the like and I refused to put it in. I would tell them the same as Chuck. Snake oil.

Up until a few years ago, I was in the snake oil camp. I'm not so certain anymore.

The reason for my uncertainty is that until recently, the goal of the oil companies was to furnish the best lubricant possible in terms of preventing wear for a reasonable time.

Unfortunately, the goals have changed - now, they appear to be, don't hurt the cats, and get the best fuel economy possible without blowing the engine up in normal driving, while assuming that you have an engine designed and built less than ten years ago.

Eventually, it will be tough to find the viscosity and formulation needed for our antique engines...