Ed Ruiz

Consider the source.

Lane

When I had my 928s thats all I ran in it was Mobil One and I really didn't recall any serious oil leaks. But then I read an artical about the leaking of oil after using syn. oils in engines. What they said was happening was that some oil seals are not compatable to the syn. oil make up and that the seals actually lose their elasticity allowing oil to leak by , or contracting to the point of becoming to tight on the sealing surface causing excessive wear, allowing oil to leak out. Now this is usually happening in the older engines. I do know that in my '79 930 I switched from syn. oil to a High grade dino oil [SWEPCO 306] and the oil leaks and burn off reduced dramatically.

Jim_H

I use Amsoil 20/50 severe racing oil, what are the detergent properties of Amsoil?

Jim Hurtt

PatrickP

Jim:

This link has some info on 20/50 which you may find helpful. If not, I believe there is also a link to contact Amsoil directly.
http://www.1st-in-synthetics.com/racing_oils.htm

DoubleNutz

Hmmmm, Mobil One and oil leaks huh? That is interesting. I have since I converted to Mobile One noticed an increased consumption of oil. I did not really have such an issue when I used non-synthetic oils. Additionally, I was told the last time I was at Spokane buy several 928 brethren that they noticed puffs of bluish oil smoke coming from my exhaust when I would "get on the throttle hard". This was never observed before I cut over to the synthetic stuff last year. I guess I am now worried because I go check my oil more frequently becuase i know it is being comsumed rather quickly. On a good track day I can be down as much as a quart. As I said earlier this was not the case when was using the non-synthetic stuff.

Any ideas out there about what is going on in my 928?

p@

DoubleNutz

By the way , since I have been considering it, what makes Amsoil much more different from Mobile One?

p@

Darren '85S

After switching from conventional over to Mobil 1, I have actually noticed a drop in consumption. As far as comparing the synthetic oils, I believe that they are all very good. Even the amsoil tests show that they are all doing a good job (the wear numbers are pretty small). For me it is more convenient and cheaper to stick with mobil 1 (can be bought at kmart for $4/quart). Amsoil seems to be more expensive and I’m not sure who even carries it.

P AKA sharkdog

Okay guys, I'm pleased to see some of the information in my previous posts being "quoted" by others, so I guess I'm having the desired effect on the group.

First of all, Synthetic oil will not CAUSE a problem in your engine. The detergent factor Ed mentioned, about cleaning away deposits that might be keeping oil in the motor, may have some merit (on a really dirty motor). I think this is especially true on an antique powerplant, but not especially true on a 928, simply because most 928's are probably pretty clean inside due to what they are, and the care they probably receive.

Old wives tales, back when synthetic came out, indicated that synthetic didn't have enough ester to swell the seal. This was intitially true, but it has LONG since been fixed, forget it, don't repeat it, because doing so is spreading bad info. Synthetics have esters added nowadays for this very reason. You can buy the stuff in a bottle to swell your seals, if you really must, but I don't recommend any additive, especially the Slick 50, Prolong, etc.

If you have a leak in your motor, the synthetic superior flow will flow out the leak quicker than dino oil will. It will also drip internally into valve gear too if your engine has a lot of miles on it, and you may see a bit of a puff upon starting. This, too, is because of the superior flow. This would account for oil use in older motors, but you still will be getting the superior lubrication and initial drive-off benefits of the Mobil-1. I use it in my 944 with 146,000 miles and I get a puff of smoke in the morning upon start up. I also use it in my volvos, 928, and twin Ford 427 powered Chris Craft.

If you compare Castrol 20-50 for instance, it will flow down to minus 15 degrees. Mobil-1 15-50 will flow down to minus 55 degrees. Which one do you think will cause more spots on the pavement? Youre right, if you have a leaky motor, internally or externally, you'll see more oil on the pavement with synthetic. Reason being, synthetic has UNIFORM molecules rather than irregular clumps of molecules found in "natural" oil, and synthetic molecules are all SMALLER than the clumps found in natural oil. Therefore, in some cases the natural oil is the preferred choice. For me, I use the Mobil-1 15-50 all year round, regardless if it's zero degrees outside or not, it flows superbly and it's got to be one of the very best you can use. Ever try to wash your hands after changing the Mobil-1???? You'll notice something about the oil, it's almost impossible to get off your hands with soap.

All the best, merry motoring Ed, good post Darren!

P

P AKA sharkdog

Oh yes, one more thing I learned from the Mobil Petroleum Engineer.......he suggested "trying it" in the older engines (I interviewed him, and several other engineers, back when I was doing some research for the Antique and Classic Boat Society guys) and if it didn't prove to work well, then he said to simply switch back to what you were using before.

Ed mentioned the high detergent factor cleaning away deposits that might be working to keep oil in, and this may have some merit at gaskets, but I don't understand how this would be working at seals.

In a modern engine like a 928, if you try the Mobil-1 and it seems to not work for your particular situation, then take good notes, switch back, and see if the irregular clumps of molecules work better. Then continue to use what works best.

(and no, I'm not associated with oil sales in any way, I'm an architect)

all the best, P