disallow wrote:Yep, I'm on the fence when it comes to some oil additives. I've used Duralube in my older cars, and they didn't explode. Whether the product did anything to help, I guess we could argue. I think it did. Car had issue with oil burning and hesitation before, after using the product it did not.
I've run Lucas Synthetic Oil Stabilizer in both my old 98 civic and in my 05 path. My 98 civic had 190psi compression with +/- less than 5psi at 300k kms (186k mi). That is what it was from the factory. Was that because of the oil additive? No idea.
Here's more or less why. Whatever you were doing with additives for that engine with that oil did not take it that far out of spec. So long as viscosity stays within the range for all surfaces (bearings, rings, etc.) and you don't do anything out of the ordinary in operation, rings and cylinder liners should essentially last the life of the engine. Meaning so far out there it might as well be forever.
The rings slide on a layer of oil (the honed grooves help entrap it for this purpose) in an elastohydraulic lubrication condition. From experiments in the 80's we know about 80% of an engine's lifetime wear occurs in the first 20 minutes or so of operation as asperities are worn down. After that wear (volume of material removed) decreases logarithmically over time.
So long as the engine is operating within design limits and there isn't some kind of material, design, lubrication or other failure, you
should see factory-spec compression for the life of the engine.
Other people have not been so lucky with Lucas, Slick 50 or other additives as they changed viscosity. They also had other side effects; I believe Slick 50's initial problems were with detergents attacking engine hoses.
With the Pathy, I've never had to do my timing chain tensioners, though I am sure I had heard the noise under acceleration when the engine was cold several times. Since running the oil stabilizer, I've never heard it.
Lucas works by increasing viscosity. The chain and tensioner shoe are likewise in elastohydraulic lubrication with a fluid film in between, where some surface to surface contact occurs. If viscosity increases distance between the two would likewise increase.
However, you could get the same effects by a.) changing your oil or b.) changing your oil to a higher viscosity. These courses of action would give you some idea of the final viscosity of the oil in your engine.
It's also unlikely however that this "fixed" your tensioners if they were indeed wearing out. Eventually you will hear that wonderful metal on metal contact if that's where you were going. There's a number of other things that sound like the tensioner noise. Ask me how I know...
And if they're really wearing out to the point where you heard the chain on metal, they're not unworn now...
Once again, not very scientific. I always loved the sales displays for these, which tell you NOTHING about how the product will perform when actually at operating temperature. Maybe you've seen the display with some plastic gears in it, you turn the conventional oil side and the oil basically does nothing, but with the product in it, it bonds to the gears better to 'ensure better lubrication'. That is a joke for sure.
Well, it works that way because it increases viscosity. Notice that they don't say that because that would be a marketing fail to be that honest: "Put this in your 10W-30 and it will be something higher...what, we don't know, but it's awesome!" However they do list a bunch of things that equal higher viscosity, such as using their product will result in higher oil pressure, etc.
Interestingly they claim it will increase efficiency, which is contrary to using higher viscosity oils.
So there! Explain my completely non-imperical and non-measureable experiences!
t
I once had a long discussion with an aircraft mechanic who owns a Honda RC45. Could not convince him that running lower than specified engine oil wasn't a swell idea since his engine temp was lower (as it should be) and "it hasn't blown up yet." But then this guy had his own machine shop so I figured he was okay with rebuilding his engine if it came to it
I can tell you it's not a good idea to guess at lubricants because your engine is designed around them (especially viscosity), and additives are considered a bad idea. I can also tell you that while higher viscosity equals more protection, too high of viscosity isn't good either. You raise the operating temperature of the fluid, drag, and some other things. Total guess at what's really in your engine when you dump a bottle of that stuff into a liquid that meets stringent specifications for everything else...
