Maintance

[Mike McKown]

I too, have seen the worm tracks,

but not in many years and not in one of my engines. The two I have seen in that condition had unknown service and were full of sludge, just like engines of 40 years ago were expected to be. Generally speaking, if an engine has had long oil change intervals and it is still free of sludge inside, you will not expect to see bearing damage from the effects of acid. At least that's been my experience.

The PCV valve has done as much for engine longivity as anything else the engineers have come up with.

I would agree that if your engine has a malfunctioning carb, choke or ignition problems, you might want to change your oil more often. But then, you should have fixed that in the first place. The same applies if you use your car to putter around cruises, parades and such. If you get it good and hot everytime you get it out, I'll stand on what I stated. It has worked well for me.

I have lost a few sets of bearings. It was because of loss of oil supply to them. Not acid attack. But, that's another story.

[Dick W.]

Re: I too, have seen the worm tracks,

The two worst engines that I have seen were (1) 1940 Ford that I bought. Had sat for over 15 years. The babbit for all practical purposes was gone. (2) A Jeep that was used at a summer home. About 200 miles per year. Owner told me that he thought because it did not have at least 2000 miles on the oil it did not need to be changed. Wrong.

Then again these engines were non PCV and not with modern oils of today either

[Jack H.]

Re: the oil and filter should be changed BEFORE

Hum, lack of acid is one of the STRONG points of synthetic oils....

The 'natural' byproducts of the combustion process are VERY hot H2O and CO2. Now, presume the piston rings are slightly imperfect and there is SOME degree of blow-by into the crank case. Then, presume the oil is petroleum based and has SOME degree of sulfur in it. You get H2SO4 (sulphric acid) formation in the crank to some degree....

That's why diesel engines with their MUCH higher compression ratio (greater blow-by silhouette) recommend using oils with low sulphur content. But, a fully synthetic oil would have little/no sulphur content to start with and should therefore wind up with little/no sulphuric acid formation in the crank case.