Generalities Bill, just generalities. I'm sure there are many different oil grades specified in the owners manuals if you look to every automaker on the market today. Point was that generally speaking that’s what takes up most of the shelf space today. And yes, I did see that S.A.E. 0w20 mentioned in a few places, haven’t read much about it though. Must be loaded with some sort of new polymer type of Viscosity Modifiers obviously the egg heads compounded something new. Imagine that, no shear friction from your oil even at winter temps, who’d have guessed.
As we've talked about in the past, I was involved with the midgets and sprints some years back. I've been out of the ‘loop’ for some time now, but I've still got some old buddies that are still going at it and my nephew is still running a couple of midgets around the midwest. One of our friends has an engine shop down in Indy and does mostly race engines; he’s still running a sprinter himself. He's often mentioned the difference he sees between engines that are running the straight mineral oil and the synthetic blends. According to him there’s a night and day difference. He says that even after long hard races the engines look like they haven’t even been run.
About that straight weight oil availability, up around here as I said, it’s getting so hard to find I might have to start using multigrade in my oil cans.
I had a real loose 216 that I’ve been running for the last four years and the first thing I did when it followed me home was to drain and fill with Rotella-T. With the bad oil scrapers it was using so much oil that I couldn’t afford to use a synthetic in it. Hoping to get it back from the engine shop this week. I had it bored .020” over, alum pistons, conrods reworked for inserts, etc. I had the head completely rebuilt a few thousand miles ago so I should end up with a zero time engine for next spring. I’m very definitely going to be running synthetic as soon as the break-in oil is done doing its thing. I’ll probably be looking at one of the racing grades because of the high ZDDP content. No need for a heavy weight though, with that newly rebuilt short block, the bearings will be nice and tight so an S.A.E. 20 weight will serve the purpose just fine.
I taint gonna get into a contest about the engines of today running closer tolerances. They are “held too” closer tolerances during manufacture than my 216 was simply because of the strides that we’ve made in the machining processes. A Stovebolt that has been rebuilt in a modern machine shop will be just as precise as a newer engine. The running tolerances haven’t changed much and our main concern is with bearing and piston clearances. Fact of the matter is, that today’s engines being built with aluminum alloy blocks and heads the clearances very much more than they do in a cast iron block and head. The selective fit of the bearings in the Stovebolt results in a very close tolerance bearing surface. Much of the myth that the older engines run larger tolerances comes form the fact that people are looking at worn out engines. There are as many variables to consider in a discussion like this as there are fish in the sea. When you compare expansion coefficients of the metals used to build our engines, Alum pistons in iron block not good, Alum pistons in Alum block good, Iron seats and guides in Iron head good, Iron seats and guides in Alum head bad, Iron crank in Iron block good, Iron crank in Alum block bad. The way around the incompatibilities is by engineering the tolerances, which we understand much better today than we did 50 or 60 years ago.
Gotta go feed the live stock,
DG
