Stearns-Knight

I appreciate all the help I have gotten on this subject, but unfortunately it's all moot now. The car was totally destroyed when my shop burned to the ground last August.

I've already opened up the diff. The gears are is great shape. I just want to keep them that way.

Thanks to everyone who contributed advice, technical articles, etc. I still can't claim to be the world's expert, but I now feel like I'm a fairly well-informed buyer and have made my decision. I bought Phillips 66 ISO 460 Compounded Gear Oil. It's a non-EP compounded worm gear and steam cylinder lubricant. It was one of only a few with an ASTM D130 copper corrosion test rating of 1A. That appears to be the most important factor, to protect the gear from corrosion. Even though they all claim to be safe for non-ferrous alloys, nearly all of the other lubes, including Chevron Meropa, are rated 1B. Phillips also specifically states that this product is recommended for differentials on antique and classic cars. It's hard to find any of them in quantities less than a 400-lb barrel, but I was able to buy a 35-lb bucket online from Petroleum Service Company. And you don't have to be a distributor or company to order from them.

I see this thread has been inactive for a while, but I'll reply anyway. I have a Stearns-Knight 5-passenger coupe with an aluminum body which I'm pretty sure was made by Philips (they built the regular coupes). My car has no tags on it, and I didn't find any screw holes anywhere on the lower cowl as you mention. Stearns-Knight used several body builders, and on most of them the body tag was inside the car, on the lower forward part of the right door. I didn't find one there either, but it's hard to tell because the upholstery in that area was in pretty poor condition. Anyway, if the reproduction badges are still available, I'd like to buy a couple. I can be contacted directly at duane at duaneperrin dot com.

I see these posts are from more than a year ago. Can I still order a set? I have a Stearns-Knight, but it has the same Timken worm drive rear end as Stutz. Please put me in touch with the guy who is making (or has made) them. Thanks. Also, I have heard many a story about how the gears have been ruined by using the wrong oil, but have yet to get a definitive answer as to what is the right fluid. See my thread under general discussion.

Thanks, everyone for your input. I figured the SAE and ISO viscosity scales were different but didn't have a correspondence chart until now. The stuff that Restoration Supply sells is Chevron Meropa ISO 1500, which according to the chart has a viscosity roughly equivalent to SAE 250. That makes sense. But I don't have any info on how much the viscosity changes with temperature. What does the owners manual say? Nothing! Stearns was in the habit of building cars first and then printing manuals at a later date. The company went out of business a couple of months after this car was built, so any info in the owners manual was only preliminary, and was never finalized. Haven't found the silver bullet yet. Still looking.

OK, I'm slowly getting educated, but I'm not quite there yet. Here is my plain-English description of the problem as I now understand it. Please tell me if I'm essentially correct or if I'm still missing something. 1. A hypoid gearset has spiral-cut teeth on the driving gear that sort of "walk" partly forward and partly sideways along the teeth of the driven gear, whereas in a worm drive the worm is essentially a screw, the "threads" of which slide along the teeth of the driven gear. The hypoid has higher contact forces and meshing friction, hence the need for EP additives. The worm has more sliding friction, which results in higher operating temperatures, hence the need for a higher viscosity oil. 2. The corrosion problem comes from sulphur, which most EP additives contain (although some newer ones may not?). I'm being led to the conclusion that I don't need or want an EP oil. 3. What viscosity? Are SAE and ISO viscosity scales the same? I've seen recommendations from SAE 140 to ISO 1500.

I've had several people recommend using Penrite Transoil 140. Apparently that is safe with non-ferrous metals (from a corrosion standpoint), but the Penrite website says "DO NOT use with any type of hypoid gears". It doesn't say why. Hypoid gears are defined as those for which the axes of the input and output shafts do not intersect. So a worm drive is, by definition a hypoid gearset. I have found other sources that say any oil used for hypoid gears must contain EP (extreme pressure) additives. That makes sense to me, but Penrite Transoil 140 is a non-EP oil, so it seems like that wouldn't be appropriate. My guess is that is why Penrite says it should not be used. So I'm back to square one. Any petroleum engineers out there?

I'm restoring a 1929 Stearns-Knight eight. It has a worm-drive differential with bronze gears. Stutz used the same type of rear end, as well as some others. Does anyone know the proper lubricant to use for non-ferrous gears?