100 HP flathead what oil?

When Ford developed the flathead engine it speced out 10 winter 30 summer. This was not just an idle whim. the vescosity of the oil needed to prefon the proper lubrication and cooling is determined by the bearing clearance. By using a heaver oil you prevent the bearing from cooling and thus increase wear. The tighter clearance, heaver oil will cause the by-pass (Relief) valve to open which causes more heat. However it does make the oil gauge read higher, if that's what your looking for.
 
I had a bunch of Mobil 1 15-50 left over from my Hemi race car and decided to try it. I have used the last few years with no problems. It leaks a spot or two, but no more than it did before.
 
Remember when your engine is at operating temperature your oil flows like water,so at start up you want your oil to flow like water,so thin oil at start up I think is what you would want! I'm using 10-30, my next oil change I'm trying 5-30! I'ts a 8ba new rebuild. Pete
 
Modern oil has polymers in there that hold the film build when hot. When I was a kid, I couldn't figure how they got thicker oil when hot and thin oil when cold since that is impossible for straight grade oils. After watching a guy dump a big bale of polymer material into a batch of multi-viscosity motor oil being blended up, it finally started to make sense. That polymer material really expands when it gets hot. On a fresh motor, I'd stick to SAE 10W30. After it gets worn out you can go to the 20W50 stuff. We used SAE 20W/20 for winter when I was a kid. We switched SAE 30 in the summer time. We changed the oil for each season change whether it had a lot of miles or not.
 
HPR30 Penrite 20-60 mineral has the zinc additive in it already approx. 1600ppm. Designed for SAE 30 replacement.
 
I wonder why we need Zink in the oil now? Waz it used back in the 30's and 40's. The stock engine has only 40lb/ft spring pressure and I only use 50 on the L-100. Don't you think our oil today is better than the old stuff.
 
You must log in or register to reply here.
Back
Top