Engie oil

[Drbrown]

I also use 10w30 detergent - usually Penn State and include a quart to a half quart of Marvel Mystery Oil (MMO) with the change. Been using MMO since the 1950's. When purchased, this '47 had a sticky valve and it seems the MMO helped free it up. Oddly, my '47 has no oil filter but I change the oil every 1000 miles and it drains out quite clean. I use 165 thermostats but the engine runs at about 175 to 180 by itself.