The steel pistons were phased out for aluminum several years before the 239 for the 1939 Mercury 99A came on line. The tin can sleeves were still around on some but not all. Some folks liked those steel pistons. Ford played with a lot of different ideas over the V8 era.
Not so. The steel pistons and sleeves were used on Ford and Mercury at least into 1940. In fact most engines is this era were steel sleeved.
By golly you are correct. I had thought it was prior to that but in was in that 39 40 range that they started using aluminum with all replacements being aluminum. There were both steel and aluminum pistons for the 99A. The 09A for the 40 Mercury were all aluminum. All were domed whether steel or aluminum on the 239 engines. I found some steel domed ones on flea-pay. The V8-60 used steel pistons through the end of production in 1940. The 9N engine had 99A pistons but it doesn't specify if they were steel or aluminum types.
By golly you are correct. I had thought it was prior to that but in was in that 39 40 range that they started using aluminum with all replacements being aluminum. There were both steel and aluminum pistons for the 99A. The 09A for the 40 Mercury were all aluminum. All were domed whether steel or aluminum on the 239 engines. I found some steel domed ones on flea-pay. The V8-60 used steel pistons through the end of production in 1940. The 9N engine had 99A pistons but it doesn't specify if they were steel or aluminum types.
59AB block in our shop. The owner wanted later distributor, thus the change in front. Note flat pistons.
59AB block in our shop. The owner wanted later distributor, thus the change in front. Note flat pistons.