I have seen slice sof Cast iron let into port faces, mostly to correct poor cores or badly machined ports so should be fine for a new build.

As for rust, your iron casting is just as likely to rust as any steel but for either good running practice will leave a coat of steam oil on the surface between runs.

I do it a lot for IC engines either an iron liner in a fabricated outer as it is easier to join steel than iron. Or Iron in iron to form a water jacket that is not practical to cast with cores on a small scale.

The one that springs to mind was on a 4″ compound traction engine, the guy set it in with araldite and I think a couple of small CSK brass screws in the corners.

The other way would be to make the plate a little larger than the inside of the valve chest so the chest would hold the plate from being able to come out of the  portface.

Hi Ian,

I made a small alloy engine with cast iron inserts in the cylinder and the cross head guide.

Also a cast iron port face jb welded and screwed in place. The engine runs really wellgeoff

I’ve known of a Simplex and a Springbok with mild steel cylinders, no liners. The Simplex ran for at least 25 years until the builders death and subsequent sale, the cylinder blocks were cut from solid bar and the steam chest a TIG welded fabrication. The Springbok had Fabricated TIG welded and brazed cylinder blocks and again ran for a few years to my knowledge. I believe the pistons were CI and the builder always used commercial IC engine piston rings, for a moped and a Honda cement mixer engine respectively. His engines were very heavily used, but well cared for and I can’t recall any problems with rusting. I do remember someone remarking that his mild steel cylinders wouldn’t last ten minutes, his reply was ” well they are fifteen years old already!”. As far as I can recall the only castings he ever used were for the wheels of his engines, the rest were either fabricated or cut from MS bar stock.