Hi, I am gradually putting together a 20HP Stanley engine from parts with the aim of building a car the same way. It's a hard way to do things but does spread out the cost! The block I have is perfect - excellent threads, no cracks, and only about .003 wear in the bores - except for the valve faces which have been machined down to the flat surrounding them. I am wondering if it is possible to cut new valve ports in a piece of 1/8" plate and epoxy and dowel them into place. They could be lapped with the valves first. A friend of mine did a similar thing with a cylinder bore when he machined into the steam passage of a cylinder block where something shifted during the cast. He simply machined it oversize and epoxied a cast iron liner in place and it put in many years of work without problem. A valve face is a little different and I am not sure exactly what force would be trying to shear the epoxy. But with a dowel in each corner. I cannot see it moving. Of course, ther may be a problem with differin expansion amounts when hot. It would be difficult to do with cast iron - what would be the best material - bronze, steel??

I am still on the hunt for parts so if you have any spare 20HP parts you will never use and want to sell or trade ( I have an assorted collection of extras!) then let me know!

Thanks

jeff

Ron Hardwig repaired his valve 20 h.p. faces by silver soldering new steel valve faces to the block. In operation, the cylinder block can see 450 degrees F. when you have up about 500 p.s.i. super heated steam. Epoxy usually doesn't work at these high of temperatures.

I did consider silver soldering but the thought of getting the block hot enough without something distorting put me off. There are some high temperature epoxies out now that could possibly handle it. Duralco 4703 is supposed to handle 650 degrees with a 12000 psi tensile strength.

Do you know how the steel valve face wore - the coefficient of friction between steel and cast iron is I think about a third higher than just cast iron against cast iron? Not sure if this is an issue or not. I know bronze has a much higher coefficient of expansion than mild steel due to the copper content so bronze probably isn't an option as it would eventually shear the epoxy.

Jeff

Ron's model 70 is running just fine, and has benn for about 5 years now.

you have to watch useing resin type filler and epoxy under steam conditions, alot of materials hold up to high tempatures, but not to steam. Big difference.
silver solder sounds like a much better way to go to me.

I'd suggest building it up with braze welding, where the melting temperature of the filler (typically 870 °C to 980 °C for bronze alloys) is usually lower than the melting point of the base material (1600 °C for mild steel). As I understand it (and I stand to be corrected) that's higher that the temps in a steam engine. BW is pretty simple, cheap, and foolproof. (I've done it, so it can't be that difficult.)

Ron Hardwig repair was the cleverest I’ve seen. It’s the way to go.
Jeff it’s written up in one of the SACA Bulletins. The only thing I would have done different would be to bring the whole setup to my heat treater and let him put it in his oven to control the temperature.

Rolly

I remember a talk Hardwig gave on his method of dealing with the valve face...and what he did was take it to a guy who knew what he was doing, and had it furnace brazed...which is a process in which the entire block is brought slowly up to the brazing temp-then allowed to remain there for a given amount of time, while the silver solder melts And bonds the piece to the block...then slowly the complete assembly is brought back down to room temp.

Cheers---Chuk

Chuck I questioned doind such a thing but ihad concers with possible embrittlement problems with the iron as you would be esentially heat treating it.

All my cast Iron casting after I get them from the foundry I send them to my heat treater for stress re-leaving. Controlled reheat and cooling keeps them from warping like a pine board when you’re machining them. For the last ten years I’ve only been using Ductile Iron 85-55-06 Nice stuff or 100-70-03 or structural steel castings A-148

Rolly

HI Jeff,
I am facing the same repair with a 20 hp 740 . The vale faces are flush with the surrounding area, and I am considering silver soldering a piece of mehanite ,or even steel to the old surface.
Wondering if anyone can update the techniques and results mentioned in this thread.

Rod Hardwig in Illinois did his 740 valve ports by brazing new steel faces in place. It worked well. Others have also applied new faces too. The last block that I did, I had it cast iron welded up and then machined on a mill. There was a lot of hand work done afterwards to make it usable again. If I had it to do all over again, it would be a tough decision as to which way I would go. Probably cast iron welded up again. I have been there and done that. I screwed up that cylinder block in 1990 by using too much reverse pedal on the Colorado Springs, Colorado down hill from Cripple Creek, and not giving it an occasional shot of oil/throttle on the way down.