Does cast iron work harden?

[garethp]

My dad's just bought a 1910 Buick which has fixed heads, the valves are in an insert which pushes into the top of the heads and has a screwed ring to hold them in. The insert includes the valve seat and guide and is tubular and not much bigger OD than the valve, 7 of them are missing so we need to make some, I suggested getting some hard seats and inserting them but there wont be enough material around the seat.

Someone he spoke to said the whole thing is cast iron and to get some sg cast bar, machine it to match the insert we have and that the area that forms the valve seat will work harden as the valve repeatedly closes. Its the first time I've heard that cast iron work hardens!

 

[KemppiFrog]

Sounds an interesting engine.
All the mini engines (and most others of that era) with cast iron heads, did not use inserts. The seats were just machined in the head. As your engine is presumable low reving, can't see a prob in what was suggested.

 

[TechnicAl]

No cast iron doesnt work harden as you cannot cold work it

 

[penfold]

I'm not aware of CI work-hardening, but some of the newer types have some peculiar properties. After extensive running you might get carbon enrichment in the surface, but it's not likely to have a meaningful effect.

 

[500e]

Made some valve cages for a Buick 19 some years ago will see if I have drawings about, what model is yours.
A handy site think it has Buick thread some where, did a lot more work on Essex Railtons than Buick.

http://forums.aaca.org/forum.php

 

[garethp]

I thought the work hardening sounded unusual!

Its is an interesting engine, two separate barrel/head units, totally exposed valve gear and its something like 3.7litre

Its a model 10, I'll have a look at the aaca forum, I've been on the Brass Buicks Yahoo site but it seems a bit quiet.

I'll see if I can get some photos over the Christmas holiday, for full effect it needs the enormous sump underneath but its a bit like a barrel and needs supported to stop it capsizing!