casting

[david simmoParticipant @davidsimmo]

hi on gun metal casting(cylinders) whitch is best gunmetal to gunmetal or gunmetal to s/steel it for the pistons and bobin(vavle) thanks dave

[david simmoParticipant @davidsimmo]

cylinder

[Sub MandrelParticipant @submandrel]

Hi David,

Gunmetal does not wear well on gunmetal. It wears best with a harder metal.

In general avoid two similar metals moving against each other, the exception is cast iron.

Neil

[JasonBModerator @jasonb]

I'd probably opt for brass for both the piston and valve, keep the stainless for the rods

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hi David ,

A lot depends on what type of engine it is , how big it is and what running it will do .

Tell us a little more if you want to and we’ll be able to give more definite answer.

Regards ,

MikeW

[david simmoParticipant @davidsimmo]

hi mickw it a3 1/2 gauge brittania hopefully along time thanks dave

Edited By david simmo on 25/08/2013 15:20:29

[Sub MandrelParticipant @submandrel]

So presumably piston valves. I'd suggest stainless steel, finished to as smooth and close a fit as you can get.

Neil

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

As Neil says stainless steel is a good option .

Other options include modern engineering plastics and properly ringed valve designs where the spool material itself matters less .

In smaller sizes piston valves often fail for secondary reasons like inadequate lubrication or by being unable to float freely on valve spindle .

Often said that there is no side load on piston valves therefore they don’t wear – this I’m afraid is untrue – there can be significant side loads if the whole valve drive system is not well thought out – worth a review of what the set up is in your engine .

Regards ,

MikeW

[Author]

Posts