Swapping material

[Alan Gordon 4Participant @alangordon4]

Hi Guys, I am in the final throws of finishing my Vega Twin crankcase. I decided to look at a start on the cylinders, and I see, that they are to be made from EN8m steel ( case hardened) complete with "light Alloy" pistons.

For my education could anyone advise what would be the disadvantage ( if any) of swapping this around and making the cylinders out aluminium and the pistons out of the recommended steel ?

[Alan Gordon 4Participant @alangordon4]

Cylinder / Piston

[Anonymous]

All round bad idea. Think reciprocating mass. You may need to beef up the connecting rods.

Andrew

[Dave HalfordParticipant @davehalford22513]

The pistons will be very heavy and it wont rev + the out of balance forces will be much bigger.

[Alan Gordon 4Participant @alangordon4]

Thanks guys, It was just a thought. still learning !

[JasonBModerator @jasonb]

How much do you intend to run the engine? if not much then En1A will do as is would be easier to machine and no risk of distortion when heat treating or if you wnated to use EN8 then leave untreated, I've done both options on various engines though all with aluminium or iron pistons.

Edited By JasonB on 18/04/2020 18:28:38

[JasonBModerator @jasonb]

Just had a read of teh old article and think you are getting mixed up. The prototype was made from mild steel and cyanide case hardened which he then goes on to describe the machining process. However he also describes making from EN8M which does not need any treatment

[Alan Gordon 4Participant @alangordon4]

The reason for the question was simply that I have enough Alloy to do the cylinders and not enough steel to do the pistons, hence the question, but thanks everyone for your help and advice. It is appreciated.

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