Small IC engine camshaft design

[Moper361]

Hi all ,I have just completed a small steam engine and am in the throws of setting a new challenge for myself .

I fancy having a go at building a small IC engine from scratch similar basic design to my steam engine I have just finished .

Basic specs
26mm bore
30mm stroke
Rod length approx 112 mm long
2 x flywheel at 115 mm diameter

I am unsure if to try with atmospheric inlet valve or mechanical on both inlet and exhaust .

I have never built an IC engine before and would like to gather basic information for thoughts on a camshaft that would work for either types of valve arrangement

I don't want to get to brain washed with the since of cams etc but want something basic that would be workable .

I would be working along the lines of a mushroom follower design lifter so a cam with quite steep ramp could be used as I can make a camshaft like this on my set up here without to much issue .and think this is more inline with what older engine designers used .

Any help or feed back appreciated

Regards Nat

 

[Cogsy]

If you do a search for the Webster engine plans, they would make a great starting point for you (it's a common first IC build for many). The cam specs on those plans would work just fine for your engine. I believe it's an atmospheric intake valve rather than cam operated. Atmospheric intake vales eliminate the complexity of machining (or otherwise assembling) a multi-lobe cam with the correct timing. The only downside to them is that they can be a bit 'finicky' to get the spring tension right, but a bit of trial and error solves that problem.