Stuart Cylinder Problem

[klank]

I have been slowly and very nervously working on my first engine - a Stuart 10H.
Bed plate and sole plate finished apart from dealing with the crankshaft beds for the latter. (Do I invest in a ball end slot mill, or just run a drill through them?) I have a vertical mini mill.

My main problem (for now) is the cylinder.
I have bored the cylinder and faced the valve chest area to dimensions given in the plans.
Unfortunately, when machining the end flanges to the cylinder, I ended up with one flange thicker than the other, even though the overall length of the cylinder was to the correct dimension.
This meant that the valve ports cast into the cylinder were not lying "central", by 1mm.
I have now machined the thicker flange a bit more and got the middle valve port dead on centre (to the axis of the cylinder), but realise that the overall length of the cylinder (flange to flange) is now approx. 1.2mm too short.
Will this affect the running of the engine, as the stroke will be compromised?
Would it be better to obtain a fresh cylinder casting from Stuarts and start again?
Any help/advice would be much appreciated.

[Tel]

You will probably need to shorten the throw of the crank by .6mm to compensate, otherwise there should be no problem

[klank]

Thank you Tel - appreciate the reply.
I had wondered about that sort of fix but couldn't work out the dimension.
Will the valve eccentric/throw need altering also?

[sideshow]

or just make the piston 1.2mm thinner ?

[ron]

Or buy a new casting from Stuart and have another go at it? I don't think it's very expensive.
Ron

[klank]

Thanks for the replies, Ron/Sideshow.
I think I will get another cylinder and try again. If I mess that one up, I can fall back on the original and shorten the stroke as Tel says.

[Alan]

Hi Klank

I know exactly what yoiu are going through, I have spent a wee bit of cash buying spares from Stuart. However I am learning as I go along and allthough I still make a cock-up's at least they are becoming less and less.
Once you get the machine running it will be well worth it !!
Regards

Alan