Block markings

[Tony Betts]

I would say you have quite a museum piece there.

I take it all the numbers on the engine match.

The bores and pistons look as if they could still be in quite good condition.

I be tempted to say if you are not putting a Phoenix crank in? And keeping it original. I'd clean it and keep the pistons and original bore.

If there is no wear lip at the top of the bore, and no scoring in the bores. You may find the sideways movement in the piston is because original pistons were expansion pistons, so they needed a larger tolerance.

Were as our modern slipper pistons are zero expansion. So the tolerances are far less.

Tony.

[Chris KC]

Tony has a good point there, if they are solid skirt pistons they require about 3 x the bore clearance of split skirts so might seem 'loose' by comparison when cold. I don't remember ever seeing 'Austin' marked pistons before and would definitely think twice before shelving them.

[andrew34ruby]

   
Split skirt piston, the A30 again.

[Bob Culver]

Are the pistons original pattern ie 5/32 wide rings and no skirt split? Replacement rings could be a problem and often of very heavy section leading to the top groove wearing excessively. With medium worn bores (.005 os so taper) and drilled oil rings our car used almost no oil with this type of piston. Second rings usually hardly wear and top groove can be turned for two thin rings.
Simple fully split pistons as the A30 went out of favour. The skirts rapidly closed up and failure as illustarted was common. (I sold a Javelin witha skirt missing. cash sale) There were several peining or shot blasting processes to expand the skirts...often followed by failure.