Austin Ruby pistons and con rods

[Colin.beadle]

Hi everyone

I'm currently restoring a 1935 Ruby engine and I have the Pistons still connected to the crankshaft  I want to replace the Pistons due to bastard size rings. My question is haw do I get the Pistons detached from the con rods. The Pistons are attached by a compression stud under the piston canopy. I don't want to put too much pressure on punching out the gudgeon pins until Last  known her suitable method.  ANy advice will be appreciated  colin

["Slack Alice" Simon]

The small bolt under the piston goes through a groove in the gudgeon pin, so you cannot remove the gudgeon until this bolt is taken out.

[Chris KC]

Not following you Colin - why replace the pistons?

[Colin.beadle]

Hi. The Pistons are ok but the slots in the Pistons are not standard size and my research says I either need to mill out the sets or purchase new Pistons
S and either way I need to remove them from the Conrods


Cheers

[Bob Culver]

By slots do you mean the ring grooves? Are they substitute pistons with non standard rings? If the piston can be identified rings will likely be available. Bore size may not correspond to standard oversizes.
I suspect vey few would have ever changed pistons with the rods still attached to crankshaft.
To avoid twisting rods or vice marks, the gudgeon should be gripped between plugs when undong the setscrew. A critical and delicate part of the engine and best not messed with unless aware of all the factors.
Are you near any club that can guide you?

[Colin.beadle]

Hi

Yes there are 4 grooves 2 oil and 2 compression
Whilst the compression rings are OK the oil groove thickness is insufficient for the new standard rings I have.

[Ian Williams]

Surprisingly I would agree with Bob that rings will almost certainly be available for your pistons, what is the bore size and ring width?