heilan lassie cylinders

[malcolm evansParticipant @malcolmevans23899]

Hi, have recently accuired a 31/2″ lassie , the cylinders are not sealing, there are fitted “o” rings to the cylinders which I intend to replace , I have taken the drive pistons out of the bores no problem but I can’t see an easy way to get at the valve pistons out, I have taken an end cap off piston bore and can see the nuts down inside which locates the piston in the bore but I don’t think I am working from the right end I don’t think the assembly should be dissmantled from within and it won’t come out from the front as it has a domed cover with no apparant fixing, there is no gland on the cover and no means of turning the dome , it has supposedly been built to the words and music of lbsc, would the valve pistons have any seals on them or would they be plain bobbins in the bores ,if no seals are fitted to the piston/ bobbins I see no need to go any further with the stripdown just re “O” ring the drive pistons and re assemble .the cylinders are bronze and the bores are pefect to look at, PS what’s the best “O” ring for resealing the pistons, Malc

[malcolm evansParticipant @malcolmevans23899]

[John BaguleyParticipant @johnbaguley78655]

Hi Malcolm,

 

The piston valves are just plain bobbins. The end covers are a push fit, although LBSC suggested putting 4 bolts into the end of the valve liner. As you say, there aren’t any glands on the rear cover to seal the valve rod. They are only subject to exhaust steam pressure and a slight leak won’t cause any problems.

 

Viton O rings are probably your best bet as they are a bit tougher than silicon. Are you sure it’s the piston O rings that are leaking? It’s possible that the valves are leaking if you are getting steam going straight up the exhaust when you open the regulator.

 

John

[malcolm evansParticipant @malcolmevans23899]

Hi John, thanks for that! I am getting a bit more sorted on the beast now, have got the valve out of one of the blocks the bobbin looks to be in good condition hope the others are as good if so I`ii be sorted , the centre cylinder looks to be a pig to get at, will try a set of viton piston rings, if it is the bobbins/bores passing a lot of steam I`ll give the delrin trick a go and make new bobbins out of that

[Author]

Posts