Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

No need to dismantle the crank at all. In fact that is the worse thing you could do as the fywheel is a press fit and drawing it off, and it will come off without a puller, can mean that it may not be a tight fit when put back so it becomes a loctite job.

Try this. Remove piston from cylinder. Put spring on the screw and push through hole hard so spring is well compressed. THis will give you plenty of exposed thread so screw on the cylinder just a couple of turns. Replace piston and fit over the crank pin. It will be easiest if you turn the crank round so that the pin on the carank is as far away from the cylinder as possible . This means the least amount of strain on the bolt and spring. Then hand tighten the hex bolt as required once all sitting nicely in place.   

Hope this helps.

No need to dismantle the crank at all. In fact that is the worse thing you could do as the fywheel is a press fit and drawing it off, and it will come off without a puller, can mean that it may not be a tight fit when put back so it becomes a loctite job.

Try this. Remove piston from cylinder. Put spring on the screw and push through hole hard so spring is well compressed. THis will give you plenty of exposed thread so screw on the cylinder just a couple of turns. Replace piston and fit over the crank pin. It will be easiest if you turn the crank round so that the pin on the carank is as far away from the cylinder as possible . This means the least amount of strain on the bolt and spring. Then hand tighten the hex bolt as required once all sitting nicely in place.   

Hope this helps.

Thank you, thank you. Did that and it went back with no problems. Does the screw need to be screwed in as far as it will go?

Brian

As Stuart said, not all the way and it takes some fine tuning, BUT if you don't go tight enough the spring and screw will work loose and go flying across the room