Crank pin re fixing

[Ian RParticipant @ianr]

5 inch steam loco 2 6 2 wheel configuration. The crank pin in middle driving wheel worked loose. Can remove pin from wheel and connecting rods and re secure pin in wheel using Loctite 638

Question concerning replacing motion and coupling to forward/reverser.

Can I just reconnect reattach the connecting rods ?    Will the timing still be correctly set as quartering not changed and connecting rods on the opposite side still attached to crank pin.

I am unsure how to proceed to rectify

[Nigel Graham 2Participant @nigelgraham2]

If all you are doing is refitting the pin in its original hole the alignments and timing should be unaffected.

If the work needs a new hole and pin you’d need ensure true concentricity with their original forms.

[Ian RParticipant @ianr]

No I am using the original hole in the wheel. I will need to remove the coupling from the pin end to refit it in the wheel.

This coupling has a linkage to the forward / reverser and then to the valve push rod.

[duncan webster 1Participant @duncanwebster1]

It might clarify the issue if you confirm the type of valve gear. From the limited info given I suspect Walschearts

[Brian Baker 2Participant @brianbaker2]

Greetings, depending on how the pin was fixed in the first place, you will need to retime the walscharts valve gear if fitted.  Also, with Walscharts gear there is a lot of force on that pin carrying the return crank, I would suggest that you pin the crank pin in place after loctiting in with, as you suggest 638 grade.

Make sure the whole area is clean and oil free, I suggest you use the loctite cleaner, well worth it.

Regards

Brian B

 

[Ian RParticipant @ianr]

Duncan

Its Walscharts gear

Why do you think the timing needs to be adjusted ?

This is the question I am struggling with If just reassembling the motion how would the timing need adjusting.

[duncan webster 1Participant @duncanwebster1]

The angular position of the return crank is important. If the crankpin is taken out, unless it was somehow prevented from rotating in the wheel, that relationship will have been lost. If there is a pin preventing rotation you are in luck, otherwise it’s start again.

[Ian RParticipant @ianr]

Duncan

The pin was removed as it locked the motion there is no pin preventing rotation.

What method of resetting the timing is the easiest ?

Remove piston covers to ascertain top dead centre or take off valve covers to see inlet and exhaust position?

[bernard towersParticipant @bernardtowers37738]

I was once told that the best way is to have low pressure in the system and tubes on the exhaust dunked in jars of water. Dont know if that helps as I have never done it!!

[duncan webster 1Participant @duncanwebster1]

Ian, you have a pm.

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