Molly 0-6-0 motion problem

[David Bothwell 1Participant @davidbothwell1]

Not enough valve movement

[David Bothwell 1Participant @davidbothwell1]

I purchased a psrt made Molly a while back, it ran on air at first. Then a part of the motion broke (delicate sliding link) after a re assembly the engine does not go. I have spent a long time re-making various parts including crank axle, eccentrics and improvement to reverse stand and lever.but after re-assembly there is not enough movement across the valve faces to open and close them. The mechanism (Stephensons link I think) seems quite complex with two sets of sliding links etc., Any suggestions/adv ice would be most welcome as this has become most frustrating

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Timing incorrectly set?

Edited By Jens Eirik Skogstad on 21/10/2017 09:07:26

[David Bothwell 1Participant @davidbothwell1]

Thankyou for the reply, I think it is just a combination of small things that are causing the problem, for instance there is "play" in the final part of the movemnet (between the "rocker" and the connection to the valve chamber) i.e. you can rock the rod and open the valve, or close it. I thought of making the rods a bit longer!

[David Bothwell 1Participant @davidbothwell1]

I just wanted to post that I have solved my motion problem (at long last) the problem arose from the guidebars (for the piston rods) being too long and thus restricting the rocking action of the expansion link, simple solution is to saw off the excess and re-fit, thanks to those who replied. I suspect had I included a picture somebody may have spotted the problem and saved me a long (six weeks) trying to work out what was wrong!

[Ian Johnson 1Participant @ianjohnson1]

Glad you sorted out the problem, I'm building a 3 1/2" Molly too! Difficult to find much info on this model.

I got as far as building up the frames, axles and buffers then work stopped as other things took priority.

You say it is part made, It would be great if you could post up your progress, hopefully it will give me inspiration to start again.

Ian

[David Bothwell 1Participant @davidbothwell1]

Hello Ian,. Yours looks nicer than mine. I should have mentioned that the loco mechanism is almost complete. I can recommend that you go to Stationroadsteam and consult their archive. There you will find a useful set of pictures by either entering Molly or Jinty. There are also pictures of (what I am assuming) Martin Evans alternative motion, man y thanks for your reply

[Ian Johnson 1Participant @ianjohnson1]

Thanks for the link David. And despite looking I think I have probably only seen one of these Molly's at model engineering shows.

Just noticed the dates of the original postings, my photo is a few years old too!

Ian

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