Skip to main content
Sign In or Register

View Basket

This thread has been locked and can no longer be posted to.

Locking cranks

Replies 10

Views 638

Gayhalo
Gayhalo

5 posts

View User

discussion starter

Posted at 12:18:25 Mon 5 Apr 2021

This isn’t new but it has beaten me. I have not had a OO Guate for 60 years and bought a very old (1973?) pannier tank. I have driven myself nuts quartering and straightening crank rods. I have the rods straight in all directions and the pins at right angles to the crank in all directions. It all still locks. Has anyone else been there and found a solution?

i have considered buying another engine but I fear they will all have a similar problem.

96RAF
96RAF

19740 posts

View User

moderator

Posted at 12:28:16 Mon 5 Apr 2021

What if you take the rods off on one side. Can you eliminate one side or the other as the fault.

If still locking with both sides off them it is a gear train problem.

http://www.halton96th.org.uk/robs_rails.html

Last Edited 12:28:45 Mon 5 Apr 2021
Posted 12:28:16 Mon 5 Apr 2021

Gayhalo
Gayhalo

5 posts

View User

discussion starter

Posted at 12:58:49 Mon 5 Apr 2021

@96RAF

Thanks for your interest. It locks with one crank and the motor removed. It looks to me like I have a problem with one crank. I have searched but can find no new cranks to buy.

Last Edited 13:24:57 Mon 5 Apr 2021
Posted 12:58:49 Mon 5 Apr 2021

96RAF
96RAF

19740 posts

View User

moderator

Posted at 16:22:49 Mon 5 Apr 2021

A pity no new parts are readily available. If you have a service sheet and can find a part number it is surprising what a google search will find.

Close inspection required to see if you can find where the foul is occurring.

Does any crank or rod have a worn hole allowing enough displacement to create a geometric lock. Often such a lock out will be directional. If worn it may be possible to rework the hole back to round and fit a bush.


http://www.halton96th.org.uk/robs_rails.html


Posted 16:22:49 Mon 5 Apr 2021

Going Spare
Going Spare

3007 posts

View User

Posted at 19:22:19 Mon 5 Apr 2021

For a loco of that age, there will be only one crankpin on each side, on the centre wheels, with pins on the coupling rods locating in to holes on the other four wheels where crankpins would otherwise have been. Has one (or both) of the crankpins been pushed inwards so that it/they are fouling the chassis block? The crankpin should be flush with the surface of the wheel at both front and back.


Posted 19:22:19 Mon 5 Apr 2021

threelink
threelink

862 posts

View User

Posted at 10:50:18 Tue 6 Apr 2021

Assuming the gear train is ok and the rods are straight and matching (don't laugh - I had a similar problem until I found that one of the rods had been replaced by one very similar but not exactly the same) then the problem can only be quartering or something fouling the rods. It's worth checking that one of the wheels has not been pushed in to allow an axle end to protrude and foul the rod and also worth checking the backs of the wheels. I had an old pannier (Triang, I think) with rods held in place by crankpin screws into a small square of brass let into the back of the wheel. The brass square had got out of position and was fouling on the chassis. Stick at it - I'm sure you will get there.


Posted 10:50:18 Tue 6 Apr 2021

Gayhalo
Gayhalo

5 posts

View User

discussion starter

Posted at 14:26:42 Tue 6 Apr 2021

@threelink


Thanks for all the help everyone. As my problem is there with no motor and only one crank on and it locks when the crank is at center axel position it looks like one crank is too long. Threelink may have it right that I have a similar looking crank that is slightly long.

I have I hope solved the problem. I have found (and purchased) a second hand chassis that is claimed to “run freely” so it either dose or it goes back. I would have preferred to fix it just for the satisfaction but this project is to convert the engine to battery that I have achieved and the locking is getting in the way.

Last Edited 14:55:40 Tue 6 Apr 2021
Posted 14:26:42 Tue 6 Apr 2021

atom3624
atom3624

4006 posts

View User

Posted at 15:37:48 Tue 6 Apr 2021

Just a question - easily done.

Is one side's coupling rod upside down?

Al.

Last Edited 21:52:57 Thu 8 Apr 2021
Posted 15:37:48 Tue 6 Apr 2021

DBfan
DBfan

206 posts

View User

Posted at 18:29:04 Tue 6 Apr 2021

Have you got them on the wrong side ??


Posted 18:29:04 Tue 6 Apr 2021

Gayhalo
Gayhalo

5 posts

View User

discussion starter

Posted at 21:08:00 Thu 8 Apr 2021

Is one side's coupling rod upside down?
Al.


I don’t think it is possible as the axels are not equally spaced. I guess you could swap sides and turn them upside down but it should not lock anyway.

Last Edited 21:52:33 Thu 8 Apr 2021
Posted 21:08:00 Thu 8 Apr 2021

Gayhalo
Gayhalo

5 posts

View User

discussion starter

Posted at 21:08:52 Thu 8 Apr 2021

Have you got them on the wrong side ??


I don’t think it is possible as the axels are not equally spaced. I guess you could swap sides and turn them upside down but it should not lock anyway.

Last Edited 21:53:25 Thu 8 Apr 2021
Posted 21:08:52 Thu 8 Apr 2021

Bassett-Lowke Members Login

Forgotten Your Password?

Need to Register?