Getting my valve gear in a twist - Heidi

SevenOfDiamonds

SevenOfDiamonds

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Hello all

My LGB Heidi (20272) was running round the garden just fine but suddenly made a graunching sound and came to a stop. I recovered it to my workshop along with the single piece of silver-grey plastic I found alongside it.

On closer inspection, the loose item was the part of the valve gear that sits above the running plate (one of which is shown circled in blue in the photo below). The equivalent one on the other side was also missing but, based on a rattling sound, I found it when I removed the loco body.

Armed with photographs from the LGB website (albeit of a 20274), I was able to re-seat the two pieces of plastic, and connect them onto the appropriate pins on the remaining valve gear. On one side of the loco, everything looked like the photo but, on the other, what should look like this (note the green parts) . . .

1655383662042.png

. . . was actually like this (facing the wrong way, and the "horizontal component" somewhat bent) . . .

1655383745905.png1655383846122.png

My question is how do I return it to its correct orientation with the least amount of disassembly (and risk of further damage)?

Do we have any "valve gear experts" on here?

Cheers

David
 
SevenOfDiamonds said:
Hello all

My LGB Heidi (20272) was running round the garden just fine but suddenly made a graunching sound and came to a stop. I recovered it to my workshop along with the single piece of silver-grey plastic I found alongside it.

On closer inspection, the loose item was the part of the valve gear that sits above the running plate (one of which is shown circled in blue in the photo below). The equivalent one on the other side was also missing but, based on a rattling sound, I found it when I removed the loco body.

Armed with photographs from the LGB website (albeit of a 20274), I was able to re-seat the two pieces of plastic, and connect them onto the appropriate pins on the remaining valve gear. On one side of the loco, everything looked like the photo but, on the other, what should look like this (note the green parts) . . .

View attachment 300246

. . . was actually like this (facing the wrong way, and the "horizontal component" somewhat bent) . . .

View attachment 300247View attachment 300248

My question is how do I return it to its correct orientation with the least amount of disassembly (and risk of further damage)?

Do we have any "valve gear experts" on here?

Cheers

David
Click to expand...
David

When I acquired my Heidi a little while ago and posted photos of it, it was pointed out to me that the valve gear was incorrectly positioned, on both side in my case, identical to yours. Given that the linkages are very loose and that plastic is very flexible, I gently pushed mine back into the correct position without ant issues.

Before

dig 211203001.JPG

After

dig 220208002.JPG

David
 
David1226 said:
Given that the linkages are very loose and that plastic is very flexible, I gently pushed mine back into the correct position without ant issues
Click to expand...
Thanks David

I had read those exchanges at the time but "the little grey cells" had clearly forgotten them.

For the benefit of anyone finding this thread in the future, you are right . . . but I needed to manually turn the driving wheels to get the valve gear into a position where I could fix the alignment without there being too much strain on the (already slightly bent) plastic components.

Back on the track, all seemed well for 30 seconds or so, and then I heard that graunching sound again. Having checked that nothing on the valve gear was binding, I unfastened the bottom plate. The cog on the front driving axle had moved off the splined (?) part of the axle, and was clear of the drive cog (so only two wheel drive?). The graunching noise was obviously "when the corners met", and the valve gear problem was a symptom of a different problem, rather than being the main problem! To my surprise, I was able to slide the cog onto the splined (?) part of the axle, in line with the drive cog. Expecting to find that I would have to remove the bottom plate several times more (to get the quartering spot on), I was pleasantly surprised that Heidi now ran smoothly at the first attempt.

Before letting the loco back into revenue-earning service, I suspect I ought to run the loco on rollers for half an hour or so in the workshop, to make sure my "fix" will last.

Has anyone else had the problem of a drive cog slipping sideways on the axle? Recent operations have all been round the circuit in an anti-clockwise direction (and the cog had slipped "outwards"). Could that be the cause (or, at least, a contributory factor)?

PS Despite my earlier wish for "the least amount of disassembly", before reading David's advice, I had already discovered how to remove the cylinder moulding (and the step in front of it) to give more play in the valve gear in general. It took two attempts to put them back, mind, but all good now.

Cheers

David
 
SevenOfDiamonds said:
Thanks David

I had read those exchanges at the time but "the little grey cells" had clearly forgotten them.

For the benefit of anyone finding this thread in the future, you are right . . . but I needed to manually turn the driving wheels to get the valve gear into a position where I could fix the alignment without there being too much strain on the (already slightly bent) plastic components.

Back on the track, all seemed well for 30 seconds or so, and then I heard that graunching sound again. Having checked that nothing on the valve gear was binding, I unfastened the bottom plate. The cog on the front driving axle had moved off the splined (?) part of the axle, and was clear of the drive cog (so only two wheel drive?). The graunching noise was obviously "when the corners met", and the valve gear problem was a symptom of a different problem, rather than being the main problem! To my surprise, I was able to slide the cog onto the splined (?) part of the axle, in line with the drive cog. Expecting to find that I would have to remove the bottom plate several times more (to get the quartering spot on), I was pleasantly surprised that Heidi now ran smoothly at the first attempt.

Before letting the loco back into revenue-earning service, I suspect I ought to run the loco on rollers for half an hour or so in the workshop, to make sure my "fix" will last.

Has anyone else had the problem of a drive cog slipping sideways on the axle? Recent operations have all been round the circuit in an anti-clockwise direction (and the cog had slipped "outwards"). Could that be the cause (or, at least, a contributory factor)?

PS Despite my earlier wish for "the least amount of disassembly", before reading David's advice, I had already discovered how to remove the cylinder moulding (and the step in front of it) to give more play in the valve gear in general. It took two attempts to put them back, mind, but all good now.

Cheers

David
Click to expand...
At least you didn't end up getting cranky about it.

David
 
SevenOfDiamonds said:
Has anyone else had the problem of a drive cog slipping sideways on the axle? Recent operations have all been round the circuit in an anti-clockwise direction (and the cog had slipped "outwards"). Could that be the cause (or, at least, a contributory factor)?
Click to expand...
I have not had this problem with my LGB Rhaetia. But did run into a similar issue with the drive gear position on the splined axles of a LGB 24450 Ge 2/4 and a 21427 Ge 4/4 III. I think they came from the factory with poor alignment. The gear grinding did not start until the locos had been operating awhile. I did posts about these few years ago. LGB 20450 and brethren drive gear issue and Gear mesh issue on LGB Ge 4/4 III, No. 2x42y.

And, yes if the drive ger slipped a cog or two (or completely disengaged) on one axle it could have easily been the source of the valve gear problem.

Edited after re-reading the original post.
 
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SevenOfDiamonds said:
The cog on the front driving axle had moved off the splined (?) part of the axle, and was clear of the drive cog
Click to expand...
Did you check if the drive gear was cracked? It should not slide without some significant resistance - it should be tight on the axle.
 
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Had the same issue with the cross wobbled bar on my Heidi. But it has also occurred on my TL45 Pfiffi as well but just as easily resolved. Fortunately nit had the gear misaligned issue though when pushing forwards no power the wheels cad drop out of correct quarter as the gear can slip out a cog or two. Lumpy running generally a guide to this issue.
 
phils2um said:
Did you check if the drive gear was cracked? It should not slide without some significant resistance - it should be tight on the axle.
Click to expand...

All good, thanks, as proved by my subsequent testing on rollers. There was considerable resiastance to sliding it back into position. To start it moving, I used a wide-bladed screwdriver, levering the cog away from the motor block casing. The final part of the move was a little easier (but I can't remember how I did that part, just relieved that it kept moving).

Cheers

David
 
meiningen8 said:
A similar problem can afflict early versions of the Saxon Mayer. I have one which occasionally flips while in motion .
Click to expand...
Ditto with my Sachsen, several times. It is a problem which has afflicted 3 of my 7 U Class locos too.
Usually, I have been able to ”flip” them back but a couple have broken.
Bring back metal rods.
 
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