fitting a Mashima 1626 motor into Hornby 61XX

[swiftbeam]

Hi Guys,

 

I love big GWR Prairie Tanks, but unfortunately only Hornby seem to make the 61xx, this model, as I understand it, is old tooling. I have asked on this forum if Bachmann intend to make an up to date version of the 61xx to the quality of their 45xx, 55xx and 56xx, it seems not. It would also seem unlikely that Hornby will update this model as well. I've hunted high and low for a really nice brass kit, nothing, or white metal, still nothing.

 

Note

*Now informed there are at least two kits*

 

So it seems I'm stuck with my Hornby R2143. My model is actually in perfect condition with not a hair out of place, but it could do with a little more fine detail and maybe a repaint to bring some 'pop' back to the finish. However, my biggest gripe is it's running quality, even fitted with a Zimo DCC decoder (suppression removed) it's not the smoothest.

 

I have scrutinised the all the moving parts and can not find anything that could cause 'iffy' running, everything is free and silky smooth. However, the motor is a little lumpy at low speed when run uncoupled from the chassis and I suspect, this gets no better in the model at higher speeds.

 

So, after a little looking and poking about, I have decided to remotor my 61xx and fit a large flywheel to her at the same time. I have decided a Mashima 1626 will fit, being almost the same size as the original 3 pole (YES, 3 POLE!!!) can motor.

 

The Mashima is 26 x 16 x 13.6mm 2mm Double Ended Shaft 12v.

I also have a milling machine and lathe, and a will to to use them !!

 

​I have liberated the die cast chassis from the model and now just waiting to take delivery of the motor any day now. I will keep you all posted as to how I get on fitting this motor and how the model performs after it's transplant :-)

 

mashima-mh1626

 

Edited October 9, 2017 by swiftbeam

[Clearwater]

Hi

 

For reference, there’s at least two 4mm 61xx kits available:

 

http://www.sefinecast.co.uk/Locomotives/New%20and%20Revised%20Loco%20Kits%20Page%205.htm

 

 

http://www.brassmasters.co.uk/gwr_41xx_51xx_61xx_2-6-2t.htm

 

It’s also usually worth a quick look on Miss Prism’s excellent listings at gwr.org.uk

 

Cheers

 

David

[swiftbeam]

Thank you for the links, I had no idea. May well be an option if the remotoring does not work out. 

[dajt]

Looking forward to following along.

[swiftbeam]

I've just discovered Scale Link!

 

Hunting through the gear sets has found me a 60:1 worm and wheel that will fit in my 61xx (the 50:1 would as well) Original Hornby is about 25:1.

 

1.5mm motor shaft, I'll need to ream out to 1.95mm

Wheel is 1/8", so will need to turn an expanding tube as the axle is 3mm

The centres are 9.5mm, just about a perfect match to the Hornby.

 

So I should get a much faster turning motor at much lower speeds. Together with the better motor and flywheel, running 'should' be awesome !

 

http://www.scalelink.co.uk/acatalog/Sundry_Items__Lead_Foil__Chain_Etc_.html

 

Fingers crossed.

 

I guess I could also have just fitted a new full gearbox, oh well, this is a bit of a journey of discovery for me!

Edited October 9, 2017 by swiftbeam

[DCB]

I don't think the motor or gearing is the issue with the Hornby 61XX.   I have experience of the Hornby large Prairies, they are not good runners We tried  a couple as replacements for a Farish 81XX on a Triang chassis on banking duties but even after much running in it still ran unevenly as if it had a wheel out of round or quartering issues.  Relegated to local passenger turns they still makes the coaches shuttle back and forth at low speed After much investigating  I found the unevenness was due to the axles moving around in the chassis which gives the impression of poor quartering.  I suspect it is incurable

However the Bachmann 43XX chassis is silky smooth until the wheels fall off and should fit the Hornby 61XX bodyshell as the prototypes were almost identical forward of the rear coupled axle, and cobbling up a  rear pony truck should be a doddle.

Edited October 10, 2017 by DavidCBroad

[swiftbeam]

Thank you for that, some things to think about, I will check the quartering.

 

I will also make some better bearings to take out the con rod slop and make sure the wheels all turn smoothly once in the chassis before the motor goes in. If she still runs badly, it can only be the sloppy axles as you say. If it is, I'm sure I can make a set of good fitting bearings and fit them to the chassis.

 

I have tools and the willingness to do it.

 

Lets hope I'm not wasting my time!

[swiftbeam]

[swiftbeam]

Quick run down on what I did. 

 

Turn off the blank shoulder on the gear until it centres,

Drill out gear to 4mm,

Turn up a 4mm blank shaft with extra shoulder,

Insert blank, solder into gear,

Turn down to size,

Drill out the gear to fit shaft perfectly,

Cut 2mm thread and replace grub screw.

 

Drill out the worm to 2mm, fit on motor,

 

Turn up flywheel,

 

Mill out chassis,

 

Trim up front mount,

 

Mill up brass motor keep mount.

 

In a nut shell, it all works very well, the chassis runs very smoothly and has a very nice slow speed, there is no more stuttering. The Hornby wheels are not particularly central, so I think my next job will be to get some better quality wheels with the holes in the correct place!

Edited October 13, 2017 by swiftbeam

[Horsetan]

....The Hornby wheels are not particularly central, so I think my next job will be to get some better quality wheels with the holes in the correct place!

I was about to suggest driving wheels from the Hornby "Grange", but then remembered that the crankpin position is wrong for the Large Prairie.

[Graham456]

So !

How much would you charge to do mine only two of them...........

Not expecting a reply just being cheeky in the faint hope,