J11 to J39

[Theakerr]

Now that Comet is in a state of transition I was looking at my J11 and J39 (which runs like the proverbial cxxx.  Measuring the wheel diameter,  the axle spacing and doing a look see fit, I think it should be possible to replace the old J39 chassis with a J11 chassis.  Anyone done it?

[Scottish Modeller]

Hi Theakerr,

 

Sounds like a long way round to a short job!

 

Yes - the wheel size is correct but....

 

Why not just replace the old J39 chassis with a Bachmann J39 one?

 

Thanks

[Thane of Fife]

The chassis have a very similar wheelbase, and I fitted a BEC J11 with a cut down Comet J39 chassis.

I like the Comet chassis and it's easy to build. It would also leave a lot of space for lead in the unused space in the boiler.

 

Thane of fife

[Theakerr]

Thanks for the feedback.  I have built two comet chassis and they are not bad at all but with the price of a motor and gearbox the total is about the same as a J11 plus as I said potential availability.  Re getting a replacement J39 chassis, no point.  It is still the old split frame pile of junk.  Bachmann actually replaced one at no charge and even the new one was a poor runner.  

[34theletterbetweenB&D]

I am another who has done it. The wheelbase is as near perfect as matters not, 1" different in length overall in reality. Initially it looked as though the rear securing point on the J11 chassis would line up to engage with the screw boss under the cab, but it turned out that the original screw hole needed plugging and a new screw hole creating about 2mm further forward so that the wheels were properly centred in the splashers. One screw has proved quite enough to retain the body on the chassis.

 

Be careful thinning down the plastic bodysides especially in the firebox, as quite a lot has to be removed for an easy fit, I accidentally cut into a representation of a mud hole from behind, so that the centre fell out. Easy enough to fix. My tender already had pick ups arranged on the split chassis principle to compensate for the plating being all worn off the old split chassis' wheelsets, so it is now an all wheel pick up loco.

 

The running is way better than from the graunchy old split chassis which has done many miles in the near twenty years I have had it, but I am still looking at the intrusion of the new chassis' motor into the under boiler space. I think that it would be quite possible to reposition the motor on the chassis, and may do this unless Bach show progress on the new wiper pick up chassis announced some time ago for the J39. I have made no changes to the J11 chassis, so it will slot right back under the J11 body should Bach roll out the J39 upgrade. (The J39 was an occasional visitor in my area, the J11 a real rarity, thus the preference for having the J39 as the runner.)