rivarossi 4-8-8-4 big boy 4005 remotoring advice needed

[kenofchaos]

Hi every one. Ive got an old Rivarossi HO big boy (model number 1254  running number 4005) and its original motor is dreadful but i did pick it up for £75.

Can anyone suggest a suitable motor replacement. Ive seen other posts on people modifying them to take better 5 pole can motors.

my Main problem and the reason for this post is i am having trouble pinning a particular motor type down.

A lot of the posts i have read are several years old and the links they post no longer work.

I am confident in being able to do the work as i have done many bachman split chassis DCC conversions with great success the issue is just sourcing parts ( motors and drive shaft couplers) any advice would be massively appreciated.

 

cheers.

[Loconuts]

I had one of these back in 1975, picked it up new for £50 from Howes of Oxford.

 

I replaced the motor for a Portescap motor, cannot tell you which one as it can from our R&D department from work. It was connected direct to the gear box but I had to make a bracket up to mount it. Sorry not to be too much help as it was along time ago.

 

Loconuts

[34theletterbetweenB&D]

This is the early version with the big three pole motor in the cab is't it? (Humungous great loco, 2 inch long drive shaft between motor and first gear tower - and they put the motor on view in the cab!)

 

Options.

 

If you are otherwise happy with the loco, the motor runs reliably, and you are using DCC, get youself a Zimo decoder - the budget MX600 will do - and that has the adjustments and more to beat the rather basic motor into submission performance-wise. But it will hum and whine at dead slow, nowt can be done about that. (Did one such years ago for a friend using a Zimo MX64, and that transformed it from lumpy at dead slow to smooth; the motor noise inescapable.)

 

Or, you need a 2mm shaft motor, (nothing smaller than a five pole 1628 can for a real perfomance improvement)  and to grind a flat on the shaft to take the drive coupler. Shorten the loco drive shaft to suit the motor positioned as far back as possible (external sleeving glued on the shortened pieces) glue motor to internal frame, job done*.

 

Or you take 2 x 2mm shaft motors and do the same job twice to power the two engine frames separately.* Seen this done by a long deceased american friend, He took the traction tyre off the front too, so the front engine slipped on starting, neat effect.

 

* One cautionary note, you need to assess the required flexibility for your minimum radius layout curve and check that the loco drive shaft is still long enough to allow suifficient movement as the rear frame moves to take curves,

[Horsetan]

Could you post a picture of the loco chassis please and quite possibly I or anyone else may be able to suggest a possible replacement fo the loco.

 

Do the innards look like this?