Hornby 08 EM conversion problems

[The Ghost of IKB]

I need help!

I've used Gibson wheels and cranks to re-gauge my Hornby 08, but try a I might I can't get the bloody thing to run.  I can't get the Con rods to work reliably, they work for half a revolution of the wheels, maybe a bit more but then buckle in the middle and then end up locked up or even going backwards!

What am I doing wrong?

[Jeff Smith]

Have you got any pictures?  Are you using the original Hornby connecting rods?  Are the cranks set at about 90 degrees apart?

[CloggyDog]

I need help!

I've used Gibson wheels and cranks to re-gauge my Hornby 08, but try a I might I can't get the bloody thing to run.  I can't get the Con rods to work reliably, they work for half a revolution of the wheels, maybe a bit more but then buckle in the middle and then end up locked up or even going backwards!

What am I doing wrong?

 

Sounds like one or more of the cranks is slipping on the axle ends, either too loose a fit or they split when forced on the axle ends. The quartering also needs to be spot-on, ideally using a jig to set the cranks at 90^o

 

My original conversion of a Bachmann one with Gibson wheels exhibits the same problem.

 

See if you can identify which (and how many) cranks are loose or split. Loose ones - a tiny drop of Loctite may solve it, but make sure the quartering is good and don't get the stuff anywhere near the crank pin! Split ones - try the Loctite method, but if that doesn't work, AG does sell additional cranks to replace the split ones.

 

HTH

[5050]

Are the AG fly cranks recent production ones or AG originals?  I have an idea that the original AG produced ones were prone to splitting (the Class 14 ones certainly did for me) but I had heard that Colin identified the reason for this and has amended the production method to overcome it.  However, I'm still not convinced that moulded fly cranks will work as there is not the 'restraining' element of the steel tyre to resist the outward force of the axle being pressed through as happens with wheels.  For my 08 chassis (using a Crownline kit and a highly detailed Lima body) I machined my own brass fly cranks using a lathe but obviously not everyone has this facility.

[The Ghost of IKB]

I'm using the Hornby con rods. The crank are I think the later AG one - only bought a couple of months ago.  They don't appear to be split but do seem to slip on the axles,  I avoided gluing I was worried I'd stick everything up!

This quartering business is far trickier than I thought!  Is it best to do one side at a time? or one axle at a time?

[RexAshton]

I'm using the Hornby con rods. The crank are I think the later AG one - only bought a couple of months ago.  They don't appear to be split but do seem to slip on the axles,  I avoided gluing I was worried I'd stick everything up!

This quartering business is far trickier than I thought!  Is it best to do one side at a time? or one axle at a time?

The quartering doesn't need to be too terrifying.

Thing to do is first fit the wheels and axles setting them to the correct gauge. Then remove the motor to allow the driven axle to rotate. Fit the cranks to one axle locking them in place with Loctite 601 or similar retainer. This is not an adhesive and wont glue things up solid if you use it sparingly. At this point it's vital to get the cranks at 90 degrees. Slightly over won't be a problem but make sure they're not less than 90. When the Loctite has gone off (generally only takes a few minutes) move onto the next axle. Fit and Loctite one cranks (It doesn't matter which side. Fit the rods then fit the crank to the other side adjusting the quartering until the chassis runs smoothly and Loctite it in place. Move onto the third axle and do the same. You should now have a smooth running chassis which should need nothing more that very minor adjustments. When everything has cured re-fit the motor. If there are any tight spots they may be caused by a tight crankpin clearance which can be eased using a tapered broach.

Hope that makes sense.

[The Ghost of IKB]

Thanks for that Rex - I now know what I'm doing with my afternoon off tomorrow.

[Jeff Smith]

I have used plenty of Gibson wheels for kits but having converted a Bachmann 57xx using an Ultrascale P4 drop-in wheelset which come ready gauged and quartered with the drive gear already installed, would stick to these for conversions.  Yes, they are more expensive but so worth it!  Brass is the cheaper option and barely noticeable once painted.

 

I have no connection with Ultrascale.

[The Ghost of IKB]

HI Jeff

I've used ultra's and gibson on bogie'ed diesels and found them both easy to use.  The cost of the ultra 08 set and the 6 month wait encouraged me to go for the gibson's for the 08's.  The loco' are quite old and cost less than the wheel sets! 

[Jeff Smith]

Fair comment.....I remember the wait.....!

[RexAshton]

I have used plenty of Gibson wheels for kits but having converted a Bachmann 57xx using an Ultrascale P4 drop-in wheelset which come ready gauged and quartered with the drive gear already installed, would stick to these for conversions.  Yes, they are more expensive but so worth it!  Brass is the cheaper option and barely noticeable once painted.

 

I have no connection with Ultrascale.

Jeff

I'd agree with you if it wasn't for the very long delivery times (currently six months).

[Izzy]

Don't know if this might be something to take a look at but a few months back I converted a Bachmann 08 to P4 using some old 1/8" bore Gibson wheels I had which I used on the original Bachmann axles by bushing the wheel centres with some delrin bushes. I thus used the original outside cranks but still had some running issues which I traced to the coupling rods.

 

I am not sure if the Hornby ones are the same (I think they might be) but these are two part affairs with a pivot joint, but the joint was very poor, loose and sloppy, and so the actual rod distances moved/altered with each rotation, causing the wheels to 'catch' at certain positions since the rear axle is actually the driven one, (the joint is on the rear portion - so not helpful).

 

The easy answer was to solder up the rods solid, so the distances were constant, and open up the play on the crankpins to allow a small amount of easy up/down axle movement - you don't need much for it to work.

 

As I say it might not apply to the Hornby model, but perhaps worth checking.

 

Izzy

[The Ghost of IKB]

I did wonder about having the rods in two pieces.  It does seem to be looser than ideal, and with no compensation it doesn't seem to serve a function.

[The Ghost of IKB]

Well I've worked out one cause of the problem.  The rotation of the wheel is unscrewing the pins and nuts holding the crank onto the con rod, thus it get very sloppy and then it buckles up.  Going the other way tightens it again!  Do I glue the pins into the cranks, and then glue the nuts on?  This would appear to do it (i think) but there's a risk of gluing the whole thing solid

[Porcy Mane]

I've converted Bachmann 08 (EM) using Brassmaster Coupling rods and Hornby 08(P4) when I've used Bill Bedford 08 rods all using Gibson wheelsets apart from one when an Ultrascale conversion was used. Even on the Ultrascale conversion One Crank needed a slight tweak to remove a slight tight spot and was a bit of a devil to find.

 

I've now standardized on Gibson conversion sets (Mr Seymour now provides 2 spare cranks with each conversion set) using Ultrascale balance weights and coupled with Bill Bedford 08 Rods thinned to prototype depth. For crank pins I use countersunk brass 14 BA set screws with bushes cut from brass tube. There is no logic in it but I find I can screw the brass set screws into the cranks keeping the set screw perpendicular but when I do this with steel crank pins at least one goes in with a wobble.

 

With the rods I've found a small amount of slack is helpful on the knuckle as this helps achieve a small amount of vertical play on the axle and also allows horizontal movement of the centre axle when going travelling through curves.

With quartering I've always done is by eye, one axle at a time. With the Hornby 08 I do the front axle first then the middle. I use a 0.8mm bolt through the coupling rod knuckle so it can be split front/rear.

With the two front axles mounted in the chassis I fit the front half of the coupling rods and check for free running turning the wheelsets by hand. Once happy with the front and middle axles the full coupling rods are assembled and the rear axle mounted and all checked.

 

The pic should make things more clear.

 

 

Once I've got things all together I find my biggest problem is getting the electrical pick ups to contact reliably.

P

 

Edit: I forgot to add, I use spacers cut from brass tube to limit sideways movement of the front & rear axles.

[Izzy]

Well I've worked out one cause of the problem.  The rotation of the wheel is unscrewing the pins and nuts holding the crank onto the con rod, thus it get very sloppy and then it buckles up.  Going the other way tightens it again!  Do I glue the pins into the cranks, and then glue the nuts on?  This would appear to do it (i think) but there's a risk of gluing the whole thing solid

 

If you are using the AG type crankpins, a top-hat bush with a washer and nut to lock it onto the wheel, (you put a 14ba countersunk screw through the wheel/crank from the back), then it would seem that you have made the bushes too small for the thickness of the coupling rod boss, and is why they are tightening one way and un-screwing the other. You thus either need new bushes that are a bit longer - a bit of side-play is never a bad thing - or reduce the boss thickness to suit the bush

 

 

 

 

Once I've got things all together I find my biggest problem is getting the electrical pick ups to contact reliably.

P

 

 

 

Don't know how the Hornby pick-ups work, but I replaced the Bachmann ones with hard brass wire - can't remember whether it was 0.3 or 0.45 now - to rub on the wheel treads after the originals proved less than satisfactory. These have proven totally reliable.

 

 

 

 

Izzy

[The Ghost of IKB]

Job done!  It now runs ok without unscrewing or locking up.  Thank to everyone for the advice, now need to improve those pickups!