Performance difference on 'identical' locos

[Old Tom]

I've just run my Accucraft Caradoc and Mortimer back to back and realised that the Mortimer is a far better loco, even though they are both about the same vintage. I've never had any issues with the Caradoc and always thought it was a good runner - but Mortimer is excellent! It's a far gentler loco pulling away from a dead stop, it's easier to control and even has a far better chuff (both fitted with Summerland chuffer pipes).

So my question is:

What could cause the difference between two locos that share the same boiler and running gear? Could the timing on the Caradoc be ever-so-slightly out? If so, has anyone got a 'how to' guide to setting up the timing on a Caradoc? (I know by reading posts on this forum that Accucraft would be very helpful in sorting the problem if I sent it to them, but I'd lke to try fixing it myself )

But then again.... it could be something else causing the problem, so any suggestions would be gratefully received.

 

[bobg]

I think Tom, it could be a number of things and I'm sure others will have ideas as well. I doubt that even two identical locos will perform exactly alike, so the difference must be significant to concern you. Yes it could be different valve timings, even if set up by the same person (doubtful). It could be down to different water levels in the boilers. It could a difference in the burners, or gas pressures, one run-in more than the other. It could be so many things it could be a long and difficult job to find them all. One way to try and prove it might be to swap parts (like burners) from one loco to the other. Good luck in your endeavours, and keep us posted.

Edit, Just re-read this and realised it might not say what I meant. It 'is doubtful that the same person set up both valve gears.

 

[tagorton]

I've just run my Accucraft Caradoc and Mortimer back to back and realised that the Mortimer is a far better loco, even though they are both about the same vintage. I've never had any issues with the Caradoc and always thought it was a good runner - but Mortimer is excellent! It's a far gentler loco pulling away from a dead stop, it's easier to control and even has a far better chuff (both fitted with Summerland chuffer pipes).

So my question is:

What could cause the difference between two locos that share the same boiler and running gear? Could the timing on the Caradoc be ever-so-slightly out? If so, has anyone got a 'how to' guide to setting up the timing on a Caradoc? (I know by reading posts on this forum that Accucraft would be very helpful in sorting the problem if I sent it to them, but I'd lke to try fixing it myself )

But then again.... it could be something else causing the problem, so any suggestions would be gratefully received.

Almost certainly the timing ? but this is easy to check. First of all turn your locomotive over and put the loco in reverse gear. The scribed line on the centre piston valve should just disappear into the steam chest. If not then adjust by means of the two locknuts on the end of the valve rod. Put the loco back into the neutral position. Secondly lay the locomotive down on one side and move the wheels as if the locomotive is moving forward. As your main axle cranks move to the 6 o clock position the scribed line on the valve rod should just disappear into the valve chest. If not alter as above. Turn the locomotive over and repeat. You have now timed your locomotive.

Another tip here. You have one locomotive that you feel runs better than the other. Undertake this check first on this loco ? but of course make no adjustments. It will give you a far better feel for the proper check on the loco that is not running so well. Just make sure it is set up the same The above is the easiest check to do and the most likely area where there is a going to be a problem.

 

[Old Tom]

Thanks Tag, job sorted.

The scribe line didn't quite make the piston, let alone disappear, unlike the Mortimer.

So, if I'd have got Mortimer 1st, I'd have said that the Caradoc had a problem when I bought it and probably sent it back. But because I got the Caradoc 1st, I thought that was how they all performed.
Very interesting.

So check your timing lads, it could be you've been running a slightly below par loco.

 

[tagorton]

There are various little quirks with these locos ? but setting the timing kills 98% of all known germs.

 

[Railfan]

OK, now you've got me thinking. The next time I'm ready to run my Caradoc, I'll have to check the timing. Just to be sure, no known problems. Thanks for the quick, easy check.