K27 counterweights difference

[grayfitz]

 I received my replacement counterweights yesterday and decided to fit them this morning. I was using the 12 step instructions per this site, and fitted the first one and noticed the short side rod when fitted back on does not line up straight. I compared a new weight with an old one and found the spacing on the screw shaft to be wider on the new weight. If we were replacing all weights this would not matter, but the three driver makes the shafts out of line. Perhaps this is why other owners after having the weights changed complain of a thunking noise. Could you please advise on this .Thanks GRAHAM (Australia)

[Jon D. Miller]

Graham.
I'm not sure I understand your reference to the screw shaft.  Is this a reference to the crank pins on the counterweights?

I've replaced eleven sets of counterweights.  Now that's not a lot of counterweights but in each case the replacements lined up just fine and the side rods were straight.  You no doubt have noticed that the side rods are segmented (hinged).  This is probably to allow for a certain amount of "flexing" as a one piece side rod would have a tendency to bind.  So, there could be times when the side rods are not on a perfect plain since each axle is independent of the others.



From this picture you can see that the side rod is on the same plain from back to front.

Now possibly you received a set of counterweights that where not properly drilled and taped.  If that is the case then you'll need to get another set from Bachmann.  But, as I said with eleven sets installed this situation has never come up. 

If it were my K-27 I'd install the replacements and see how it operates.


JD

[grayfitz]

Thanks JON, Yes I do mean the crank pin on the weights , but its not the side view Im refering to,but its the view from underneath while I had the loco upside down. The small spacer on the new weight  crank pin is nearly twice the width as on the old weight pin , which puts the short crank between #3 wheel and #4 wheel out of line,If you could check an old crank against a new one to see if my new set are faulty. I hope you can understand this, Regards GRAHAM.

[Jon D. Miller]

Graham,
I can't help you with your situation.

I pitched the original weights so don't have any to check against.

Had a K-27 owner stop by to run his #453 that has had the weights replaced.  He did not retain the old weights.

On both my 455 and the 453 we looked them over carefully. We could not see any misalignment of the side rods.

I would suggest that if you still think there is a problem, it will have to be resolved by Bachmann.  I do doubt however that any replacement counterweights will be different from  those you now have. 

This is the best that I can offer on your situation. 

JD

[grayfitz]

Mr Bach man, Ive been trying to send message & photos of my problem, but cant get it thru. I get;; ERROR upload older full;;How do I clear folder to send? GRAHAM.

[mickb]

Hi graham
my replacement counterweights are same as yours about .5mm more metal in the collar around the pin for the coupling rods than the old ones.
I have installed them anyway and there appears enough play in the various coupling rod joints to cope with the difference.
It may be that the replacements that arrived in Australia came from the second batch and that they are slightly different from the first batch.

Mick

[grayfitz]

Thanks Mick, I will see if I can get an answer from Bachmann as I am not satisfied that after a while having them running out of line there would be irregular wear.You might be right about different loco batch weights.I dont know of anyone here in Auz that has a K27 to compere with. Regards Graham.

[the Bach-man]

Dear Graham,
I don't have a set of old counterweights for comparison. I guess the big question is: How does the loco run with the new weights?
Have fun!
the Bach-man

[grayfitz]

 Hi Mr Bach man,I see that mickb has the same weights as me,Its not so much as how it runs now but the out of alignment will have an effect on it in the future against normal wear. Are all the weights the same as I received,or were there some with the same dimensions as the origonals. I really would like to get a ruling on this mistake before I complete the changeover of weights on my loco. regards Graham.

[grayfitz]

Hi again Mr Bach man, Any answers to my questions on reply #8 Regards Graham.

[grayfitz]

 Mr BACH MAN >>>Well after all the fuss I made over the counterweight  crankpin spacer being wider than the origonals,I fitted my replacement weights today and as I inspected each old weight I noticed wear marks on them where the side rods  had been rubbing,against them,hence the wider spacer to keep the rods away from the weights. Only trouble now is that #3 weights that dont get replaced have nasty marks on them ,my loco has only done less than 30 minutes running .I would suggest everyone check #3 weights after a few hours running.  Regards to aLL Graham.