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Offline antycapp  
#1 Posted : 11 April 2021 21:21:02(UTC)
antycapp

Italy   
Joined: 20/02/2021(UTC)
Posts: 10
Location: Lazio, Rome
Good evening everyone,

I'm here to ask you a problem probably
mechanical, but which I tried to solve independently by looking
both on the site and on the web, but of course as you would imagine without
success

This marklin 3083 (of which I have also carefully read the exploded view)
on the curve of radius 1 with the curves to the right presents a
front wheel wheelie phenomenon before the trolley

I took the cart apart, but he's innocent. I got out of control
load and the phenomenon has remained indifferent, it is greatly attenuated
in the opposite direction or with the curves to the left.

It occurs to me that the drive is on the right rear wheel
and therefore the resulting force can actually lead in extremis
to a detour towards the outside in the right curve

Not so in a left-hander.

I hope I have filmed so that you can analyze the problem and maybe
suggest me a reasoning to follow

I also tried to replace, remove or move the hoops
of adherence, but without success. The boards are straight, I have examined them
on a truncated track and they seem to me on the same axis, that on the straight
the place is fine

the load control is at zero, but it also does so with the one activated

Thanks for any help

Video curve R1 to the right



Video curve R1 to the left
I learn, I learn!
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Offline antycapp  
#2 Posted : 13 April 2021 11:03:09(UTC)
antycapp

Italy   
Joined: 20/02/2021(UTC)
Posts: 10
Location: Lazio, Rome
Problem found!
Blame the connecting rods

Only with the right one is perfect


with the left one instead


But how do I proceed now? It is the first time that I have come across such a problem .....

Thank you
I learn, I learn!
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Offline antycapp  
#3 Posted : 13 April 2021 11:30:35(UTC)
antycapp

Italy   
Joined: 20/02/2021(UTC)
Posts: 10
Location: Lazio, Rome
Video to analyze .... better than that I did not

He has an impediment, he sobs and gets up the front left up to get on the rail profile
In fact, it sobs only when cornering, only with the left wheel arrangement fitted and only in the right R1 bend

I learn, I learn!
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Offline marklinist5999  
#4 Posted : 13 April 2021 12:45:38(UTC)
marklinist5999

United States   
Joined: 10/02/2021(UTC)
Posts: 3,074
Location: Michigan, Troy
Driving rods bent perhaps, or one wheel connected to them in the wrong position?
I don't think the frame is bent?
Offline antycapp  
#5 Posted : 14 April 2021 07:46:23(UTC)
antycapp

Italy   
Joined: 20/02/2021(UTC)
Posts: 10
Location: Lazio, Rome
It was the left central axis shifted slightly upward. I compared the right ones with the left ones and then I gently forced a click down the middle left one. Now it is OK.

I learn, I learn!
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Offline hxmiesa  
#6 Posted : 14 April 2021 20:09:36(UTC)
hxmiesa

Spain   
Joined: 15/12/2005(UTC)
Posts: 3,519
Location: Spain
This possibly happens because the wheels are not quartereds correctly.
The connecting rods must always be completely horizontal on both sides, BUT there should be an exact 90º difference of the circular position of the rods between each side.

This un-quartering can be caused by the flanges sliding on the axles, or the connecting rods being bent.
That kind of damage can happen if somebody tried to PUSH the locomotive on the track, where the friction of the motor results in huge forces being applied through the traction-tires of the driving wheels.

The remedy is to carefully quarter the wheels again, which requieres some force applied to the wheels, so be careful not the bend the rods and/or further weaken the flanges grip on the axle. (once they have slipped, they will slip even easier the next time some kind of force prevents normal movement!)
Best regards
Henrik Hoexbroe ("The Dane In Spain")
http://hoexbroe.tripod.com
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Offline antycapp  
#7 Posted : 15 April 2021 10:10:09(UTC)
antycapp

Italy   
Joined: 20/02/2021(UTC)
Posts: 10
Location: Lazio, Rome
Many thanks hxmiesa, this is information that I basically knew, the loco was purchased used but in excellent condition, but I do not know its history, so it is possible that it has received some mistreatment on the tracks as you say. I wonder if there is a way to measure 90 degrees precisely. I have made the correction by eye and it seems to be fine. Confused
Thank you
Antonio
I learn, I learn!
Offline kiwiAlan  
#8 Posted : 15 April 2021 18:30:51(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 8,082
Location: ENGLAND, Didcot
Originally Posted by: antycapp Go to Quoted Post
Many thanks hxmiesa, this is information that I basically knew, the loco was purchased used but in excellent condition, but I do not know its history, so it is possible that it has received some mistreatment on the tracks as you say. I wonder if there is a way to measure 90 degrees precisely. I have made the correction by eye and it seems to be fine. Confused
Thank you
Antonio


I wouldn't worry about it being precisely 90 degrees, so long as it is 'close enough'. It is more important that the three wheels on a side have their rod attachments at the same angle so the connecting rod is in a straight line at all times.

Offline waltklatt  
#9 Posted : 15 April 2021 19:38:22(UTC)
waltklatt

United States   
Joined: 17/03/2012(UTC)
Posts: 138
Believe I see the wheels are not freewheeling in the axle housings.
Did you remove the wheels and put them back on?
Check the wheel spacing and flexibility of the axles in the housings.
Also check the linkages, they should be free of binding and loose against the bolts.
Walter
Offline antycapp  
#10 Posted : 15 April 2021 19:48:44(UTC)
antycapp

Italy   
Joined: 20/02/2021(UTC)
Posts: 10
Location: Lazio, Rome
Hi Waltklatt, thanks for the advice, I would like to avoid disassembling the wheels due to inexperience, now they go quite well. However, my English is not very good but I understand that I don't have to tighten the connecting rod bolts very much?

Thank you
Antonio
I learn, I learn!
Offline antycapp  
#11 Posted : 17 April 2021 18:34:50(UTC)
antycapp

Italy   
Joined: 20/02/2021(UTC)
Posts: 10
Location: Lazio, Rome



So once the problem was identified, the desire was to obviously eliminate the phenomenon, having time and doing tests on tests I could see that the problem therefore

It resided on the left axes and therefore the right ones were to be taken as a model for the so-called quartering (i.e. each wheel must follow the previous one by 90 ° up to the driving wheel).

But unfortunately this was not enough as I read here and there that once this quartering has been fixed there is also a small tolerance that can give problems and in fact there was a point during the rotation on the left axes where the main running gear. that is, the one that connects all the wheels made resistance and therefore not only raised the left front wheel, but also caused a jolt of the loco.

The wheel that in the end remained witness of the now small phenomenon remained was the left front wheel which was the one that had the most tolerance of all and which by hand was very difficult to move a little for fear, a little for inexperience and a little because they slip between the fingers.

Then a tool I used to change the batteries of watches came to my aid: a case opener that I would like to submit to you as a tool to be included among those useful for site maintenance (maybe there is a similar one for this hobby and I didn't know it)
Apricasse da orologiaio.jpeg

Of course I am also attaching the video of the wheels finally adhered to the tracks during the left turns


and with its cloak and tender


Hello everybody ThumpUp
I learn, I learn!
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