Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines
Builds, Repairs, Show Your Machines! => Technical Tips, Builds, and Help => Topic started by: Jim on March 20, 2019, 11:53:42 pm
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No piston packing
Try some graphite string around one or two grooves
Dennis, I just rang MSM and double checked with the owner John and he stated that they don't use any packing on the pistons on the Pevensey or Echuca type models.
Still mucking around with it now, I think I got the position right for TDC and BDC with it just cracking at each end. Still mucking around with the ecentric timing which I have to say is a bit of a PITA.
Hi Jim and all,
1st off... hope you all had a great Christmas and I will take this opportunity to wish everyone a very Happy New Year.
Jim... please find attached pdf's which explain how to set the valve and eccentric for a steam engine.
The method required is determined by the type of slide valve the engine has... i.e... a valve with no steam LAP, or a valve with steam LAP... if you read the write up it will explain the difference and how to proceed.
There are sequence diagrams for both types so one of them will be what you require.
I hope these are of some help.
Best regards.
Sandy.
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I actually had the same issue (along with a few others) with my Pevensey as whilst it ran ok, as soon as i hooked up something to the pulley i quickly found it couldn't pull the skin off a rice pudding! :o
After a lot of mucking around trying to troubleshoot the issue, i found that the slide valve was put in the wrong way! ??? :-[
So if anyone else has a Pevensey/Echuca with the same problem, your valve should be like this on the port face:
[attachimg=1]
One you have that set you need to make sure both port openings are equally spaced by using the nut to adjust the valve travel. If you have a reversing engine like mine, you may find you have to file some material out of the anchor quadrant if it won't run in both directions after altering the eccentric timing.
Hope this helps.
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I think pretty much everything has been suggested and going by your first vids they don't run too bad Jim. Interesting to see inside these MSM engines and the machining looks very nice, i love the fact they are made out of bronze too!
Most Stuart engines like the 10V/10H only have oil grooves like your piston and some of the larger ones would have iron piston rings. I know my PMR #3 has nice teflon piston rings and some of my other models have o-rings fitted both of which give a great seal.
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I have some meters of it from the Demon from years ago. How do you use it?
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Dennis, I just rang MSM and double checked with the owner John and he stated that they don't use any packing on the pistons on the Pevensey or Echuca type models.
Still mucking around with it now, I think I got the position right for TDC and BDC with it just cracking at each end. Still mucking around with the ecentric timing which I have to say is a bit of a PITA.
Would still be interesting to see if it makes any noticeable difference...
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No piston packing
Try some graphite string around one or two grooves
Dennis, I just rang MSM and double checked with the owner John and he stated that they don't use any packing on the pistons on the Pevensey or Echuca type models.
Still mucking around with it now, I think I got the position right for TDC and BDC with it just cracking at each end. Still mucking around with the ecentric timing which I have to say is a bit of a PITA.
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No piston packing ???
Try some graphite string around one or two grooves
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Piston 'looks' ok
[attachimg=1]
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I've done some polishing Dennis.
[attachimg=2]
[attachimg=3]
[attachimg=4]
[attachimg=5]
[attachimg=6]
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You need to remove the steam chest cover and check the valve is moving equally .
Your timing can not be too bad as it runs
Is the surface between valve and ports smooth?
I would try holding the engine on it side (steam chest up ) to see what happens .
Is there any oil in there .
Does adding oil help ?if it does then I would be looking very closely at the surfaces .
Another thought is air getting past the piston ?
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Help & Advice please on the timing of this engine....as I state in the video I'm far from the expert in this.
Any help much appreciated.
https://youtu.be/4SwW_ppbqdc