Help with Accucraft Blow Down Valves

GWhizz

GWhizz

Offering Garden Railway Holidays in SW France
Hi,

Can anyone advise on Accucraft Blow down valves?

  • I have an early (smaller cylindered) Accucraft Lyn on loan/ option to buy.
  • No matter how much I tighten the blow down valve it will not seal
  • I've unscrewed the outer hex tube and removed the valve inner to inspect
  • I can see that the cone of the tap does not fit snuggly into the matching end of the tube, hence the leak
  • ANY IDEAS on a solution ???
  • I looked at the valves on my other Accucraft locos, but they seem to use a completely different design using O rings
  • I tried using various O rings but does not work with this design ( they just ride down and block the venting holes
  • Unfortunately DJB make a nice replacement system for most Accucraft but not the Lyn (the gas tank is too far back)
CAN ANYONE HELP / EXPERIENCEDE THE SAME PROBLEM?
 
Hi Brian, I'm not sure which valve you mean, can you put up a pic please?
 
I generally wait, leaving the valve open until well steamed up! And once it blows clear steam rather than excess water, close the valve to raise pressure in the recommended Accucraft method! It works great on my other three Accucraft locos.
 
Yeah, Ok, now I see what you are up against. Yes, that taper should seat in the cone and form a seal, but they never were the best of sealing valves, so if there is any distortion in either face then it will leak. I would suggest that the best repair would be to fit a whole new valve. However Accucraft are not good at supplying spare parts, so obtaining one may be difficult. To fit an "O" ring to the existing valve would require the plug, and possibly the seat, to be re-machined to hold it. There are various places that should be able to supply a suitable part, Simon Whenworth perhaps, at Anything Narrow Gauge, or others.
 
I would think about trying a Small O Ring that fits quite close to the End of the Pointy bit to see if that helps.
JonD
 
Hi Brian.
Try lapping it in with some valve grinding paste.
 
GWhizz said:
Great idea, but tried it to no avail!
Click to expand...
Sorry it failed, looked like a possible non destructive option.

Have you thought about asking the 16mm Society Forum? If you are not a member certainly worth thinking about joining. Though not sure how many members woukd be in your neck of the woods, there are some Frenchmen.
JonD
 
As an alternative to grinding paste how about Brasso, or you coud find what I think is called jewellers rouge a very fine paste used for grinding glass, I remember this from my astronomical days when some made their own mirrors for telescopes.

Shaun
 
I would recommend contacting Accucraft UK. They recently supplied a replacement for my Wrekin.
This consisted of an identical drain fitting, mounted on a copper pipre, with boiler banjo fitting.
 
Accucraft have the new type of bottom part as a straight replacement. Why don't you give them a call? Tho' they are closed this week after Llanfair.
 
As others have suggested, I would recommend contacting Accucraft. Their after-sales service goes way beyond that experienced elsewhere in everyday life.
 
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