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Engine basics => Engine set up tips => Topic started by: Joe Messinger on June 30, 2007, 08:52:59 PM
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I'm sure this has been addressed here in the past. I can't seem to find anything in the archives. Question: Does anyone have a good fix for keeping the collar on a ST NVA in place (tight)? Seems sooner or later the thing loosens and lets the needle valve vibrate and move.
I have several of Randy's PA NVA set ups and they work fine but I hate to abandon all the standard ST assemblies that I have.
Any advice appreciated.
Thanks,
Joe
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Question: Does anyone have a good fix for keeping the collar on a ST NVA in place (tight)? Seems sooner or later the thing loosens and lets the needle valve vibrate and move.
Get PA NVAs LL~ LL~
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Steven,
As I mentioned in my question, I have some PA nvs. I'm interested in finding a way to improve the ST nvs that I already have.
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Only trick is getting the collar just tight enough... Needs to be to where the needle is hard to turn but can still be turned.
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Hello,
I imagine I'll end up replacing most of my ST NVAs with PAs. As Ty mentioned, the only problem with the STs is the collar staying put.
I guess I just have trouble discarding something that could-possibly- be fixed. Growing up in the 1950's, if I was fortunate enough to have a bicycle, Flexible Flyer sled, or later a car, when something broke or didn't work on these things you either fixed it or walked. Replacing it wasn't really an option. I suppose I'm still of that mentality. Also, if I can take something that isn't working and somehow improve or repair it, I get a sense of satisfaction from doing that which is absent when I throw the old thing away and buy a new one. Often, it's not worth the effort and is impractical but I still try.
I might wrap some teflon tape on the ST threads. Probably won't help much but we'll see. Next step, call Randy and order some PA valves. . .
Thanks for help.
Joe
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Granted the PA assys are excellent but I've never had a ST assy that wasn't serviceable with a little judicious tightening of the retaining collar.
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I do not have much experince with ST NVA, but here is one I had at Brodaks a few weeks back.
See thread:
http://stunthanger.com/smf/index.php?topic=5639.0
Paul H^^
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I've never had that problem (that I recall), but I check the collet from time to time. I took some cheap slightly undersize flat wrench and dremeled it to fit. You might try inserting a #11 blade in the split in the end of the spraybar and expanding it slightly.
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Joe, I think you'll eventually come to the conclusion that the gland nut isn't turning, just the threads loosening. At least, that's my view on the ST NV Assemblies. I used them for combat, and speed, where it was common practise to close the NV, then open it for starting. The Randy Aero/Nelson NV assemblies would have been dearly loved, in those days. The thing I like about them, is you can tighten them VERY tight, but still adjust the NV. You might consider cutting the end off the ST spraybar and making a plastic cone to turn it into a PA clone. H^^ Steve
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Thanks Steve and all. The ST nvas aren't too troublesome on the profile planes I have as the collar is easy to get to. Some of my planes with cowling present a problem.
I think I'll replace the ST nvs in the cowled planes with PA nvas and just frequently tighten the others.
Regards,
Joe