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Engine basics => Engine set up tips => Topic started by: frank mccune on March 07, 2022, 04:08:28 PM

Title: Suggestions for nva to fit large case stunt engines?
Post by: frank mccune on March 07, 2022, 04:08:28 PM
     Hello All:

      What nva should I purchase to fit venturi/crankcase width of .750”?  There many size available that suggest that they work in ST and Enya .60 engines.  Would these fit the wider engine like the OS SF .46 and it’s clones?  My preference is the Enya nva.

       Suggestions/comments?

       Tia,

       Frank
Title: Re: Suggestions for nva to fit large case stunt engines?
Post by: Craig Beswick on March 07, 2022, 05:54:59 PM
Hey Frank,
I have Enya 60220 at home. I will measure how far it can span and where the hole is in relation to a 19mm, 3/4", opening and get back to you.
The 3/4" is outside diameter, yes?

Craig
Title: Re: Suggestions for nva to fit large case stunt engines?
Post by: Craig Beswick on March 07, 2022, 06:43:58 PM
Frank the Enya 60220 I have is 18.5mm wide with the needle fully closed and the nut done up to the needle!
.75 of an inch is 19.05mm. If you wound out the needle one and a quarter turns you should have enough to fit your case but you can never shut off the needle fully!
The hole in the NVA is close enough to centre not to matter.
Or, you could file off a couple of thou off the case and all is well?

Good luck, I hope this helped.
Craig
Title: Re: Suggestions for nva to fit large case stunt engines?
Post by: frank mccune on March 07, 2022, 11:02:46 PM
       Hello Craig:

       Thanks for your prompt reply.  Yes, the distance is 18mm.

       I hope that all is well with you and yours Down Under.

       Tight lines and stay well,

       Frank
Title: Re: Suggestions for nva to fit large case stunt engines?
Post by: frank mccune on March 07, 2022, 11:07:32 PM
      Yes Craig, the outside of the case where nva will go measures .750” or perhaps 18mm.

       Stay well,

       Frank
Title: Re: Suggestions for nva to fit large case stunt engines?
Post by: Peter in Fairfax, VA on March 08, 2022, 11:00:35 AM
If it helps, I'm running an ST NVA in an SF 46.  Works great and ready for its third season.
Title: Re: Suggestions for nva to fit large case stunt engines?
Post by: Peter in Fairfax, VA on March 08, 2022, 12:42:20 PM
FYI,

The SF 46 measures .732" where the NVA installs. There are three ST NVA lengths, not sure if this is the medium or long version.  Installed, with needle in place and typical operating tension, outside of tension nut to outside of fuel nipple is 1.395"

Peter 
Title: Re: Suggestions for nva to fit large case stunt engines?
Post by: Steve Helmick on March 08, 2022, 03:57:04 PM
I'd suggest calling or emailing Randy Smith, but I admit to being VERY happy with his Nelson-style assemblies. I've never used an Enya, but know they're very similar to the OS equivalent. I have used those, and don't like anything with a ratchet. It's possible that others don't like collet-style, but it escapes me why that would be. Randy's are a huge leap better than even genuine Super Tigre stuff.  H^^ Steve
Title: Re: Suggestions for nva to fit large case stunt engines?
Post by: Brett Buck on March 12, 2022, 01:33:52 PM
It's possible that others don't like collet-style, but it escapes me why that would be.

   Because you can easily be misled into too fine an adjustment.


Quote
Randy's are a huge leap better than even genuine Super Tigre stuff.  H^^ Steve

   Drastically better than the ST, the needle is supported better, it seals better, and the teflon insert has the effect of damping the vibration that was the most insidious problem with the stock ST needle, which tended to vibrate like a tuning fork occasionally, when you happened to turn it to a length that lined up with the running frequency.

    Brett