My new-to-me Enya 60 AAC has a white delrin venturi insert and an Enya NVA, with typical click stops.  On my 5% nitro fuel and a Zoar 13-5 prop, the engine runs with the needle open about 1-1/4 turns.  The click stops are coarse and indistinct.  I would rather have an L-shaped needle with an adjustable tension nut, like an ST NVA, RSM NVA or PA NVA.  Will I need to drill the case?  Thoughts?

thanks a million for the advice,

Peter

   How does the engine handle in general? Do you have it in an airplane and can get lap times? What kind of RPM changes do you get per "click" and do you get consistent results?  You will most likely have to open up the hole for any of the other NVAs that you mention. The best thing to do is measure. Go to the engine list and there is a listing pinned to the top of different engines, venturi and needle specifications. Check those out and see how your venturi measures up. It may be a simple matter of dropping down  .005" or so in venturi size. The needle valves you mention are are larger in diameter than an Enya unit and this will give the same effect. Running a slightly more restrictive muffler can have this effect also. One and 1/4 turns open could be in the ball park. Make any changes one at a time and re-fly for several flights. Even cutting down prop diameter will take some load off the engine and affect how it needles. We just need more to go on.
    Type at you later,
    Dan McEntee

Peter, if the standard NVA doesn’t work for you (and I’ve never had a problem with them), Enya also sell exactly the sort of thing you mention, so definitely no case drilling required.
http://www.enya-engine.com/store156C_1/index.php?main_page=product_info&cPath=0&products_id=373

My new-to-me Enya 60 AAC.......

I'm a bit confused here because the only 60 AAC from Enya was the old 60X which, although a bit heavy, was a beast of an engine (in R/C form). The first version of the later 61CX was ringed with ABN then the second (red headed) version was ABC. Both of mine came with the Enya special needle valve mentioned above, a brilliant design IMO, because all that's needed to remove the spray bar complete with needle valve is to remove the locking nut from the inlet end.

With the spring clip thing , you used to ' tune ' the fit . Generally the Enya should be spot on , But decent long nose pliers ,
you can bend at the base and bend at the begining of the swage , so theyre parrallel to the needle , and ' just firm ' .

Obviously if theyre pressing in like blazes , it gets awkward turning it half a click . 

Another THING , is ' on the bench ' throw on a length of fuel tube , blow and fiddle . It should SHUT OFF ! .
about somewhere the wind whistle has half a turn from low to full bore . so about the middle of that there is about where you should be , running .
AS theres differant needle overhang ? lengths , not all Enya Needles in All Enya Spraybars will do what you want . Like shut or unshut enough .

So a few minutes clowning about , with blowing & adjusting , with your ear up close , gets a bit of insight into its setability .

OOPS ,



SO , you can see the tangs need to be PARRALLEL to the knurling ,
with it dissasembled , on the bench . And ensure the base / hole is unbent or re flattened before bolting it up .

ESSENTIALLY , if the inner tang was at the same dimension as the inner knurl , it'd hold and be light adjustment .
A olde Taipan one ive got is fingertip adjust. roll fingertip on the knurl . Never shifts .

You could leave one tang sticking out . Just have one engaged . But the main thing is there parrallel when on the needle . A very good pair or two of pliers helps ' blueprinting ' the tin tang ting .   

I'd pressure check your crap trap, the plastic on those things gets brittle and you could have an air leak.

All good.  With a freshly cleaned fuel filter and the ST NVA clone, it's back to single flip starts.  Runs seem consistent, though quite windy today.  Don't really love the Brodak Monoject 140 ml / 5 oz syringe, as it dumps fuel out the back if pressed hard while fueling.

Thanks again for the info that 4mm NVAs fit an Enya 61CX.

Peter