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Speed,Combat,Scale,Racing => Combat => Topic started by: Jim Roselle on July 24, 2017, 02:55:02 PM
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Hey all,
I recently acquired a Fox 36x I plan on putting on a Demon. Can I use the stock needle with a bladder?
Thanks,
Jim
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PRobably, but it is usually better to take an OS .10 needle and mount it flat, so it does not get torn off in an inadvertent inverted landing.
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As long as the stock needle will close off fuel flow, it will acceptably meter pressurized fuel flow. I've used 36X needles/needle assemblies on my brace of 35/36 X motors w/bladders (pacifiers, pen bladders, surgical tubing bladders, etc, etc) since the beginning of time and they do fine IF the assembly will close off completely. You can determine if it will satisfactorily shut off flow by attaching a clean piece of fuel line to the needle nipple, completely screw the needle inward until it's fully seated, then suck on the fuel line. If it makes suction, it's closing off perfectly fine, and the assembly will be more than adequate for pressure use.
Good luck!
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Thank you,
How many turns open would you recommend starting at?
Also how critical is all castor fuel in this engine? Can I get away with something similar to power master 10/22?
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Thank you,
How many turns open would you recommend starting at?
Also how critical is all castor fuel in this engine? Can I get away with something similar to power master 10/22?
Fill the bladder clamp it. Then rotate the crank to close the venturi.
Point the nose down and release the clamp. For a 36 open the needle just to the point of a steady stream with an occasional drip. Just the start of a steady stream. That should get you close enough to start it.
1/2a should be drop drop drop and 15 should be drop stream drop.
Sent from my iPhone using Tapatalk
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Hi again Jim:
You're asking someone (me) that has been a "castor only" advocate since day one, even before my employment at Fox Mfg from 1970 - 1975. Seeing as I no longer want to unduly risk my old X engines, nowadays I keep the nitro low (10%) and the castor at about 20% or so... a far cry from my 40% - 50% nitro days!
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Power Master GMA 10 nitro 22 oil will be a good fuel to feed your Fox and keep it happy. I use it for my McCoy 35 lightning bolt with a pacifier on my Hornet with no ill affects.
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I know Andre has been very successful with the fox engines, so it's worth a shot if it can close the pressure off completely.
I've only used the OS needle like Rich Perry mentioned on my big block stuff. It's really good quality and a nice smooth adjustment.
OS part number 21181902
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Jim
I can NOT play combat any more and have several of the OS remote needle assy in both sizes...
you may have one --gratis ---just for the asking
I was taught to use the 21081909 (10RC) for the .15 .25 engines. and the slightly larger 21181902 for the .35/.36
PM me you address and which one you prefer to experiment with
MNSHO... my playing with Bladders improved immensity when I started trusting remote needle assys... the stock/ ST/ and even the PA venturi needles were all a PITA to mess with....
IMO the beauty of the RVNA is back out of the prop ... near to where I am fussing with clamps or fingers to pinch off fuel ----and once set as described above...pretty easy to just let engine heat a little and ear tweak for launch
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Hi Dane:
Thanks for the vote of confidence. The old X engines really are a good platform if you treat them fairly.
As for using only stock NVA's: That's a holdover from my days at Fox when it would be strictly VERBOTEN to use a different brand!! I do recall that Phil Granderson used an aftermarket NVA on his X engines, but I can't recall what brand.
BTW, if an NVA doesn't seal off just right for bladder use: A short piece of brass tubing filled with solder and drilled out with a very small drill, which is then spliced between the bladder and the NVA, will retard the flow so that NVA can be used. Also, it will make for more fine tuning if one feels they need it. Again, though, stock NVA's have served me well since the 1960's. I haven't had to resort the brass tubing trick.
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Hi Dane:
Thanks for the vote of confidence. The old X engines really are a good platform if you treat them fairly.
As for using only stock NVA's: That's a holdover from my days at Fox when it would be strictly VERBOTEN to use a different brand!! I do recall that Phil Granderson used an aftermarket NVA on his X engines, but I can't recall what brand.
BTW, if an NVA doesn't seal off just right for bladder use: A short piece of brass tubing filled with solder and drilled out with a very small drill, which is then spliced between the bladder and the NVA, will retard the flow so that NVA can be used. Also, it will make for more fine tuning if one feels they need it. Again, though, stock NVA's have served me well since the 1960's. I haven't had to resort the brass tubing trick.
I did use stock NVA's on my Fox .36x (needle and ball bearying types) but I also used with great success, OS MAX NEEDLE VALVES on both the Foxes and Super Tigre Combat and G-21 .35's. If you get away from stock Fox parts, I would certainly recommend the OS MAX NEEDLE VALVES. As others have said, the main thing is that you must be able to shut off fuel flow under full bladder pressure. OS MAX parts seemed do this with more reliability and precision than stock Fox parts. D>K H^^