Leaky Needle Valve

WingingIt74 Wed Feb 13, 2013 4:51 pm

Has anyone tried pipe dope or just regular grease? I haven't yet... just curious.

The engine that always seems to give me problems is Brandon's 020... might give automotive grease a try.

pkrankow Wed Feb 13, 2013 5:27 pm

Whatever you use keep it on the threads only. I would go for the grease. Probably Vaseline (petroleum jelly) The fuel will wash it out over time, but that is OK. It will probably stay put for a whole day of flying.

Phil

**RknRusty** Wed Feb 13, 2013 6:10 pm

Agreed. Don't use teflon tape as I've heard suggested elsewhere. The stuff can shred and foul the works.

WingingIt74 Wed Feb 13, 2013 6:37 pm

I would figure teflon tape would be too thick.

**RknRusty** Wed Feb 13, 2013 8:29 pm

WingingIt74 wrote:I would figure teflon tape would be too thick.

It might be, but some people have managed to cram a layer in there... or so they say. I don't recall where I have read that.

**Cribbs74** Wed Feb 13, 2013 8:47 pm

RknRusty wrote:
WingingIt74 wrote:I would figure teflon tape would be too thick.
It might be, but some people have managed to cram a layer in there... or so they say. I don't recall where I have read that.

I've done it, it works. However, it makes the needle really tight and as you say it can foul the works.

Fuel tubing and a washer..... Easy and lasts longer than all thee above.

Ron

WingingIt74 Wed Feb 13, 2013 8:53 pm

I would think grease would be perfect

**Cribbs74** Wed Feb 13, 2013 8:57 pm

WingingIt74 wrote:I would think grease would be perfect

Try it! Let us know, it would certainly look better.

tru168 Wed Feb 13, 2013 10:43 pm

I used grease, but fuel will wash it away very fast. my new engine having strong vibration problem , even with balanced prop. the needle loosen in minutes.
I have to grease the needle to maintain nice seal. silicon tubing method wont work for me, the needle will be very sensitive if i use silicon tubing. obviously, I need a new back plate and needle.

gcb Wed Feb 13, 2013 10:59 pm

I like Blue Loktite. Make sure you do not use a type that permanently seals! Also...use it sparingly. I screw the needle in some, then add the Loktite so it won't wick all the way to the needle.

George

**RknRusty** Wed Feb 13, 2013 11:25 pm

tru168 wrote:

I used grease, but fuel will wash it away very fast. my new engine having strong vibration problem , even with balanced prop. the needle loosen in minutes.
I have to grease the needle to maintain nice seal. silicon tubing method wont work for me, the needle will be very sensitive if i use silicon tubing. obviously, I need a new back plate and needle.

Is it possible you have one of those crooked drilled Killer Bee cranks? That can shake pretty hard. You can see it wobble when you hand turn the prop.

WingingIt74 Thu Feb 14, 2013 6:31 am

What about a silicone grease?

**RknRusty** Thu Feb 14, 2013 7:22 am

What about thick fuel tube. I had to stack the #2 washer on top of a #4 to keep it in place and it's pretty tight. Tighter than the slim tube.
Leaky Needle Valve Tach_r10

WingingIt74 Thu Feb 14, 2013 7:40 am

I'm not fond of the fuel tube idea... just looking for a different solution.

John Goddard Thu Feb 14, 2013 7:54 am

The cox confessional.....

Dearly beloved....

Squirted some Hylamar/Hermatite 'alike' type sealant
From threads up on n/v last night screwed the rough
2.5 turns in and pushed the tubing over the thing as well.
Outa the corner of my brain I kinda noticed recently that
Using the syringe on the one fuel nipple of this particular
Backplate that however slowly I depressed fuel appeared
In the ports do praps my issue is the reed rather than the n/v.
Roll on this afternoons garden Coxfest.
Very Happy

crankbndr Thu Feb 14, 2013 7:56 am

RknRusty wrote:What about thick fuel tube. I had to stack the #2 washer on top of a #4 to keep it in place and it's pretty tight. Tighter than the slim tube.

I noticed that needle setup in Kims photos, nice work. Im going to copy it.

John Goddard Thu Feb 14, 2013 8:03 am

Perhaps not it's just started raining for a
Change

ian1954 Thu Feb 14, 2013 8:15 am

I would put this (or similar) - not a lot, just a little (enough to coat the threads) in the threaded valve. When set, screw the needle in and let it cut its own seal and check that you have not managed to gum the whole thing up!

http://www.maplin.co.uk/silicone-adhesive-sealant-46001

tru168 Thu Feb 14, 2013 8:30 am

Yup, you bet ! the prop wobble when I flip it. I swapped the crank with normal one and vibration stopped.

RknRusty wrote:
tru168 wrote:

I used grease, but fuel will wash it away very fast. my new engine having strong vibration problem , even with balanced prop. the needle loosen in minutes.
I have to grease the needle to maintain nice seal. silicon tubing method wont work for me, the needle will be very sensitive if i use silicon tubing. obviously, I need a new back plate and needle.

Is it possible you have one of those crooked drilled Killer Bee cranks? That can shake pretty hard. You can see it wobble when you hand turn the prop.

WingingIt74 Thu Feb 14, 2013 8:34 am

ian1954 wrote:I would put this (or similar) - not a lot, just a little (enough to coat the threads) in the threaded valve. When set, screw the needle in and let it cut its own seal and check that you have not managed to gum the whole thing up!

http://www.maplin.co.uk/silicone-adhesive-sealant-46001

I think that would make a needle setting pretty permanent... I wouldn't try it.

**RknRusty** Thu Feb 14, 2013 8:45 am

tru168 wrote:
Yup, you bet ! the prop wobble when I flip it. I swapped the crank with normal one and vibration stopped...

Great, I'm glad you found it. There was a bad run of those a while back but they're all good now. Bernie at Cox International may replace it for you, he was good enough to swap out mine. KB cranks are stronger but Babe cranks consistently run faster for me.

ian1954 Thu Feb 14, 2013 9:18 am

WingingIt74 wrote:
ian1954 wrote:I would put this (or similar) - not a lot, just a little (enough to coat the threads) in the threaded valve. When set, screw the needle in and let it cut its own seal and check that you have not managed to gum the whole thing up!

http://www.maplin.co.uk/silicone-adhesive-sealant-46001

I think that would make a needle setting pretty permanent... I wouldn't try it.

Maybe it is my wording. The sealant would already be set (and when I say set, it remains pliable and rubbery) before you insert the needle. Inserting the needle after setting would creat a close fitting and flexible set of threads.

John Goddard Thu Feb 14, 2013 9:53 am

I had chicken at my local Chinese last night.

That was rubbery too.
Very Happy

Just got back from treating the neighbours.

Seems better with the sealant and tube than with just the tube.
How long for I ask myself.
lol!

WingingIt74 Thu Feb 14, 2013 9:58 am

Here is a fuel resistant grease
http://www.aircraftspruce.com/catalog/cspages/ezturnlube.php

ian1954 Thu Feb 14, 2013 10:01 am

John Goddard wrote:I had chicken at my local Chinese last night.

That was rubbery too.

Just got back from treating the neighbours.

Seems better with the sealant and tube than with just the tube.
How long for I ask myself.

Sure it wasn't Seagull?

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