Yes, that is correct; no glow power needed after starting. You will need to richen your carburetor from the stock settings. It usually is good to start at about 2 + turns out on each needle, and then fine tune from there, but it of course differs from carb to carb and engine to engine. Occasionally it is necessary to raise the metering lever in the carb regulator a touch to help richen the mixture. Try it first with the needles screwed out as mentioned.

AV8TOR

thanks guys!
i'll get some vids of it running when i get it going sometime next week, most likely monday. (the engine is on an airboat)

shaun

---A thought for those of us running full time glow power---
I noticed that my glow plug and Zenoah adapter doesn't thread nearly as far into the head as the original spark plug, effectively lowering compression. I'm going to make an adapter out of the spark plug with the glow plug extending to the same length as the spark plug electrode (as soon as I have time).
I'll keep you posted--

The trick here is 4 parts.

1) Being able to tighten the glow plug in the glow adapter.

2) Being able to get an adapter on the glow plug to power it.

3) Getting the glow plugs tip into the combustion chamber, a concaved end on the glow adapter helps.

3) Not lowering the compression raito with the glow adapter.

These make for a pretty deep and thin walled glow adapter.

If you can make one like this I'd buy one......

I just finished the adapter. Gutted the plug, filled the end with a brazing rod, drilled and tapped for 10-32. Then went in with a 7/16 drill deep enough to get the plug to extend past the bottom of the adapter. Squared up the bevel with an endmill in a drill press to give the plug a good seat. This leaves roughly 1/32 of meat between the outside and inside threads of the adapter. I'm going to have to spin down a 5/16 socket to get it in on the plug, and then make a connector to leave on the plug full time. Planning to use a wheel collar. Hopefully I'll get it finished and running tomorrow. I'm off to work--I'll post more tomorrow if this works.

I'm thinking about quite different approach. Instead of making a removable adapter it's better to make a permament insert. What I mean is an insert that will screw into the sparkplug hole from the inside and set there forever (not sure if loctite would work). The depth of the insert would be the length of the glow plug treaded part. This way the glow plug would go straight into the cylinder and there will be enough spaca between the glow plug and the old spark plug's thread for you igniter or wrench. Something like ere below.

Something that would thread in from the bottom would work well.

There would be plenty of room to get the glow power adapter in.
The glow plug would be in a great place.
You could even raise the compression if done right.

But God help you if it came loose in flight.

I found a 10/10 fuel that is ez for me to get at my hobby shop.. but there is allot more caster oil then senthetic Im not sure one what the % is on it but the woman on the phone from the co. said that it is mostly caster, very little sinthetic.. Will this work? Is there a problem running a fuel with little or no senthetic? (I know Im not spelling it right but i hope you can see what Im trying to ask)

Paul

The castor oil should be fine.

AV8TOR

Castor is hard to beat for lubracation.
Synthetic burns cleaner.

Just thinking, how many times the spark plug got loose during the flight If done right it shouldn't be an issue.

I'm going to make one to see it it's possible. I will cut the external thread (spark plug thread) on my lathe a little oversised. That should do it. Anone know what kind of "greese" would keep this thing forever?

When I was a pipe fitter we used a joint compound called "Expando"

You mixed it with water and as it dried it expanded.
It is some good stuff. I may still have some around.
Let me look and I'll PM you. We could meet, I'm over in your area often any way.

Or I could put some loose power in an envelope and send it in the mail, News at 6 o'clock.

P.S.

What do you think of my version of your drawing?

I've heard of JB Weld being used to hold cylinder sleeves in diesel engines successfully....

If it was made with the flange as in the second drawing, it could be properly tightened as well.

AV8TOR

Those are wet sleeves and the JB Weld mostly just holds water pressure.
The head holds the sleeve in. But JBW is some awesome stuff.

You could ding up the threads a little put lock tight on it, or JBW, and screw it in and it would probably stay forever.

No need to hurry. We can meet some day anyway.

That's exactly what I ment - in my drawing there was a flange - just hardly can see that, as jpg compression took it away This flange would be used to also to tighten the insert in the head. A little tool-wrench something like 1/4-28 screw driving the insert from the insideshould do the job.

I'm not affraid of insert falling of when engine is running, but I need to prevent it from unscrewing while you tighten the glow plug.

You could cut left hand threads on the O/D of the adapter, then when you tighten the glow plug it would tighten the adapter also.

You lost me with that one.... How could you screw a left hand threaded adapter into a right hand threaded spark plug hole??

AV8TOR

This is spark plug thread - it is always right hand.

When I first converted a ST 3000 to gas, I was running the 1/4 X 28 spark plug. It really gave a lot of problems running the engine inverted because the plug fouled so easily. I tapped the head for a 10mm plug. It turns out that the head was too thin and soft and the 10mm plug blew out the first time I ran it. I made an adapter out of brass much like the one that is being described. There was a flange inside the combustion chamber, I turned out the head so the flange would fit. The adapter was made to accept a 10mm plug. However I bored the head out so I could use a 5/8" left hand tap. The threads on the outside of the adapter were cut left handed, but the inside for the 10mm plug were standard right hand. I didn't use anything to seal or lock the threads. Installing the plug lockes the adapter into the head.

One more question before I power up my lathe. Do you think 6061 will be good for this insert? Or should I use steel.

I don't like mixing brass with alu because of differnet temperature expanson and corrosion (electical). 6061 might be strong enough to hold the glow plug's thread. My first gutted spark plug had aluminium insert for glow plug. and It still holds strong. Actually it holds to the gutted spark plug only by press fit from the inside (ther is a little flange from the inside) and I never had a problem. So it might work.

I think the aluminum should work fine. A lot easier to machine as well...

AV8TOR

http://www.rcuniverse.com/forum/m_58...anchor/tm.htm#
http://image.rcuniverse.com/forum/up...82/Pn37417.jpg

This is an alternate full time glow plug connector idea might be helpful in a tight location.

The Gas/Glow mixture burns hot enough that I had problems in my early experiments with a glow plug connector being soldered. I made one out of a wheel collar with a wire soldered to it and it fell off, (solder melted) after a minute or so of running. So if you use a homemade connector with a soldered wire, be sure to use a high temp silver solder.

Another problem in our Gas/Glow application, is that you will either have to drill a hole in the side of the plug adapter shell for access to the set screw, or slot the adapter. And all this can be a big pain in a cowled installation.... I like the "Head Lock" style of connector, but it DOES rather irritate me to pay 10 bucks for a simple connector.

AV8TOR

Finally got the engine running with the new adapter and an O.S. lc3 plug. I think it's supposed to be hotter than an F. The transition is a little better, but still not good. I'll try it again with an F, but I think I'll be able to get by running glow power only to about 1/3 throttle.

AV8TOR---
What brand head lock connector do you use, and what is the O.D. of it where it fits into the adapter?
Thanks...

I use the "push and twist" type head lock glow plug connector by Model Products mostly. It is a snug fit inside the plug adapter shell, but it works and doesn't require modifying the adapter. There is a cheaper one, (about 5 bucks) from MPI that has a rubber boot and is a 90 degree type. It works fine as well, but you have to cut a slot in the glow plug adapter for the 90 degree portion of the connector.

Even Walbro states in their technical manuals that for a good transition the engine has to be adjusted richer than a perfect idle mixture. I have found that with Gas/Glow it needs to be slightly richer still....

On board glow power at idle does make the mixture settings less finicky though, and it's kind of convenient as well to just flip a switch instead of hooking and unhooking glow power to start the engine, especially on an inverted, cowled installtion.

AV8TOR