Calvinman

Hello All,

I have been having trouble with my glow engines and it seems to be related to my glow plugs, but I am not sure why they are going bad. I had nothing but trouble getting my engines to run this spring (MDS48, OS46FX and a RJL60) and thought my fuel went bad, a fresh gallon and things improved, but then trouble again with only the OS running reliably(but not very responsive to needle valve settings).

I have put about a gallon of fuel through the MDS48 with an extremely rich setting to break it in, the RJL is lightly used and I have been running it slobbery rich and leaning it out after each flight. I checked my flight box fueling system for leaks, but not sure, I have started connecting the return and liquid line together a few inches outside my fuel jug to eliminate leaks at the pump or elsewhere.

When I fuel my aircraft I hook the return line to the muffler pressure line from the tank and the liquid line to a fuel dot or to the carburetor line. I defuel the planes after I am done flying. I add a little WD40 to the engine and start it up to run out any fuel left over in the crankcase and a few drops of afterrun oil after that(blue blocker I think).

When I start my engines I use a power panel and drive my glow plugs to the green, but this may be too much(only as good as the calibration?), can anyone tell me how bright the glow plug should be? I removed the glowplugs from all engines and all were a little distorted and all were a little crusted(a flat white/silver slightly grainy look)

My questions are, am I overdriving the plugs, is my use of WD40 and afterrun bad for the glowplugs, will running the engines very rich cause this type of result on the glow plugs or a combination of the above? I used to always use WD40 before I got out of RC for a while 15 years ago and had no problems, but just because it is called WD40 does not mean it is not actually WD41 or up after all these years. If my fuel did go bad, would this affect the glow plugs?

Thanks,
Calvi

JohnBuckner

My Feedback: (1)

Hi Calvin, personally I would loose the practice of using the WD40. If the purpose of that is as an anti-foaming agent well I believe all the modern fuels include antifoaming agents.

One other thing and this is only my opinion is the use of a old fashioned rheostat controlled power panels are responsible for more destroyed glow plugs than actual use in a running engines. A few, very few of the modern glow drivers such as the Radio South units which do control the current but not the operators are fine in my opinion and/or the single cell type ignitors Those are the only two types I have used for years

Also consider the glow plugs themselves contrary to popular belief they do not last forever as long as they glow. They do gradually loose the precious metal coating over x number of run times. I sometimes cringe when the fellows are having fussy engine run and replace the plug which may well cure the problem but then turn right around and save the old plug like it was gold or something then saving for what? Likely just more lost time at the field when they stick that plug in something else because it still glows.

John

Calvinman

Hi John, I used to use the WD40 as an afterrun oil. Yes I find it humerous saving old glow plugs. It may well be that all 3 plugs decided to croak at the same time, I too like the one cell igniters, as long as they have the indicator on them, but that is a way down my "must have list" a starter without a cord is first. I am going to try setting the rheostat significanly lower from now on. I have not burnt out any glow plugs with my power panel yet, I always turn it down to zero when I am done with it, but now that I have said that I am now doomed to pop one

Calvi

Gray Beard

My Feedback: (-1)

I gave up the use of after run oil years ago. It can gum up the glow plugs but that usually caused them to burn out as soon as I put the juice to them. WD-40?? For what use??
MDS engines are high compression engines and designed for zero nitro fuels, I found when using store bought fuel {Powermaster} they ran best with nothing higher then 5% nitro. I had several of the .58s and .68s but never the .48 but would assume they are the same deal. The Russians never figured out how to build a carb either or perfect metal casting so after a short time Horizon had so many problems and returns of the MDS engines they dropped them. When they run they are really a strong engine. For parts you can find them at most swap meets.

Calvinman

Hi Grey Beard,

I started out my flying career using "Marvel's Mystery oil" but found it hard to start my engines after. I switched to using WD40 which the engine would idle on so I figured I was clearing out all the fuel by doing this. I never had a problem with my engines doing this but I am not going to bother doing this anymore. I will just run my engines dry and turn them over with the electric starter for a few secs after that.

Yes I bought 5% for the 48, it seems to run strong.

Calvi

aspeed

I only use after run oil on more than 15% nitro. It is the nitro that forms the rust, not the oil in the fuel mixture. Haven't had a problem. A distorted plug usually means too high compression or too lean runs at least. Maybe add another head shim to the offending motor.

Gray Beard

My Feedback: (-1)

I live in a very dry climate and just running the engines dry works very well. It burns out all the alcohol and nitro and leaves behind a film of castor oil. For long term storage I still strip the engines and clean them then use fresh SIG castor oil as a film, it doesn't harden if it hasn't been burnt or heated. WD-40 in the past was a great starting fluid, we used it as a starting fluid in the small engine repair shop. I forget what they removed or no longer put it it that was the part that burnt but it no longer has it in the oil these days and is no longer a starting fluid. It shouldn't have a lot to do with the plug though but I can't be sure of that. In Canada I'm sure you get a lot of moisture in the air so running dry and a little after run shouldn't harm anything? Perhaps at the end of the season using those old plugs people are tossing out may be a good thing to use instead of a good one? Just to button up the engines.
Once I figured out that the MDS were designed for FAI fuel they were OK, well, the .68s were but the cases broke on three of my .58s right where the big muffler mounted to the engine. I finally gave away the last of them a year or two ago but found another really good cheap stump pulling engine for two stroke use and have been happy with them.
This is just a guess but there may be oil fouling on your plugs from your after run oil?

flyinwalenda

My Feedback: (5)

I've repaired enough power panels over the years because they were blowing out plugs but that is never really an intermittent issue. When they fail they fail all of the time and will always pop plugs until it is fixed. The pulse generator in the panel may be on it's way out.
In my opinion WD40 is as much of a moisture magnet as the glow fuel. I never use the stuff on anything I don't want to rust.
I use Marvel Mystery Air Tool Oil as after-run and never had an issue with it.. Glow engines start up and smoke for a little bit.
The plugs I've had the most luck with lasting the longest are Fox Regular and Miracle plugs.

Gray Beard

My Feedback: (-1)

I heard so many good things about the FOX plugs I gave them a try and agree, they are really good plugs and cost way less then the OS. I run them in my YS engines and they work great.

bigedmustafa

My Feedback: (2)

I too am a big fan of Fox glow plugs. I like the Fox RC Long with idle bar for most of my two-strokes; they don't need the idle bar, but the plug is medium-hot like an O.S. #8 plug, and the idle bar doesn't hurt anything. The Fox Miracle plug is my go-to plug for 4-strokes and larger 2-strokes that seem to need more heat.

I rarely use after-run oil. I bought some when I first started flying, but I always fly with castor oil as part of my lubrication. In ten years, I haven't had to replace any bearings in any of my glow engines. I just run them dry when I'm done flying them, and the residual castor film is enough to keep the bearings rust-free and turning smoothly. If I know I'm putting an engine in storage for a while, I'll hit it with a few drops of after-run oil and bag it to keep it protected against moisture and the elements.

I've been told that Automatic Transmission Fluid (ATF) works well for both after-run oil and smoke oil. Hopefully someone with more experience can confirm that.

Rodney

Calvinman, if you are having problems with all your engines it is not the fuel or the glow plugs. Most probably it is something that is getting into your engine which causes a coating over the platinum in the plugs. As you probably know, glow engines run because of the catalytic action of the platinum and the alcohol in the fuel. If a coating collects on the plug, this catalytic action is adversely effected. Very likely there is some thing in whatever you are putting in your engine that is causing this to happen. WD40 just very likely might be the cause of your problem, also some anti foaming agents can cause this problem. Quite some time back there was an article in one of the model magazines that delved into this problem of coating a glow plug element with different additives but I can not recall where and have not taken the time to try to search it out again.

Granpooba

My Feedback: (5)

Switched to " Marvel Mystere Oil " years ago as an after run oil and storage oil. Have had no problems with any engines since. Also add it to the gasoline in all my lawn equipment. Its a marvel ........... LOL

Ohhhhhhhhhhhh and basically I run OS # 8 plugs.

rgburrill

It's not the nitro that forms the rust it's the water the left over alcohol absorbs from the air. And that is why after run oil is good - it mixes with the minimal amount of fuel left in the engine to keep water absorption down..
BTW, any cheap air tool oil works just fine - I used Kmart for years.

aspeed

I don't use the Fox plugs too much. I found the elements to be a bit fragile with the higher compression motors. Otherwise they seem fine for regular motors. Got to watch for the OS and other Japanese motors with the mid reach plugs, and the Fox, K&B, Fireball, and Merlin plugs being either short or long. WD 40 is mostly Kerosene and the propellant which is likely propane or butane. I can't see it doing any real harm. I would guess that it evaporates and leaves nothing to protect in the form of oil. It sure is handy with the spray can for everything though. I really haven't had a problem with rust since the ABC motors came out and 10% is in the rules for racing and speed. That is all I use pretty much now.

Tony Iannucelli

My Feedback: (193)

RG got it right. Alcohol left in the crankcase and on the bearings draws moisture. Here in Florida, rust starts forming on the way home from the field. Air tool oil / 3 in 1 / or any similar is fine for after run. The plugs might have carbon buildup, the engine might not be running cool enough, or they might have been run a bit lean once or twice. All killers. Use an OS 3 or 7 or 8. I've had some last a whole season here, and that's 11 months!

cloudancer03

My Feedback: (22)

Hard to say.with o's 46 I always used as plugs.i didn't use alot of after run or additives period unless the engine is going to sit for a long period.i have seen in my nitro days past a few pilots start their engine and squirt a few drops of mystery oil in the opening.it supposedly blows out any carbon build up.m

flycatch

My Feedback: (26)

I'll start by saying I can't comment on after run oil since I have never used any but I will comment on glow plugs and power panel. Glow plugs can be rated; good, better and best. It all has too do with the heat range of the engine. Both Enya and OS sell excellent plugs and you can find the right plug for your engine by looking at the charts provided by the manufacture. Keep in mind that the coil is made from platinum and the amount dictates the heat range of the plug. Plugs other than OS and Enya should only be purchased if your looking to save money. Power panels are also rated; good, better and best. I stopped using them myself but if you want one of the best try to located one made by ACE or SonicTronic. I'm using a portable device sold by RCATs and destroying a glow plug with this unit is a thing of the past.

Calvinman

Thanks for all the replies guys, it is going to take some time to digest all this info. Good thing I am heading for the lake for a couple of weeks when I get off work in the morning Too bad I won't get a chance to try running the engines till I get back. Grey Beard, I put a Mac's muffler on the MDS because I read the heavy stock mufflers are prone to breaking. The muffler is for an OS 50 which Mac's says is a better volumetric match for the os 46 than the one they list for the os46?

Calvi

jester_s1

Two things that will eat glow plugs quickly is running too lean (which you say you aren't doing) and bearings that are going bad. Neither of these may be your problem, but it's something to think about. WD-40's active ingredient is fish oil, and I doubt it does any good to protect your engine. You mentioned that you haven't seen much needle valve response; that sounds like air leaks. If you are leaking air, you could be going lean in flight which would eat glow plugs.

tony0707

Flighing only glo for 41 years , a lot
Best all around plug is the K@bB 1-L , runs strong forever unles you run it lean or have air leak issues that cause lean runs and heat build up
They are still available on line , but we're the local hobby shops best plug for decades
Used a lot of after run after every days flying for a long time , only to find it be a bit of a problem when flying the plane every day for some time
The problem was the need to burn off the oil the following day for a while for the engine to start to perform as it should ,is time wasted
No after run ,better next day run up from the get go
Is good to store glo engines for medium or long range only
My storage mix is half mystery oil and half tran fluid
Always run some castor oil in your two cycle glo fuel
My fuel choice has been Morgan Omega 15% nitro in all my size engines from 46 to 1.80
My engines run long and strong on Omega for 25 years
No need to do very much internal engine repair with the fuel used above
Soon as you see your glo engine start to run differently than it usually does (not taking the usuall NV setting ) you should immediatly be looking for and finding an air leak of some kind getting into the engine
I say immediately because the air leak is going to cause your engine to run hot and lean creating more heat that is desirable ,and possibly enought to damage the aluminum enough to warp it, doing perminent damage to the engine
Do watch for that situation
If the leak developers in the air , the engine will shut down and run odd when you try to fire it up
Lean runs will cause a plug to go bad, often giving the plug a whitish looking coating
The K@B plugs are supper durable and the only plug I have used outside of trying some others over all my years flying glo
My two cycle engines really run great for decades

drac1

My Feedback: (4)

FYI. WD40 - Water Displacement 40 = It was on the 40th attempt that the inventor got the formula right.

As already said, too high compression will cause the plugs to go frosty. I have never used after run, just drain the tank and run the engine until it stops.

I don't have glow plug problems, they last forever. Also, fuel doesn't go bad. It gets contaminated if not stored correctly.

Calvinman

Hi Drac, I have never had trouble with my engines either until taking up the hobbie again recently. because I am having problems with all three of the engines I am running right now it makes me suspect the fuel. I may have an air leak in my fueling system in my flight box. I do not know how fast fuel will become contaminated if it is exposed to the air. I do store my flight box in a cool basement and the temperature stays fairly constant so I doubt this is the issue. Is there a way to tell if the fuel has become contaminated?

Calvi

drac1

My Feedback: (4)

Having problems with 3 engines at the same time does sound like fuel. Unless you can see water or some contamination in the fuel I don't think so.

I would mix up a new batch of fuel and try that in one of the engines and see if that fixes the problem.

Failing that, start by going through the complete fuel system, tank to carb. But only work on one at a time until you solve the problem, then go to the next one.

jester_s1

Fuel goes bad/gets contaminated mainly by absorbing water from the air. So partially used jugs of fuel that are left to sit for a long time can do that. I've had the last 15-20 ounces of fuel go bad in a jug before when I had drained my tanks back into the jug multiple times. Exhaust by products and who knows what else changed the color and made my engines run erratically. Now I put unused fuel in a separate jug and use it for soaking gummy engines.

hsukaria

Calvinman,

You mention that you came back to the hobby after some time. Are these planes old? When was the last time you replaced all the fuel tubing? I know from experience that fuel tubing is good for a couple of years and then little pin holes or cracks begin to appear. Most of the time, they are not visible. Leaky fuel tubing may explain lean runs and the discolored and out-of-round glowplug coil.

Make sure that you are using the appropriate heat range plugs for your engines. If some of your engines are high compression/low nitro (MDS) and others are low compression/higher nitro (OS), you may not be able to use the same glow plug type on both.

Also, make sure you are using propellers in the right range for your airplane/engine. If the prop is too big, you will load down the engine and it will overheat (based on my own experience too). One of my engines began to lug down when I switched props from MA to APC, even though they were the same size.

Let us know what turns out to be the culprit, I'm curious.

P.S. I lost an OS 55AX engine last month when dirt got into the carb and caused a lean run. The piston liner peeled because of the lean run. What happened was my fuel clunk/filter in the fuel jug fell off the tubing and the clunk was my only filter in the line. I was at the bottom of the jug and pumped up debris from the bottom right into the plane's fuel tank. So now I have the clunk/fliter plus another inline filter in the fuel pump/jug.