Author Topic: Contaminated glow plugs (Read 1969 times)

Russell Shaffer · « **on:** June 09, 2008, 03:29:40 PM »

I have 4 new glow plugs that I think got contaminated by gasket sealer in a used Enya 35. I finally tore it completely down, cleaned it with several solvents and then used Power Disolver. I ran it this morning and it didn't screw up the 5th plug. The bad plugs look fine, they glow fine, but the engine will only run for a short time with the battery connected. Does anyone have any ideas on restoring these plugs, or should I just pitch them? None of them have more than about 5 minutes on them, seems like a waste. So far I have soaked them in acetone, laquer thinner, boiled them with dishwasher detergent and heated them with a propane torch. They will start an engine but not keep it running.

ray copeland · « **Reply #1 on:** June 09, 2008, 04:05:10 PM »

When i get an old glow plug i want to restore, i turn it up and fill it with brake cleaner and let it soak a few minutes, most have worked fine after that.

Jim Thomerson · « **Reply #2 on:** June 09, 2008, 06:20:20 PM »

I put them in my "small junk" film cannister in my field box. After a while they are fine. I only use one when I burn out a plug at the field and don't have a new one.

Russell Shaffer · « **Reply #3 on:** June 09, 2008, 09:52:03 PM »

What brand of brake cleaner, Ray.

Jim Oliver · « **Reply #4 on:** June 10, 2008, 07:14:07 AM »

Quote from: Ty Marcucci on June 09, 2008, 11:14:05 PM

I have always considered plugs, props, fuel and filters as consumables.

Add: Models, also------if no "consumable", at least "expendable".

They all have an expiration date---it's just not printed on the model.

Cheers,
Jim

Tom Perry · « **Reply #5 on:** June 10, 2008, 01:14:35 PM »

Quote from: Russell Shaffer on June 09, 2008, 03:29:40 PM

I have 4 new glow plugs that I think got contaminated by gasket sealer in a used Enya 35. I finally tore it completely down, cleaned it with several solvents and then used Power Disolver. I ran it this morning and it didn't screw up the 5th plug. The bad plugs look fine, they glow fine, but the engine will only run for a short time with the battery connected. Does anyone have any ideas on restoring these plugs, or should I just pitch them? None of them have more than about 5 minutes on them, seems like a waste. So far I have soaked them in acetone, laquer thinner, boiled them with dishwasher detergent and heated them with a propane torch. They will start an engine but not keep it running.

A lot of people don't know that the platinum reacts to the methenol by producing heat. Sounds like the platinum is not being exposed. The same thing happens when low nitro is used with a cold plug.

The only Idea I can come up with is try burning off whatever is causing the problem by putting a battery to the plug for an extended period, or even use a higher voltage and a rheostat to let a few more amps through. If you burn he plug

out you are no worse off then now.

Steve Helmick · « **Reply #6 on:** June 18, 2008, 05:58:20 PM »

If the gasket sealer is silicon, then gasoline is a good solvent...tho any hydrocarbons are tough on silicon sealer.

Otherwise...Glowplugs seem to develop this trait after a period of storage. A solution would be a good thing, if you find one. If you do, please publicize it here!

Then, I have to ask what brand of glowplugs these are...I'm really unimpressed with Fox glowplugs. My opinion is that any glowplug made by Ohlsson Corp. is good...ThunderBolts, K&B, Zinger, RO-Jett, and most other USA brands are made by them. But not Fox, Nelson, Merlin, Glo-Bee, and Fireball. I don't know about the SIG, SonicTronix, Tower, and R/C car brands like O'Donnell, Traxxas, etc., and dunno if Randy Aero has a glowplug of his own. I remember Brett writting that Rossi glowplugs do that early stoppage trick without fail. Probably a heat range issue (too cold). OS plugs work well, but high priced.

Steve

Kim Mortimore · « **Reply #7 on:** June 18, 2008, 07:27:37 PM »

Does this mean that using gasket sealer on the plastic backplate of an LA46, for example, can result in fouled glow plugs?

Thanks,
Kim Mortimore

Steve Helmick · « **Reply #8 on:** June 26, 2008, 09:37:46 PM »

Russell didn't specify what sort of sealer was used, but silicone sealer is so very popular these days, I maybe made a leap that I shouldn't have. He did say Enya .35. Note that aluminum backplates, rubbed on by a rod or crankpin, will also degrade glowplugs...including complete ruination. I'm not sure what the aluminum does to the glowplug element...physical attack, or chemical attack, or something else.

It seems likely that might be one of the reasons that OS went to the plastic backplate on the LA's, remembering that most R/C fliers likely to use them would probably use an "electric finger", their sleeve bearings and thrust washers might eventually allow crank/backplate contact during starting. Wouldn't want a reputation as a glow plug eater, right?

Steve

Kim Mortimore · « **Reply #9 on:** June 27, 2008, 01:24:31 PM »

Quote from: Steve Helmick on June 26, 2008, 09:37:46 PM

Russell didn't specify what sort of sealer was used, but silicone sealer is so very popular these days, I maybe made a leap that I shouldn't have. He did say Enya .35. Note that aluminum backplates, rubbed on by a rod or crankpin, will also degrade glowplugs...including complete ruination. I'm not sure what the aluminum does to the glowplug element...physical attack, or chemical attack, or something else.

It seems likely that might be one of the reasons that OS went to the plastic backplate on the LA's, remembering that most R/C fliers likely to use them would probably use an "electric finger", their sleeve bearings and thrust washers might eventually allow crank/backplate contact during starting. Wouldn't want a reputation as a glow plug eater, right? Steve

Good stuff, Steve. I hadn't heard about backplate aluminum particles attacking glowplugs before. It makes sense. Seems like there is always something new to learn about our simple little one-bangers. Keeps things interesting!

Kim

Russell Shaffer · « **Reply #10 on:** June 28, 2008, 04:30:59 PM »

Here are some details. The engine was badly gummed up when I bought it. It is an old Enya 35. I just soaked and squirted with assorted cleaners until it turned freely. When I reassembled it, I used "sensor safe" silicone on the the venturi insert because it seemed too loose to me. I also used permatex sealer on the front housing. Now, permatex is soluble in alcohol, so maybe this wasn't such a good idea. With a new plug, the engine would start and run well for just a couple minutes, then needed the battery hooked back up, then wouldn't run at all. This happened 4 times before I finally saw the light. These plugs after being damaged won't run in other engines, either. After the 4th time, I did a good tear down and clean up and made a gasket for the front. No sealers anywhere. I think it is fixed now, the compression is great, the bushing is tight, the rod is good. It runs out a tank without trouble. Two of the bad plugs were Fox, and the other two look like Thunderbolts. I tossed the packages, but I'm sure of the Foxes. The bad plugs have been soaking in brake cleaner and airing out, alternately. When I get a chance to try them in another engine I'll report the results. I think the moral of this story is "Don't put goop in your engines!!". I don't really think that there is any blame attached to the glow plugs.

Alan Hahn · « **Reply #11 on:** June 28, 2008, 07:55:35 PM »

I recommend simply tossing the plugs. You will never again be confident (or shouldn't be confident) that they might fail you when the plane is in a compromising position (like climbing out of the last loop of the clover!--ouch!).

I don't think this is a simple cleaning issue. I am guessing the silicone has bonded onto the element. Soaking in cleaning fluid might remove crud, but not something chemically binding to the element. It is only ~$10 to $20 loss at most. Trivial compared to losing a future plane.

Russell Shaffer · « **Reply #12 on:** June 28, 2008, 08:18:04 PM »

Actually, Allan, I pretty much agree with you. I had an engine quit dead in a wingover and there wasn't anything I could do to save it. Lucky it was a Streak and the wing glued back together OK. I'm still nervous when a plane is in an area where a sudden engine failure will cause disaster. It just gripes me that I ruined 4 plugs so easily.

Author Topic: Contaminated glow plugs (Read 1969 times)

Russell Shaffer

Contaminated glow plugs

ray copeland

Re: Contaminated glow plugs

Jim Thomerson

Re: Contaminated glow plugs

Russell Shaffer

Re: Contaminated glow plugs

Jim Oliver

Re: Contaminated glow plugs

Tom Perry

Re: Contaminated glow plugs

Steve Helmick

Re: Contaminated glow plugs

Kim Mortimore

Re: Contaminated glow plugs

Steve Helmick

Re: Contaminated glow plugs

Kim Mortimore

Re: Contaminated glow plugs

Russell Shaffer

Re: Contaminated glow plugs

Alan Hahn

Re: Contaminated glow plugs

Russell Shaffer

Re: Contaminated glow plugs