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  #1  
Old 04-04-2007, 10:01 AM
mistergerf mistergerf is offline
 
Join Date: Feb 2006
Location: San Francisco, CA
Posts: 58
Default How do you clean a sparkplug ?

Back in my teenage days of lawnmowers and motorcycles, I used to scrub them out with a wire brush. Somehow that doesn't seem appropriate, even if 4 of my spark plugs are motorcycle spark plugs (LSE Ignition).

Any recommendations ? The air operated doodat from Avery ? The vibrator thingy with the funky little blade ?

g
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  #2  
Old 04-04-2007, 10:38 AM
az_gila's Avatar
az_gila az_gila is offline
 
Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
Exclamation Harbor Freight

One of these from Harbor Freight... at $17, but frequently on sale for $10



The only change is to enlarge the spark plug hole on the rubber front piece from 14 mm to 18 mm for the larger aircraft spark plugs...

And a dental pick to get the balls of lead out from the bottom... Free ....just ask your dentist for a used one...

gil in Tucson
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  #3  
Old 04-04-2007, 12:24 PM
phil9diesel phil9diesel is offline
 
Join Date: Mar 2007
Location: Upper ny
Posts: 78
Default With one of these

[quote=mistergerf]Back in my teenage days of lawnmowers and motorcycles, I used to scrub them out with a wire brush. Somehow that doesn't seem appropriate, even if 4 of my spark plugs are motorcycle spark plugs (LSE Ignition).
Any recommendations ? The air operated doodat from Avery ? The vibrator thingy with the funky little blade ? Answ: A bobby (diaper) pin.
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  #4  
Old 04-04-2007, 12:57 PM
gasman gasman is offline
 
Join Date: Mar 2007
Location: Sonoma County
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Exclamation BUT IS IT REALLY CLEAN!

When you think that plug is ready to go back into the engine, take a small paper cup and put about an inch of gas in it.

Take the plug and dip the (engine) end into the gas, slosh it up and down like you are trying to wash something out!

Then look in the bottom of the cup.
That grit was just ready to go into your motor. This is a must after bead blasting a plug.

Warren
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  #5  
Old 04-04-2007, 04:17 PM
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Mel Mel is online now
 
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Location: Dallas area
Posts: 10,769
Default

Quote:
Originally Posted by gasman
When you think that plug is ready to go back into the engine, take a small paper cup and put about an inch of gas in it.

Take the plug and dip the (engine) end into the gas, slosh it up and down like you are trying to wash something out!

Then look in the bottom of the cup.
That grit was just ready to go into your motor. This is a must after bead blasting a plug.

Warren
Then blow it out with compressed air.
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  #6  
Old 04-04-2007, 04:59 PM
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gmcjetpilot gmcjetpilot is offline
 
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Posts: 4,285
Default Great Reason to Buy Tools

I used ATS (Aircraft Tool Supply) to show you tools to do a spark plug cleaning.



You will need a 7/8" or 3/4" deep socket. There are special sockets for aircraft spark plugs, but you can get a way with deep sockets some times.

You need a way to organize the plugs like a TRAY. You can make one of wood or metal to hold the plugs with the cylinder number and TOP or BOTTOM position. When you clean plugs you usually rotate tops and bottoms and move to the next cylinder and need to keep track of them.

For a 4 banger switch these pairs:
1T to 4B
2B to 3T
1B to 4T
2T to 3B


-Vibrating tool for getting the lead deposits out of the deep pockets on side of center electrode. The cost is not too much. The Pro ones are expensive, but $25 gets you a cheap one. You could probably pick it out manually.

-Gap tool Cheap and Expensive (You can get cheap ones on up to very expensive. It precisely bends the massive electrode without damage to the center conductor or porcelain.)

Bead blast (Harbor freight has them on sale for next to nothing sometimes.) -AND- You will need blast medium

-Gap measuring tool -OR- (cheaper) Gap measuring tool

Spark Plug Thread Lubricant (This is a must, BUT only put a drop in the top two threads. Use sparingly. You don't want any of it to get on the end of the plug or in the cylinder. Keeps plug from seizing in hole.)

-Extra washers (Washers get worked hardened over time or damaged. You can re-soften (anneal) old washers and re-use by heating them with a propane torch. String one from a safety wire and hold over the torch until the color changes, barely glows dull in a darkened room, than quenched in water. The quench is not really necessary or critical, just convenient. You will need a little gas torch. Acetylene is a good way to melt them. Soft and melt is not far apart. Propane is safer.)

-Spark Plug "Pressure Tester" It puts the plug under pressure and checks it can spark. Its not something you are going to buy ($500-$1400) but most FBO's have them. Try and do a test before reinstalling.

Reinstall but DO NOT OVER TORQUE! You should use a sensitive INCH-POUND torque wrench, preferably one that is calibrated. I use a plan old beam type for the plugs. Lycoming calls for spark plugs to be torqued: 30 Ft. LB (360 in. Lb) to 35 Ft. Lb (420 In. Lb). I have no reason, but I tend to under torque just below the 300 in-lbs. Never had a plug get loose.

Clean the spark plug lead and contact before reinstalling. The lead nut (3/4" or 5/8") does not need to be too tight. There is a spec torque but its too hard to read on a nut you can't get a socket on, so I just make it snug. Just don't over do it. It's very rare people under torque, unless they just forget to tighten it all together.


If you DROP a spark plug once DROP it twice, in the trash. A hairline crack can damage an engine and cause pre-ignition. So if it hits to floor throw it away.

Cleaning plugs is fun and its a great excuse to buy a bunch of tools.

PS: DON'T USE GAS FOR CLEANING IF AT ALL POSSIBLE! Its a great way to catch on fire or blow your hanger up. Use part cleaning solvent or mineral spirits. We all have done the gas thing, but it's not really safe. It's very flammable.
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Last edited by gmcjetpilot : 04-04-2007 at 05:50 PM.
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  #7  
Old 04-04-2007, 05:17 PM
RV6_flyer's Avatar
RV6_flyer RV6_flyer is offline
 
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Location: NC25
Posts: 3,508
Default

Quote:
Originally Posted by gmcjetpilot
I used ATS (Aircraft Tool Supply) to show you tools to do a spark plug cleaning.

You will need a 7/8" deep special socket for aircraft spark plugs.

-Vibrating tool for getting the lead deposits out. The cost is not too much.

-Gap tool Cheap

-Gap measuring tool

Spark Plug Thread Lubricant

-Extra washers (Washers get worked hardened over time or damaged over time. You can re-soften the old washers and re-use by heating them. Hold over torch till they change in color, barely glows in a darkened room, than quenched in water. You will need a little gas torch.)

If you DROP a spark plug once DROP it twice, in the trash. A hairline crack can damage an engine and cause pre-ignition.
Thanks George. I edited out of your post what I do not use and left what I use. By not doing the bead blast, I am getting over 1,000 hours on plugs using mags. I do use a CHAMPION erosion gauge to check to see if the plug is worn out. After 1,988 hobbs hours, I am still on my 2nd set of spark plugs. They were put in with about 900 hobbs hours back in 2001 right before I flew to Alaska.
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  #8  
Old 04-04-2007, 05:37 PM
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gmcjetpilot gmcjetpilot is offline
 
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Posts: 4,285
Default Great tip

Quote:
Originally Posted by RV6_flyer
By not doing the bead blast, I am getting over 1,000 hours on plugs using mags.
I'll keep that in mind. Thanks for the tip. Makes total sense.
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Raleigh, NC Area
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  #9  
Old 04-05-2007, 01:50 PM
glenn654 glenn654 is offline
 
Join Date: Feb 2005
Posts: 592
Default plug cleaning

I've read that Hopps #9 bore solvent and a brass bristle brush works well. I've haven't tried it yet but probably will.

Glenn
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  #10  
Old 04-05-2007, 02:26 PM
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osxuser osxuser is offline
 
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Location: Pasadena CA
Posts: 2,484
Default

Even with bead blast (I have the Champion $$$ unit I got for cheap from a closing A&P school) plugs can last 1000 hours. Just don't blast them a ton, and keep the engine leaned correctly so buildup doesn't happen as much. Advantage of the Champion unit is the ability to check the plug before it is reinstalled, but for most people the price is prohibative.

At some point the question stands... $150 is cheap insurance every 500-700 hours right? If you are straight mags, you need a 500hr inspection, i'd at least consider replacing them then.

A couple words of (perhaps) wisdom. Drop the anti-seize. It doesn't seem to do anything, dry torque to 30Ft/Lbs. Also if you are REALLY looking to save money, the old gaskets can be annealled and reused. At $2 a spark plug pull to check, it doesn't seem that expensive, but it's a little. I ususally anneal unless the customer REALLY wants new ones, they work fine that way.

FWIW, Champion SPECIFICALLY says do NOT wire brush the electrodes of their plugs.
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