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Fri Feb 26, 2010 8:43 am

Sand blasting spark plugs used to be common practice in the old days to clean them up for reuse. Since I have some used, but not worn German W7CC0 BOSCH plugs that still have lots of life left in them (Please note that this is not a BOSCH vs NGK thread), I would like some advice as to how to go about this. I have the plugs, access to a sand blaster and time to do it. Since I have never done it before, I am seeking any tips, such as type of media to use, how to prevent damage etc.

Fri Feb 26, 2010 8:49 am

I've never done it, but Harbor Freight sells a neat little inexpensive kit as well as the media:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=32860

Fri Feb 26, 2010 9:08 am

Sand blasting tends to round the center electrode which is already a problem with older plugs, it can also damage the porcelain. Sharp edges on the electrode help make the plugs spark easier, so it yours are worn they may be beyond use. With the long life W7CCO plugs they don't round easily though, I know mine always used to look new after 60-80K miles of use.

On my 83 1/2 which is a worn out oil burner, I clean my plugs every 5K or so as they build up a pretty good level of dry deposits in that time. I use a modified dental pick to do so, cleaning the metal parts of the electrodes well and scraping the inside of the metal base. I try not to touch the porcelain as scratches there will be detrimental to plug performance.

I felt like Santa came yesterday, I just received a pile of German NOS W7CCO plugs which I had bought on eBay. I have tried a variety of plugs over the years and the W7CCO's were unquestionable the best so getting a stash is great.

Fri Feb 26, 2010 9:13 am

Wildthings wrote:
I felt like Santa came yesterday, I just received a pile of German NOS W7CCO plugs which I had bought on eBay. I have tried a variety of plugs over the years and the W7CCO's were unquestionable the best so getting a stash is great.
I hate you :evil:
What about blasting with glass beads, will that still tend to round the edges of the electrode?

Fri Feb 26, 2010 9:16 am

I do it all the time adjusting SUs but you need to get all the sand out clean wash then blow them out no glass beads in the cylinders please.

Fri Feb 26, 2010 4:22 pm

I have been doing this for years, I gently bend the side electrode up away from the center electrode just enough to get a thin jewlers file in between the electrodes before blasting then after blasting I file the center electrode square again then re-gap and clean very well.

This method will only work a couple of times before the center electrode is to short.

Phil

Fri Feb 26, 2010 6:49 pm

Spark plugs just don't cost that much.

Fri Feb 26, 2010 8:09 pm

and they last how long?

Fri Feb 26, 2010 11:39 pm

I have a spark plug cleaner / blaster, I thinbk it's a Victor--had it for years, bolted to the back of my roller cabinet.
It doesn't use silica sand or other harsh abrasives.
The stuff is green, and blasts the plugs really clean without eating away at the electrodes or porcelin insulator---when your all done blasting you flip the lever on the side of it, and it blows the plugs clean with an blast of air--gets all of the abrasive out of and inside, around the insulator---

It has a recapturing bag on the bottom of it so your never losing any product.

These tools have been around since Henry Ford built the first automobile.
They work really well without chewing up the plugs----

Sat Feb 27, 2010 7:12 am

Terry Kay wrote:
It doesn't use silica sand or other harsh abrasives.
The stuff is green, and blasts the plugs really clean without eating away at the electrodes or porcelin insulator---
Terry. Any idea as to what the green stuff actually is?

Sat Feb 27, 2010 8:13 am

Perales wrote: Terry Kay wrote:
It doesn't use silica sand or other harsh abrasives.
The stuff is green, and blasts the plugs really clean without eating away at the electrodes or porcelin insulator---
Terry. Any idea as to what the green stuff actually is?

Coolant :roll:

Sat Feb 27, 2010 9:10 am

<<Terry. Any idea as to what the green stuff actually is?>>

No I don't.
It came in a plastic bag with the tool, and said plug cleaner.

I poured it in the top of the tool 35 years ago after I mounted it on the back side of my roller tool box-

Take a look over at E-Bay at the spark plug cleaner's.

They have them from $8.95 to $1200.00, and I saw a couple of listings just for the plug cleaning compound.

There's a couple of neat plug cleaning cabinets with tester's
included---
AC Delco,& Champion.
Antique stuff--

Sat Feb 27, 2010 9:17 am

<<Coolant :roll:>>

There ya go Bobby--
I forgot to mention the hydroponic plug cleaning units--

You fill the plug cleaner devise up with ethylene glcol, and it uses high air pressure along with the geeen stuff to blast away any carbon deposits on the electrodes.

Flip the lever to air only and it dries them off, all in two simple moves.

Sorry I missed that unit. :oops:

Sat Feb 27, 2010 9:50 am

Great for hemorrhoids too.

Sat Feb 27, 2010 10:25 am

I once ran the maintenance at a place that had a pile of two stroke engines. Before I started there the place was run by an old school mechanic who would clean plugs repeatedly instead of replacing them. Nice cleaner mounted on the wall, just like TK is talking about. At the time I started, there was hardly a decent plug left in the fleet and all the equipment ran like it. I immediately began changing out all the plugs and started a policy of cleaning the plugs only few times before replacement. This would be dropped to only a single cleaning before replacement by the time I left years later.

One machine that doesn't start because of a bad plug and that has to be loaded up and dragged back to the shop is going to cost more in lost production and mechanics wages than buying enough plugs to replace every last one in the fleet. Not a very good trade off.

As for automotive engines, most modern engines don't foul plugs very readily so that by the time they need cleaning they are going to be pretty high mileage. Here again I think the value of cleaning is pretty questionable. If the cleaned plugs give you 20.5 mpg verses a new set of plugs that gives you 21.0 mpg you have saved nothing and withing a couple of tanks will instead have cost yourself a fist full of Georges.

As I said I do clean the plugs on my oil using 83 1/2. This engine uses enough oil to foul the plugs, especially #4 every 5000 miles. Even here I don't try to get very many extra miles out of a plug, they are all getting swapped out at least every 15K, often less. I would rather save on gas mileage and have good performance than save a few bucks on plugs.

Sat Feb 27, 2010 11:21 am

It seems like a cleaned plug , especially in a two stroke engine lasted for only about a quarter of the time of a new one.
If the oil mixture was too rich--it didn't make any difference what you used, new or cleaned, the plug would foul pretty quick anyway .

I used the cleaner for 4 stroke Briggs & Kohler engines that were worn out, and oil fouling the plug--

It worked OK.

It's pretty much a tool of the past, is an OK fix in a pinch situation.

I think the plug cleaner was a tool that would get you a couple of extra miles out of a set of plugs back in the great depression--durr
ing the war.
Like recapped & re-grooved tires.

Sat Feb 27, 2010 1:30 pm

Abrasive materials containing aluminum oxide (certain blasting media, sand paper, emery cloth) can permeate the surface of steel. Not sure about how much that can affect the performance of a spark plug (or how it affects copper and other metals). Just something to keep in mind while scavenging the depths of Vanagonland.

Sat Feb 27, 2010 2:17 pm

I was listening to one of our local car radio shows, a pretty good one, and they said that no one cleans plugs any longer for two reasons--modern plugs last so much longer than the old ones did, and because the modern ceramics are soft enough that when the cleaning medium scores pits in the surface, more carbon than before will accumulate there.

I've been known to use a dental pick and a few shots of brake cleaner on lawn mower plugs--we still have our Lawn Boy 2-stroke, that has nothing going for it except perfect functioning since 1982.

Best!

Sat Feb 27, 2010 9:44 pm

I do clean my plugs, but don't overdo it. I have a bench-mounted abrasive blaster fed by an air hose - 50 psi gets the job done, but slowly. If you go the same route, buy a cheap ultrasonic cleaner to get *every* bit of abrasive grain out of the plug and the threads before reinstalling.