Does abrasive cleaning spark plugs leave residue that causes engine damage?

[TJ Hopland]

I watched a video where a guy was reading some service bulletins from I think the 1960's published by Briggs and Stratton.    The bulletin said that they had to investigate the cause of early engine failures and found it appeared to be the residue left over from abrasively cleaning (sand blasting) spark plugs.    They said they actually went out to several gas stations and had plugs cleaned then came back to the lab and just further cleaning them with gas they were getting between 30 and 300 milligrams of material. 

The only reason I even clicked on the video was I was doing some garage cleaning and ran across my spark plug cleaner that I have not seen in a long time.   Also found my chainsaw which has been sitting for a couple years.   Got er all cleaned up and used the cleaner on it then that night saw the video.   Today I went out and pulled the plug and looked it over and cleaned it with brake clean and compressed air and didn't see any signs of any debris. 

They were gone by the time I was buying gas but I am told that there was a time when some gas stations had the cleaning machines out by the pumps or on the side of the building like an air hose and it was for sure a standard and often used piece of equipment for the shop.   

Mine I think I have had for 20+ years now and was likely the very first wave of cheap imported tools.   At times I have used it a lot almost always on small engines but occasionally on tractors and antique engines that are difficult to find plugs for and tend to crud them up fast.   I never really thought about leaving grit behind but I think besides flipping the little lever on the machine to 'off' and blowing more air to remove excess while its still in the machine I usually hit em with at least air if not air and brake clean before I put them back in.

Just wondering from those that were around when those were commonly used what do you think of what Briggs said?   Were they so heavily used and poorly maintained that the sand was more of a carbon goo?  And it would just lodge this goo into the plug and if you were not careful you were likely leaving a lot of crap in em?

For those that never heard of such a thing it looks like they are still commonly available from all the usual sources and all the current ones appear to be pretty similar. 

https://www.northerntool.com/shop/tools/product_13249_13249


I have never used a vintage one only seen them in museum types of settings.  It appears that they had multiple steps that all happened at the same bench top box.   I assume one of them was the sandblasting process.  What were the others?  I assume there must have been some sort of place you held the plug to gap it?   What else did they do?  Did they maybe have a model T like buzz coil in them so you could test them when you were done?
     

[Lexi]

Not sure, but I had an old time mechanic tell me that care was needed when cleaning spark plugs. I seem to recall him saying that certain foreign matter, if conductive, and if it gets embedded in the wrong spot on the plug (such as the insulator), could cause unnatural arcing when the plug fires. Can't see how sand could do that, but who knows what other kinds of media or contamination in the sand might be used or present. In theory I suppose that is possible and that it would not be good for an engine. Clay/Lexi

Edit: Then there is the matter of whether you should change the plug's metal crush gasket (if you got them). I think you are supposed to but I never did and don't remember any issues. I guess if it caused an ever so slight compression drop that also would not be good.

[Clewisiii]

Ok well maybe I am an idiot but I just run mine under a wire wheel.  Honestly I just do that for lawnmowers and such.  I will buy new for the car as needed.

["Cadillac Kid" Greg Surfas 15364]

Hey man t wasn't THAT long ago.  I was taught to wash the plugs after blasting them. We used what was then the solvent of choice, Stoddard Solvent.  If that wasn't handy the good old Carbon Tetra Chloride was there, but the plugs were washed after abrasive blasting.
Greg Surfas

[MaR]

My father was an aircraft mechanic and he had a rather fancy (for the time) Champion spark plug cleaner. It had a sand blaster and a parts washer built together and was fully automatic.

[Lexi]

My father was an aircraft mechanic and he had a rather fancy (for the time) Champion spark plug cleaner. It had a sand blaster and a parts washer built together and was fully automatic.

Washing with a solvent afterwards does make sense. The mechanic also told me to never clean them with a wire wheel, probably for the reason discussed in my first post. Clay/Lexi

[INTMD8]

I suppose no opinion on cleaning them since they are so cheap if I'm taking them out, I'm replacing them.

[chrisntam]

Portawalls?

What’s that?

[fishnjim]

Fairly common up until the '60s to see plug cleaning machines at gas stations/garages.   
Not sure of all the causes but suspect 6V, low compression, and lead gas gave more deposits and poor spark.   Conductive deposits disperse the spark and eventually won't occur.   Path of least resistance isn't the gap.
By the '60s higher compression, 12V, etc. it seemed to slowly disappear in favor of plug replacement.   Plugs became cheaper than pulling, cleaning, returning.   Same with points and condensers.   The points file went the way of the buggy whip, but some still in use.   
Then platinum tipped, etc. plugs came along, aka "Spark Wars" and those can't be cleaned - strips off the coating.   And sizes tended to standardize, then smaller plugs for HEI, etc.
With a now dispos-all society, it lead to pollution and garbage mountains.

[Lexi]

Portawalls?

What’s that?

Fake whitewalls that you could apply over a blackwall tire. In the mid 70's I had installed an NOS set of yellow portawalls to match the color of my '56 CDV that I used to own. Here is a color shot of the car with those yellow portawalls in about the late 1970s. These were narrow portawalls, (most were about 4 inches wide), and you can see the whitewall on the tire. So two tone tires was the effect with the narrow portawalls. Clay/Lexi

[savemy67]

Hello TJ,

"Does abrasive cleaning spark plugs leave residue that causes engine damage?"

I would answer with a qualified, No.  Abrasive material runs the gamut from silicone carbide to baking soda.  The type of abrasive used might determine whether any residue remained from the abrasive material.

More likely is the case that a fouled plug, obviously in need of cleaning, is fouled with not only carbon soot, but also oil.  This "mixture", already on the surfaces of the plug, will entrap some of whatever abrasive material is used.  If a thorough cleaning is not performed, some abrasive material might remain, especially in the crevice between the insulator and the plug shell, only to be dislodged later, and perhaps doing damage to cylinders, pistons, etc.

Blast media work by impact, the force of which removes dry encrustation (paint, rust) from the base material.  If there are any wet encrustations, such as grease, oil, moss, etc, the effectiveness of the blast media's impact is greatly reduced.  I recommend a thorough degreasing before attempting to sandblast something.

Having sand-blasted everything from a part that could fit in the palm of my hand to entire automobile frames and underbodies, using silicone carbide, aluminum oxide, coal slag, glass beads, and beach sand, I can say that every part needs to be thoroughly cleaned after being blasted, regardless of the blast media.  I usually clean my parts with acetone immediately after blasting, followed immediately with an appropriate primer.

Remember, cleanliness is next to Henry Lelandliness.

Respectfully submitted,

Christopher Winter

[Tpicks55]

Well as a older ,should be in a museum, guy and aircraft mechanic on round engines and square ones too.  We  cleaned  spark plugs all the time on the aircraft and cars. I have used a good champion cleaner that cleaned with abrasive blew the residue off set the gap and spark tested all in one machine. I've also used the simple ones with just the abrasive.  When you do clean  plugs you have to use your eyes and check for cracks in porcelain, crud left over just as good practice. If you drop it its toast.  Us museum guys like clean parts and up to specs or your wasting time. As stated there are lots of abrasives with different grits that you can use so just watch which ones you use.

[wrench]

Funny that aircraft mechanics have come up in this discussion. Like many questions philosophical, the answer lies in the question. If you blast the plugs, then yes, Virginia, you must blow off and spray and blow off the residual abrasives.

A buddy of mine had upgraded from a single engine airplane to a twin engine and when he bought it we talked about cost and he was like ‘yeah, 24 spark plugs!’

So you dont just toss out plugs from an airplane.

Also, back in the day, in a car with a manual choke, you could flood and foul a brand new set of plugs very quickly so cleaning was a practical task.

People were more frugal back then and we had not developed the just in time inventory  ‘disposable society’ that we have now that is clearly biting us in the patootie.

[D.Yaros]

I have a spark plug cleaner like the one pictured.  I am sure they are still available on ebay, Amazon and at Harbor Freight.

I use mine annually on my Toro power lawnmower and that engine has been firing for over 25 years now!

[kkarrer]

Hit 'em with a good dose of carb spray with that little red nozzle attached and that's always done it for me, but you can also put them in one of those little sonic cleaner for a few minutes after blasting or using the wire wheel.  Just be sure to put them in right side up.  You'll be surprised at what comes out.  Harbor Freight has inexpensive ones that will do the job.
Ken Karrer
Cen Tex CLC  Reg. Dir.
1932 AW Phaeton
1963 convertible