It’s a known fact that engine components need to be maintained periodically. In this day and age we have a “throw away and replace” mentality in which we’re taught to just replace parts and toss the old ones. In the early days of automobiles just about EVERYTHING was rebuildable or serviceable. For pennies on the dollar you could buy new seals and brake components, fuel pumps, etc. In those days being a DIY guy or gal was a necessity and not a choice.
This quick tip is regarding extending the life of the spark plugs in your engine in your car, truck, lawn mower, snow blower, etc. Instead of tossing the plugs in the trash, save yourself some money and recondition the plugs. Take your plugs out of the engine and use a media blaster to clean the business end (electrode). This doesn’t take a lot of time as you’re just blasting off the residue left from use. The Eastwood Blast cabinet, Small Job Blast Kit, or the Speed Blaster are the two best options for the job.
Once you have the plugs blasted, use compressed air to clean out the end of the plug and you can gap the plug(s) to spec. The result will be a better running engine with better fuel economy; all for free! Do this before storage so you’re ready to go the next time you want to run it.
Words: Matt M
Pics/Tech Tip: Mark R.
Don’t do it. Plugs are cheap. Changed plugs in my Mazda 3 at 60,000, just pulled those Bosch Iridiums at 170,000 and put them back in.
At one time we owned 7 vehicles and at this altitude here in CO, the older engines would foul plugs due to the fact that some carbs can only be leaned out so much. My solution to this was to use an ultrasonic bath like the jewelry stores use. (I am a goldsmith by trade) you can pick an inexpensive model up at Harbor freight. Using an equal parts mixture of Mr. Clean, Ammonia, and water, soak the plugs for about 5 minutes and rinse/dry with compressed air. This will leave the electrode, and insulator unharmed, and looking like new. They will rust if you leave them wet though.
As an old timer mechanic this tip is outdated. In the days of leaded gas plugs would become encrusted with lead deposits at around 5-6 thousand miles, and blasting was the cure because labor rates were much lower than cost of parts replacement. Plugs were about a dollar each, labor to r&r, blast and re-gap was $2.00. At 10,000 plugs were routinely replaced. Blasting for more than about 3-5 seconds could change heat range by shortening insulator nose, many plugs were blasted for 10-15 seconds to clean them thoroughly.At 10,000 plugs were ready to fail from cracked insulators, compression leaks at the joint where porcelain met steel shell, as evidenced by grey to black ring on porcelain at that joint, glazed porcelain, etc. Also bear in mind that those older engines would be tuned every 5-10,000 miles, and needed such things as valve adjustments, points filed, carb adjustments, valve jobs at 40,000, overhaul at 100,000, oil and filter change every 1,000, etc. With today’s engines, fuel injection, advanced electronics, better oils and filters, etc., all of that maintenance is a thing of the past.With today’s lead free gas and improved ignitions, plugs should run at least 50,000 miles without any attention (that is the federal emission standard)
As an oldtimer Ford mechanic I recall blasting plugs on the Champion machine, setting valve lash, filing points, grinding valves at 40,000 miles and rebuilding engines at 100,000 miles. Plugs in those days became lead encrusted in otherwise good running engines in 5 to 6 thousand miles, and labor rates were low enough to make those efforts worthwhile. Even with these maintenance tasks plugs were routinely replaced at 10,000 miles due to other failures such as worn out electrodes, cracked nose insulator, compression leakage where the body of the plug meets the porcelain insulator, evidenced by a grey to black deposit at that joint. Today’s engines, lead free gas, better oils, electronics, fuel delivery systems, etc., make all of that unnecessary. This “tip” is outdated for anything built in the last 30 or so years.
Charlie & Greg were on to something – cleaning is good, but having nice, sharp corners on the electrodes lowers the voltage requirements of the plug even more.
Hello Gerry,
Computerized engine controls have more spark energy than points or even early electronic ignition systems. That does not make changing plugs any less important though. Excessive plug gaps overload the coil & driver circuits, causing failure. That can be very expensive when the Engine Control Module operates the coils. I also agree that on many newer cars it’s not worth the time to clean when it takes 3 hrs. to change plugs.
what about soda blasting. it doesnt leave any residue after you rinse it.
While this “Tech Tip” sounds like a money saving idea, I think it’s counter intuitive on many vehicles given the time/effort it would take to remove, clean/recondition them, and reinstall. I would suggest replacing with Brand New spark plugs instead of trying to squeeze a little more life out of old spark plugs. Furthermore, if there are excessive deposits on the spark plugs, that would suggest a mechanical problem with that cylinder. Suppose it depends on how tight your wallet is….
Not worth the effort and also consider the possibility of getting loose media into your engine if not perfectly clean. The cost of replacement and longevity these days make this effort questionable. Also consider taping off your plug threads if you do blast the plug tip end.
walnut media
spark plugs today are made to last 100,000 miles. the cost of the plugs is not worth the time and effort to clean. years ago working in the dealership we had to clean them for warranty. that’s in the past.
walnut shell media
Be careful with the grit media my Grandfather used to do this as a rop on a point set tune up However as plugs got smaller and electrodes changed the chance of contamination grew Now the best solution is to spray them with starter
fluid and light it up with a torch works great on flooded engines Check the gap add antiseize to the threads and dieelectric to the insulator and your good to go
Years ago I remember an old timer telling me never blast the plugs because you will kill the finish on the tip and ceramic. He suggested wire brushing, who’s right.
i know you can clean reg spark plugs but can you also clean iridium plugs too?
I have used spark plug cleaner/blasters on serviceable spark plugs for 50 years, and remember a Champion tester/cleaner stand in my dad’s Gulf station. I still file back the ground electrode to half way across the center electrode, like we used to do to make something similar to a “Splitfire” for performance and smoother running. Works well on small engines. New style fine center wire plugs aren’t made the same way to allow or need this filing.
Interesting – Back in the day, there used to be a canvas bag with sand that the sparkplug fit into and you used your compressor to sand blast them. This had the unfortunate consequence of pitting the ceramic and the plug fouled much easier than with the smooth ceramic. I think if you used walnut shells or plastic media this would work and not pit the ceramic , but it looks like sand was used based on the pictures.
I’m an old timer diy guy and in a talk of young and old guys this was brought up and it was mentioned that todays cars don’t need this care because the computerised engines don’t need this, the computer will adjust for the spark gap and thus the firing of the sparkplug is automatically taken care of, if this is true or not have no clue. what is your take on it .How long will it take to replace the sparkplug. Thanks for your response Gerry D.
As an aircraft mechanic on piston driven fighters, I can remember cleaning spark plugs in this manner and also cleaning the plugs on our own vehicles.
Of course we had to clean the plugs very often, like every 5-10 thousand miles on our cars, on the aircraft, whenever they started to run rough.
enjoy the tech articles, keep them coming
Additionally, use a small flat file to “square up” the electrode to remove the rounded edge before re-setting the gap.
I picked up one of the old air powered mount on the wall spark plug sand blast cleaners at a garage sale many years ago and use it regularly. I looked on Ebay and found several new and used ones, how come you do not sell them?
I’ve done this many times. I’d suggest taping off the porcelain insulator so the sand doesn’t wear off the finish. This can cause the plug to short.
I used to do the same thing and always worried about that one stubborn piece of media falling off in the engine. A friend of mine who was an Air Force mechanic told me to try carb cleaner. Son of a gun, it works very easy and gets things clean. What do you think?
Media blasting plugs is an obsolete practice due to the inability to completely remove the blast media after cleaning. This media is then introduced directly into the cylinder, accelerating wear. This turns out to be false economy, trading the cost of replacement plugs for shortened engine life. This tech tip may do more harm than good.
Are you sure it’s such a good idea?
The old Lodge type plugs were serviceable because they could be dismantled by unscrewing in two halves enabling thorough cleaning inside but you were always warned that if you sand-blasted the conventional one-piece plug that grit (media) might become embedded in the plug only to be released later with the heat of the engine risking bore damage. They used to say too that wire-brushing a plug to clean it could “metalize” the white insulator nose, causing a short.
This will lengthen the life of your secondary wiring and ignition coils also, because it keeps your system load down.
That’s all well & done as long as the tip is not too far gone. If the tip is too damaged from use the spark could be interrupted and it could cause a difference in resistance & heat transfer.