Spark Plug Cleaning Machines

[lazyuniondriver]

I was taught abrasive spark plug cleaners were an unacceptable method of cleaning plugs, so I have never owned one. Some gas engine manufacturers' also warn against their use.

The use of abrasive cleaners can allow abrasive media particles to become trapped in the crevice between the insulator and the metal plug base leading to misfiring. Media particles can also later become dislodged and ingested into the combustion chamber and cylinder. Erosion of the porcelain insulator and metal electrodes is also a concern.

An acceptable method of cleaning spark plugs I learned is to first use a brass or nylon bristle brush to remove the deposits from around the center electrode, the insulator, and the ground electrode.

Next, the most important part of the cleaning task is using a spark plug cleaning tool with a slightly rounded blade to scrape around the depths of the crevice between the insulator and the metal base using caution not to crack the insulator. This tool looks like a feeler gauge blade rounded length ways to fit in the crevice. Cleanliness of the crevice was stressed to prevent intermittent misfiring.

Compressed air is then used to rid the crevice of loosened deposits. The plug is then cleaned with solvent, dried and inspected for damage to the center electrode insulator.

A propane torch is also acceptable to use after the solvent cleansing to totally evaporate the solvent and remaining petroleum deposits. The plug must be well heated then allowed to cool to the touch by itself so the torch is infrequently used by most people when pressed for time.

Both electrodes are now inspected to determine if the plug is serviceable for re-use. If deposits remain on either electrode that cannot be dressed with a file or the electrodes are burned rounded, replacement of the plug is suggested.

If everything checks out good and the plug will be re-used, the most accurate method of adjusting the air gap between the center electrode and the ground is with the proper sized electrode bending tool used in conjunction with a wire gauge, not a flat blade feeler gauge.

Today's spark plugs installed in modern engines allow electrodes to burn to the point of necessary replacement before fouling occurs so cleaning is no longer necessary.

Plugs must be changed or removed and inspected at factory recommended intervals' because thread seizure between the plug and head can become an issue long before the plugs fail to spark or become fouled.

[gusbratz]

I have a little sand blasting plug cleaner from harbor freight, I love it. Makes my plugs look like brand new. I should post some pics. My plow truck could use a rebuild and fouls plugs. I clean those 3 or 4 times through out the winter. People say tiny bits of grit get trapped in the edges. I don't know if I buy it. Maybe if it was a 5000$ built race motor I would worry about it but my farmall or my plow truck are not exactly Swiss watches.

[tnestell]

A propane torch is also acceptable to use after the solvent cleansing to totally evaporate the solvent and remaining petroleum deposits. The plug must be well heated then allowed to cool to the touch by itself so the torch is infrequently used by most people when pressed for time.

Don't use brake cleaner for this. Jeff Silvey posted a warning in the safety forum a while back about what can happen when brake cleaner and heat come together.

[Rick Prentice]

I clean all my plugs with the handheld unit I bought from the snap-on truck, but as stated by lazyuniondriver, I also have to set down with a very fine pick and unlodge the tiny pieces of sand that gets stuck. Every plug I've ever cleaned has had sand trapped someplace, so it is a concern. I also use compressed air and brakeclean to flush things until I'm confident the plugs are ready. By the time I'm finished with all the plugs, the brakeclean is evaporated. They do look like new when the job is completed and the success rate for me has been perfect so far. I do have a set of jewelers magnifiers (loops?????) that come in handy for this job.

Rick

[Boss Hog]

We had an AC Delco Spark Plug sandblaster at the first Chevrolet Dealership that I worked at in the early 70s
Boss

[Billy Fussell]

We had a Champion spark plug sandblaster where I used to work.

[Rudi]

There was a Champion Spark Plug Cleaner for sale on my local Kijiji, linked to it, but like a dummy I can't find the pics. One of the negatives that got posted a couple times was the amount of sand that collected in the plugs using a cleaner such as this. I guess using Rick's method, it would have solved the problem. Mind you at $3.00 or so a plug, it is only $12.00 to change out a set. On the other side I guess if you have say 30 Cubs, it would come in handy

[John *.?-!.* cub owner]

One of my concerns about the abrasive cleaners is that the sand roughens the ceramic insulators making it build up carbon on the surface faster the next time.

[lazyuniondriver]

...my farmall or my plow truck are not exactly Swiss watches.

I had a '75 Vega that towards the end before its demise would foul plugs so fast I would swap them out at lunch with a set that had been soaking from the day before to rid them of the the accumulated oil for a trouble free ride home.

The engine companies who caution against abrasive plug cleaning may have been mostly the aluminum block, aluminium cylinder wall manufacturers.

[clodhopper]

I do have a set of jewelers magnifiers (loops?????) that come in handy for this job. Rick

Those work great for this kind of work. It is pronounced "loop" but spelled loupe. In fact, they work great for any kind of fine inspection work!

[Larry Barb Dotson]

The AC spark plug cleaner is not supposed to use sand, but glass beads. The tiny round beads do not leave sharp edges that roughen the porcelain
like sand does. This also allows cleaning out with air as the rounded particles do not wedge in the tight spots. The glass beads will eventually break and split into sharp pieces. At this time you need to change the glass beads. I have used this unit for 25/30 years with great success.
Larry Dotson