cleaning spark plugs: Process

Clem Clement

Clem Clement

Well-known member
yesterday I cleaned my spark plugs.
I was thinking about my late Uncle Raeman who taught me all I know, low these many years ago. Uncle Raeman helped me thru life before and after my Daddy died when I was 19. He taught me how to clean the plugs using a brass wire brush. He then said to always squirt oil in each cylinder to help soften any buildups. He also put oil on each plug's thread for easy tightening. He felt the oil helped seal the plug thread. Certainly on a horizonal head like a Chrysler product, if the plug was loose the oil would bubble as the engine ran. He also coached to never put the same plug back in its hole. Sometimes, if the rear cylinder was oil soaked, he made sure that plug went in a good cylinder. These were the 50's when replacement was the last option.
clem
 
i remember those days when i worked in a garage, you never replaced any thing, you repaired it, rebuilt carbs and fuel pumps, filed points, cleaned spark plugs as you said, i also had a little tool with a bent end on it about an inch long, you used it to reach down in the plug to pry out the carbon, that was before we got one of those fancy machines that you plugged the spark plug in and it blew sand and air on it to clean them, much faster and did a better job than doing it by hand, it also tested the plug and condensor, if they checked out you used them again, that was when an oil change included oil filter, lube all the grease fittings, checked trans and diff, radiator water, brake fluid, air in the tires and cleaned all the windows, inside and out, that was when service meant something
 
Hey Clem,
You're a lucky man, indeed, for having had such relative and mentor!
I was just doing this plug cleaning job on my '36 engine, using a basic old time 'blast' tool that nailed to my work bench. This item uses sand/silica media to blast/clean. I also use the brass wire brush process that you do! The plugs came out perfect...despite the .050 existing gap! Where you use oil, I use 'neverseize'. Yeah, replacement is still a problem of supply for huge plugs like this '36 uses..for slightly different reasons,eh. Regards
BTW- one cavaet...USE GOGGLES when blowing sand/anything...not just seeing glasses. One badly bloodshot eye this morning where a speck got to a vessel!
 
One thing I found about sandblasting plugs is that a blasted plug didnt last as long as one that was brushed....I guess the blasting made the ceramic rougher so that the deposits would adhere easier.
 
We clean hundreds of plugs each and every year at the Newport Hill Climb. Have two sizes ( big one for the Model Ts) clean em , gap them and reinstall them works like a champ.
 
I"m hearing bad things about sand blasting plugs. Having to do with residual sand getting into the ring grooves. I guess if you blow the plugs clean with air after the sand blasting, that should clean things up.
 
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Hey Clem,
This is a pic of the 'new fangled machine' that I use with brass brush, and have for nearly forty years, to clean my spark plugs. I found that a 'new' version(cheaper made/cheap price)is available at Harbor freight..heck, they even include a small amount of silica sand! Regards
 

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you do have to be carful about residul sand in plug.you can also set plugs on piece of steel and burn them clean with propane torch,takes 3,4 minutes per plug.esp if there gas fouled.works great.been doing it for years.never once hurt the plug.let them cool and blow them off good.
 
I had a blaster just like that until I ruined a set of 1948 Indian Clyinders from sand . I threw it way in the trash. Be very careful it only takes a small amount of sand to become a file once it gets into the rings. I use a brass brush now.
 
I belong to the school of thought that says sand blasting a plug breaks the glaze on the porcelain. It works fine but then the rough surface makes it easier for deposits to adhere shortening the life to the next cleaning interval. That opinion did not stop this item from following me home.

plugtester.jpg
 
Jerry,I would not use that machine,in fact I would get rid of it.Please give me your address a when you plan to put out front of your house for trash.Phil
 
I'm with Jerry. As cheap as GOOD NGK plugs are and as long as they last I never DEEP clean them. Once in a while if I have them out I clean the ends with a small wire brush and rince them out with carb cleaner. However it is good to test them on a tester that has adjustable air pressure to simulate fireing under compression. Some plugs will fire and look good up to 25 lbs of compressed air but above that the compression blows the spark out. G.M.
 
On aircraft engines we clean the plugs all the time , Blast them and file the edges flat and test them under pressure. Never have problems with them. Bill S.
 
Bill Steiner said:
On aircraft engines we clean the plugs all the time , Blast them and file the edges flat and test them under pressure. Never have problems with them. Bill S.
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The issue is not does it work but does it result in a shorter interval to the next cleaning. My modern truck the labor charge to change plugs is $300. so nothing but new. With a routine cleaning at a fixed interval it makes little difference since they will be cleaned again before it matters. Modern plugs are throw away to me but with original 80 year old plugs I don't want to do anything that might shorten the life.
 
Using anything metal on the porcelain that is not glazed ( the combustion chamber side can transfer metal causing a conducive electrical path
And has been said, if you have to clean them because of carbon fouling fix the mixture problem
 
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