Spark plug?

guido

Well-known Member
Hello
How often do you replace spark plugs in you engines. I have on occasion replaced good ones just because. Lost of plugs go to the trash, I know that many though are still good,

Guido.
 
If the ENGINE has ALUMINIUM ALLOY heads with out steel inserts for Spark Plugs( EG. Ford,V-10,V-6) it can be a big $$$$ mistake changing Spark Plugs. I had a brother.I would get him to use his SCOPE and show me which plugs are faulty by the lack of or increase in voltage to fire the plug.
Now with the heads on my CASE 610B,JD "D",JD "AR",JD "520" and 15-30 McCormick the plugs seem to never require replacing. I do run the FUEL AIR ratio LEAN and COOLANT temp at least at 180F.
Bob...
 
I started changing the plugs in my 1979 pickup...until I saw that the new ones looked just like the old ones. So far as I know it still has 3 or 4 of the original plugs and it was still working fine last year. When all the engines had points and condenser, there was enough current through the plug to erode the tip. Electronic ignition changed that with much lower current so if the plug isn't misfiring, I don't change it.
 
Unleaded gas and EI have made plugs last almost indefinitely, the only thing I worry about is them seizing.
 
Car and truck about every 5 years. Garden tractors and antique pulling tractors get changed every year and other tractors get changed when needed. I pull the plugs on chainsaws every year to check engine but haven't replaced a plug since changing to Op-ti 2 in gasoline.
 
100,000 miles on cars, and as needed on everything else.

I have a champion plug tester/cleaner, so i can clean and test plugs under compression. All plugs fire at room pressure, but many fail at 70 lbs or more. My experience shows that a good plug stays good. It may need cleaning due to flooding or running rich, but with the external_link gas fouling up carbs all the time, I clean the plugs, retest them and put em right back to work. With 20 old small motors around the plug tester/cleaner is a life saver.. The 13 honda motorcycles are very picky about plugs firing under high compression and the tester saves me a lot of grief. Even half of the plugs are either marginally weak or fail on the lawn mowers when pretesting, so only the good ones stay around. Ironically the old tractor style plugs all test pretty good as a rule.
 
The company Eastwood did a thing about cleaning plugs and all these mechanics got on the comments saying that was outdated and may get glass shot in the engine blah blah. I still just put them in the glass beader and blow the shot out to unfoul plugs. I just make sure there is not glass shot stuck in them.
 
My 1999 F150 is on its second set of plugs with 260,000 miles on it. When I changed each time the plugs still looked good at 100,000 miles. Amazed me for sure.
 
Hello again,

How about air cooled engines? They do get tossed a lot, especially the two cycle ones,


Guido.
 
I clean mine with black beauty, then , as you say, just make sure ther eis no cleaning media left in them before re-using.

I havn't bought plugs in years, and I run lots of gassers..
 
tractors? when i get them, part of the basic go thru everything deal.
Truck? when they need it, they tell me when.
Little engines? when they don't start immediately when I use them.
(I [i:8e7ce41d1d]hate[/i:8e7ce41d1d] start pull ropes)
 
Haven't bought any plugs in years, and a couple of my older chainsaws might have 40 year old plugs, and they do get used! People that change a lot of spark plugs are parts changers, not mechanics!
 
(quoted from post at 12:53:06 10/25/15) Hello
How often do you replace spark plugs in you engines. I have on occasion replaced good ones just because. Lost of plugs go to the trash, I know that many though are still good,

Guido.

I had to pull one of mine to get wrench room to replace a temperature sensor. The plug (on my 1956 Ford 640) is a well rusted Mobil brand. It looked pretty old; and I have no idea when Mobil had their own brand pf spark plug. I wire brushed it and put it back because it looked good and gapped OK. If it ain't broke don't fix it. It used to be a 30,000 mile job when cars had points, so I guess if you are having ignition issues and have 700 hours on the engine since the last plug replacement it might be time.
 
(quoted from post at 08:12:51 10/25/15) If the ENGINE has ALUMINIUM ALLOY heads with out steel inserts for Spark Plugs( EG. Ford,V-10,V-6) it can be a big $$$$ mistake changing Spark Plugs..
Bob...

You must not use anti-sieze on the threads. My first job was as a VW tech. I even use it on iron heads and all exhaust hardware. Cheap insurance.
 
(quoted from post at 23:32:04 10/27/15)
(quoted from post at 08:12:51 10/25/15) If the ENGINE has ALUMINIUM ALLOY heads with out steel inserts for Spark Plugs( EG. Ford,V-10,V-6) it can be a big $$$$ mistake changing Spark Plugs..
Bob...

You must not use anti-sieze on the threads. My first job was as a VW tech. I even use it on iron heads and all exhaust hardware. Cheap insurance.

You have made conflicting statements about the use of
anti-sieze? Any how that was not the question. I have found easy to follow manufacturer recommendations, and procedures.
Leave it to the engineers and the proven way. One instruction and installation manual comes to mind, among others. While still working I had to install trailer tail gates assy. Some of the trailers had none. One note on the installation instructions go my attention, it stated: Before you do it your way...................................... try our way first!

Guido.
 
Whenever necessary. Then I replace the entire set.

I don't think my dad ever replaced and entire set in his life. If a plug acted up, he figured out which one it was and replaced just that one. A few months later he'd go through it all again with another plug.

But then, I walked past their car once and saw about an inch of 3/16" stove bolt sticking out of the top. Turned out a screw holding a sun visor had stripped out and instead of just using the next size bigger sheet metal screw, he drilled a hole and put a stove bolt all the way through. Didn't even cut off the excess.
 

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