How did those plugs differ from the stockers?

@@jiyushugi1085 The plugs were made in special heat ranges. The plug used depended on the ambient temperature, barometric pressure, and humidity. This sensitivity is seen on cars that run at Bonneville Salt Flats for example.

I wouldn't brag about that, Champion's are the worst spark plug on the planet, I won't even run them in lawn mowers or weed wackers, they foul easier than any other plug and if by some miracle you do get them to light off they're never right after that. Here's a prime example, 30 years ago a friend of mine and myself rode across the state to see a friend of ours who we'd go spend a weekend with once a year and go to a local bike festival out there with him, this guy changed motorcycles like we change socks, every time you'd see him he had a different one, on this trip he had a 75 FLH Harley that had drag pipes, because it had an individual pipe coming off each cylinder you could tell the rear cylinder on that thing needed rebuild because it was puffing blue smoke out like a locomotive, he started the weekend with an 8 pack of Champion plugs for that application and every time it fouled one in the rear cylinder he'd just throw it away and replace it with a fresh one. We told him that when we left we'd leave my buddy's bike with him and take his bike back across the state with us and rebuild the top end of the engine for him and when we were done one day we'd meet him half way on the turnpike and trade bikes back, Monday morning when we went to leave the weather had turned miserable, it was fall and during the rest of the weekend we had beautiful 70 to 75° sunny weather, Monday morning was around 50° and raining, when we left there was 3 spark plugs left from that 8 pack, before we even got out of that town the 3rd one had fouled at the 3rd stop light we hit. After nursing it into a parking lot I took one of the plugs and rolled down the main street of the town looking for an auto parts store and came across a mom and pop place, walking inside dripping wet, cold and miserable I plopped down the plug on the counter and told the guy I needed an 8 pack of them, he told me he didn't have Champions but he did have the equivalent in Autolite, not caring what he had I got an 8 pack of the equivalent in Autolite, anything as long as I could get back to him and we could finally get on the highway to try getting out from under that rain. When I got back he put an Autolite in that thing and not only did it fire right up and not foul at the rest of the stop lights we hit on the way out of town and not only made it all the way back across the state but he rode that bike every day for 2 more weeks on that same plug in that rear cylinder that was smoking like a chimney everywhere we went before we rebuild that top end, the same plug all that time and it NEVER missed a beat. Well that was enough to make me a believer, ever since I've run nothing but Autolite's in everything I own, my kick start only Harley became much easier to get started, the difference was noticeable to say the least especially in the winter, every chainsaw I've ever taken into the woods has never let me down, every lawn mower, weed wacker and anything else that uses a spark plug has never caused me as spark plug related problem since I switched exclusively to Autolite, when I buy something brand new like a mower or chainsaw I stop at an auto parts store on the way home and buy a pack of Autolite plugs and put one in before I even start it, those things will fire in a bucket of oil, they'll even run in a Ford!!!

I use Champion "X" sparkplugs in my Tractor

Restoring vintage aircraft is definitely for the rich.

This is exactly my experience. I would bring my fouled plugs to the shop, and a junior aspiring A&P would clean and test them with a tester just like what @jiyushugi1085 described. That's why I had 3 sets. One in the engine, and 1-2 being cleaned & tested.

Run valve stem seals in your engine's and keep your fuel system in good order and you won't need to do that, just run them until the electrode is no longer serviceable. I've been building Harley engine's for year's, all their mid '81 and earlier engine's that didn't originally have valve stem seals I absolutely refuse to rebuild without fitting them on, what a huge difference it makes, it takes 3,000 miles for oil to turn black instead of 500 miles, you can actually read the spark plugs and not just for fuel ratio but you can also read the timing on them like a modern engine because after 100 miles they're not black from oil deposits. I've helped a few buddies out with car cylinder head's, the old school V8's that used umbrella seals I've told them if they buy the cutter and mandrel (if it's a size that the old, and some new, Harley's didn't have, some are in which case I already have them) then I'll do all the work for free as long as I get to keep the tooling. There's nothing like the modern valve stem seals that press on the top of the guides, they keep all that oil out of the combustion chamber allowing you to lean out the mixture and run more timing without getting detonation. In this day and age running any engine without valve stem seals or even those old umbrella seals is insanity, the difference the modern press on seals make in an old engine is night and day, it's the single most effective update you can do to the older engine's.

My uncle had a sparkplug cleaner in the shop on his farm. My cousin was putting the plug wire on the tester on a plug and I turned that sucker on. He took about a dozen good zaps before he could let go of the plug. Lol We laughed out butts off.

@@bobbybishop5662 We hooked ours up to a metal table.....

That's a lot of plugs. Those Wasp radials are amazing!

Quenching - definitely.

The outside of the plug is attached to the engine and will remain at engine potential (neutral, ground whatever you prefer). Whether the magneto charges the inner electrode with positive or negative potential with respect to the engine is irrelevant, it's the outer that retains the neutral / ground potential.

@@incandescentwithrage Sorry, but electron theory is pretty much accepted. Positive to negative except in the source.

@@michaelsamson3276 I'm going to ignore anything further you have to say. First you make a pedantic and irrelevant point about spark plugs. Secondly you incorrectly assert that electrons flow positive to negative. They don't.

10$ washers could br 1000$ in an aviation application 😅

@@rkan2 Aircraft owners are generally super cheap about operating expenses. Plug washers are a perfect example. Conversely, many refer to 'AMUs' where 1 AMU = $1000. "How much was your engine overhaul?" "65 AMUs"

​@@rkan2 Spark plugs and washers are considered consumable items, and don't need the same rigor as other aircraft parts (PMA'd, 8130 'yellow tag' history, or even a serial number). You could cut your own washers out of a copper sheet if that's what you chose to do.

The magnetos look like vintage tractor magnetos.

.0.012-0.014 gap is not only a very tight range but under any gap setting specifications I’ve ever seen. My Lycoming O-360 and an O-320 I had previously had a gap spec of 0.016-0.022. I question that A/P’s advice and would check the engine manufacturers recommendations.

Everything 'airplane' is a different level of expensive. Engine overhaul (not a new one) is north of $50K for a 6 cylinder engine. They're often overhauled after 16-1800 hours of run time.

That would make sense. If you are stocking plugs for wartime use, make them the same if possible.

@@nickydoes yea they apparently waterproof too

I've never seen anything but common automotive style plugs in outboards. So you have a model or example that used different plug types? Seems like OMC tried a lot of crazy cool ideas.

@@nickydoes Google "surface gap spark plug". There are several different types

If recall Mercury or OMC was using in their outboard engines (2-stroke variants) what was labeled a "surface gap" which was a fixed gap. There wasn't a center electrode the plug fired diagonally across which they stated improved performance because of the more exposed spark. Even though that still occasionally fouled, I always thought because the center electrode length between the tip and the insulator was too short this allowed contaminants to build up on the insulator and short across to the plug housing. Once they were fouled they couldn't be cleaned and reused, because the insulator material was too porous. I don't know if they use that type of plug anymore. Mazda used a similiar type, twin ground electrode spark plug in some their rotary engines along with Toyota in their more conventional smaller 4 cyl engines.

Mercury Outboard was the first to use " gapless" plugs meaning they had no negative side electrode but used the whole threaded perimeter. It took their high energy Thunderbolt ignition to fire them at high rpm. Less chance of fouling but more importantly there was no welded on negative electrode to come off and eat the piston and bore. I still use them on my high rpm 2 stroke outboards that l drag race. One note... they are impossible to read for tuning so l use standard plugs of the same heat range for that. Gary RKG Outboard Drag Racing

Good points. Thanks for sharing. These are resistor plugs as well.

A few have replied about this, and I wasn't aware. It makes sense. Thanks all for sharing this!

Wait! These are for the military? We'll run materials tests, x-ray tests, and document the origins, and charge $10,000 each!

That’s bs Running your engine harder will have cleaner plugs unless you’re burning oil and low on compression.

@@fastinradfordable Why then does he need so many spark plugs ?

avgas lead builds up regardless. Aviation engines run most of their life at or above 80% power.

Yes, it's either a pneumatic thingy, or a motor-driven wheel that slings 600 grit abrasive at the plugs. Or - you pick the lead out with a dental pick.

@@nickydoes Carbon is probably from oil drawn past the intake valve stem seals (steady vacuum there). Try a quality umbrella style or replace the stock ones that may be baked and leaking .

Many aircraft engines are now certified for fine wire plugs.

When reliability is key single failure points and electronics are the enemy

Today's diesels tear apart propellers. Unleaded fuel is here, though.

It's $10, same as if you don't own a 172.

A gapping tool threads over the plug, then a lever pushes the electrode in or out. www.aircraftspruce.com/menus/ep/sparkplugs_tools_gapping.html

Thanks for that clarification. Design evolution at work. Reminds me of a book you might enjoy "The Evolution of Useful Things" by Henry Petroski.

Copper is face-centered cubic, and can't be quench hardened. Quench or air cool - same results.

@ormtheelder The annealing process is actually softening the copper, not hardening it. You want the copper washer to soften for reuse.

I just put a bunch on a length of coat hanger get em changing color then drop 'em in a pan of water. It'd be nice to make a washer holding tool (on a lathe) that would hold the washer just proud of its surface so you could flatten it on a piece of wet/dry on a surface plate.

They are cleaned and softened by quenching in white vinegar.

Some airplanes are certificated to run on 'mogas' auto fuel. A new unleaded fuel 'G100UL' from GAMI in Ada, Oklahoma, was recently approved by the FAA with STC for all aircraft as a replacement for 100LL (the current 'blue' leaded avgas). That'll make a good video topic!

The electrodes do separate. It's reasonably rare, though. When it does happen, it's not often catastrophic. It usually takes out a single cylinder - gets stuck in a valve.

Fascinating anecdote.