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The only scenario that makes sense is that the shop dropped the plug. This lead to a crack in the ceramic, perhaps just a hairline fracture. After sometime the ceramic gave way and exploded, thus taking the metal portion with it. I cannot think of any other explanation for how the metal tip ended up in the state that it is in. It's not like the piston or valve could have interfered.
Friend's TRX300 atv piston. Part chunked off and bounced around for a while before destroying the rings. The top ring broke in half and pieces of it lodged in the top of the piston.
You would be surprised what can travel through the combustion chamber w/out much damage, and then how something very small sometimes can do a ton of damage. You lucked out. I would never wait 100k miles to change plugs in any 4.6 or 5.4 due to the known issues. Glad it worked out!
Absolutely true. Seen a tractor eat a valve that fell into the cylinder and spit it out. Replaced the heads and compression tested and still had the upper end of factory specs... Those tractor diesels were made bomb proof.
Seriously, too lean, too much timing or both? The blue appearance of the piston makes me say lean.
Don't really know. Buddy bought it used, not running. Previous owner 'raced' it.....don't really know how fast you can get a turd TRX300 to go but he tried hard, apparently.
Don't really know. Buddy bought it used, not running. Previous owner 'raced' it.....don't really know how fast you can get a turd TRX300 to go but he tried hard, apparently.
Slightly faster than walking speed, definitely slower than jogging speed
never heard of a broken spark plug problem with the 4.6... it's a one piece plug.
I researched doing my own plugs on a 2002 4.6L and there is a lot of documentation I found that the early modular motors had issues with the plugs seizing and snapping during removal. Especially on plugs with 75,000+ miles on them.
Lol, did my plugs last summer when I had a misfire, was replacing the Champion 7989s that were in it with new ones. Side by side comparison of what I found in cyl 3 vs what it should have looked like.
12-22-2015, 04:14 PM
