Well, the #1 cylinder head thread stripped . I tried the Auto Zone insert but it wouldn't bite - I guess the hole is still too small. Local wisdom suggests removing the head to rethread to avoid chips and potential damage to zero clearance piston. Any comments ? Oh, yeah, its a 1999 forester with the EJ25 engine.
Dave
Maybe the same people that came up with the "Coolant Conditioner" have designed a Spark Plug thread conditioner too... In all honesty, you can drill the hole(use the recommended size drill ) CAREFULLY/SLOWLY from outside.Use a shopvac to pull any chips out the top of the cylinder.Remember..the aluminum chips are softer than the rings/walls/valves. When you insert the "Helicoil" IT *MUST* BE PROPERLY POSITIONED! If done properly, it will be stronger then the original hole.Do it correctly as you get ONE chance. This is why you use a "Clicker" wrench AND "Anti-Seize Compound" on ALL sparkplugs.Don't go with that...turn 1/2 more turn after it's snug crap. Chances are the last person to replace them fractured the threads, it eventually blows out.They don't need to be in as tight as wheel lugnuts.
"Porgy Tirebiter" wrote in news:oDfWh.17386$ snipped-for-privacy@newssvr13.news.prodigy.net:
And forget about buying your sparkplugs at a "big box"! I've run into too many factory seconds. They may be selling the same name brands but when the profit margin gets thin so does the QC.
Later, Joe
I heard this from a mechanic:
Shove pantyhose into the cylinder through the spark plug hole. Drill. Remove pantyhose.
theory: the shavings get caught in the hose.
I think I would grease up the drill bit to trap the chips, but would test it somehow to be sure it worked. Stuffing the combustion chamber sounds good, but I'd want something sticky also.
What does a factory-second plug look like?
CompUser wrote in news: snipped-for-privacy@news.tds.net:
Exactly like a regular plug, which is why they're such a problem.
The ones with obvious defects get tossed. No major manufacturer wants junk being sold with their brand on it. Then there are the others.
Most manufacturers are constantly updating and upgrading their production machinery. The newest machines can hold the tightest tolerances. These machines also have the highest priced "production time" because they're still being paid for. By the time a machine is paid for it isn't holding the dimensional tolerances it did when new, but is still producing a usable product at a lower price than the new machine. Eventually it wears to the point that the scrap count wipes out the savings and it gets sold to a third world company making "odd brand" plugs.
The plugs on sale in a "big box" are being sold on a razor thin margin. Even if it's a name brand, it's the least expensive production that they're still willing to put their name on. While you may not be able to tell a difference with the naked eyeball, if you sit down with a thread micrometer and a pitch gage you'll spot it in a few minutes. You'll find threads that are over/under sized, and not concentric with the plugs axis. Sometimes you actually *can* see a problem. Hold a straight edge against the threads so it lines up with the side electrode. The gap between the straight edge and the electrode should be greater than the depth of the threads. I've seen side electrodes welded on so far out there was no way you could screw the plug into the hole without damaging threads in the head.
Later, Joe
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