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ok first things first. Im going to worn everyone right now that i know absolutely nothing about part names. I know what im doing when it comes to most things that have to do with an engine but im horrible with names of all kinds. So with that out of the way i think i have a farely big problem but im not sure. Tonight i was doing a full tune-up on my 78 chinook with a 20r and one of the spark plugs i had a really hard time getting out. Well i finally got it out with much muscle :weight_lift: , lol, and i think who ever changed them last time cross threaded it and when i took it out this time it brought most of the threads in the block with it. So my question is to fix this properly do i have to replace the head? and my other question is will the spark plug be ok because i was able to put the new one in but im afraid it pushed some big shavings in the cylinder and im not sure if the spark plug will be ok in there where its not really tight. Please help. :headbonk:

Edited by fisherman120
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This does not bode well for the wallet.

The spark plug MUST be tight, its holding back 1000s of PSI when the engine is running.

Shavings in the engine are BAD juju. Take off the cam cover and SLOWLY turn the engine over by hand until the bad cylinder has the piston at the top AND both valves are closed. Put it in 4th gear set the parking brake. Remove the spark plug and with a long thin air nozzle and air compressor stick it in the cylinder and blow. The air will swirl around the cylinder and MAY carry the shavings out the spark plug hole.

A helicoil with the head on is iffy and you may not have enough head left to tap for the insert. Have a professional check it out if possible

FWIW always use anti seize on spark plug threads when installed in an aluminum head.

Good luck

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Good plan with the piston at tdc also grease the cutter and the tap well with some thing like wheel bearing grease and go slow most of the shavings will stick to the grease. The helicoil kits work very well the treads are very deep so you should have no problem repairing the hole. The drive tab on the helicoil is meant to brake off when the installation tool is reversed (locks the helicoil in place) so you will want to use needle nose pliers to brake the tab so you can remove the tab with the pliers as it brakes.

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Your orginal problem may be the lack of anti seize and not crossthresded. Many times the alumium will stick to the steel spark and you will pull out the threads.

I think the techie word is galling.

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If the 22r has a alumiun head there's a tap and screwin insert (kit) that seems easer then a heil coil to repair the hole the shavings if Alumium should blow out just cranking it or pack in some cotton cord and pull out shavings after doing the job.

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Just a random thought. Would it be possible to tie a soft piece of cloth to a flexible wood/welding rod, and coat it with light grease, bring the piston to top dead center and pull the chips out that way. Everyones thoughts would be most welcome since it may well happen to me. Steve

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Compressed air does a good job I have done dozens over the years and have never had a problem. A nice long tip helps or even a small hose hooked to the tip so you can get deep inside. Get out what you can you can't do any better then that. The worst possible scenario would be between the vale and the seat but aluminum is soft and it won’t last long. As I say in 35 years of working on engines I have never had an issue redoing spark plug threads just be as careful as you can.

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Thx a lot for all the input guys i will give it a shot when i get the time. but at the time of the incedent i had a trip planned for the next day so i decieded to brave it out and see what would happen. It turns out that i must have gotten the spark plug just tight anuf because i made a 500 mile trip without one single problem, and got 23mpg to boot. But during some of the down time this winter i will fix the problem more permenantely. thx again for all the info. :ThumbUp: O and sorry about the spelling guys im terrible at it and i could not get my comp to download the spell check :Poster_oops:

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If it held for 500 mi you should be good to go....Don't screw with it. If you ever have the head off THEN fix it right. NEVER remove that spark plug again unless your going to fix it

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