#7 plug hole stripped
Thread Starter
Instructor
Joined: Feb 2009
Posts: 218
Likes: 11
From: Portland Maine
#7 plug hole stripped
well? I thought changing my plugs and wires over the winter would be a great idea!!....I replaced all the plugs and wires with no events other than a few skinned knuckles... then theres #7...(plug nearest to the fire wall drivers side?) It came out ok, with the right swivel and extentions, but for some reason the new plug will not go in. I'm afraid the first thread or two in the head maybe stripped. So i can not seem to even start the new spark plug in. A friend used a mirror and could see the stripped thread. Any suggestions on how to clean up that first 2 or 3 threads? so i could get that plug started again??? I realize the last thing i want to do is drop any shavings in the cylinder.... ugh
much help is needed....im already having nightmares about bring the car somewhere and having the head taken off
Please and thank you!!
much help is needed....im already having nightmares about bring the car somewhere and having the head taken off
Please and thank you!!
Burning Brakes
Joined: Mar 2008
Posts: 983
Likes: 36
From: Middle Of Kali CA
IF you can get a thread chaser (not a tap) to start in the hole straight, you might get it worked out. Grease up the chase tool and it will grab most if not all the shavings. Worst case it jacks up the thread even worse. Than pull the head.
Pro
Joined: Nov 2005
Posts: 626
Likes: 0
From: Fresno CA
Did you start the plug by hand for the first few threads or did you use a socket on it?
If you were starting it by hand I don't think you'd be able to strip any threads. I use a short piece of rubber hose pushed onto the top of the plug and use it for grip to hand start a plug. Be sure to put on some antiseize on the threads.
#7 is notorious for being a pain to get at. You can remove a few things around it to get a better angle and more access. I believe the egr air tubing unbolts EZ and will help.
If you indeed have stripped this , you pick the best/worst one to deal with! I don't see how you could use a tap on this( no visual). Youd probably make it worse. Might have to swallow your pride and call in a mechanic on this.
Good luck with the repair
If you were starting it by hand I don't think you'd be able to strip any threads. I use a short piece of rubber hose pushed onto the top of the plug and use it for grip to hand start a plug. Be sure to put on some antiseize on the threads.
#7 is notorious for being a pain to get at. You can remove a few things around it to get a better angle and more access. I believe the egr air tubing unbolts EZ and will help.
If you indeed have stripped this , you pick the best/worst one to deal with! I don't see how you could use a tap on this( no visual). Youd probably make it worse. Might have to swallow your pride and call in a mechanic on this.
Good luck with the repair
Racer
Joined: Aug 2010
Posts: 349
Likes: 7
From: San Diego CA
When I was working with aluminum head airplane engines it was customary to tap in helicoils without removing the head. Aluminum shavings can be blown/vacuumed out the cylinder. There needs to be enough room to work the tap straight of course. Although timeserts are supposedly better for aluminum heads than helicoil. yeah, and I would let a mechanic do it either way.
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
Lisle has spark plug thread chaser tool for 7 bucks, get that, than you 2 choices
1> greased up thread chaser tool and go only couple threads back out, clean the thread chaser tool and use ear cotton swab dipped in oil, insert in plug hole wipe as much as you can but dont go too deep, repeat couple time with different swab.
than try new spark plug try thread with fingers only, still no go than repeat above procedure and again go only couple threads more.
2> Bring the piston up and use chaser tool DRY with no oil or grease must be dry, go few threads and back out, now vaccumed out or use air blow (if you have compressor) if not use keyboard compressed duster.
If both methods dont work or afraid to do, than pull the heads, take it to machine shop let them drill tapped and use heli coil, or just tap re-thread and go from there.
at the worst head gasket, new head bolts for one head only and your labor. BTW pulling head and install is not that bad, weekend job with most hand tools only.
1> greased up thread chaser tool and go only couple threads back out, clean the thread chaser tool and use ear cotton swab dipped in oil, insert in plug hole wipe as much as you can but dont go too deep, repeat couple time with different swab.
than try new spark plug try thread with fingers only, still no go than repeat above procedure and again go only couple threads more.
2> Bring the piston up and use chaser tool DRY with no oil or grease must be dry, go few threads and back out, now vaccumed out or use air blow (if you have compressor) if not use keyboard compressed duster.
If both methods dont work or afraid to do, than pull the heads, take it to machine shop let them drill tapped and use heli coil, or just tap re-thread and go from there.
at the worst head gasket, new head bolts for one head only and your labor. BTW pulling head and install is not that bad, weekend job with most hand tools only.
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Thread Starter
Instructor
Joined: Feb 2009
Posts: 218
Likes: 11
From: Portland Maine
i did indeed try to put the new plug in by hand. i just ripped off an old boot to a plug wire to get good grip on it...and i also removed the egr air tube...I did read up on it and knew going in that #7 is the worst so i decided to do it last...After about 30 min of not being able to even get the plug started by hand i decided that it wasnt the wrong angle so we dicided to then use the mirror to look at the initial thread. it just looks rounded....thats why im wondering if theres a good way to clean it up enough to get the plug started.
I'm guessing my first mistake is waiting the recommended 100,000 miles to replace the original plugs...i have 92k on it and am kicking myself for not doing it earlier.
I'm guessing my first mistake is waiting the recommended 100,000 miles to replace the original plugs...i have 92k on it and am kicking myself for not doing it earlier.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Helicoil will probably be the only option. I would however, find a respectable machine shop and go ask questions. Maybe they have some way of getting it done without removing the head but being its #7...not to sound bad or anything but that's the worst.
Pro
Joined: Nov 2005
Posts: 626
Likes: 0
From: Fresno CA
Did you notice any threads off the head on the plug from #7. It seems the other plugs would also have this issue too if was from age and seizing.I wonder if they had been changed earlier and the damage was done then.
I might let it sit and rest a day and have another go at it when your not as upset and frustrated. At this point you dont have much to loose, maybe try and chase the threads with a tap as you planned.
I might let it sit and rest a day and have another go at it when your not as upset and frustrated. At this point you dont have much to loose, maybe try and chase the threads with a tap as you planned.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Removal shouldn't have messed up the threads. I would try the greased chasing tool to see how far it will go in by hand (no wrench) then try the plug again. Pull the AIR tubes to get more room (leave the check valve in place).
Drifting
Joined: Sep 1999
Posts: 1,574
Likes: 2
From: Orlando FL
did you try just sticking your finger in the hole to feel is the threads are messed up? The threads are a little bit recessed so maybe your friend thought some were stripped away.
I change that plug by feel and with out taking any additional parts off. I have to lean down and have my face near the mirror to get my arm in the correct position to line up the plug for that hole.
For a quick yet cheap check take one of the easier access plugs out, feel how that hole is supposed to feel then examine the #7 and compare.
I change that plug by feel and with out taking any additional parts off. I have to lean down and have my face near the mirror to get my arm in the correct position to line up the plug for that hole.
For a quick yet cheap check take one of the easier access plugs out, feel how that hole is supposed to feel then examine the #7 and compare.
Drifting
Joined: Feb 2007
Posts: 1,793
Likes: 7
From: Santa Maria Ca.
Trying the old plug in that hole is a good idea,any chance that the first thread on the new plug is fubared?
You CAN get to that plug fairly easily from underneath after you remove the exhaust,but that might be just as much work as pulling the head(if it comes to that,and I hope it doesn't)
You CAN get to that plug fairly easily from underneath after you remove the exhaust,but that might be just as much work as pulling the head(if it comes to that,and I hope it doesn't)
Le Mans Master
Joined: May 2005
Posts: 6,366
Likes: 249
From: Fort Lauderdale, Florida
I had the same experience on the same spark plug, #7. Before I resorted to any drastic measures, I first waited until I calmed down and was more relaxed. Next, I used a mechanic's mirror to look into the hole to see if the threads were really screwed up too bad. Even though I was having trouble with threading in a new plug, the threads looked okay. I got a thread chasing tool at Sears Hardware store and after I greased it up really well, I very slowly, a little at a time, worked it into the hole. After successfully threading it in, I ran it in again a couple of times more with grease to get out any possibly remaining shavings. I then cleaned the threads up really well. Anti-seized the new plug and it went in perfectly and tightened properly. It has been many miles now and I've had no problems. Take your time and you won't have to pull the head. Good Luck!
Racer
Joined: Feb 2003
Posts: 418
Likes: 28
From: Evansville IN
There was a thread recently about a reverse spark plug hole threading tool.
Also, I'd get everything out of my way to get a good straight look at that hole. Doesn't take long to get the exhaust manifold off.
Take a 90° pic and a mirror and clean it up maybe?
HTH
Also, I'd get everything out of my way to get a good straight look at that hole. Doesn't take long to get the exhaust manifold off.
Take a 90° pic and a mirror and clean it up maybe?
HTH
Thread Starter
Instructor
Joined: Feb 2009
Posts: 218
Likes: 11
From: Portland Maine
I did alittle research...im going to try the thread chaser with a lot of grease....the thread pitch of the chaser is of some concern....i want to get the size right (obviously). is it 14mmX1.25?
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
I have a thread pitch gauge. I'll measure up a plug, and post the size for you.
14mmX1.25 is the correct size thread.
Last edited by Quicksilver Vert 01; Jan 31, 2011 at 08:52 AM. Reason: added thread size