...and I don't want to take the head off. It won't go all the way in...maybe 1/3 of the way. Look like the person who rebuilt my head may have damaged when he was chasing the hole. I literally just got done putting the head back on the car and now this. I was thinking of getting a tap and re-tapping it, while vaccuming out the bits of metal. Then maybe blue locktite. What do you think...any other ideas?
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Help! Repairing cross-threaded spark plug hole
- Thread starter bmwpower
- Start date
ranger_dood
Well-known member
I think your only option is to re-tap it. But even then, I would be worried about it forever, until it finally shot the plug out of the hole....
plapczynski
Member
I have retapped for a helicoil insert in these instances.
Thoroughly grease the tap and run it in a turn, back it out and then clean and regrease. Hopefully the grease will catch most of the filings. The just insert the helicoil as per instructions.
Paul
Thoroughly grease the tap and run it in a turn, back it out and then clean and regrease. Hopefully the grease will catch most of the filings. The just insert the helicoil as per instructions.
Paul
plapczynski said:I have retapped for a helicoil insert in these instances.
Thoroughly grease the tap and run it in a turn, back it out and then clean and regrease. Hopefully the grease will catch most of the filings. The just insert the helicoil as per instructions.
Paul
You know, this might be doable. Didn't think of the grease, good idea. Can I try to re-tap it, and if that fails, still have enough metal to tap for the helicoil?
ranger_dood
Well-known member
Ah, yes... forgot about the helicoils... It might make the project faster to pull the head off, though. How accessable are the holes?
Paychk
Member
Hello
Longtime lurker/newbie here, I've seen on the car shows a new tool for restoring spark plug threads; the tool collapses & is inserted into the plug hole. The tool expands and engages the good threads that are near the combusion camber. It is then backed out, hence the name Back-Tap, here are some links.
http://www.google.com/search?lr=&ie=UTF-8&oe=UTF-8&q=KD Back-Tap
http://www.handsontools.com/store/list_products/?already_submitted=1&search_desc=back-tap&x=0&y=0
Hope this helps
Paychk
Longtime lurker/newbie here, I've seen on the car shows a new tool for restoring spark plug threads; the tool collapses & is inserted into the plug hole. The tool expands and engages the good threads that are near the combusion camber. It is then backed out, hence the name Back-Tap, here are some links.
http://www.google.com/search?lr=&ie=UTF-8&oe=UTF-8&q=KD Back-Tap
http://www.handsontools.com/store/list_products/?already_submitted=1&search_desc=back-tap&x=0&y=0
Hope this helps
Paychk
kartracer55
Well-known member
- Joined
- Jun 21, 2005
- Messages
- 5,317
dont take shortuts. Take the head off, and do this elsewhere. Dont even thing if attempting this on the motor. There is a reason cars run air and fuel filters. Little pieces of **** getting into the cylinder will score the hell out of the cylinder walls and it will wind up costing youa ton of money later on, and youll be kicking yourself for not taking the head off.
A helicoil might work, but if you dont dont 100% what you are doing, take it to a machine shop. They will give very good results, and you wont risk screwing up your head. Maybe talk tot he guy who built it about what happened.
Jim
A helicoil might work, but if you dont dont 100% what you are doing, take it to a machine shop. They will give very good results, and you wont risk screwing up your head. Maybe talk tot he guy who built it about what happened.
Jim
kartracer55 said:dont take shortuts. Take the head off, and do this elsewhere. Dont even thing if attempting this on the motor. There is a reason cars run air and fuel filters. Little pieces of **** getting into the cylinder will score the hell out of the cylinder walls and it will wind up costing youa ton of money later on, and youll be kicking yourself for not taking the head off.
A helicoil might work, but if you dont dont 100% what you are doing, take it to a machine shop. They will give very good results, and you wont risk screwing up your head. Maybe talk tot he guy who built it about what happened.
Jim
This sounding like a better idea the more it sinks in. Space is limited, the hole is deep in the head and the plug inserts on an angle...all the odds are against me on fixing it in the car. It might actually be quicker, like some of you said. I'm going to bring it back to the guy who did it and see what he says...undoubtedly he'll probably say I did it...we'll see.
Once I do take it off, the best method to fix it is how? Drill it out and put an insert in? Or a Helicoil? Or are they one in the same?
If anyone needs an expert at removing and reinstalling a BMW M30 head, give me a shout.
Thanks everyone. I'll keep you posted.
kartracer55
Well-known member
- Joined
- Jun 21, 2005
- Messages
- 5,317
Lol I cant even afford a bmw, even a 3 series lol.
A helicoil is an insert, but usually its a whole kit that you buy and it has a special tap in it, and a bunch of helicoils. Its probably better to have a machine shop do it so your not stuck with all the damn helicoils. Look up that thread somebody did on "repairing damaged threads" or something like that.
Also, What I saw somebody do an a racing motor once was literattly double the size of the hole, tap it, insert a plug, then drill and tap the center of the plug ffor the same spark plug.
If you look on the inlet of an IR impact, or maybe any impatct, and you look to see where the air plu is screwed in, there will be a hex on there, like it can be removed with a wrench. That is almost like a reducer bushing, but it is made out of steel, and threaded into the aluminum handle of th eimpact gun. What this does is protects us from ourselfs, because as you apparantly know, its easy to cross thread aluminum, a bit harder to do it with steel. I forget the "technical" name for them, but ill look them up.
Good luck
Jim
A helicoil is an insert, but usually its a whole kit that you buy and it has a special tap in it, and a bunch of helicoils. Its probably better to have a machine shop do it so your not stuck with all the damn helicoils. Look up that thread somebody did on "repairing damaged threads" or something like that.
Also, What I saw somebody do an a racing motor once was literattly double the size of the hole, tap it, insert a plug, then drill and tap the center of the plug ffor the same spark plug.
If you look on the inlet of an IR impact, or maybe any impatct, and you look to see where the air plu is screwed in, there will be a hex on there, like it can be removed with a wrench. That is almost like a reducer bushing, but it is made out of steel, and threaded into the aluminum handle of th eimpact gun. What this does is protects us from ourselfs, because as you apparantly know, its easy to cross thread aluminum, a bit harder to do it with steel. I forget the "technical" name for them, but ill look them up.
Good luck
Jim
kartracer55 said:Lol I cant even afford a bmw, even a 3 series lol.
A helicoil is an insert, but usually its a whole kit that you buy and it has a special tap in it, and a bunch of helicoils. Its probably better to have a machine shop do it so your not stuck with all the damn helicoils. Look up that thread somebody did on "repairing damaged threads" or something like that.
Also, What I saw somebody do an a racing motor once was literattly double the size of the hole, tap it, insert a plug, then drill and tap the center of the plug ffor the same spark plug.
If you look on the inlet of an IR impact, or maybe any impatct, and you look to see where the air plu is screwed in, there will be a hex on there, like it can be removed with a wrench. That is almost like a reducer bushing, but it is made out of steel, and threaded into the aluminum handle of th eimpact gun. What this does is protects us from ourselfs, because as you apparantly know, its easy to cross thread aluminum, a bit harder to do it with steel. I forget the "technical" name for them, but ill look them up.
Good luck
Jim
I can't afford them either, which is why I'm still trying to keep alive my old 535i, circa 1990. Seems like once they get so old everything starts to go on them (ie, like my headgasket, which is why I'm in this predicament in the first place).
kartracer55
Well-known member
- Joined
- Jun 21, 2005
- Messages
- 5,317
hey 14 years isnt bad. We have a 98 durango and the rear carrier bearings have failed TWICE, we have had A/C problems, A slightly blown head gasket, bad reverselight switch(what a project), We just put in 1400 in ball joints (thats with the freind-of-the-mechanic discount) because 98 ball joints wernt recalled. All in all there was about 13,000 of warrantee work, and out 1400 because it just went out of warantee. The muffler is going, so A big flowmaster is goin on, assumign we keep it.
Jim
Jim
Ed ke6bnl
Well-known member
kartracer55 said:Lol I cant even afford a bmw, even a 3 series lol.
A helicoil is an insert, but usually its a whole kit that you buy and it has a special tap in it, and a bunch of helicoils. Its probably better to have a machine shop do it so your not stuck with all the damn helicoils. Look up that thread somebody did on "repairing damaged threads" or something like that.
Also, What I saw somebody do an a racing motor once was literattly double the size of the hole, tap it, insert a plug, then drill and tap the center of the plug ffor the same spark plug.
If you look on the inlet of an IR impact, or maybe any impatct, and you look to see where the air plu is screwed in, there will be a hex on there, like it can be removed with a wrench. That is almost like a reducer bushing, but it is made out of steel, and threaded into the aluminum handle of th eimpact gun. What this does is protects us from ourselfs, because as you apparantly know, its easy to cross thread aluminum, a bit harder to do it with steel. I forget the "technical" name for them, but ill look them up.
Good luck
Jim
those are thread serts and McMasters and Graingers sells many sizes along with many other suppliers not sure they have the spark plug size. some even have locking pins on the sides not sure that is good for this application were a good seal is so important. Ed ke6bl
I think I'm going to get one of those Back Tap devices and give it a try. Worst comes to worst, I'll have to pull the head anyway. I'm hoping the inner 2/3 of the thread are fine. I'll flush everything out in the chamber when done (WD40 and my mini vacuum setup) a couple of times just to be safe. If I can't get the Back Tap to hookup for a good portion of the inner threads, I'll pull it out and call it a day.
Paychk
Member
Any news on this?
Oh, yea... forgot to keep eveyone up-to-date.
I ended up calling the company to find out where I could buy one of their BackTaps. They gave me the name of a couple of places near me. I gave them a call, but they were all distributors and would not sell to the public. One lady was nice enough to give me the name of one of the stores she deals with. I gave the store a call and they said they could have it for me today. The intent here was to get this thing ASAP since I didn't want to pay for shipping, etc. I paid about the same as I would have if I had bought it off of the internet, but I got it the same day. This thing was quite expensive (~$70), I might add.
SO.... I followed the directions on the packaging and greased up the threads on the BackTap. The tap was not as long I would have liked it to be. It was increadibly hard to use it since my spark plug holes were so deep. No matter what I did, I could not get the tap to hook up to the threads. I even tried it on another hole and it would not hook up to the threads. I must have tried for about 2 hours over 2 days to get this thing to line up...no dice.
In the meantime, I got a call back from the shop that cleaned the head to begin with. They basically told me it was not their fault since they "went nowhere near the spark plug holes". I would think they would have at least chased the holes to remove any **** from the cleaning process, but that was not the case.
I pretty much ran out of options at this point. My only solution was to try and screw the plug into the hole past whatever was causing it to bind. If it stripped the hole, I'd have to pull the head anyway, so I gave the following a try: I greased up the plug really well and filled up the electrode area with grease in an effort to catch any crud that came off of the threads. I also used my mini vacuum setup and Q-tips to keep everything as clean as possible in the hole. I screwed it a little ways past the 1/3 point and it was still quite tight. I backed it out and cleaned everything up, vacuumed and regreased. This continued for every partial turn into the hole the spark plug would go. Each time I pulled it out, not much of anything was on the plug or in the hole. I finally got to the bottom and it snugged up nice. I pulled the plug out and reinserted it a couple of times to make sure everything was good. No problems. I tried to torque it and it took the recommended torque spec without stripping out. The plug was in proper alignment in the hole as compared to the other plugs. I was happy (and relieved). I've been driving the car everyday since and no problems to date.
Thanks again for everybody's help. If anything good can come out of this...chase your spark plug holes BEFORE putting on your head...PLEASE.
I ended up calling the company to find out where I could buy one of their BackTaps. They gave me the name of a couple of places near me. I gave them a call, but they were all distributors and would not sell to the public. One lady was nice enough to give me the name of one of the stores she deals with. I gave the store a call and they said they could have it for me today. The intent here was to get this thing ASAP since I didn't want to pay for shipping, etc. I paid about the same as I would have if I had bought it off of the internet, but I got it the same day. This thing was quite expensive (~$70), I might add.
SO.... I followed the directions on the packaging and greased up the threads on the BackTap. The tap was not as long I would have liked it to be. It was increadibly hard to use it since my spark plug holes were so deep. No matter what I did, I could not get the tap to hook up to the threads. I even tried it on another hole and it would not hook up to the threads. I must have tried for about 2 hours over 2 days to get this thing to line up...no dice.
In the meantime, I got a call back from the shop that cleaned the head to begin with. They basically told me it was not their fault since they "went nowhere near the spark plug holes". I would think they would have at least chased the holes to remove any **** from the cleaning process, but that was not the case.
I pretty much ran out of options at this point. My only solution was to try and screw the plug into the hole past whatever was causing it to bind. If it stripped the hole, I'd have to pull the head anyway, so I gave the following a try: I greased up the plug really well and filled up the electrode area with grease in an effort to catch any crud that came off of the threads. I also used my mini vacuum setup and Q-tips to keep everything as clean as possible in the hole. I screwed it a little ways past the 1/3 point and it was still quite tight. I backed it out and cleaned everything up, vacuumed and regreased. This continued for every partial turn into the hole the spark plug would go. Each time I pulled it out, not much of anything was on the plug or in the hole. I finally got to the bottom and it snugged up nice. I pulled the plug out and reinserted it a couple of times to make sure everything was good. No problems. I tried to torque it and it took the recommended torque spec without stripping out. The plug was in proper alignment in the hole as compared to the other plugs. I was happy (and relieved). I've been driving the car everyday since and no problems to date.
Thanks again for everybody's help. If anything good can come out of this...chase your spark plug holes BEFORE putting on your head...PLEASE.
Paychk
Member
Thanks for the update! I agree; all of the sparkplug holes should have had the threads chased, if not ALL the threaded holes.
Glad to hear it worked out.
Glad to hear it worked out.
sberry
Banned
eze-lok thread insert, the heat will be too much for locktite though. I would only tap it enough so the thread insert bottomed out. If I could see the hole well enough to see how well it worked and how much thread damage it had done I would likely fix it on the car if I could, maybe vaccum the cyl out with a flexable soda straw after. Maybe hook the vac to the plug port and roll the engine over to **** up any debris. I dont think I would be overly concerned about a couple of metal shavings, they are small and will blow out. Dirt thru the air is so abrasive it does all kinds of damage but a couple shavings will blow out.