Heli coil or not?
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Senior Member
Joined: Jul 2001
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From: Nashville
Heli coil or not?
I still have 21K miles left on my warranty. I blew out my spark plug the other day and want to race Saturday. I have a lot of mods that I don't want to remove if I don't have to. Should I just use a heli-coil and forget it? Thanks for your opinion.
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From: DFW
easterisland,
I've talked with Jim@JDM about this before. He has installed the heli-coils before and from what I understand they work well.
I think I would look into installing the heli-coil before I would take it to ford. I would just rather do the work myself thats all.
Give him a call....
I've talked with Jim@JDM about this before. He has installed the heli-coils before and from what I understand they work well.
I think I would look into installing the heli-coil before I would take it to ford. I would just rather do the work myself thats all.
Give him a call....
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Joined: May 2001
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From: Richmond, VA, USA
why heli-coil your head and screw up your warranty when ford will replace the entire head for free?, but have it your way. as for your engine pull question, I'm not sure how they do it in your area (it's really a matter of preference for the tech doing the job) but you don't have to pull the engine to replace the head, however in about 45minutes - 1 hour you can have the entire cab and body of the truck up in the air while the frame/engine etc still sitting on the shop floor. this is the easiest way to do any work on the engine. just my .02
later,
chris
later,
chris
Last edited by superfords; Sep 26, 2001 at 01:27 AM.
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Joined: Dec 2000
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From: Nashville, TN
dont screw up your warranty.........take it to Town and Country.......that will probably be your only bet........i wouldnt fool with something that ford could find and then void your warranty...........dont be a dummy................
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Joined: Sep 2001
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From: San Mateo, Ca. (Bay Area)
racing can wait, replacing parts on your truck cannot. I would HIGHLY recommend getting it fixed the proper way, and get your truck runnin good, instead of doing a "qwik-fix." Just my opinion, best of luck which ever road you choose! 
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Joined: Apr 2000
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From: Stinkin Joisey
If it was mt truck, I would go to Ford and have the head replaced. Iam sure the motor doesn't have to be pulled to change heads. FYI... I have used heli-coils in motorcycle heads many times with no problems.
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From: EVERYWHERE
Easter,
Ok..here my story on this.
I had this happen to the number 5 plug. When it blew (13 lbs boost) It sounded like a MAJOR exhaust leak. And in my case, I was NOT able to thread it back in for a trip home, so I actually drove it like that for about 5 miles.
What we did for reapirs was use a heli-coil. YES..its not recommended by FORD, but I was OVER warranty and really needed this FIXED ASAP.
I am proud to say that after 12K, and 3 plug changes, the heli-coil never backed out. And this is with also many, many Nitorus runs. And we all know what kind of cylinder pressures that could make
I did use plenty of LOK-TITE when I installed, so I guess that helped as well.
If your going to do it yourself. Be sure to clean all the shavings the best you can. I had a vacuum with a small hose on the end that allowed me to get down into the cylinder to suck all the shavings out.
Ok..here my story on this.
I had this happen to the number 5 plug. When it blew (13 lbs boost) It sounded like a MAJOR exhaust leak. And in my case, I was NOT able to thread it back in for a trip home, so I actually drove it like that for about 5 miles.
What we did for reapirs was use a heli-coil. YES..its not recommended by FORD, but I was OVER warranty and really needed this FIXED ASAP.
I am proud to say that after 12K, and 3 plug changes, the heli-coil never backed out. And this is with also many, many Nitorus runs. And we all know what kind of cylinder pressures that could make
I did use plenty of LOK-TITE when I installed, so I guess that helped as well.
If your going to do it yourself. Be sure to clean all the shavings the best you can. I had a vacuum with a small hose on the end that allowed me to get down into the cylinder to suck all the shavings out.
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Joined: Jun 2000
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From: Milford, Ohio USA
Heli-Coil Is N-O-T A Cob-Job!
Gentlemen:
There seems to be a feeling here that a Heli-Coil (perhaps better stated as a "thread insert") repair is tantamount to a cob-job (some sort of quickie, rinky-dink fix). This is FAR from the truth.
Steel bolts (or other threaded objects) torqued into aluminum threads will always present a certain amount of peril. The more the bolt is removed and re-installed, the more damaged the threads will become. Little pieces of grit will eat at the threads. Any amount of over-torque will weaken the threads. Heat cycling will weaken the threads. Creep stress will weaken the threads. Eventually, especially if the bolt is frequently removed, the thread will fail. This will provoke the "mechanic" to cry out "Oh Shizznit!" or something like that.
There are several brands of very highly-engineered thread inserts, the most well-known being Heli-Coil. They make jillions of sizes and a few different types, for example, the insert for a blind hole differs from the insert for a hole that is bored through (like a spark plug hole). A kit, containing several inserts of a specific size, a drill bit, a tap, and an insertion tool isn't cheap, but you get what you pay for...
Once inserted, you have a very precise threaded hole of original dimensions, but with very smooth, hard steel threads. These threads will last for several lifetimes (they're extremely hard) and will be difficult to pull out of the mother aluminum (the outside of the insert is larger in size than the original hole and deeply threaded).
If you look at a well-built aircraft engine, chances are that all of the threaded holes into aluminum contain a Heli-Coil as an OEM spec. Ditto on most high-budget racing engines, especially where fasteners have to be frequently removed. It only makes sense.
I've spoken in the past about my built, HIGLY pampered Suzuki GS1100E that I used to ride and race. I put 82,000 miles on the thing before it finally tried to kill me for the LAST time, and to keep it in the condition that I DEMAND all of my machinery to be in I found myself tearing the thing down quite frequently. I'm talikg about a valve lash adjustment every month, head removal several times a year for combustion chamber and port polishing, and so on. Naturally, despite use of a good torque wrench, threads in the aluminum head and block started failing. I tore the engine down, carted the parts into our machine shop at work, and put a Heli-Coil into EVERY hole with aluminum threads. This included, as I recall, 16 into the head where the valve cover bolts down, perhaps 20 into the block where the cam bearing caps bolted down, two into the block for a couple of funny-looking studs, and all four spark plug holes. Trust me - after gingely threading bolts into holes with insufficient torque for the application and STILL pulling the threads out, you'll find the Heli-Coil to be a godsend.
Now, when you throw in the warranty issues of a Lightning, things get a little more difficult. If you're going to do it, go all the way. The fact is, if you're the type who is always pulling plugs (nitrous guys) and the type who is subjecting the plugs to higher-than-normal pressures (nitrous guys), you will eventually be blowing out plugs anyway (considering the marginal thread design). The best way to go would be to remove the head (you'll have to pull the head anyway to properly perform the job, although you might be able to cob the job with the head in place), drill out all four of the spark plug holes, and Heli-Coil them all. You'll never have to worry about stripping the hole or blowing out a plug again. Just work slowly, deliberately, and carefully, since you only really get one shot at the job.
My only concern, looking at the situation, is that you might not be able to find an insert that is "short" enough, if there are only four or five threads in the OEM application. You don't want to have any of the insert protruding into the combustion chamber. Someone will need to investigate that.
There seems to be a feeling here that a Heli-Coil (perhaps better stated as a "thread insert") repair is tantamount to a cob-job (some sort of quickie, rinky-dink fix). This is FAR from the truth.
Steel bolts (or other threaded objects) torqued into aluminum threads will always present a certain amount of peril. The more the bolt is removed and re-installed, the more damaged the threads will become. Little pieces of grit will eat at the threads. Any amount of over-torque will weaken the threads. Heat cycling will weaken the threads. Creep stress will weaken the threads. Eventually, especially if the bolt is frequently removed, the thread will fail. This will provoke the "mechanic" to cry out "Oh Shizznit!" or something like that.
There are several brands of very highly-engineered thread inserts, the most well-known being Heli-Coil. They make jillions of sizes and a few different types, for example, the insert for a blind hole differs from the insert for a hole that is bored through (like a spark plug hole). A kit, containing several inserts of a specific size, a drill bit, a tap, and an insertion tool isn't cheap, but you get what you pay for...
Once inserted, you have a very precise threaded hole of original dimensions, but with very smooth, hard steel threads. These threads will last for several lifetimes (they're extremely hard) and will be difficult to pull out of the mother aluminum (the outside of the insert is larger in size than the original hole and deeply threaded).
If you look at a well-built aircraft engine, chances are that all of the threaded holes into aluminum contain a Heli-Coil as an OEM spec. Ditto on most high-budget racing engines, especially where fasteners have to be frequently removed. It only makes sense.
I've spoken in the past about my built, HIGLY pampered Suzuki GS1100E that I used to ride and race. I put 82,000 miles on the thing before it finally tried to kill me for the LAST time, and to keep it in the condition that I DEMAND all of my machinery to be in I found myself tearing the thing down quite frequently. I'm talikg about a valve lash adjustment every month, head removal several times a year for combustion chamber and port polishing, and so on. Naturally, despite use of a good torque wrench, threads in the aluminum head and block started failing. I tore the engine down, carted the parts into our machine shop at work, and put a Heli-Coil into EVERY hole with aluminum threads. This included, as I recall, 16 into the head where the valve cover bolts down, perhaps 20 into the block where the cam bearing caps bolted down, two into the block for a couple of funny-looking studs, and all four spark plug holes. Trust me - after gingely threading bolts into holes with insufficient torque for the application and STILL pulling the threads out, you'll find the Heli-Coil to be a godsend.
Now, when you throw in the warranty issues of a Lightning, things get a little more difficult. If you're going to do it, go all the way. The fact is, if you're the type who is always pulling plugs (nitrous guys) and the type who is subjecting the plugs to higher-than-normal pressures (nitrous guys), you will eventually be blowing out plugs anyway (considering the marginal thread design). The best way to go would be to remove the head (you'll have to pull the head anyway to properly perform the job, although you might be able to cob the job with the head in place), drill out all four of the spark plug holes, and Heli-Coil them all. You'll never have to worry about stripping the hole or blowing out a plug again. Just work slowly, deliberately, and carefully, since you only really get one shot at the job.
My only concern, looking at the situation, is that you might not be able to find an insert that is "short" enough, if there are only four or five threads in the OEM application. You don't want to have any of the insert protruding into the combustion chamber. Someone will need to investigate that.
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Joined: Dec 2000
Posts: 3,451
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From: Portland, Oregon. USA
I have to admit some bias on the subject since I am a factory Rep for Heli-Coil. When and if my blows it will have Heli-Coil inserts installed in each plug hole. As stated above the end result will be much stronger and durable. One of our sales demo tools we use is an aluminum bar drilled and tapped with a 1/4-20 Heli-Coil insert installed. In the demo I torque a 1/4-20 grade 8 bolt until it fails (breaks). I can then unscrew with my fingers the broken portion and re-use the undamaged Heli-Coil threads. Keep in mind to repair your head properly you will need to remove it. There are two styles of inserts available for plug repair. Solid inserts and coiled inserts. I would recomend using the coiled inserts for our heads. The solids inserts have a tendancy to work loose over time and back out with the plug. The coiled inserts will not. They are more expensive but will out last the life of the truck.
Any application that has aluminum threads needs to have an insert. If anyone would like more info buzz me. Or try
http://www.emhart.com
Click on the Heli-Coil icon.
Any application that has aluminum threads needs to have an insert. If anyone would like more info buzz me. Or try
http://www.emhart.com
Click on the Heli-Coil icon.
Senior Member
Joined: Jun 2000
Posts: 648
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From: Milford, Ohio USA
Damn Straight!
That's what I'm talking about!
Strangely, I also have a 3/4-inch thick aluminum alloy bar with a single Heli-Coil insert in a hole sitting in my garage. This was my "practice piece" before I started drilling on the mighty Suzook. You can indeed snap off a bolt in the hole without any thread damage.
Ditto on the recommendation for the "coil-type" insert. I've seen the solid ones and am not very impressed.
Strangely, I also have a 3/4-inch thick aluminum alloy bar with a single Heli-Coil insert in a hole sitting in my garage. This was my "practice piece" before I started drilling on the mighty Suzook. You can indeed snap off a bolt in the hole without any thread damage.
Ditto on the recommendation for the "coil-type" insert. I've seen the solid ones and am not very impressed.
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Joined: Sep 2000
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The way I see it you have two viable options. Keep the truck and fix it right by removing both heads and doing the inserts or do as I did and cross thread the factory plugs back in best you can and trade the sucker in!
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Joined: Jun 2000
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From: Monrovia, CA
Originally posted by THEAUTOMAN
The way I see it you have two viable options. Keep the truck and fix it right by removing both heads and doing the inserts or do as I did and cross thread the factory plugs back in best you can and trade the sucker in!
The way I see it you have two viable options. Keep the truck and fix it right by removing both heads and doing the inserts or do as I did and cross thread the factory plugs back in best you can and trade the sucker in!