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Discussion Starter · #1 ·
I just replaced my head gasket on my sled and as I was torquing up the head I stripped the threads inside the block. (yes I had a torque wrench set to specs 35ft-lbs, so not sure if I had is set correctly or what...)

Anyhow, the question is what to do now. I figure I could tap out the hole for a slightly larger bolt, although have also been told a helicoil would work. What is the best way to solve this.

Would appreciate feedback on any first hand experience. BTW, this is for an '98 Indy 500 with the Fuji block. Is there lots of meat there to re-tap? Thanks!
 
G

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Hi,
I work in a Machine Shop and also teach Machine shop and Welding at the college. From past experience, I have found that a helicoil is one of the best fixes for stripped aluminum. You don't remove much material, the stud remains the same as the rest of them, and the new insert is steel. I have used them for stripped spark plugs, blocks, exhaust bolts. Everything. You can buy Helicoil kits at automotive parts stores for the spesific size that you need. They come with 5 or 6 inserts, the special tap and the installation tool. If you have any questions you can contact me directly and I will be glad to help.

Dennis
 

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Discussion Starter · #4 ·
That's good news. I assume I can do this with the engine in place. No need to remove the block?

What was the brand of the one in the picture you attached.

Also, you say you can reuse the same bolt then. Guessing the tap on the heli-coil just takes off enough to accept the spring? Must be pretty thin.

Thanks a bunch for the info!
 
G

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Yes, you can reuse the same bolt. The tap supplied with the kit cuts new threads that would be about the same size as the next bolt size bigger but cuts them with the same threads per inch as the original bolt. Then I put some RED Lock-Tite in the thread and install the insert. They work really well. Actually they work better than the original thread because they are steel and don't gall or strip out once installed. You can torque them even farther that the original thread. There is a little tang that you break off once you have the insert installed flush with the top of you block. Make sure break off that tang and remove it before installing you head bolt.
You can install them while the block is still in the sled. I have done spark plugs without even taking the head off.

Dennis
 

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btw, for the 12mm nuts on the heads of fuji motors, the correct torque is like 15 ft-lbs!!!!

-Dean
 

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Discussion Starter · #7 ·
I'll have to check my specs again tonight.

BTW, Dennis will these inserts work okay since the head bolds have more engangement than a spark-plug? Are there longer inserts available, or will the short inserts provide enough engagement for the higher tension required in the head bolts. Also, what brand do you use or was shown in your pic?
 
G

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Yes, they do make longer and shorter ones. All you really need to do,if you have a deep hole, is to install one insert double the normal depth and screw another one in on top of it. Just screw in two of them. You will need to break off tang from the deep one first and then screw the second one right in on top of it. Then break the tang off the second one. Pretty easy. If two of them end up sticking out of the block, you can take a dremel tool with the cut-off blade and grind off the part of the helicoil that is not flush with the head.

Dennis
 
G

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I don't know what the size of head bolt you are using I am guessing it is about 6mm. One of those inserts will hold as much as a 6mm bolt can stand, but like I said intall two of them if you think you need to.
Helicoil is the name brand, they were the original manufacturer. The kit in the photo is an aftermarket brand. They work just as good and cheaper. It is from a company called Cal-Van Tools. "Fix-A-Thred" is the name of there insert kit. The one in the picture was for a 5/16 bolt. I just mentioned spark plugs cuz they seem to get stripped out pretty often.

Dennis
 

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RIGHT ON DENNIS!!!!

Now this sort of exchange between sledders is the best, makes the Nanyo/Devv thing seem really stupid.

TUSF at it's best, all hail Chief Foo, Chief Boffin, and the Mod-Warriors!!!
 

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Just wanted to say great info from Dennis,... I've used helicoil(s) alot in the past.. (altho not cause i wanted to)... great fix... and great info
 

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Discussion Starter · #13 ·
Excellent help indeed, thanks again Dennis.

BTW, checked the torque specs last night and got to the root of the 'problem'. The torque spec for the 10mm bolts I have is 24-26ft-lbs or 35 N-M. The problem started when I switched from one metric torque wrench (set at 35NM) to the imperial and set that to 35ft-lbs!!!! Stupid, stupid, stupid. I won't make that mistake again!
 

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Excellent info Dennis! I've never heard of such a thing before. Info like this, can really save someone some serious coin. Thanks again!
 
G

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Indy 5,
Don't knock yourself around to much on your mistake. It has been done a thousand times before. I have seen people twist off 1/4 bolts that needed to be set in Inch/lbs and used a Foot/lbs wrench. I always tell my students that it is ok to make a mistake if you learn from it. "I personally have learned almost everything I know by mistake."
I like to use a little anti-sieze on bolts that need a specific torque and subjected to heat. Spark plugs are the worst. They don't get changed for years and will sieze into the head. Then when you screw them out, the aluminum threads come out along with the plug. Not the case on snowmobiles so much cuz they have all that 2 stroke oil soaking into the threads, but street bikes and subaru engines it happens alot.

Glad I could help you.

Dennis
 
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