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Triumph TR6 - HeliCoil

Hi All,

I was browsing the archives and found the threads (no pun intended) on using HeliCoils, and have a few questions. (I am actually rethreading a bolt on my boat engine, but given the spirit of sharing knowledge on this BBS, I didn't think anybody would mind.)

1.) What do you hold the tap with? I presume there is a special tool that didn't come with my kit. Is this tool vastly superior to say a vice grip?
2.) A friend of mine recommended using "cutting oil" when driving the tap. I suppose this makes sense, would normal WD-40 or motor oil be fine?
3.) For the hole I am rethreading, I am supposed to use a 25/64" drill bit, but the closest thing I have is 3/8 (24/64"). Do you think the extra work to tap a smaller hold than recommended is worth the $7 to buy the exact bit? (The engine block is also cast iron, a 4.3 GM block.)

Any advice on doing this is definitely welcome! (E.g. drill straight?)

Thanks ahead of time!

Ignatius
Ignatius Rigor

There's a standard handle that balances real well if you have room to use it. If it's in a fairly tight area, a crescent wrench might work ok. You should use some oil (I think motor oil is fine). Just take your time and back the tap out often to clear the chips and kind of cut backwards, too. You really don't want to break the tap in there!
Tom

Helicoils are great as long as you follow the instructions, and NO a smaller drill could only result in a snaped off tap! Is the hole you are repairing a blind hole i.e does it go through the material or how deep can you go? The tang on the end of the helicoil needs to be snapped of after insertion so if you are inserting into a blind hole the depth of the hole needs to be at least 2times the width of the thread, The best results are always with cutting fluid or though into cast iron you could even do it dry, do not use WD 40 as it is made to lubricate and prevent metal on metal wear let alone damage to either surface. On the subject of what to hold the tap with try to find a socket or a ratchet type tap holder and the longer you can find the better as you can keep it square to the workpiece much better than a short T handle. Hope I have been some help
C Parker

Thanks All! I will get a handle, cutting oil, and the exact size drill bit. I have gone this far, what is a little bit more $$$.
Ignatius Rigor

Ig- Let me know if you need something. I might have it.
Don K.
DON KELLY

Hi Ignatius

Cutting lube.

If your dealing with Cast iron any medium oil will do.

Boat your likely Aluminum so don't use oil. Will gall. Antifreeze is the best. For all your doing open the rad cap on anything and get a bit on the bit and tap.

Word of advice. Use only Helicoil brand and get the kit for the size and thread pitch you need. Everythings included. Nope not cheap but work forever.

Drilling a straight hole if the set is exact for the repair should go simple with a little care. Drill will follow path of least resistance.

Bill
Bill Brayford

Ignatius--If it's not too late, consider using Time-Zerts
http://www.timesert.com/

Rick O.
Rick Orthen

Hi Rick

Yep there better in some apps but you had better be a machinist with a full bag of tricks to properly install with equal strength to a heli-coil. Requires very good and quite an array of equipment beyond kit and most home users tool boxes. Needs dead on factory precision otherwise worse than useless.

Heli coils put into a somewhat close hole due to inexperience or poor tools will almost always hold as well or better than the original in aluminum. Time-serts require exact. Thats how there designed.

Never heard what the app was. But if its aluminum? And not critical like a head. Use the helis. If its a head or critical part under lots of stress have it done by the pro's. The heli will probably work though.

Followed your URL to see if there was something I had missed lately and realy had a chuckle on there plug repair suggestions not removing the head. Yep spin that engine over to blow the chips and debris that may have??? GEEEEEES dropped down on the large piston out the little plug hole???? Or up into a valve or over onto the piston wall much more likely?

My opinion
Bill
Bill Brayford

Bill, Thank you for your always excellent practical advice. Don't think I'll be doing a plug repair the Time-Zert way!

Rick O.
Rick Orthen

Hi All,

I just rethreaded the hole, and it was much easier than I feared. I was really surprised how easy it was to tap the new threads in. I did get a handle for the tap, but ended up just using a small adjustable wrench since it worked better in the space that I had to work in.

Thanks for all the advice!

Ignatius
Ignatius Rigor

Cool, glad things went well!
Tom

Mr. Rigor- From my past hassles with the little wrench,I spent some change and got a tool that has a ratchet action to it. Both directions and center for no ratchet. Works great. If you need to do it again let me know.
Don K.
DON KELLY

This thread was discussed between 26/05/2004 and 03/06/2004

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