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Heli-coil strength
https://www.slantsix.org/forum/viewtopic.php?t=28349		 Page 1 of 1
Author:  WyldeBill6 [ Sun Apr 13, 2008 1:30 am ]
Post subject:  Heli-coil strength
I noticed the new head I got for my motor has a heli-coil in one of the holes that you use to lift the motor. I take it I shouldn't trust this to lift the motor when I'm reinstalling it. Or are they stronger than I think. I have no experience with them, so any help would be appreciated. On another note, this motor has been fighting me all day. Busted a bolt on the timing chain cover. Fortunately it came out easily with an EZ out. Then I busted one of the manifold studs installing it in the head. That one broke my EZ-out and has still not come out. going to try to drill it out tomorrow. This motor just doesn't want to get finished. I do have the rocker arm assy on and cold adjusted for now and just about ready to drop back in, if I can catch a break. Thanks for any info on the heli-coils.
Wylde Bill
Author:  itlldo1 [ Sun Apr 13, 2008 5:00 am ]
Post subject: 
Not sure about the helicoil stregnth, but if you broke off a good quality ez-0out off in the head you may have your work cut out for your for the day.
I don't think you're going to be able to get it out w a drill bit. If there is anything protruding above the face of the manifold you may want to try seeing if you can grab it with a pair of vice grips to get it wiggling. Other than that your biggest tool is going to be patience with a small hammer and a punch. When I broke off the manifold studs on my head, I drilled and retapped them and used never seize on the new studs. I've been in the same situation that you're in with the ez-out, and I didn't want to repeat it. Good luck-walk away from it if its getting to you and come back to it later.
Author:  tophat [ Sun Apr 13, 2008 6:56 am ]
Post subject: 
I don't know about your helicoil hole.

Your manifold stud hole should go all the way through to the water jacket. If it was a really good easy out, it will be super hard steel. Try a good punch to shatter it. I had a tap break and that worked for me. The next choice is a carbide cutter on a dremmel tool. If it is a good easy out plan on several hours, and maybe a few cutters, as it is a very slow process. I doubt you will be able to drill it out, even with a cobalt bit.

TopHat
Author:  66aCUDA [ Sun Apr 13, 2008 8:51 am ]
Post subject: 
Dont trust the Helicoil!!!!!!! Ive had them cut loose with way less pressure than that. If its PROPERLY installed it might work but who knows. Not worth the chance IMHO.
Frank
Author:  Rick [ Sun Apr 13, 2008 9:15 am ]
Post subject: 
I wouldnt trust a heli-coil anymore than I had too. However, a friend of mine was building his small block chevy race engine and while torquing down the heads an outer head bolt stripped out. I have no idea why. He started it by hand and ran them down with a speed wrench but while using the torque wrench it gave way. He heli-coiled it , probably said a silent prayer or two, and bolted it down and it held just fine and went thru a rebuild a few months later and still worked.
Author:  Aggressive Ted [ Sun Apr 13, 2008 10:12 am ]
Post subject: 
I have a 78 head just like that. One heli-coil and a broken stud and a bad bolt hole where you lift engine.

On the broken stud, I broke off a tap in the same hole. I ended up drilling 4 small holes and ground a 1/4" drive socket wrench with a dremel so it had 4 points to fit the holes, sprayed the area with Kriol, hammered/tapped it in and twisted it out by pushing it in and turning the shaft with a 6" crescent wrench. It came right out much to my surprise.

Before that, I had broke a few drill bits trying to drill the holes, but tapped them through with a punch. Broke off the punch and tapped it through with a finish nail punch. It had more of a taper to the shaft so I could twist it out with out braking it.

I ended up using JB Weld on the Helicoil. It is in for good and has never leaked since.

On the lifting bolt hole, it used to leak like a sieve. Nothing would stop it so I used JB Weld again and glued in a stud. It works just fine and does not leak. :D

So there is hope, just take your time.

After you get them all in use silver Never Sieze on the studs and brass Dorman nuts. They will never rust like cheap steel nuts and cause the studs to break. :D
Author:  slantzilla [ Sun Apr 13, 2008 10:31 am ]
Post subject: 
If it was installed correctly a heli coil will be stronger than the original hole.
Author:  LUCKY13 [ Sun Apr 13, 2008 6:09 pm ]
Post subject: 
I agree they are very strong, but the trick is "if it was installed right". The problem is, if it was not and it comes loose on you while installing the engine who's car, or life will be hanging under it ?

IF a bolt fits in it with no problems and does not show signs of to much clearance in the threads ( be able to wiggle the bolt around) I would not hessitate to use it for bolting a chain for install. I would just inspect it real close to make sure, and watch it close when you start picking the engine up . Pick the weight up and only raise the engine a few inches off the ground to give it a closer inspection on what it appears to be doing. The Slant Six is a pretty heavy engine and not to be taken lightly when lifted.

With that said, I would propably use it if all looks good.


Jess
Author:  BigBlockBanjo [ Tue Apr 15, 2008 7:50 am ]
Post subject: 
Trick from a diesel shop I worked at.....

If a stud is broke off in a head, you can put a nut of appropriate size over the hole(hold it with a pair of vice-grips or similar). Then using a hot MIG welder, melt into the stud and gradually fill the hole until your even with the bolt face. The weld won't stick to the cast iron, and you can put a wrench on the bolt and screw 'er out! The trick is making good penetration into the stud. It's worked for me....my .02...
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