Helix coil
07-17-2006, 12:37 PM
#1
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Helix coil
Does anyone have experience using helix coils? Specifically, for head bolts.
Some time back I had submitted a tread "Water in Oil", received a lot of good responses from the membership. I at last found the time to research the problem with the water in oil problem. Not the usual suspects, it appears that my son when he installed the head bolts during the build forgot to place thread sealant on the head bolts. The cause for the water in the oil. Was good to see that I did have a good head gasket and intake gasket seal.
Having said all that, when I went to re-installed the heads, new gaskets, sealant applied to all head bolts (ARPs) I noticed that one of the bolts would not torque down. The number 17 bolt in the torque pattern on the passenger side. Not a good sign.
Thanks, Mike
Some time back I had submitted a tread "Water in Oil", received a lot of good responses from the membership. I at last found the time to research the problem with the water in oil problem. Not the usual suspects, it appears that my son when he installed the head bolts during the build forgot to place thread sealant on the head bolts. The cause for the water in the oil. Was good to see that I did have a good head gasket and intake gasket seal.
Having said all that, when I went to re-installed the heads, new gaskets, sealant applied to all head bolts (ARPs) I noticed that one of the bolts would not torque down. The number 17 bolt in the torque pattern on the passenger side. Not a good sign.
Thanks, Mike
07-17-2006, 02:32 PM
#3
Safety Car
Originally Posted by 65-vette
Does anyone have experience using helix coils? Specifically, for head bolts.
I've personally not done a head bolt, but as an engineer, I would say you could do it without any problems at all. In fact, after the heli-coil, the threads may be able to take more torque/load than the original drilled/tapped cast iron.
Do a net search on heli-coil…….. I’m sure the facts are out there.
.
Last edited by 66427-450; 07-17-2006 at 02:37 PM.
07-17-2006, 02:36 PM
#4
Would you plan on doing the heli-coil with the block in the car?
Is #17 on the bottom of the block or on the top? On a BB, do all the bolts go into the water jacket like on a SB?
Could you drill and tap the hole, then somehow plug every other orfice and flush the filings out?
Mark
Is #17 on the bottom of the block or on the top? On a BB, do all the bolts go into the water jacket like on a SB?
Could you drill and tap the hole, then somehow plug every other orfice and flush the filings out?
Mark
07-17-2006, 02:56 PM
#5
Burning Brakes
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I used to work in an engine machine shop, and we would Heli-Coil block threads all the time. NO problem, just make sure you go in straight. A magnetic base drill works best.
07-17-2006, 04:20 PM
#6
Safety Car
All you need is enough 'meat' around the particular hole you intend to repair.
Contact the Helicoil people, ARP won't know Shinola, all they can tell you is about bolts.
Contact the Helicoil people, ARP won't know Shinola, all they can tell you is about bolts.
07-17-2006, 05:21 PM
#7
Drifting
There are several other thread repair systems that present advantages over heli-coil.
Timeserts, Keenserts, Keyserts are examples & there are others. Rather than using a diamond-shaped (in cross section) coil of stainless or carbon steel 'wire' like heli-coils, these systems use ‘solid’ bushings that thread into the prepared repair area. They have different means of locking their male threads in place. They use standard drill sizes & standard taps. For example, a 7/16-14 UNC head bolt would use a Keen-sert bushing that threads into a standard 9/16-12 UNC female thread -- not some heli-coil unique heli-coil supplied “9/16-14” tap. Keenserts are secured by drifting 4 keys down into the base metal locking the insert’s male threads into the female threads of the repaired hole.
Chip control from drilling & tapping is something that should be carefully considered. At least #17 bolt is easy to access. It is one of two 'intermediate length' bolts – perhaps it extends into a coolant cavity. You’ll want to use a magnetized drill block for both drilling & tapping to keep things square. Recommend magnetizing the drill & tap as well. Grey iron tends to shed small chip particles rather than curly coils -- some thick grease on the tap might be worth considering, as well. If #17 is found to be a blind hole, you may need to make (or buy) a bottoming tap to use after getting things started with a typical (tapered-start) fluted tap.
Timeserts, Keenserts, Keyserts are examples & there are others. Rather than using a diamond-shaped (in cross section) coil of stainless or carbon steel 'wire' like heli-coils, these systems use ‘solid’ bushings that thread into the prepared repair area. They have different means of locking their male threads in place. They use standard drill sizes & standard taps. For example, a 7/16-14 UNC head bolt would use a Keen-sert bushing that threads into a standard 9/16-12 UNC female thread -- not some heli-coil unique heli-coil supplied “9/16-14” tap. Keenserts are secured by drifting 4 keys down into the base metal locking the insert’s male threads into the female threads of the repaired hole.
Chip control from drilling & tapping is something that should be carefully considered. At least #17 bolt is easy to access. It is one of two 'intermediate length' bolts – perhaps it extends into a coolant cavity. You’ll want to use a magnetized drill block for both drilling & tapping to keep things square. Recommend magnetizing the drill & tap as well. Grey iron tends to shed small chip particles rather than curly coils -- some thick grease on the tap might be worth considering, as well. If #17 is found to be a blind hole, you may need to make (or buy) a bottoming tap to use after getting things started with a typical (tapered-start) fluted tap.
07-17-2006, 09:13 PM
#8
Aluminum Block ZL-1 were factory equipped with helicoiled head bolts threads to make up for the softer aluminum block. Since then, there are stronger solutions if there is space around the threads - Keenserts or inserts like them come to mind.
07-18-2006, 01:57 AM
#9
Race Director
Heli-Coil is fine in a blind hole, like BB blocks mostly have, IIRC.
I would suggest a Keysert, or similar, with sealant on the outside of the insert, if you are going into a water jacket. The Keysert is a very permanent fix.
The Heli-Coil, while easy to use and an attractive fix, can back out during repeated bolt install/uninstall.
Doug
I would suggest a Keysert, or similar, with sealant on the outside of the insert, if you are going into a water jacket. The Keysert is a very permanent fix.
The Heli-Coil, while easy to use and an attractive fix, can back out during repeated bolt install/uninstall.
Doug
07-18-2006, 07:13 AM
#10
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Thanks guys for all the feedback and information.
I will research what information I have been given while traveling and hope to get back to the rebuild of the rebuild in early August.
I would hate to loose this block, matching numbers and all to the likes of a head bolt not torqueing down.
Again, thanks for all the help.
Mike
I will research what information I have been given while traveling and hope to get back to the rebuild of the rebuild in early August.
I would hate to loose this block, matching numbers and all to the likes of a head bolt not torqueing down.
Again, thanks for all the help.
Mike
