Thread Repair Options Helicoil vs Others

Farmall 1066 · Apr 26, 2013

Spent half last night drilling out rusted and galled head bolts on a Wisconsin VH4D engine. These are notorious for this, and this one was worse than most
Ended up installing 12 Helicoils in it. Got me to thinking and was wondering what you guys prefer? Never had a problem with HC's, but have used Time-Serts too and thought they were pretty neat.
What do you like, and why?

shurik06_83 · Apr 26, 2013

coils are one time use if anything has to come apart the guy taking thing apart will hate you , I had to do a few late model cammery 4 cyl . they have a problem where the head bolts rip right out of the alum block , I solved this by drilling the holes out a hair re-tapping them and not using bolts but studs ,studs can be screwed into the block by hand with minimal force on the new threads and when you drop the head on the studs and turn the nuts down your only getting a pulling force on the new threads , but with bolts your getting a pulling and twisting that can rip the threads out of weak material

ssentt · Apr 26, 2013

Time-Serts :beer:

This page covers everything I could of thought of. They're just better. Solid threaded bushing. http://www.youtube.com/watch?feature=player_embedded&v=A4sS3T6g84I

thinmac · Apr 26, 2013

I'm not sure that it will be an option in your current situation, as it doesn't preserve the original bolt size, but normally rather than restore threads I drill them out and cut new ones.

The trick is to figure out which larger thread has a minor diameter closest to, but just over, the previous thread's major diameter. That way you can get full new threads without enlarging the hole any more than is needed. The last one I did went from 14mm-2 to 1/2"-20.

Jim Johnstone · Apr 26, 2013

I hate heliocoils. Timeserts and EZ Lok inserts are my favourite. EZ Lok has the advantage of using standard off the shelf taps since they just open the hole the next size up and use an insert with the old damaged thread size on the inside and the bigger thread size on the outside. The downside to them is they take up more space.

Farmall 1066 · Apr 26, 2013

These threads were too far gone to have had a chance at holding torque. Got all but one bolt out w/o damaging threads. I just wasn't going back together the way it was.
Never had a problem removing an old Helicoil...just use a pick to bent it inwards, then wind it up with a needle nose pliers.
Can't say I have ever had a Helicoil repair fail either, but myself, have been impressed with the Time Serts...Always noticed they are all I see used in motorcycle shops, FWIW.

Skin · Apr 26, 2013

I don't have any experience with time-serts so i'll use this thread to pose a question. On something like the Subaru flat four boxer engine how would one of those work since the head bolt hole is blind until a few inches down. Seems to me time-serts require that collar be countersunk which wouldn't work in that case without removing a lot more material than a heli-coil would require to get the insert deep enough. Or do you just wait until they release a specialty insert? Or am I wrong all together?

KU_MechE · Apr 26, 2013

+1 timeserts

freedomgli · Apr 26, 2013

Heli-coils can be annoying but they work fine in certain applications. I just bought a few Timesert kits. They're not cheap but I have a feeling I'll like these much more.

CWP1616L · Apr 27, 2013

I like Keenserts if there's enough room.

Drew_flux · Apr 27, 2013

I prefer a Timesert over a helicoil. but if I cant get a timesert in time, the helicoil box is always in the tool room.

Danglerb · Apr 27, 2013

Timesert only kind my friend uses, or I borrow.

Farmall 1066 · Apr 27, 2013

Good point, Freedommgli, the Helicoil is the only one I know of that can be stacked for deep holes, or can be used in one that is counterbored.

Smiliesafari · Apr 27, 2013

I like Keen-Serts also. Standard taps and full thread contact.

joedodge · Apr 27, 2013

Timesert hands down but have pulled one right out of a Cadillac block trying to torque the heads down even when done properly heated and lock tighter and sat overnight. So they have there down falls too.

Applesauce · Apr 27, 2013

Definitely prefer Time-Serts. The kits aren't cheap, but the hardware they include are of immaculate quality.

Dimitri · Apr 27, 2013

CWP1616L said:
I like Keenserts if there's enough room.

At the machine shop I worked at, we had these and Helicoils.

In my biased opinion after using both, Keenserts, unless specified by the customer not to be used, or there is no room for them, is the only real good way to fix a threaded hole.

Dimitri

Moose-LandTran · Apr 27, 2013

I use V-coil kits, same as Helicoils. They've always worked fine and never let me down. Maybe they're not the best, but they're still pretty damn good.

redwrench60 · Apr 27, 2013

Skin said:
I don't have any experience with time-serts so i'll use this thread to pose a question. On something like the Subaru flat four boxer engine how would one of those work since the head bolt hole is blind until a few inches down. Seems to me time-serts require that collar be countersunk which wouldn't work in that case without removing a lot more material than a heli-coil would require to get the insert deep enough. Or do you just wait until they release a specialty insert? Or am I wrong all together?

I prefer time serts hands down. Properly done they're a permanent and strong trustworthy repair.
Skin, if I'm understanding your question right you can get timesert inserts in different lengths to accomadate deep and shallow blind threaded holes. But I almost always just grab the long ones and if needed I trim and de burr them on the bench grinder to fit. (on the non shouldered end of course)

Outlawmws · Apr 27, 2013

I've also never had a properly installed Helicoil fail, and if you haven't either, then why look further? :dunno:

I've used hundreds, and spec's thousands to be installed, no issues and yes, they can be removed and reinstalled if push comes to shove...

gahrajmahal · Apr 27, 2013

X2 for Keenserts. I used them for aluminum castings that had heating elements cast into them. We bolted manifolds and pumps to the castings with o-ring seals. The castings were heated up to 600 deg. F. We would get the old units in for service after 5 or more years out in the field. The original fasteners would come right out. The fasteners were assembled with never sieze.
They also come in solid in case your original hole was put in the wrong place. You could offset drill and tap to correct the mistake and not loose any structural integrity.

Man of Many Vices · Apr 27, 2013

shurik06_83 said:
coils are one time use if anything has to come apart the guy taking thing apart will hate you , I had to do a few late model cammery 4 cyl . they have a problem where the head bolts rip right out of the alum block , I solved this by drilling the holes out a hair re-tapping them and not using bolts but studs ,studs can be screwed into the block by hand with minimal force on the new threads and when you drop the head on the studs and turn the nuts down your only getting a pulling force on the new threads , but with bolts your getting a pulling and twisting that can rip the threads out of weak material

Very smart. Wished I knew this before installing six time-serts on wife's 2002 4-cyl Camry two months ago.

Thread Repair Options Helicoil vs Others

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