Helicoil or Timesert

[Zachsquatch]

Folks, I got myself into a pickle, so I want to fix it right.
I was installing a timing guide onto my wife's car and ended up with a bolt that just kept on spinning and never made it to torque specs. The engine is aluminum and the thread size is M6x1.
My initial solution was to use helicoil, however, the threads are recessed inside about a 1/4 of an inch. This is a problem because the M6 helicoil requires a 1/4 inch drill and the first section of the hole is larger than 1/4 of an inch...that means the threads are either deep or it tapers inside. The other problem is that the tap for the M6 helicoil will cut into the first section of the hole. So, the first section of the hole hole is larger than 1/4 of an inch for the bit, but will be cut by the tap. My fear is that the threads will not be strong enough at the beginning and the instructions want the coils a 1/4 turn below the top of the hole. I don't think it's going to work unless it's okay to thread the coils deeper than instructed.

My other solution is Big Sert by Time Sert. More or less it is an oversized, but more robust insert. Instead of drilling 1/4 of an inch, it will be drilled out .290 and make the first part of the hole suitable for threads...while allowing the use for the original bolt size.

M6X1.0 Big-Sert Kit - Thread Repair Install

Bel-Metric sells metric hardware & specialty automotive supplies nationwide. Visit our website to purchase metric fasteners, nuts, bolts, Time-Sert kits & more.

belmetric.com

I'm leaning towards the Big Sert, but I welcome your input folks.
Thanks.

 

[tnt_motorsports]

A couple thoughts come to mind here...

• You could try JB Weld. Not my favorite solution but I have used this in certain instances in the past
• You could try a 1/4" bolt. It is slightly bigger than an M6 (1/4" = 6.35mm)
• if neither of these turn your crank, I would use the threaded inserts. I has been years since I have used Helicoils.

just my $0.02

 

[atikovi]

Helicoil is 50 year old tech. Time Sert is the way to go.

 

[Trav]

Folks, I got myself into a pickle, so I want to fix it right.
I was installing a timing guide onto my wife's car and ended up with a bolt that just kept on spinning and never made it to torque specs. The engine is aluminum and the thread size is M6x1.
My initial solution was to use helicoil, however, the threads are recessed inside about a 1/4 of an inch. This is a problem because the M6 helicoil requires a 1/4 inch drill and the first section of the hole is larger than 1/4 of an inch...that means the threads are either deep or it tapers inside. The other problem is that the tap for the M6 helicoil will cut into the first section of the hole. So, the first section of the hole hole is larger than 1/4 of an inch for the bit, but will be cut by the tap. My fear is that the threads will not be strong enough at the beginning and the instructions want the coils a 1/4 turn below the top of the hole. I don't think it's going to work unless it's okay to thread the coils deeper than instructed.

My other solution is Big Sert by Time Sert. More or less it is an oversized, but more robust insert. Instead of drilling 1/4 of an inch, it will be drilled out .290 and make the first part of the hole suitable for threads...while allowing the use for the original bolt size.

M6X1.0 Big-Sert Kit - Thread Repair Install

Bel-Metric sells metric hardware & specialty automotive supplies nationwide. Visit our website to purchase metric fasteners, nuts, bolts, Time-Sert kits & more.

belmetric.com

I'm leaning towards the Big Sert, but I welcome your input folks.
Thanks.

Tap it for M7x1, it takes an M6 hole, just run an m6 drill bit down the hole then tap. The M7 bolts are commonly available at Ace or HD.
Tapping for M7 takes a lot less meat away then tapping for a coil or sert. Make sure the hole in the part being bolted on has enough play for the extra 1mm (it usually is no problem), the head will be 11mm instead of 10mm.

 

[Trav]

Helicoil is 50 year old tech. Time Sert is the way to go.

Helicoils are perfectly fine in many applications and can be just as strong if not stronger than serts.

Helicoil Type Inserts Technical Study of Strength and Pullout - Cross Tools Co

 

[Astro14]

Follow Trav’s advice. Fresh threads can be cut, and a proper repair made. JB Weld, hope, and SAE bolts are not parts of a proper repair.

 

[another Todd]

. My fear is that the threads will not be strong enough at the beginning and the instructions want the coils a 1/4 turn below the top of the hole. I don't think it's going to work unless it's okay to thread the coils deeper than instructed.

I could be wrong but seems to me that Helicoils can be stacked to go as deep as you want into the hole.

 

[Trav]

I would be difficult to "stack" coils but they do sell different coil lengths.

 

[Job]

Tap it for M7x1, it takes an M6 hole, just run an m6 drill bit down the hole then tap. The M7 bolts are commonly available at Ace or HD.
Tapping for M7 takes a lot less meat away then tapping for a coil or sert. Make sure the hole in the part being bolted on has enough play for the extra 1mm (it usually is no problem), the head will be 11mm instead of 10mm.

Good advice. Now I know 7 mm bolts are easy to get. More info to store for next time.

 

[Donald]

Can I ask what a Time Sert is? I know what a Helicoil is and have a few.

 

[Trav]

They are threaded solid bushings as opposed to wire coils.

 

[Astro14]

++ TIME-SERT Official Threaded inserts for stripped threads, blown out sparkplugs,

threaded inserts threaded, stripped threads, threaded inserts, blown out sparkplugs, stripped threads, stripped out theads, inserts threaded inserts, ford sparkplug repair, threaded insert thread repair spark plug ford blown, blew out ford sparkplug, stripped theads, threads stripped out...

www.timesert.com

The kit. Drill Bit, tap, reamer (for the countersink) and installation tool.

Drill, tap, and counterbore the hole.

Then, as you install, the insert is expanded and locked into the threads.

A very secure installation. Overkill for some applications. But good enough for head bolts on BMWs for example.

Here is the counterbore operation for the flange of the insert. Finished holes on the right.

 

[Trav]

They make aluminum inserts for spark plug applications in aluminum heads also. The first time I ran into these things was when I was a kid, VW dealers sold them for 10c ea for the air boxers which was the only engine available at that time. They were steel and only needed a 16x1.5 tap with no other cutters for installation, they worked great on old Corvair engines too.
Talk about going back in time. LOL

 

[Cherrybomb]

Don't be worried about the 7mm.suggestion.Check for the bolt availability before you start.

 

[another Todd]

I would be difficult to "stack" coils but they do sell different coil lengths.

Man, it's been about 30 years but we used to stack them by inserting one all the way down the hole then breaking off the tang, and inserting another right on top of it. The end of the thread on the first one butts up to the start of the thread on the second one. Once we filled the threads with the coils we just cut it off if it wasn't flush.

 

[Trav]

I never had the need to do that but I think it may want bind where they meet, maybe not. I would like to try it the next time I want to do something for the heck of it on a piece of scrap.

 

[vavavroom]

Last year I was also wondering whether I should use a Helicoil or a threaded insert. I was inclined to use a threaded insert but after listening to Trav I went with a Helicoil and I have not regretted doing so. The bolt in the helicoil hasn't moved one iota since I installed it. I now would use a threaded insert only for a part that sees repeated bolt removal.

If interested, start reading on page 3 of this thread: https://bobistheoilguy.com/forums/threads/bolt-extractor-and-max-torque.338204/page-3

 

[ElectroMechanoMan]

I have on occasion made my own timesert like repairs in a pinch. Cut off an oversized bolt and drill out and tap the center for the original bolt. Tap the stripped hole to the oversized insert and turn it in and lock with green loc-tite. It works well as I said in a pinch. I like a timesert better than a helicoil because I’ve had them spring apart in a Solartron point drum level instrument that has a number of electrodes to measure level. It came with the helicoils inserted from the factory to prevent the electrodes from galling to the body of the instrument. I was removing the electrodes for inspection and every one of the helicoils came out and tore up the threads in the body. The factory repair was timesert.

 

[Trav]

Obviously the wrong part for the job was used or not installed properly its that simple. A helicoil can actually be stronger than a Time-Sert but will loose some strength after repeated fastener removal (not a just a few times)

 

[ElectroMechanoMan]

Same thing I thought at the time. At least, none of the electrodes got stuck in it. All of the components are stainless steel and are hard to machine.