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I’ve never — knock on wood — had the “fun” of trying to repair stripped threads in a key mechanical component, but I’ve seen various options. It seems that the two main contenders for thread inserts are Heli-Coil® and TIME-SERT®, but I don’t know which one works better for which applications and materials. TIME-SERT® requires drilling, counterboring, and tapping before installing the insert. A typical TIME-SERT kit, with all the required tools and several inserts, costs around $74. Heli-Coil preparation needs drilling and tapping before installing the insert. A Heli-Coil kit, with a tap, the installation tool, and several inserts, will be about $27.

So, all you Toolmongers out there with experience in this area, what’s your favorite? Are there alternatives?

Time-Sert [Manufacturer’s Site]
Time-Sert Street Pricing [Google Products]
Time-Sert Via Amazon [What’s This?]
HeliCoil [Manufacturer’s Site]
Helicoil Street Pricing [Google Products]
Helicoil Via Amazon [What’s This?]

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31 Responses to Thread Inserts: HeliCoil or Time-Sert?

  1. bajajoaquin says:

    I’ve only used Heli-Coils. I had to repair one of the threads on my motorcycle’s brake calipers. I was a little intimidated, but was plesantly surprised at how smoothly it went.

    So, while I can’t speak comparitively, I’m pretty happy with the Heli-Coil’s performance on aluminum.

  2. Alex says:

    I’ve also only used helicoils, but had good experience with them. Also, they can be “built into” parts made of soft material (brass, aluminum, maybe even plastic) from the start, to prevent stripping and crossthreading damage from ever happening. A great product.

  3. Gareth says:

    I’ve used Heli-Coils once. Vibration stripped the threads that attacked the muffler to an 85cc model aircraft engine.

    The head was cast aluminum so it was pretty soft for the tap to cut. The process was pretty easy to perform. Its kinda scary because you are thinking “if I mess this up THEN WHAT?”. Just stay calm and follow the instructions.

    I learned later that on full scale aircraft they install Heli-Coils in aluminum from the get go to prevent this problem.

    I have never heard of TIME-SERT® till you posted this but I always wondered if there were other brands.

  4. johnnyp says:

    Check out Keensert® . Not only do they make inserts , but studs also.

  5. I can’t say I “love” Heli-Coils, but when you need ’em, you need ’em. Looking at the time-sert, I don’t like the flange on top that keeps it from turning down into the hole. There are times when your only option is to go deeper than the original hole and bury the heli-coil way down there to get at good metal.

  6. Shopmonger says:

    Patrick, I am with you….can’t really say i love them…

    I love not having to use them….. But when i do….Boy are they great


  7. DanS says:

    I used to work at a manufacturing plant. For some reason TheNewGuy always thinks it’s a great idea to put 6mm screws in with an impact.. We went through boxes of coils. I’ve never had one come out. In fact, when we did stress tests, the screws with coils usually last slightly longer.

    I have no experience with inserts. I imagine it works about the same.

  8. george says:

    i tried helicoils back in the early 70’s. just was a real pain and gave other issues. i’ve used timeserts since with no issues.

  9. Old Donn says:

    Like some others here, I never knew there was anything but Helicoil. Whenever I went to the parts store, that’s what I got. Haven’t used them as much as some of you guys, but haven’t had any problems either.

  10. rob says:

    well I have used both insert and helicoil but not these time serts
    some other kind

    while helicoils are good the inserts I used were way better hands down
    every header bolt on my truck has one do to the previous owner
    I have used them in cast aluminum from new to prevent pull out
    but inserts are way nicer I have used inserts on spark plug holes on my last car I had to do the number one hole not sure why but it was a common problem with the car lots have had this issues granted it is 20 years old

  11. Ted says:


    Helicoils for most general uses and “first” repairs. Timeserts for special applications like Cadillac headstuds or over-sized holes that require a bigger insert.

    I have racer friends who will drill out perfectly good threads in aluminum to do prophylactic helicoil installs — a helicoil is much stronger than the original thread, stands up better to repeated assembly/dis-assembly and is less likely to have dissimilar metal corrosion fastener seizure issues.

    Cheers, Ted

  12. PutnamEco says:

    There are also others in the threaded insert game, Triserts and ReCoil come to mind, Recoil seams to have better tooling than Helicoil, but IMHO Helicoils inserts are of better quality. I prefer wire inserts over solid as I believe they do less structural damage to the original piece.

  13. heywood j says:

    after working as a ski tech these are gold in the “oshyts” category…a lot of the newer skis don’t have much metal in them (or the topsheet in particular) and will strip very easy since they also don’t use solid wood cores as much anymore.

    I have a helicoil in one of the holes of my rear binding on a pair of skis…has lasted fine.

  14. russ says:

    How do either of these hold up to high torque…75 ft lbs (50Nm) or greater?

  15. Pencilneck says:

    Each has it’s place. The cars I work on have cast aluminum motor mounts and every so often the threads will strip out. Said mount cost around $130-ish where as I can repair it with a HeliCoil kit for about $40 total.

    The oil pans are also made out of aluminum and Jiffy Boob must use the 4 foot breaker bar when torquing the drain plugs, thus stripping the threads out of the oil pan. The oil pan cost about $350-ish to replace for parts and labor, where as the Time-Sert kit is about a $100 repair total. It is a bit awkward to keep everything lined up when drilling/tapping the oil pan. As a result, the hole might “crooked and so that the drain plug doesn’t seat flat against oil pan, thus not making a good seal and drip oil. I’ve got about a 98% success rate though.

  16. Fritz Gorbach says:

    Used I think a 3/4 helicoil (or maybe 5/8) to repair a hole where a coupling connected a 100hp motor to large recip compressor with no problems yet a year later. The bolt would have been torqued to between 175 and 250 # I guess, and it is in almost constant rotary motion.

  17. russ says:

    Thanks Fritz

  18. I just bought a time-sert kit for 12mm bolts x1.5 for my kawasaki.

    i basically stripped the aluminum oil pan, and i didnt like the design of the heli-coils for my purpose so i went with the time serts.

    it was super intimidating, and i basically followed the directions(plus an added step of coating the drill bits with white lithium grease to attract the shards of aluminum.

    and with a little red loctite, the job went pretty smoothly, and so far its been 2 days and i am happy to say that i am please with the product. I will post again if issues arise, but helicoils looks solid, and were recommended to me, but I reckoned that the time serts were more suited for my purpose(a sealed oil pan) and so far, so good.

  19. Satya says:

    Used I think a 3/4 helicoil (or maybe 5/8) to repair a hole where a coupling connected a 100hp motor to large recip compressor with no problems yet a year later. The bolt would have been torqued to between 175 and 250 # I guess, and it is in almost constant rotary motion.

  20. Nigel says:

    I have helicoil experience and time sert experience
    Time serts are aerospace grade used by NASA and Air Force

    Time serts also Come in kits not all require counter boring
    Not all the time serts Have a shoulder to stop it from going all the way down. Call them and be specific on your needs they were pretty good to deal with
    Only thing I recommend is to not use the driver bit they give you, jut use the intended original bolt size
    If it is in good condition

    I trust time serts more than helicoils
    And they take more abuse as they are one piece of soft steel not a spring shape strand like a helicoil

    I plan on installing time serts in all my oil pan bolts and my valve cover bolts for a turbo motor

  21. PHIL DERUYTER says:

    The comment on not using the original Time sert driver is totally incorrect. The last few threads in the insert are left undersized and the driver is actually a form tap for the size of the bolt to be installed in the insert and when it is run through the full length of the insert it cuts the last three threads to the correct size and at the same time causes the exterior dia. of the insert to expand thereby locking it in place.

  22. Tyler C. says:

    ^ Phil Deruyter is absolutely correct. You need to use the time sert driver. You’re effectively doing the same thing using the bolt again like you said, but the kit is intended to work together. I’d say always use the driver.

  23. Michael F. says:

    Got news fer ya — NASA uses helicoils, too. Built an experiment for spaceflight — helicoils to minimize wear from continual reassembly. Higher ups decided on the helicoils — engineering decisions r based on many factors incl economic.
    Deciding on thread repair 4 a Harley wheel. Anybody use threadlock between the heli or insert and the base material?

  24. tweaker says:

    Michael F – I use helicoils when the studs pull out of the Harley engine cases (Evo & Twin Cam). I use a small drop of red locktite before installing every time. As long as the aluminum cases don’t deterate, they’ll be there to stay. Been doing this for years.

  25. time-sert man says:

    I’ve used both and consider time-serts superior by a wide margin. Heli-coils and their clones produce a very sloppy fitting female thread, meaning the “coil” is too small in section or the tap is too big in diameter–take your pick–and thread engagement is poor. This sloppiness has been apparent and annoying with every heli-coil repair I’ve done. Time-serts produce a stronger and much more precise female repair in which I have total confidence. It’s a better threaded hole than the undamaged aluminum original, hands down. I can’t give heli-coils the same praise.

    People who have not used BOTH are obviously not qualified to answer.

  26. Eric says:

    Just wondering, is the tap in a Timesert m14x1.5 kit be the same size as the tap found in a Helicoil m14x1.5 kit?

  27. Ozzie says:

    I’ve used both. Helicoils have their place, but in a high load area, I’ll use a timesert every time. As for the shoulder on the insert. The tooling for the timesert cuts a recess that the shoulder sits in, This prevents you accidentally running the insert too deep. That’s why timesert offers different length inserts. I replaced pulled head threads on high compression motorcycle race engines for years using timeserts. Timeserts: Pricey, not available at your local parts house, require a little skill, sizes for just about everything(including those darn Ford triton heads, done right it will outlast the part.Can use a bigsert kit for holes that really got messed up, used a threaded “barrel” type insert, self locking.
    Helicoil: Affordable, available everywhere there is a parts place, somewhat limited in size availability, easy to use, in high torque applications with low strength material they tend to pull out. Spiral wound insert with break off tang(not a good thing on a through hole where you have no way to retrieve the tang-if it mattered)

    They both have their place. Currently ordering a M5x.8 timesert for a chainsaw engine. Pulled threads for the head in the case, tried a helicoil, pulled straight out before I was able to get to the correct torque. Kit, 72 bucks, new case is 300…….

    The above statement is my personal opinion, if you disagree, that’s fine.

  28. Chris says:

    There is a structural difference in the time-sert vs. the helicoil in that the time-sert is a solid piece, thus distributing the thread load across the full depth of the bore. This is important if you consider that the majority of a bolt’s load is carried by the first few threads. So in theory, the time-sert will be stronger. I can;t quote strength tests, but this is what I’ve heard. Both the helicoil and time-sert will be stronger than the original bore because the threaded hole is larger, but the time-sert may be a little stronger still.

  29. Tippecanoe says:

    I bought and used a Timesert kit for the Ford Triton.

    I first used a cheaper kit, and that worked for I think 6 months to a year. And then it blew out killing another coil and leaving me limping back home.
    I did get a second use for the cheap kit on a Cub Cadet engine that blew out a previous helicoil installation. I hope that holds, and it may as the stresses are smaller. The helicoil blowout left a bigger hole that I’d like so it is a maybe, or probably fix.

    As for the timesert kit, it is fantastic. In the end, its insert is in with a flange on the outside and a flare done by the tool on the inside, plus locktite. The kit worked really well, is high quality, and I expect the fix to last longer than the truck. The kit was expensive, but I know for a fact a friend paid $2500 or more to get his fixed. I feed the timesert kit was a bargain in comparison. And I could do more if I had to.

    • Fran Macadam says:

      Ford should pay for time-serts on those dubious engines with aluminum heads in which the spark plugs are hanging by a thread. The better idea bulb burnt out.

  30. Mike says:

    Will it hold 70 lbs of torque for the main bearings in my Cadillac thanks in advance

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