Helicoil + Loctite = bad? Problems...Helicoil experts chime in

[Tantrix]

Had a Helicoil installed in oil drain threads by an experienced mechanic who's done probably thousands of them, and he used Loctite black on the Helicoil when screwing it in.

The bike was run pretty hard for a few weeks and the drain plug was pulled for an oil change. After draining the oil, the drain bolt was put back in and using a brand-new calibrated torque wrench was torqued to 15 ft-lbs (service manual says 14-22 ft-lbs).

When approaching 15 ft-lbs, something didn't feel right and the bolt was taken out and the Helicoil inspected. Well, the Helicoil had turned about 1/2 a turn into the crankcase. As another test, the bolt was put back in and torqued to 15 ft-lbs then removed. The Helicoil had turned another 1/2 turn into the crankcase. The mechanic was called and he said bring it back and he'll put a new Helicoil in no charge.

I have since been scouring the internet to maybe find out why the Helicoil was turning with the bolt and have come across more than one site where I read that while many people use it, Helicoil does not recommend the use of Loctite when installing Helicoils. One even said they do not recommend it because it can actually cause the Helicoil to rotate which is exactly what this one did.

Is it possible that the Loctite black did more harm than good, actually causing the Helicoil to turn with the bolt? When the mechanic puts the new Helicoil in, should he be asked to NOT use Loctite on it this time?

[viper]

how are you going to keep it from turning then when there isnt a bottom to the hole ? not like putting a helicoil where there will be a stud .

[Tantrix]

how are you going to keep it from turning then when there isnt a bottom to the hole ? not like putting a helicoil where there will be a stud .

That's what I thought, but according to what I've read Helicoil says that the insert grips the newly-tapped threads on it's own and Loctite can actually allow the Helicoil to turn instead of grip like it's made to do.

I haven't been able to contact anyone from Helicoil to get confirmation of this but here's something I read in an article on another site regarding the use of Loctite on Helicoils:



"NOTE: BMW apparently wants Loctite on its inserts, and supplies the 12 coil insert with such a coating, per their books. HOWEVER, I have literature from the Helicoil company that says NOT to use such on their inserts, as it can cause them to slip (rotate)."

"Interestingly, Helicoil themselves do not recommend use of Loctite, feeling it detracts from the holding force the Helicoil exerts on the stud (spring effect)."

[tbirdscott]

The coils in my opinion are junk they never last. See if you cant get a 'SAV-A-THREAD' installed instead, I've installed a few in plug holes and never had a problem. Dont know about all available sizes but 7/16X20 is available and easy to find a bolt for and should fit the drain hole.

Scott

[Tantrix]

The coils in my opinion are junk they never last. See if you cant get a 'SAV-A-THREAD' installed instead, I've installed a few in plug holes and never had a problem. Dont know about all available sizes but 7/16X20 is available and easy to find a bolt for and should fit the drain hole.

Scott

From what I've seen, the SAV-A-THREAD kits are Helicoils. Google it and the results come up as "Helicoil SAV-A-THREAD kits".

[Dirtcrasher]

Helicoil makes a locking coil. The middle thread is distorted and keeps it from turning. I don't use loctite on my helicoils. The loctite caused the bolt to bind in the coil and the whole thing spun. They can be a *Edited**Edited**Edited**Edited**Edited* to get out...

[Tantrix]

Helicoil makes a locking coil. The middle thread is distorted and keeps it from turning. I don't use loctite on my helicoils. The loctite caused the bolt to bind in the coil and the whole thing spun. They can be a *Edited**Edited**Edited**Edited**Edited* to get out...

Yeah...I'm now thinking the new Helicoil should be put in without Loctite. I have a strong suspicion that is what caused the Helicoil to rotate. I have also heard that Loctite doesn't get along with oil or heat too well either so that probably has something to do with it too.

[ratvespa]

few things I would check, make sure the threads on the drain bolt are nice and clean. also grease them when you install it. I havent had much problems with helicoils, but as the other guy said, threaded inerts are better (if you have the room for one). Also make sure you are not cross threading. the loctite should hold it in place, I use the red and the blue all the time on harley engines and have never seen the locktite break down due to heat (except for header bolts, thats too hot for loctite)

[Bryan Raffa]

I use red lock tite on helicoils ...every once and a wile ya just get one that will like to turn.. main thing is to clean the threds before you put it in, to get a good bond.. yes heat will losen the lock tite

[Tantrix]

I use red lock tite on helicoils ...every once and a wile ya just get one that will like to turn.. main thing is to clean the threds before you put it in, to get a good bond.. yes heat will losen the lock tite

This one was done at a shop since he already had the Helicoil kit and jig to ensure the drilling/tapping was done straight. He used Loctite black on it, which was either not strong enough to hold it or it never got a good bond from the start. I guess if he doesn't have any other Loctite besides black (he should though) it may be better off with no Loctite at all.

Thanks for the all the replies fellas, this has been aggravating to say the least.

[Dirtcrasher]

Make sure he uses the self locking insert and not the plain coil insert..

[Beardoh]

[QUOTE=Tantrix;514231]Had a Helicoil installed in oil drain threads by an experienced mechanic who's done probably thousands of them, and he used Loctite black on the Helicoil when screwing it in.


Just the other day, I happend to be talking to a guy I work with about helicoils and he said to me that helicoils are only good on blind holes (ones that only go in so far, not right through) or else they will turn in when you tighten them. I would just retap the drain plug to a larger size and use a larger bolt, problem solved

[tbirdscott]

From what I've seen, the SAV-A-THREAD kits are Helicoils. Google it and the results come up as "Helicoil SAV-A-THREAD kits".

They are made by the helicoil company but they are not ciols, they are solid steel threaded on both sides and the last couple threads on the outside are slotted like knurling. You use a punch that comes in the kit to expand the outer part pushing the knurled edge into the material locking it into place, along with a bit of red locktite it will probabally never come out on its own.


Scott

[Tantrix]

They are made by the helicoil company but they are not ciols, they are solid steel threaded on both sides and the last couple threads on the outside are slotted like knurling. You use a punch that comes in the kit to expand the outer part pushing the knurled edge into the material locking it into place, along with a bit of red locktite it will probabally never come out on its own.


Scott

I see...sort of like a Keensert made by Helicoil. I guess I should have read a little further and I would have seen that. When I saw Helicoil SAV-A-THREAD I automatically thought "coil".

[Dirtcrasher]

The thing is already tapped out for a helicoil. The helicoil that locks made by helicoil is called a "screw lock insert". It is the type I installed in an 86 250SX and it never failed, that was 4 years and alot of oil changes ago.