Topic: To helicoil, or not to helicoil, that is the question...

[nickjtc]

Now it's non-riding time for me I am starting to make a list of things that need doing to Sophie.

A PO has stripped the threads on the left hand valve cover and replaced the bolts, one with a larger metric one and the other with an imperial one! The set up works fine (no oil leaks) but it offends my sensibilities that I have to use three different wrenches to take the valve covers off. Anal, ain't I?

So, I've been thinking about options, never having done this before. Should I take things apart and put helicoils in (easier said than done??) or as another option I'm thinking about filling the holes with Easyweld, drilling them out and re-tapping them (even easier said than done???).

 Never having attempted either of these procedures before I'm open to suggestions, harassment, ridicule or whatever!

[bill440cars]

                       I've used helicoils with out a problem several times. Some folks don't like them though.
       Some prefer inserts and some would say to fill the hole and go that route. Guess it all depends on
       who you talk to. I haven't helped much, have I? Just my 2-cents from my experiences.

                                                     Later on, Bill

[aptech77]

Helicoils have worked fine for me......non cycle application though. Try it. 

[nickjtc]

All right. So how do you 'do' a helicoil??

[Ibsen]

I would go for the Time-sert.

And they have a good instruction video as well.

http://www.timesert.com/video/StandardRepair.wmv

http://www.timesert.com/html/mtrcsert.html

[jtb]

"heli-cool..."

[bill440cars]

                    Generally, you drill the hole slightly larger (the instructions will indicate what size), tap the
            hole, put the coil on the installation tool (included), screw it into the hole, break the tang off of
            the end of the coil and assemble your parts. I don't remember exactly what comes with an
            individual kit, right off. You can buy individual kits or a master set. The later would be especially
            pricey. I've done spark plug holes with them and a few other things. Hope that helps.

                                                           Later on, Bill

[aptech77]

                    Generally, you drill the hole slightly larger (the instructions will indicate what size), tap the
            hole, put the coil on the installation tool (included), screw it into the hole, break the tang off of
            the end of the coil and assemble your parts. I don't remember exactly what comes with an
            individual kit, right off. You can buy individual kits or a master set. The later would be especially
            pricey. I've done spark plug holes with them and a few other things. Hope that helps.

                                                           Later on, Bill

Spot on! 

[kaysystems]

If helicoils are good enough for an aircraft engine (most removable bolts go into helicoiled threads) they are good enough for my bike

David

[nickjtc]

So, there is no danger of the insert 'falling' into the motor?

I'm all excited to give this a whirl.

[cb650]

If the oversized bolt is bigger than a heli then youll have to do some  thing else.
I've use helis with no prob. 




                         Terry

[DammitDan]

Yup, I've heli-coiled everything from spark plug holes to head bolts to seat bolts to rocker covers to valve covers to blah blah blah.  Never had a problem with a-one of them.  And my bike is still running after all that drilling/tapping.

          

All I bought for the bike was the 12mm metric and 10mm metric helicoil sets.  They came with 8 inserts and the insertion tool, and a little book that told me what size drill bit to use.

[Bodi]

Jeez, carry the wrenches.
Repairing those threads could be a nightmare, and it doesn't leak now...
I don't like helicoiling the small bolts in the head. I have had several 6mm helicoils pull out.
Timesert doesn't recommend stainless steel for use in aluminum where there are heat cycles. Helicoils are stainless...?
Or the head alloy just dislikes fine threads, we're probably both dealing with original threads being pulled out.
I doubt you can helicoil a thread that's been opened up already for a replacement bolt. The helicoil drill is just larger than the original threads. If there's room use a timesert - they need a bigger hole than a helicoil. Think about using normal steel.

[flatblack]

If helicoils are good enough for an aircraft engine (most removable bolts go into helicoiled threads) they are good enough for my bike

Well, not exactly. Helicoils are definitely an approved method of fixing damaged threads in aircraft engines and airframes, but I don't think they're the norm (i.e., most removable bolts *don't* go into helicoiled threads in an aircraft -- they go into tapped, undamaged, original threads). I'm willing to be educated, of course. That said, I'm not aware of a single helicoil on my airplane (and I've been through just about all of it -- at least once...). 

Back to the original question: Of the options, a helicoil is best. Throwing in some high-tech "goop," letting it harden and then tapping it is pretty shadetree, IMHO. The ultimate fix, of course, is the new part you'll find on eBay or in a local junkyard, clean up and lovingly install over the winter.

My $0.02...

fb

[Andrew Foss]

i have used timeserts with no problem (spark plug holes) no power tools required, very simple install and (they are supposed to be) stronger than helicoils-i beleive car manufacturers install these at dealerships for stripped sparkplug holes (i know that is not what your fixing).
-andrew

[crazypj]

Helicoils are stronger than the original threads if they are correctly installed (larger outside diameter, stainless steel)
If the small (6mm) helicoils are stripping out either they were not installed correctly or you need to buy a torque wrench (and use it ) Only time I've had issues with helicoils is when someone else 'almost' did it ( or drilled hole too big/offset, etc.)
PJ

[kaysystems]

If helicoils are good enough for an aircraft engine (most removable bolts go into helicoiled threads) they are good enough for my bike

Well, not exactly. Helicoils are definitely an approved method of fixing damaged threads in aircraft engines and airframes, but I don't think they're the norm (i.e., most removable bolts *don't* go into helicoiled threads in an aircraft -- they go into tapped, undamaged, original threads). I'm willing to be educated, of course. That said, I'm not aware of a single helicoil on my airplane (and I've been through just about all of it -- at least once...). 

Back to the original question: Of the options, a helicoil is best. Throwing in some high-tech "goop," letting it harden and then tapping it is pretty shadetree, IMHO. The ultimate fix, of course, is the new part you'll find on eBay or in a local junkyard, clean up and lovingly install over the winter.

My $0.02...

fb

I'm working for a Turbine Engine manufacturer. We use studs to hold the main cases together, but helicoils & bolts for everything else right from the factory. This is because of the number of times it will be taken apart. Not much wear on the stainless inserts, whereas the aluminum or magnesium would wear.
Not sure that this in the norm, but it's what we do (Pratt & Whitney Canada)

David

[Dave K]

I used to be a machinest in a factory that made punch presses. On aluminum parts, many were heli-coiled from the start, for strength. Makes good sense to me.

[nickjtc]

So, there is no danger of the insert 'falling' into the motor?

Never having done this I am curious as to whether this is even possible? Anyone.....?

[Dave K]

I see no reason that it isn't possible. I would feel as you do, I want all the screws and bolts to be the right ones.

[sparty]

I would go for the Time-sert.

And they have a good instruction video as well.

http://www.timesert.com/video/StandardRepair.wmv

http://www.timesert.com/html/mtrcsert.html

Now that is slick!  I am sold on the Time-serts if I ever need that type of repair - lets hope not.

Sparty

[Loudpipe]

I've used helicoils on my car to hold the whole left wheel hub to the trailing arm. They work fine and I have had them in for several years now with no sign of a problem.  As for them falling into the engine, I would think that's extremely unlikely if they are done right, but I guess it's possible.

[aptech77]

Helicoils are stronger than the original threads if they are correctly installed (larger outside diameter, stainless steel)
If the small (6mm) helicoils are stripping out either they were not installed correctly or you need to buy a torque wrench (and use it ) Only time I've had issues with helicoils is when someone else 'almost' did it ( or drilled hole too big/offset, etc.)
PJ

I don't know if I would say STRONGER. They are made of stainless (soft). You can put one in and and still strip or spin it,  like a dumb ass. Definitely use a torque wrench.

[aptech77]

If helicoils are good enough for an aircraft engine (most removable bolts go into helicoiled threads) they are good enough for my bike

Well, not exactly. Helicoils are definitely an approved method of fixing damaged threads in aircraft engines and airframes, but I don't think they're the norm (i.e., most removable bolts *don't* go into helicoiled threads in an aircraft -- they go into tapped, undamaged, original threads). I'm willing to be educated, of course. That said, I'm not aware of a single helicoil on my airplane (and I've been through just about all of it -- at least once...). 

Back to the original question: Of the options, a helicoil is best. Throwing in some high-tech "goop," letting it harden and then tapping it is pretty shadetree, IMHO. The ultimate fix, of course, is the new part you'll find on eBay or in a local junkyard, clean up and lovingly install over the winter.

My $0.02...

fb

I'm working for a Turbine Engine manufacturer. We use studs to hold the main cases together, but helicoils & bolts for everything else right from the factory. This is because of the number of times it will be taken apart. Not much wear on the stainless inserts, whereas the aluminum or magnesium would wear.
Not sure that this in the norm, but it's what we do (Pratt & Whitney Canada)

David

P & W ROCKS!!!!!!

According to FAA regs, a helicoil can only be use on a component if approved buy THAT components manufacturer or directly approved buy the FAA as an acceptable repair.   

[Jerry Rxman Griffin aka MuthaF'er]

The Time-Sert looks pretty sweet. I did my first (one & only) heli-coil recently. I was a little intimidated at drilling into my lower case crouched down while the engine was still in the bike. The correct size drill bit and tap came in the kit so I didn't have to worry about that. I was very careful to drill the hole straight then tap the threads straight. I used my 18V variable speed Dewalt for both. The heli-coil went in really easily, the bolt holds very tightly and no more oil leak.

From watching the video, I can not determine if the Time-sert hole is the same size as the hole for the heli-coil. Looks bigger to me. Correct me if I'm wrong. IF the Time-sert hole is actually larger then my preference would be to go with the Heli-coil first but only to leave enough "meat" to drill again for the Time-sert.

Jerry