Installing Heli-Coils???

[Kevaclone]

on my Johnson 90 the starter motor bolts seemed loose
on tightening them up I discovered that one had stripped the thread from inside the block and one had actually broken

today I purchased the required gear to fix it all
Ezi-Out for the broken bolt was a simple job and is done
now onto the heli-coil for the stripped thread
the kit came with the coils, installing tools and thread tap

looks simple enough, drill the hole, tap a thread and insert coils

what it doesn't tell you is two things

:-/


Do I need to drill and tap the hole the entire depth of the original?
or just deep enough to insert one coil?



The coils are only short(about 10mm) so do I use just one?
or do/can I insert more than one to get to the full depth of the hole?



I have purchased new H/T bolts that are a bit longer than the originals but they will fit without bottoming

Cheers

Kev

[Kleyny]

The 10mm coil will lengthen when you insert it.
So i would say that one would be surfice.
I think you would find that you might have a little truoble getting more that one thread to line up with one another.
I personally wouldnt drill too deep possibly 20-25mm this allows for the extra bit that the tool extrudes on application.
This is all from memory i havent helly coiled anything for a few moons now.
neil

[trueblue]

You must purchase the correct length of helicoil for the depth of hole. Too long and they don't fit in properly and you have to grind the top off which causes problems. Too short and the coil will not give sufficient thread bearing on the bolt and you will just pull it out anyway with the bolt because the bolt will require more resistance than the coil can offer for the required tension.

Helicooil kits usually come as the shortest length (the cheapest) unless you specifically specify the required length. Make sure you have the correct ones.

The drive tang on the bottom of the coil must be broken off per the instructions if the bolt is to be inserted past that point (ie bolt insertion is deeper than the bottom of the coil) If not broken off properly, the bolt will wreck the coil by stripping it inwards as it goes past the tang.

You can not line two helicoils up in the same hole - don't try it. If you were contemplating this, you have the wrong length of coils. You will see that the insertion tool has a small collar locked by a screw that is used to set the tool to the required length of the coil (lines the tang up in the right place on the slot at the end of the tool and keeps correct pressure on the coil as it is inserted. Follow the instructions carefully with this.

Helicoils are designed to be wound in, and not outwards. Make sure your hole is properly tapped out and cleaned out before attempting to insert the coil, you will wreck the coil otherwise.

Once you start inserting the coil, don't try to back it out. You have one shot at it unless very experienced.

If inserting a coil deep into the hole close to the bottom of the hole, make sure you have a bottoming tap for the helicoil set. Many times they only give you an intermediate tap which leaves a big taper in the thread where no thread is cut at the bottom of the hole. If a proper bottoming tap is not used, the coil will tighten into this tapered section, and the bolt will not go down to the bottom. (Pay particular attention to this as you have mentioned getting longer bolts!!!)

Also, when tapping out the hole, pay a lot of attention to keeping the tap going in square, and not flogging around loosely. You need a perfectly squarely tapped hole thread to make sure you have the proper bearing area for the coil to properly seat.

Use a thread cutting lubricant when tapping the hole.

Cheers

Mick

[Hagar]

Be careful - be very careful . As it's in the block you will be in strife if you stuff it up . The drill size quoted on the kit assumes it will be a nice neat hole that is machine drilled not done using a hand held drill that may have some operator wobble factor . If not confident it's worth paying a machine shop to do it if they will . I am guessing the Johnno has imperial sized bolts not metric ? . Metric can be a trap with the differing thread pitch sizes for the same bolt diameter . That one has caught a few people out . I would not want any of the old thread existing below the coil if the bolt goes that far as it will not match the coil alignment exactly and may bind the new bolt as it exits the bottom of the coil .

Chris

[Chimo]

Kev

Pay a pro!

Its not worth the problems and cost to fix if it needs it.

Some things are best left to those who do it for a living OR get someone elses motor to practise on first.......

Cheers
Chimo

[John West]

on my Johnson 90 the starter motor bolts seemed loose
on tightening them up I discovered that one had stripped the thread from inside the block and one had actually broken

today I purchased the required gear to fix it all
Ezi-Out for the broken bolt was a simple job and is done
now onto the heli-coil for the stripped thread
the kit came with the coils, installing tools and thread tap

looks simple enough, drill the hole, tap a thread and insert coils

what it doesn't tell you is two things

:-/

Do I need to drill and tap the hole the entire depth of the original?
or just deep enough to insert one coil?

The coils are only short(about 10mm) so do I use just one?
or do/can I insert more than one to get to the full depth of the hole? I have purchased new H/T bolts that are a bit longer than the originals but they will fit without bottoming

Cheers

Kev
If your a little bit handy you should manage OK ,drill the entire depth of hole to be safe but drill no deeper .The coil will stretch out to 15 mm when inserted so will achieve max strength ,1.5 x diameter = optimum strength .As suggested earlier use some oil when tapping ,and after knocking the tag off try and pick or blow the tag out, as you said your new bolts are longer and may foul on the tag if it is left in there.Edit also your hole needs to be at least 20 mm deep and tap to the bottom of the hole then insert the coil just below the surface.

[Spaniard_King]

Below is some very good advice;) It would have cost you less than the kit if you took the boat to a good engineering shop and had it done.


You must purchase the correct length of helicoil for the depth of hole. Too long and they don't fit in properly and you have to grind the top off which causes problems. Too short and the coil will not give sufficient thread bearing on the bolt and you will just pull it out anyway with the bolt because the bolt will require more resistance than the coil can offer for the required tension.

Helicooil kits usually come as the shortest length (the cheapest) unless you specifically specify the required length. Make sure you have the correct ones.

The drive tang on the bottom of the coil must be broken off per the instructions if the bolt is to be inserted past that point (ie bolt insertion is deeper than the bottom of the coil) If not broken off properly, the bolt will wreck the coil by stripping it inwards as it goes past the tang.

You can not line two helicoils up in the same hole - don't try it. If you were contemplating this, you have the wrong length of coils. You will see that the insertion tool has a small collar locked by a screw that is used to set the tool to the required length of the coil (lines the tang up in the right place on the slot at the end of the tool and keeps correct pressure on the coil as it is inserted. Follow the instructions carefully with this.

Helicoils are designed to be wound in, and not outwards. Make sure your hole is properly tapped out and cleaned out before attempting to insert the coil, you will wreck the coil otherwise.

Once you start inserting the coil, don't try to back it out. You have one shot at it unless very experienced.

If inserting a coil deep into the hole close to the bottom of the hole, make sure you have a bottoming tap for the helicoil set. Many times they only give you an intermediate tap which leaves a big taper in the thread where no thread is cut at the bottom of the hole. If a proper bottoming tap is not used, the coil will tighten into this tapered section, and the bolt will not go down to the bottom. (Pay particular attention to this as you have mentioned getting longer bolts!!!)

Also, when tapping out the hole, pay a lot of attention to keeping the tap going in square, and not flogging around loosely. You need a perfectly squarely tapped hole thread to make sure you have the proper bearing area for the coil to properly seat.

Use a thread cutting lubricant when tapping the hole.

Cheers

Mick

[John West]

Below is some very good advice;) It would have cost you less than the kit if you took the boat to a good engineering shop and had it done.
You seem to be contradicting yourself, is it best to follow the good advice or pay someone to do it for you ?
You cant beat that feeling of self satisfaction when you've done it your self.
Edit Ok I get it missed the wink.

[Noelm]

even though it may sound very daunting, with a bit of care, it is quite simple, the hole you need to drill out on your Motor is easily accessible, and a good quality drill will see you out, the advice about the "blind" tap needs to be heeded, if the hole is too shallow and you start the Helicoil, you are in sh!t up to your eyeballs, but as I aid, it is easy if you take care, everyone has a first time remember.

[Kevaclone]

even though it may sound very daunting, with a bit of care, it is quite simple, the hole you need to drill out on your Motor is easily accessible, and a good quality drill will see you out, the advice about the "blind" tap needs to be heeded, if the hole is too shallow and you start the Helicoil, you are in sh!t up to your eyeballs, but as I aid, it is easy if you take care, everyone has a first time remember.

Yep gotta start somewhere
paying someone to do it means that next time I need to do it I'm still not sure how it's done
I have a few old car parts here with similar size bolt holes so I'll do a couple of practice runs on them

thanks everyone

Kev

[wags on the water]

If you are confident in your own work, then go for it. True blue has given you all the info you need.Remember to blow the hole out thouroughly after tapping the hole.
Good luck,
Wags

[Bros]

Do they still make Keen Serts, I've used them a few times

[Kevaclone]

All done
took all of 5 minutes to do
did the bolt up tight and was all good
the only real test I guess is when the starter is fitted and turned over.
It's in for a rebuild, whisps of smoke eminating from the top plate when under load and hardly enough power to turn the engine seems to suggest it's due for it



thanks

Kev

[viking08]

Kevaclone

Only new to the forum and a fraction too late I might fear, work's a bitch hey ;)
Heli-coils are nothing to be dramitised about as now you know. However one point that the forum has not advised yourself on is; in future months / years will this bolt be required to be removed ? Hopefully not, especially if you have heli-coiled into ally. Anyway job done and satisfactorily.

Also Is that the V-Sea or the Viking model?

Cheers
Mick

[Noelm]

should be no problem taking the bolt back out, the Helicoil is just another thread in real sense, done it heaps of times.

[Kevaclone]

Viking08

it's an early V-Sea

Kev

[station-rat]

Hi Bros
Yes Keen-Serts are still avaible, but in a marine application stainless heli-coils would be my pick
Station-rat