Helicoil Repair In Engine Side Cases M6

[headcoats]

Found two knackered threads on the flywheel side, the long ones :-(

Done M8 repair before but not M6 and there doesn't look a lot of metal in those areas to drill and tap for the new thread !

Is it OK to do and any tips ?

[dusty350]

I did it on my last Lc rebuild, with the engine in the frame. Just make sure your drill is square and level to the hole and you'll be fine. I used a recoil kit (copy) from ebay. No problems once done - it was the clutch side. Have a look on page 4;

rdlccrazy.proboards.com/thread/44266/375cc-semi-hybrid

Dusty

[ringding]

I've got an M6 helicoil kit you can borrow if you want, to save you buying one for the sake of doing two threads.

[headcoats]

Jul 13, 2019 16:02:14 GMT 1 ringding said:

I've got an M6 helicoil kit you can borrow if you want, to save you buying one for the sake of doing two threads.

Thanks for the kind gesture but have ordered one,, I may find more !

[headcoats]

Cheers Dusty

Great pictures and better than the Haynes manual :-)

What size is the drill to clear the hole out, out of interest ?

The hole in the cases is deeper than the helicoil so how far is best to drill in ?

[dusty350]

Hi
The drill comes with the kit. It's a 6.3mm HSS. You want to go a bit deeper than the length of the insert. You wind the insert in slightly under flush, plus knock the tang off the end before you fit your bolt. You can get longer inserts but the ones that came with the kit I bought were fine. A bit of tape around the drill bit will ensure you don't drill too deep ! Go steady and it's an easy DIY job

Dusty

[JonW]

Ive done this as well, easy peasy with the kit. drill, tap, fit and then whack a bolt in and youre golden again.

[Tobyjugs]

You can buy different length coil inserts my advice would be to drill 3mm deeper than the length of the insert.

Drill the hole very carefully as the drill might want to bite or drill in too fast and deep.

Normally the correct size drill is provided with the coil tap.

I bought the longest inserts I could get especially for the engine cases. These were either 12 or 18 mm deep and were expensive costing 1 euro a piece

The longer the insert the more difficult it is too fit.

Remember there is a difference between the brand's helicoil,vcoil etc
If you want longer inserts you have to buy inserts which are compatible with your tap.

[Deleted]

A Recoil will fit a Helicoil however a Helicoil will not fit a Recoil

The Recoil kit is the better of the two options

Or for permanent thread repair use a Time Sert

Coils are an approximation of the original thread, they are Rhombic, or in lay mans terms a pushed over square in shape

The time sert is an exact match of the original thread, the drill size will be roughly the same, however you are replacing metal with a metal bush that will not come out, so now metal is lost, whereas a coil can extract itself if the fastener is repeatedly removed and replaced

They are more expensive, however they are a permanent fix and as easy to use as a coil

HTH

[JonW]

Ive never used the other types, but one bonus of helicoils is that the kits are cheap as chips on ebay these days. I paid about $43 (22 quid) for a set of M5, M6, M8, M10 + M12 with taps and drill bits and lots of inserts. Very hard to go past that value as its got me out of trouble many times already.

[Tobyjugs]

I once tried to buy a tap for the inserts. It was priced at 75 euros. The set including different length inserts, tap and drill was 35 euros, all the same make.