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Cylinder Head Heli Coil?

Featured Replies

All the cylider head holes look like they have heli coil repairs in them..... Or is this how they come from the factory?

As I have had the head off a few times of late three of the repairs look loose and will not torque up....

How should I proceed.

Insert a new coil?

Drill and re-tap the hole? What size is a repair for a M6??????

Thanks in advance for your help.

All the cylider head holes look like they have heli coil repairs in them..... Or is this how they come from the factory?

As I have had the head off a few times of late three of the repairs look loose and will not torque up....

How should I proceed.

Insert a new coil?

Drill and re-tap the hole? What size is a repair for a M6??????

Thanks in advance for your help.

Sounds like the previous owner was not a believer in torque wrenches. Depending on the quality of the repair, you may want to

re-insert a new coil and invest in new capscrews that don't have worn threads.

Jon

best off having an engineer look at it as you could make a mess of it especially if old steel coils need drilling out ,if its alloy just get a helicoil kit ,comes with drill tap and fitting tools

Think the drill bit is 6.3mm . Always kits like this on ebay http://www.ebay.co.uk/itm/V-COIL-M6-X-1-0-HELICOIL-TYPE-THREAD-REPAIR-KIT-/270905326007?pt=LH_DefaultDomain_3&hash=item3f133739b7 or try your local bolt supplier .

Be hard work drilling the old one's out , the inserts are stainless , maybe try pulling them out , you mite have to go up a size (M7 - M8) if the holes as been drilled slightly over .....Good luck....

  • Author

So the Bolts in there now are M6.

If I want to just re-tap and insert a new heli coil of the same size (to take the M6 bolt)what size kit will I need ?

If your staying with the 6mm bolts , studs what ever , you need the m6 kit , but you said they was a bit loose , so you mite have to go with the m7 kit maybe (7mm bolt ) .....

It sounds like you'll have to re-helicoil the barrel, if you've not done this before or are not familiar with the helicoil process I'd advise taking the barrel to an engineer to have it done. The Kits often come with the correct size drill for the special helicoil tap but not always, this has to be right! To drill and fit helicoils to all 6(?) holes in the barrel would take less than an hour for a decent engineer, once they are replaced they should never need doing again.

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