Helicoil or tap for larger stud?

Helicoils probably as easy, a little stud & bearing loctite doesn't hurt when you fit it.

An easy choice. Helicoil. Always the better option if you have a choice. The block remains std, (apart from the insert), and a Helicoil thread in ally is stronger than the original tapping. Mike.

Helicoil (or clone) every time. Less damage than fitting an oversize stud.

I think a helicoil club could work. Pay a refundable deposit for the drill/tools and just pay for the inserts used, postage and a small commission. Payment via Paypal or similar.

I've got six assorted kits with only a few inserts used.

I think Scotchclad still takes some beating for steel into ally. Could be because I had to buy a litre of the stuff which will probably see me out.

I don't know of any clones, and I have tried a few, inc Recoil etc, that are anywhere near as good as a genuine Helicoil. They are the industries choice, and all I'd ever use.

I have a few clones at work, which were there when I started with the Co a few years ago. Various inserts with fitting tools. Some with their original boxes. AFAIC they are not worth using. I'll let you know what I have if you're interested, and you can have the lot for the cost of the postage.

Less damage than fitting an oversize stud.

Sounds like a promising idea, and make the deposit greater than the price of a new set, to ensure it's return.

Helicoils I trust :-)

I've got std metric 5, 6, 8,10 and 12mm Helicoil kits. Mike.

My local decent tool shop - Belton and Slade in Wandsworth - only sell Recoil and I've found them fine. In both steel and ally. But I've not got your experience so take on board what you say. Problem is when you need those sort of things you need them now.

That's a kind offer. They're probably better than nothing in an emergency. And I'm a bit of a tool junkie. ;-) I'll drop you an email.

Indeed.

Only one. The others Recoil.

Mine are all UNC and UNF for old UK car use.

Thanks for the advice, interesting reading. Unfortunately my studs are metric fine (bloody japanese) M10x1.25, oversize stud would be M11 x

Thanks for the advice, interesting reading. Unfortunately my studs are metric fine (bloody japanese) M10x1.25, oversize stud would be M11 x

Bringing it back to the original size means that the correct bolt and head size can be used along with the correct torque. You won't need to open up the hole in the corresponding part either.

Seriously, the best repair is a helicoil.

Knowing what animals most people are, I don't think a hire club for helicoils would be a good idea.

A helicoil kit is about 35 quid IIRC, so is far cheaper than getting the job done by someone else in any case.

Mrcheerful

The replacement stud is a two-sized one - M11 one side, original at the other - basically just needs tapping out to match.

Try the local motorcycle shop, sripping metric fine threads in alloy castings is somewhat more common there.

Interesting idea! I'll have to call around and see if I can get any help.

If you fit a larger stud you generally have to enlarge the hole it goes through?

The other plus with a Helicoil is that into ally you usually don't have to drill out the old thread - so it's removing as little material as possible. The next size up stud could be the same I suppose if you're lucky.

I don't like fine threads into ally - especially for studs. I'd use normal and a thread/sealer locker - if you can get suitable studs.

Thanks for the advice, interesting reading. Unfortunately my studs are metric fine (bloody japanese) M10x1.25, oversize stud would be M11 x

I'm not really surprised, as an 11mm tap is what is known as a 'non preferred size' IOW, a bit special.

Can I ask why tapping for a larger stud woudl be more damaging than inserting a coil - from what I see you need to drill and tap for that anyway?

On ally you can get away with using the Helicoil tap without drilling. If memory serves, the tapping drill for a 10mm Helicoil is 10.2 mm. Only 8 thou larger than a stripped 10 mm hole.

There's no real problem with tapping o/s and fitting a stepped stud. Just that it's better if possible to keep the thread std, and if one has the facilities, it's usually easier.

I might end up with a kit too, though I like the idea of the coil club idea - this stud is a common problem on my engine (3sgte)

Tell me about it. I've reconned 2 of those heads.Both had stripped studs. One for Ricky, the other for Steve Gillies. I think you know both of those characters. :-)

I got round it by fitting a standard 10 x 1.5 Helicoil, then making a stud

Thanks for the advice, interesting reading. Unfortunately my studs are metric fine (bloody japanese) M10x1.25, oversize stud would be M11 x

Your cheapest solution would appear to be simple then. Fit a std M10 x 1.5mm helicoil and use a stud to match which will be easily found at any bolt stockist.

Any reason not to just use am M10x1.5 stud?

Not from an engineering POV, but I'm a bit of a perfectionist. IIRC on this engine the manifold nuts are 10mm x 1.25mm pitch flanged nuts. Rather than have an odd nut on the manufold, I thaught it aesthetically pleasing to keep all the nuts the same.

It's a philosophy I've always had when it comes to repairs on most things. Preferring to make repairs invisible unless I think there is a fundamental design flaw. Or, if doing so can't be justified in terms of cost or time.

It was just as easy to make a stud with a different thread each end, than one with the same thread both ends.

But then I'm fortunate enough to have a well equipped w/shop at my disposal, and I already had a 10x 1.25 pitch die. Mike.