helicoil

[patersom10]

anyone had to helicoil a block before, was putting my new head on yest and using my torque wrench it went pop and one head bolt now not biting,

GREAT

8 months without my valver now.... crying on a daily basis.

[Jaba]

I have never had the pleasure but I have heard others say it can be done. Obviously the front side is easier to get at.
Which means that as yours is a BX it is one of the rear ones failing to tighten .

[patersom10]

Have used thread kits on small stuff before but I'm in two minds on a head bolt. Although what other option do I have.

[Defender110]

Had a lot of success with helicoils and highly rate them but I suppose with a block it will depend how close to a sidewall or water jacket it will be?

[mat_fenwick]

My understanding is that they should be stronger than the original threads, but like Kevan suggests, it may be something other than the thread which is the limiting factor. I've never used them for a head bolt so can't give a more definitive answer!

[rutter123]

I only ever helicoiled the spark plugs on my yam rd350 some years ago but they seemed good at what they do some 30k later still good after many plug changes, but, again, never done a block, cant see why not as that's what they are for is'nt it? have a googly and see what your up against.

[BX4X4X2]

We used to have the same problem on AX1.4D with threads pulling out of the block, we used steel thread inserts and never had any problems.

[adamskibx]

I have used them once, and it was the most surprisingly brilliant things I have ever bought. The only hard part might be drilling out that thickness of thread, and then cutting the thread for the outside of the helicoil. I did a 2CV inlet manifold thread and the cutting required some care, and force, and that will be dramatically more with a wider head bolt thread I think, but should be doable.

[Thread Bear]

I take it a step stud is of no use as this can be made an almost permanent fitting. Although a well fitted thread should work I always worry they will back out next time the thing is undone. A problem not to be contemplated.

[adamskibx]

I would argue that it's very easy to contemplate this problem, given that firstly it might be OK, secondly, you intend your head gasket to last many thousands of miles and many years, and thirdly because if it did come out, you'd just fit another one.

[Thread Bear]

How do you get a half unwound insert with the bolt in and with the cylinder head still attached off the block? I have not had that particular prob but I have had failed inserts on casings and other things on restored cars bought in. 'Tiz good fun. If I contemplated longevity of repair, then this is someone else's problem, I suppose. Any way it is my fear and not, probably, reality, especially done correctly. I do like step studs though as they can offer a better answer with the load spread further. No good if the fastener is meant to stretch, though.

[adamskibx]

I'll confess my ignorance - I had to Google Step Studs - an even better idea for this application perhaps.

[citsncycles]

I've had success with helicoils before on a variety of applications, but have also had issues where the material I was trying to fit it in was poor quality. I'd also recommend buying a good quality kit - the drills and in particular taps in the cheap kits just aren't up to the job.

[rutter123]

How far down the block are the threads?

[JayW]

We used Helicoils on HGV headbolts and TMK non of them have failed. As you can imagine, some of these are are torqued down a tad more than the average car!

If fitted correctly, they are brilliant.