Snapped Head Bolt.....any Advice?

[pugpete1108 62 1 Cars]

Right well tried a stud extractor today with no luck, it just mullered the thread.

 

Gonna grab some stilsons and a gas torch and give that a go before I resort to the drill.

 

Will I be ok heating the head around the bolt? Only going to be a butane/propane torch do not too much heat

[ORB 227 1 Cars]

Stick a picture up of what you have left. It'll give a better idea as to what is what.

[pugpete1108 62 1 Cars]

Will do in the morning

[welshpug 1,626]

get the head off out of the way, will be much easier to sort then.

 

heating the head wont do jack, you need to heat the block if you are going to heat anything.

Edited March 4, 2013 by welshpug

[pugpete1108 62 1 Cars]

Sorry complete retard moment.

 

The head is removed its sat in my kitchen being ported and I meant heating the block around the bolt .

 

Weird how one word changes everything?

Edited March 4, 2013 by pugpete1108

[harryskid 193]

[nixonmi16 4]

i used these when i snaped mine on my mi16 http://www.ebay.co.uk/itm/snap-on-extractor-and-drill-set-/160983992355?pt=UK_Hand_Tools_Equipment&hash=item257b64c823 the left hand drill bits remove the stud before i had to use the extractor. also once on my old 8v had one so tight i cut the engine block with a dremel and cut the bolt in half and then folded it inwards to repair the block i oiled an old bolt screwed it in then uesd jb cold weld on the block then removed the bolt and fitted the bolts as normal i ran this engine with 2.0 8v head for 30000k no problems

[pugpete1108 62 1 Cars]

Well the was what I was faced with

 

 

But it irrelevant now as it has just snapped further down the hole.

 

Drill it is then, wish me luck

[Tom Fenton 1,526]

Lesson to learn then, next time tap all the holes out before you fit the head bolts. If one of the bolts was tight going in, then you won't have got proper clamping of the gasket, as you will have reached the torque setting due to resistance of the thread being tight, not due to reaching axial preload (stretch of the bolt).

Its good practise really when building an engine to tap out the threads in the block to avoid this kind of problem, the cast iron blocks are probably a bit more forgiving, but for me its a MUST on the alloy blocks, and highly recommended on anything.

[welshpug 1,626]

You can make a thread cleaning tool from an old head bolt too

 

Just take care you dont pop through the water pump housing, even the best have done it!

[Alan_M 66 1 Cars]

If stud extractors didn't work, then it must be seriously tight.

 

Thing is, drilling out a broken stud can be right twat but I suppose you've no option. Centre punch it so you don't spin off, build up in sizes with decent drill bits (not that B&Q s*ite).

 

How much of the stud is left though?

[pugpete1108 62 1 Cars]

lesson well learnt Tom. just bought an m11x1.5 tap to clean them before i refit the new bolts/head.

 

got about 40mm of bolts stuck in the hole but must only be about 20-25mm in the threaded part.

 

got a decent 4mm cobalt bit and have managed to get most of the way through but they are bloody tough and have blunted most of my hss bits.

 

its also tricky because the top part of the bolt (out of the thread) is twisted so not centre, ive had to go centre on the actual hole as opposed to the bolt, hopefully i come out centre from the bottom.

 

i suppose at the end of the day i can always fit an insert if i fubar the thread?

[Alan_M 66 1 Cars]

got a decent 4mm cobalt bit and have managed to get most of the way through but they are bloody tough and have blunted most of my hss bits.

 

I assume you're using a 'pistol' drill? If you're not already, try not to use too much speed. Only enough so that the bit is biting and you can visibly see progress (swarf).

Edited March 5, 2013 by Alan_M

[pugpete1108 62 1 Cars]

Yup nice and slow with plenty of lube, just how she likes it

[pugpete1108 62 1 Cars]

Well the inevitable just happened.

 

Broke a 6.5 mm bit down there just as it broke trough the bottom. Mutha f##ker

 

Looks like it's gone in wonky anyway as it came out the edge of the bolt.so I should imagine the thread is fubar whatever.

 

New bottom end then

[Tom Fenton 1,526]

Strip it and send it me I'll try and sort it. I've got the right Helicoil kit.

[pugpete1108 62 1 Cars]

cheers for the offer Tom but im sure it will cheaper for me to source another bottom end, there are loads in my local scrappy i think.

 

pita really

[kyepan 291]

helecoil?

[pugpete1108 62 1 Cars]

i would but its now got a large piece of cobalt drill bit stuck in there and even speaking to my local engine guy he said its nigh on impossible to get it out.

 

engines out now so might have a better look at it and see what my options are.

 

i dont really want to go backl to an iron block if i can help it.

[205turbo 32 2 Cars]

helecoil?

 

[pugpete1108 62 1 Cars]

Would a helicoil even be man enough for a head bolt?

[Tom Fenton 1,526]

Yes, I have repaired alloy blocks successfully a few times. The helicoil insert is stainless steel, it also acts on a larger base diameter, meaning in actual fact it ends up stronger than the original alloy threads ever were. I bought double length inserts especially so that one insert gives full thread engagement.

[pugpete1108 62 1 Cars]

What's so special about the kit? Just a tap and an insert tool at £30 a pop that's a bit cheeky.

 

But I suppose cheaper than a new block

[welshpug 1,626]

Just send it to tom, will cost you less than trying to build up a totally unknown block.

[ORB 227 1 Cars]

Do you not have a mobile specialist in the area?

 

We have a guy near us called Extract Engineering, he can come to you and get any snapped thread out. He can get Merc Sprinter injectors out in minutes, if you have every had to do this, you'll know how amazing it is!