hts2000 tinning advice

[BomberJohn]

Hi. I am a total newbie, so please be gentle! I have a small hole in an alloy cylinder head (cam bearing cap bolt sheared, then drilled out).
I figured I'd fill the hole with hts2000 and then use a helicoil kit to replace the thread in question. If I'm going to re-tap the thread I might as well over engineer it! My question is this- the hole is about 10mm across and 20mm deep. How can I best 'tin' the hole sides prior to filling? I'd thought of cutting out some alloy from the side to improve access and then filling the lot, but this seems extreme!

 

[Wallace]

Can you not use a Timesert instead? I think you will end up with a totally scrap head using the HTS2000.

 

[Mr shiney]

I would plug it. Then TIG it up at the back. This is a cylinder head that head a stud sheer off, the owner tried to drill it out and ended up drilling through the oil gallery as well. Bored the hole out to 12mm, put a plug and then fused it front and rear with the TIG then easy to drill and tap for a new stud hole. No oil leak and a solid repair.

 

[BomberJohn]

Cheers for that. The sheared bolt was inexpertly removed and the hole is both too large and off centre. The original bolt was 6mm. A possible solution might be using an oversize bolt and then tapping that 6mm, but it is probably too close to the bearing surface/cam to try. hts2000 was attractive as the bolt is close to the valve spring area and so not likely to reach a temperature that would cause issues. Warping the head could be a factor, but if I could tin inside the hole quickly, the remaining rod Could just be melted in.

 

[BomberJohn]

I should add (sorry) that the hole is accessible from only one side. I'll try and add a pic asap. Thanks.

 

[Mr shiney]

I should add (sorry) that the hole is accessible from only one side. I'll try and add a pic asap. Thanks.

So what that plug, we just through drilled it so it could be welded at the back as well, but it could just as easily have been done from the front. Its really tight fit. I have had really mixed results with that HTS. The problem with aluminium is breaking the oxide layer which is way higher than the base metal melting point. Trying to get enough heat into it resulted in melting the part under repair!!

 

[Mr shiney]

Cheers for that. The sheared bolt was inexpertly removed and the hole is both too large and off centre. The original bolt was 6mm. A possible solution might be using an oversize bolt and then tapping that 6mm, but it is probably too close to the bearing surface/cam to try. hts2000 was attractive as the bolt is close to the valve spring area and so not likely to reach a temperature that would cause issues. Warping the head could be a factor, but if I could tin inside the hole quickly, the remaining rod Could just be melted in.

Yep that head was off centre as well. It still had part of the stud left behind as the drill went off at a tangent. Taking it up larger brought it back square again.

 

[BomberJohn]

Thanks Shiney, much appreciated. I'll definitely have a go with this. I'm much more comfortable with tried and tested methodology and will probably avoid a warped head, or worse!☺