10 replies to this topic

[GregH]

Good day all,

My brother has a mini 30, 998cc.

Today he has replace the rad and when he was tightening the rad bracket through the thermostat housing the lug on the head closest to the radiator has broken off leaving him with nothing to bolt the third thermostat bolt through.
What are your recomendations.
Is the head done for?
How much are second hand heads and recon heads?

Thanks

Greg

[Mini Mad Drakeley]

if i understand this right, just remove the other 2 thermostat housing bolts and take the housing off and then get a pair of vice grips to remove the sheared bolt and replace it a picture might help though if possible

Adam

[Andrew O]

Get some pics up

[Blofeld]

replacing the thermostat stud is possible. if there is anythreat left you can try taking thethermostate housing off adding two nuts on the remaining thread and 'locking' them together so you can get a socket over it and extract the stud. be super careful as you don't want to shear it. however all is not lost as you can use a stud extractor. 998 head tend to be around £150 exchange. if other options fail.

[Guess-Works.com]

my interpretation of the question is the end of the casting has broken off leaving half a stud hole....

If so, you could get it welded up and redrilled and tapped, but welding to cast iron is not the easiest thing.

Probably cheaper to get a replacement head, and a torque wrench...

[bmcecosse]

998 heads are often given away FREE....... Search ebay for one -and certainly don't pay £150...... Maybe it can be brazed up - and indeed if it's not cracked right into the water way - a repair with chemical metal may be perfectly satisfactory. Dont attempt to stick back the broken piece - just fill the hole with chemical metal - wait till it hardens properly (so 24 hrs at least) - then drill and and tap into it - and don't overtighten! A picture would help us decide if that'slikely to work....... Also - a good chance to upgrade to a much better head! Either a 295 head - or even a 940. Come back for more advice if you go that route.

Edited by bmcecosse, 01 September 2011 - 06:38 PM.

[MrBounce]

I've got a free 998cc engine if you're not too far from Ipswich

http://www.theminifo...howtopic=201251

[bmcecosse]

There you go! Well done Mr Bounce.......

[GregH]

Thank you all for your comments,

Guess Works, you guessed it right. The lug on the head has cracked off.

An update,
He has replaced the head with one from a scrap yard.
All seems fine and he has gone off to Bath to start his career now.

However, this leaves me with a head to play with.
What equipment would be required to weld the lug back on? any ideas?

Is chemical metal a form of adhesive? therefore it would be used to "glue" the piece back on?
I think i might try a few modifications to this head and have some fun.

Thank you for the kind offer MrBounce, however as stated above he has sorted out the mini and its is now a case of me fixing this head for a spare.

Thank all

Gregh

[yellowmonster]

Chemical metal is a plastic dough-ish material which hardens or cures once it's been knead.
Once cured, it's hard as metal and can be bored etc.

[dklawson]

Chemical metal - that's a term I haven't heard before but I assme based on the previous posts that it is basically metal filled epoxy. In spite of what has been said above, if less than half a hole has been left on the head when the "chunk" broke off, I would not expect any epoxy repair to be strong enough.

As Guessworks said, welding cast iron is an art and not typically done at home. You can have it brazed by a quality shop. However, unlike what Bmceosse suggested above, if you have the broken part, I would supply it to the shop doing the brazing. They can put a bevel on the broken piece, clamp it in place and fill the void with braze. Chase the old threads with a tap to clean them up and your repair will be complete.

However, ANY repairs involving brazing and/or welding will mandate having the head resurfaced. It is quite likely to warp during repairs involving high heat.