28 replies to this topic

[Steve Rowe]

well tryed to drill it out was going well intill..... the drill bit broke..... so now im gona have to change the head now....

[dklawson]

Well I guess if you ever salvage that head... it's EDM time now. At least you've got another head to bolt on.

[miniboo]

well thats what happens when you rush!! hehe

[stormduck]

call around to local machine shops and find out who's got a "sinker EDM". That's the tool used to electrically burn holes in hard materials... and it's frequently used to burn out broken taps and studs.

is this not 'spark eroding'? if so i took my head with a broken stud and the tip of a pair of long nose plies stuck into the hole (don't ask!) and after unsuccessully drilling said that spark erosion is the only way to go to remove it and that would be about £120!! Fortunately they came up with another idea of brazing the holes and tapping the water return hole and using a threaded water tap from a Ford to make the head useable. Genious, but no help in your situation.

[dklawson]

A slang term for EDM may be "spark erosion". The term you used certainly describes the process. EDM stands for Electro-Discharge-Machining. You set up a sinker EDM by aligning a plunging electrode, supplying an electrolyte, and turning on the machine. It slowly pecks away at the offending bit. The whole time that's going on the machinist is free to do other tasks. It's not like you've tied up a person who has to babysit the process. With a cylinder head... its' not like you have to make a fixture to hold the part either. The price of 120 GBP sounds to me like the shop you asked really wasn't interested in doing the job for you... at least not by EDM.

Regardless, I'm glad the shop came up with a less expensive solution for you.

[Steve Rowe]

well thats what happens when you rush!! hehe

ill rush you the now hehe got a spare head with the car not the end of the world my mate from the local garage is gonna have a look tonite

[flamejob]

If anything is left sticking above the surface of the head, use the following method. Heat what's left of the stud with a propane torch. Remove the flame and quench the bolt with paraffin wax (not paraffin kerosene).

Anyone in the UK know where to get paraffin wax from?

I have the same problem, but I have a fair bit of bolt sticking out of the head.

[Retro_10s]

parrafin wax eh,.... try a guitar specialist,... can't remember but off the top of my head i think it's paraffin wax that's used when doing a thing called 'potting' on pickups. nasty stuff.

[flamejob]

Ta Retro

I'm sure we used some kind of seize release at the bike shop but I can't remember it's name. All this is a right pain in the arse! Hopefully cutting the thermostat pillar off will help.

[flamejob]

weirdly... I googled pickup pottong and links lead me th this:
Candle wax

So therefore, surely one could use candles for the came purpose?

[flamejob]

http://www.sparkeroding.co.uk/

This may be of use for future searches of this topic

[Ethel]

Just check you can get a replacement sandwich plate before you chop it to bits.A bit of heat and wedging off the head face may get that moving.

You could try a stud extractor. looks like theres enough stud left.

[flamejob]

After all that worrying I finally got all three out.

It seems that the thermostat sandwitch plate had corroded onto the bolts and was holding them supertight. No ammount of hammering and wedging would get it off, so I decided to angle grind it off.

After the first two cuts the bolts came out with a quick turn of the mole grips. The new housing should come today from MiniSpares and all should be fine!

[mini_kel]

After all that worrying I finally got all three out.

It seems that the thermostat sandwitch plate had corroded onto the bolts and was holding them supertight. No ammount of hammering and wedging would get it off, so I decided to angle grind it off.

After the first two cuts the bolts came out with a quick turn of the mole grips. The new housing should come today from MiniSpares and all should be fine!

If u have been working on ur mini how come ur hands are that clean!!!!