Opinions needed on this weld?
Turbo Mini Forums

Here's a pic of my cylinder head. Jus tafter some feedback if this welding is shite or not? And what has been done wrong? You can also see the 'crack' that my welder said is making the head unrepairable.

These welds are the second attempt after grinding the old ones out and they are still leaking. I think the welder has given up and just said there is a crack as he doesn't want to admit he's fucked up.





Opinions please lads.

Cheers
Matt

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

just mailed this to you matt nut ill stick it on here too


just spoke to my welding freind ian ,down in woodcote ,and hes up for looking at it tomorrow ,if you like ..

he thought after looking at the pics ,maybe it had been welded with a mig ? and that wasnt the right tool for the job ..
also german castings sometimes have a need for a special rod .if he cant do it he'd say so and not fool you around .it might be a bit chreaper .

regards
robert .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Ah cool, hopefully I'll be able to make it over, it would probably be the afternoon though? When is Ian about?

It was definitely done with a tig, as thats the only welder he has. Did he give an explanation of why the wleds might be cracking?

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Just to echo what robert said about possibly being done with a mig,if thats tig then its very sloppy.I know appearance isnt everything but still a decent welder using a tig set should be welding a lot cleaner than that in my eyes.

EDIT - Are the welds cracking or is the head cracking?

Cheers Ross.

Edited by rosco454 on 2nd Apr, 2010.

I dosen't look a great weld to me, looks like something i would produce lol.

looks like either poor or dirty metal, I reckon Roberts mate is worth a shot.

With regards to the crack, if you don't grind out ALL of the crack, it will keep coming back. You can't just weld over it, you need to dig it completely out.

Rosco - Apparently the head is cracked (the faint line that runs from the weld to the chamber) but I thought I caused that when I was cleaning the swarf off it...Doh! The welder said as he welds "the crack opens up to about a 1mm and runs to the valve seat".
Ive taken the valve out and no signs of cracking in the exhaust port and I can't see any signs of a crack in the chamber.

The welds HAVE cracked in the centre, and when putting air pressure on the head air was coming out of them.

To be fair to him, he's welded lots of things for me before without any problems but not sure if its the cast material causing the issue or maybe the technique.

Edited by matty on 2nd Apr, 2010.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Owen - He did say the same thing, to sort the crack out he'd have to remove the valve seat, mill a 4mm slot over the crack to dig it right out then fill it with weld.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

@matty Didn't your problems with this head start with frozen coolant during the winter time and might that not have caused these cracks?

Edited by Sprocket on 2nd Apr, 2010.

if the crack runs to the valve seat i think you should start looknig for another head as you'll just chase the flaw right around the casting,

done it myself years ago with a cast head,
I spent far too long trying to repair something that was unrepairable,

carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

It has cracked because there is not enough heat gone into it, which is very difficult since its such a large casting, then it has cooled too quickly and cracked again. You need to pre heat the casting - weld it with a silicon or manganese rod then let it cool very slowly in hot water.
Plus theres porosity in a casting like this that holds impurities which makes the welds porous causing the leaks.

Id scrap it and start again

Paul

I seriously doubt it!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

On 2nd Apr, 2010 Sprocket said:

On 2nd Apr, 2010 matty said:
"the crack opens up to about a 1mm and runs to the valve seat".

sorry matty it doesnt help I know, but that I cannot see

On 2nd Apr, 2010 matty said:


To be fair to him, he's welded lots of things for me before without any problems but not sure if its the cast material causing the issue or maybe the technique.

TBH Matty, I remember you having problems with coolant leaks right at the begining from porous welds. If this the same bloke?

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Do you know if it has been preheated before the welding takes place and what process is he using post weld to keep heat in the whole job?That might go some way as to why the welds are cracking.

EDIT - Just noticed Paul W made the same point further up the page,apologies for my thickness!

Edited by rosco454 on 3rd Apr, 2010.

yes thats ok matt , if you can make it earlier do, i want be back for 5 ish .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

He's not been preheating it, which sounds like why its cracking then.

He's been bolting it to his mill bed to stop is distorting, not sure if that is nessesary though?

Robert - Yeah thats fine with me, I'll try and make it over earlier.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Too long out of this forum,
Why did you weld this poor head ???
If it's fucked I've got a pair in the garage jungle, one is in need of new seats ,if interested and not in a hurry it's yours for postage cost.
fab

After reading this, i went and checked mine out as i haven't looked at it after it was welded up, and a couple of mine have minute cracks in the welds.

So looks like i might have the same problem in regards to pressure testing.

Any decent engine shop should be able to pressure test it for you

We have big problems with our magnesium castings and they need to have the crack ground right out, we normally drill them at both ends, then melt the bottom of the crack together without filler rod, then build it up. They need to be f-ing hot though.

Well Ive had robert mate have a look at it, and he rewelded it up for me. There are still a few pin holes but the solid part of the gasket cover these. I think im going to run some ceramic sealant through just to make sure though.

No sign of a crack, and now its had another 0.02" skim that mark has gone.

Big thanks to robert for putting me in conact with his mate.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Totally agree with drilling a hole each end of the crack, similiar method to glass and other ceramics. Stops the crack spreading. Something like that you would need to pre-heat also.
With castings you really don't know what properties the materials are to get rods to weld it either. :(

edit...I'm also shite at ally welding...almost as as un-pretty as the picture!

Edited by Jason G on 9th Apr, 2010.

That's great news Matt

are you going to get hold of another head just in case?

I cant stop thinking about the comment of the crack opening up as it gets hot, lol, aluminium expands a great deal when it gets hot, so if anything a localised hot spot while welding in a large casting like that, if anything, the crack should close up, but we all know why the crack didnt open up anyway.

Glad to hear its recoverable. Has it been pressure tested yet?

Do you reckon this chap Robert knows could repair my piston?