14 replies to this topic

[whistler]

I have a 12G940 36/31mm well ported head that leaks water. The image shows a pin hole in the wall between number 4 and number 3 inlet. This resulted in number 4 become a water pump and steam generator. Is it going to be possible to weld/Tig/Mig/Braze this hole or is the rest of the 'wall' likely to be paper thin?

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[cal844]

You can't really weld cast iron, it may well be possible to repair but how long it will last i can't say.

[Mervyn]

I'd happily tig that up with a pre and post heat followed by a slow cool in sand . After all, nothing to lose, the head is scrap otherwise


Merv

[Spider]

It is in a difficult place to access and in the exhaust port, as Mervyn suggest, it could possibly be TIGed though I'd probably be inclined to plug it with a Tapered Plug, which would go in throw the deck and well in to the port, then grind it back.

[Mike L]

A wall that rusts through like that usually indicates core shift during the casting process causing thin walls in some places. While that could be fixed if core shift is the root cause there are likely other thin places waiting to show themselves when the water jacket corrodes a bit more. I would replace the head. I can't tell for from the picture but if the head has been ported they might have gone a little too far there. If that is the case then it might be worth fixing if buying a fresh head with the port work done is prohibitively expensive.

[Dusky]

You can't really weld cast iron, it may well be possible to repair but how long it will last i can't say.

You can Weld cast. Its 2018 now, not 1820 ;)

[Rorf]

The reason for that hole is that the ports have been over ground - note the huge valves

[minimans]

You can't really weld cast iron, it may well be possible to repair but how long it will last i can't say.

+1 for that! could be TIG'd They have special rods for cast iron now that do not require Pre or Post heating and are very easy to use. Also brazing with gas would be a good option,

[Spider]

Why not track down a proper company who repairs heads and get an opinion & quote from them?

[nicklouse]

like http://www.expresswe...f.co.uk/welding

[Mervyn]

Slinden Services would sort it , not sure if they have a website. They do metal stitching as well as weld repairs to loads of old classic car engines and machinery


Theyre on 01530 274646

Merv

Edited by Mervyn, 07 May 2018 - 11:01 AM.

[nicklouse]

Slinden Services would sort it , not sure if they have a website. They do metal stitching as well as weld repairs to loads of old classic car engines and machinery


Theyre on 01530 274646

Merv

they do http://www.castironw...grepairs.co.uk/

[whistler]

The reason for that hole is that the ports have been over ground - note the huge valves

This is my thought as well. I think this was originally a race head and walls are well ground out. I also think Mike L is right in that corrosion from the waterways is likely to effect the other inlet valve ports. I'll see if I can find a local welding specialist for a proper inspection and opinion.

Sinden are a bit too far for me on the offchance that they can repair it but thanks both for their suggestions.

Edited by whistler, 07 May 2018 - 01:50 PM.

[Mike L]

 

Slinden Services would sort it , not sure if they have a website. They do metal stitching as well as weld repairs to loads of old classic car engines and machinery


Theyre on 01530 274646

Merv

they do http://www.castironw...grepairs.co.uk/

 

I just looked at the Slinden Services web site. Beautiful work. Back in the days when I used to do engine machine work (many years ago) they had to do the pre-heat and then use nickle rods to weld up cracks. There is another method that uses interlocking cast iron plugs with ceramic sealer. That method would not fix the thing Slinden showed as examples but it does work for short cracks like you get in the middle exhaust seats on small block Chevys.

[mikal]

This is advice for welding cast iron I received from an expert recently:

 

"You can repair weld cast iron, either by brazing with oxy + bronze rod and bronze welding flux, or stick welding with castcraft 100 nickel electrode.

I have used both methods successfully."

 

Technical info: Applications of Castcraft 100 include the repair and reclamation of engine blocks, cylinder heads, differential housings, gear boxes, pump and machine housings and cast iron pulleys etc.

 

Hope this helps..

Edited by mikal, 08 May 2018 - 03:56 AM.