Block crack - is this terminal

[Mark Dymond]

Dads rebuilding the engine on his chummy and has just noticed this crack, looks to have been there some time!
As it seems to be confined to the water jacket and the block is otherwise in good nick (according to Dad) I think its worth trying a repair.
First thoughts are to open it up with the dremmel and fill with metal epoxy. I cannot envisage a good outcome from welding - but thoughts welcome.

Also thought welcome on the cause, I wouldn't think there was any stress in this spot and last time the car may have been exposed to sub zero temperatures was 20 Years ago.
   

[Ruairidh Dunford]

This stuff is remarkably good: https://www.ebay.co.uk/itm/IRONTITE-CERA...2578080683

[bob46320]

Leave it unless you have it done by a specialist. I have repaired cast iron using both arc with ci rods and rig with as wire.
The problem is stopping the crack from propagating beyond the repair.

[Pete236]

Morning,

Lots of people are having success with getting things laser welded. The heat is minimal, it's not that expensive and I've seen. 99% success rate.
There aren't many places around though, I only know of two. One near Portsmouth and one in Aylesbury, but there must be others.

[John Raeburn]

Mark,
There are plenty of sound blocks around, I would be tempted to put that one aside and concentrate
your efforts on one that isn't likely to give problems in the future.
J

[Geoff101]

Morning,

Lots of people are having success with getting things laser welded. The heat is minimal, it's not that expensive and I've seen. 99% success rate.
There aren't many places around though, I only know of two. One near Portsmouth and one in Aylesbury, but there must be others.

Is that these folks?

https://www.contourprecision.co.uk/laser-welding

I've a collection of blocks with cracks!

[Pete236]

Morning,

Lots of people are having success with getting things laser welded. The heat is minimal, it's not that expensive and I've seen. 99% success rate.
There aren't many places around though, I only know of two. One near Portsmouth and one in Aylesbury, but there must be others.

Is that these folks?

https://www.contourprecision.co.uk/laser-welding

I've a collection of blocks with cracks!

It might be them, I'm not sure. My boss always calls them Laser Weld - but he does get his name's and meanings mixed up at times!

[Ruairidh Dunford]

This stuff is remarkably good:  https://www.ebay.co.uk/itm/IRONTITE-CERA...2578080683

Actually, I had remembered the name incorrectly - this is the stuff, perfect for small cracks like the one you have and really does work.

https://www.foxwooddiesel.com/heavy-duty-block-seal

May be difficult to get just now however.

[Mick Hobday]

I was recently recommended,  by a trusted local builder, to "Belzona" as a supplier of masonry waterproofer.  I came across their "Belzona 1111 Super Metal.  

https://www.belzona.com/en/products/1000/1111.aspx

I have no idea if it's any good, but there's a pretty convincing video of a repair to a cracked block on their website.

[A G Wood]

I've seen Belzona used to successfully repair cracked hydraulic valve blocks and pump casings.
You might want to have a lie down when you see the price of the stuff though [unless things have changed in the intervening 30 years]. It was kept under lock and key in the drawer of the manager's desk.  
Ruairidh's original pick of Irontite  worked well for me on a cracked Ford 100E head back in the day.