Block crack - is this terminal

[Austin in the Shed]

I guess it's how much you want to save that block. As others have said laser weld, Weld with one of the alloying/nickel type  rods,stitching or possibly drill and tap  and plug several places along the crack and seal with irontite which works well.
Check if the block has any other serious problems,It looks pretty rusty.Will it bore bigger ? how many broken studs etc.
I had one crack in the same place worse than that whilst out of the car ,dry ,in storage ?

[David Witton]

I have used Surelock Castings with good results. My block was cracked in usual place ie from centre stud to pots 2 and 3. Their repair has lasted about 10 years and the car still goes like a train.

[Mark Dymond]

Thanks all, should have said Dad is in country Western Australia so laser welding probably not an option with current travel restrictions. Interesting to hear of good results from in-coolant sealants, tempting easy option. Ill look into getting something delivered to him. As I mentioned he says the rest of the block is in good condition but I suspect his calibration of "good" was set in the 60's when good equaled "will run"

[Pete236]

Ah, yes I imagine that anything 'local' is several hours drive away!
It might be worth trying 'k seal' as an jn-coolant sealant. It works well to block leaksz but crucially it doesn't block radiator cores and water ways like other sealants do. Used in conjunction with a chemical metal to fill the crack from the iursidez it might just do the trick.

While I was cleaning up and inspecting an old Alvis block a month ago, I found a crack which had been filled with chewing gum - going by the amount of gunk and paint over it, was over 40 years old and had held for the pressure test!

[Ray White]

I have used Belzona on a cracked block. It works well but as has been said it is expensive. I have also used a cast iron "stitching" firm who did a fantastic job.

One thing to remember about a frost crack like this is that the crack you can see will always be only half the story. Where the metal has been forced out there will be one or two corresponding cracks that you can't see... usually in parallel. These other cracks may or may not leak but will be there. Guaranteed.

For what it's worth I would source a better block.

[Martin Baker]

I used EMP Tooling Services in Havant to laser weld a Speedy crankcase (http://www.e-m-p.biz/). They did an amazing job!
To see them welding the valve seats of a vintage Bentley block was incredible (remember the Bentley has a fixed head, so the valve seats were probably 500mm down the tunnel!).

However I decided not to risk trying to repair a crack in no. 4 bore of a Chromidium block. Call me a coward if you like!

Good luck.

Martin

[Chris KC]

Mark, I only have your photo to go on; but are you absolutely sure that is a crack and not a scratch or minor casting defect (etc.)? And is it only visible at the surface or does it emerge at the other side somewhere? You can probably assess it far better than we can online.

I'm inclined to suggest that - from what I can see - it doesn't look too severe and the block would quite likely be fine.

On the other hand - if you had just spent a packet having it re-bored and ported I would understand, but that appears not to be the case; so if in doubt surely another block would be a lot less costly (and quite likely more sound) than a repair?

[Austin Nippy]

Hi, I had problems with a badly corroded block last year and was recommended Belzona to be "the stuff". However, their smallest unit was a 1kg tub which was something like £200 plus delivery.
Another friend suggested Bond Loc B2001 which cost about £5.00 for a small tube. He has Austin 7's and worked at British Steel mending big stuff with this stuff.
After almost a year and several 1000's of miles it's still going strong.
Maybe this would help?

[Bob Culver]

The local owner of a pristine 20 had a crankcase crack repaired by an old expert using  solder. Years ago I turned replacement valves etc for my brohers sv Hillman and when all assembled found a leaking crack in middle of head. I could not face taking it to bits again . Cleaned it up and solderied in place using plumbers petrol iron. Then sold. 
Can a cover plate attached by small screws be made up? If it was all tinned first could bre filled behind with solder, or epoxy, or whatever. 
On one of the TV resto programmes there was an old 12/4 with cracked water branch on the head. It had been repaired with solder decades before.but was leaking or deemd to be. Instead of redoing, for the sake of the spectacle , they adopted extreme metal stiching method.

[Chris Garner]

I've just had an Ulster crankcase repaired by laser welding. Superb job, but not cheap. Harrison's Laser Technology of Doncaster. Recommended.
I believe one of our contributors has had a Speedy case similarly repaired.