Cracks in block

[Flintstone52]

I have a 1950 side valve MM.
When it arrived the engine was locked up.
On dismantling it I found water in the #1 cylinder, but no obvious cracks or leaks, other than evidence of gasket cement on the head gasket.
The head was seriously warped, no cracks.

After cleaning the top of the block, I found an open crack from the centre stud to the near water passage.
Also on the same stud a hairline crack running in the opposite direction.

As well as another hairline crack on another stud.

What is the consensus, repair or scrap?

[MM1949]

The cracks around the studs on the 918 sidevalve you have do occur fairly often specially around the centre stud. These cracks can be successfully repaired.

[Steve Phillips]

I have used cast iron welding services several times and always been happy with the service,
They are not cheap but the quality of their work is superb.
BTW I don't have any connection to them, I'm just a happy customer,

Steve

[Bill_qaz]

You could also consider metal stitching if available in your region.
Its a cold process no welding involved.
Here a UK sample just for info on process.
Metal Stitching Cast Iron & Crack Repair Services https://share.google/N0ef6Uloq9XA70ZZB

[oliver90owner]

Repair or ignore. Ceramic sealing might be appropriate, but who knows how deep those cracks might be. Probably been like it for decades. Biggest risk is corrosion within the crack widening it.

If I were worried, I would be consulting an expert, who has experience with these engines. If the cracks were to reach the cylinder, a stepped liner would likely avoid scrapping the block.

There is usually a repair possible - just depends on scarcity of block and cost.

[Flintstone52]

Thank you all for the input.

Finding a replacement block (sans cracks) is going to be a bit of a mission.
There are 3 options open to me:
Welding: been there before with a Mini Cooper S head, has to be pre heated and unless the crack is ground out it could propagate again.
Metal stitching with "Lock n Stitch" pins: These pins have a unique barb type thread profile, which pulls the crack closed. This was such a sucessfull system that they got bought by Wartsila Marine. My emails have gone unanswered and no one in Aus has been able to get them.
Metal Stitching with Goodson taper pins: Taper threads and cracks conjure up bigger cracks in my head... however the local industry swear by them, so that looks the way to go.

I will also be drilling and tapping out all the stud holes to M14 x 1.5 and fitting cast iron plugs pre-drilled and tapped to M10 x 1.
I need to do this as some of the holes are through to the water jacket.

BTW, all the cyl head studs are M10, and the sump flange bolts are M8. I cannot see this as being original???

[MM1949]

The threads on the 918 Morris engine are metric. Morris acquired the Hotchkiss factory in the 1920s to produce engines which was originally a French company.

[Flintstone52]

I did not know that, thank you.

[philthehill]

I think that you will find that the engine design is English but the tools that made it were French. That is why you have metric threads with Whitworth heads.

[Flintstone52]

Thank you for your input.
I had a problem removing the bearing cap nuts.
None of my SAE spanners worked.
The nuts had a split on the top which I guess formed a lock nut when pinched??
I may replace all with metric nuts/nyloc nuts.

[philthehill]

If you do replace the lock nuts with Nylock nuts make sure that the nuts are of suitable quality (at least 8.8 tensile strength) as I have found that many nuts today are of poor quality.