The Stovebolt Site Forums The Shop Area Engine Shop Repairing a cracked block - it can be done

We have a tech tip from John "53John3100" Rooney on repairing a cracked engine block.

Good step-by-step and pictures.

Peggy

The only criticism I have is the pictures are too small. I don't mean the thumbnails but the "full size" image when the thumbnail is clicked on. It's barely larger than the thumbnail and difficult to see any detail.

Tiny,

Dang! They should not have been that small.

Fixed.

Peg

That is not how I was taught to use the pining method.
I was taught to install the first pin, than drill for the next pin so it overlaps the first one slightly, and the same for the rest. This way you reduce the chance for leaks.

That's right pre'68. They should slightly overlap.

He says he did fill all along it.

The DVD they send you says and you can watch on the screen them actually repairing one step by step on how they do it with a narrator is not to do one then the next and so on, they say it weakens the block and you are drilling into some of the threads from the first pin, that is no problem but they want you to do that when there is another pin on the other side first for strength. Plus these pins threads pull into them selves they tell you instead of pushing out and spliting the metal. So they suggest every other one and then come back and fill them in, and a third pass if needed if you discover a leak when they are all in (I had to install one more in the middle of the row when I was done for a pin hole leak) The DVD and tech support person said every other so that is what I did, I suppose there are a number of ways they will work, but as long as the job gets done is all that matters to save the block. I only did one so not an expert by any means. BTW, if you get a chance check out the 3 foot hole in the cruise ship engine on their web site under "repair examples" or something like that, that they fixed with stiching pins saving the cruise millions replacing the engine. They have a string of pictures and I though it was cool looking at them. Good Luck to all with a cracked block. I am not a pro at all and if someone has a better way to do it then go for it. I just wanted to document my repair through pictures and the feeling that all is not lost just because you have a crack in the block. I felt lucky I found this method. Thanks to all the guys for all the help on my truck all along the way. That is the nice part of this web site all the help you can get from others.

John

Doing it as in the tech tip effectively accomplishes the same result as doing them one at a time. Spacing them out and then filling in the gaps is faster for sure. Welding in a sheet metal is done pretty much the same way and in the end, you get a monolithic repair.

11 Year follow-up. Hey John, how did that stitch repair hold up 10 yr down the road? I've got a small crack in the head of a 1950 GMC 216cc. Thanks for any wisdom you can share.

A company in Turlock, CA 'Lock n stitch' has been doing these repairs for many years, small jobs to huge commercial repairs.

http://www.locknstitch.com/index.html
Check them out

Here's another option, if you're not comfortable attempting such a repair on your own. Back when I was running the connecting rod reconditioning department for a big machine shop in Nashville, we sent our cracked blocks and cylinder heads to a company called "Diesel Cast Welding". They have a dedicated department for antique and classic car parts. The company has several facilities around the country. I'm not sure about their pricing structure, but it's probably a good way to salvage scarce, high-value items.

https://www.dieselcastwelding.com/

Jerry

We are the worlds crudest amateurs when it comes to cast iron welding. Do a search on "welded sides on a Ford V8 60 Tin Side block" and hide your face in shame. The welds are PERFECT and this was years before TIG or MIG existed. It was also done on a production line. I have a friend that stainless TIG welds cast iron with great results but then he can also braze cast iron with like results. He filled a fire slot between the center cylinders of a racing block, run boring bar in each cylinder just far enough to clean weld and then just "brushed" the deck with a mill for gasket surface. Zero problem with the repair. I have sewn a number of heads, blocks, and even pump housings and always overlapped the previous plug.

Thanks Jerry for the suggestion, I'll look into this. Evan, good to hear you have had good success sewing heads.
I now have more complications to the small crack in the head, so I've started a new thread.
Would sure appreciate your experience.
Jim

In the early 60's my father worked at a company called "Cyclone Excels Weld" in Imperial Calif. He learned to weld cast iron and make repair to engine blocks as well as machining. Years later he would repair engine blocks and manifolds for other Drag racers, made it look easy. I never got to the chance to learn this skill form him.

I worked for a long and agonizing summer as a welder. During a slow period when our steel was delayed (one type came from Belgium), one of the older guys taught me how to braze cast iron. There were a couple of things you could never forget to do and using an oxy-acetylene torch was the best option. Wasn't really all that difficult, but your repair was very obvious...no way to hide it. Slow work if you had a long crack. There were some DC brazing rods where we worked, but he said they were basically junk. This was 1969.

Back in the ‘50s thru the mid ‘70s there was a company called Yellow Weld (not to be confused with the current crop of Yellow Weld businesses) in OKC that specialized in repair of cast iron. Mostly truck engine blocks and oil field equipment with a few automobile engine blocks thrown in. Quality workmanship and reasonable prices. They did very well for many years. As the owners got older they couldn’t find anyone willing to learn and take over the business so it was closed and the equipment sold at auction.