The Stovebolt Site Forums The Shop Area Engine Shop Welding a cast Iron Block??

Does anyone have any experience welding a cast iron water jacket on an old truck engine?

I have a 1925 Mack AC that was allowed to freeze up in winter. The ice blew a hole in the the side of the engine water jacket in teh side exposed wall. The ice sent two pieces flying 20 feet from the truck!. I have the clean broken pieces and have been getting alot of conflicting advice on who can ...and should... fix it. "engine stitching"?, welding?

any experienced welders out there? Anyone know what their talking about? Im confused!

Thanks
Old Coes Hartland Vermont :rolleyes: :p

I haven't done it personally or anything, but I worked at a machine shop local here where Blocks etc. were welded by the local welder. It was usually torn down & hot tanked prior to any welding to ensure clean surfaces & no fire. Block is heated using an oven if possible, then welded with a nickel rod. You need an experienced welder, Ask around, the local welder here is about 80 & I am sure he has forgotten more than I will ever know about welding. Brian

Old Coes,

It looks like you have done some research yourself. I have limited experience with cast iron...here are my thoughts.

Cast iron is very high in carbon, this is the obstacle in welding it. When you weld it and melt the parent material, you change it metallurgically. This results in a hard brittle area know as martinsite adjacent to the weld. This area usually fails, or cracks.

I usually only braze cast iron..this doesn't bring the base material to a molten state which keeps it intact metallurgically speaking. The brass melts at a much lower temp than the cast iron.

It isn't unusual to arc weld cast iron using high nickel rods or special "pulse" electrodes made for this purpose. If the part is small enough, or the furnace large enough, the part is preheated, welded, then post heated to relieve stress and negate the HAZ, or heat affected zone.

I think the "stitching" process involves threaded studs that are screwed into drilled and tapped holes in cracked castings..heads etc. These plugs overlap each other and form a chain of new material.

If your Mack block has actual "pieces", this will have to be a weld repair. If the repair is to be visible, brazing might not be the process you want. The quality of the casting can make a big difference in the ability to weld repair it, and the finished quality of the repair.

It would not be unheard of the send a naked block to a experienced welding shop for repair..I would assume you wouldn't find a new block at your FLAPS!

Make sure the block is not broken and useless somewhere else, like a bulge in a cylinder. To work, the repair will have to be done by a experienced shop who does this sort of repair. You will have to be prepared to pay for their expertise.

Stuart

Thanks Guys for all your input sounds like you have some good experience.

Now do you know anyone in New England area who can do the job? ( right!) ????

Thanks
OLD Coe Si Lupton

Hartland Vermont

Yes, the iron block CAN be welded. For a STREET engine, it should be reliable enough. For a highly stressed race engine that experiences very high rpms, maybe not.

For your stovebolt...absolutely. But have an experienced welder do it.

Try a heavy equipment or farm equipment repair shop. They will have a line on who to use.

The professionals use methods to preheat the cast iron and then they use a filler rod with a high nickel content. I have seen this demonstrated on TV. In the steam process plants, they have special "electric blankets" to preheat the cast iron.
I have seen old blocks repaired using a combination of welding and stitching for the outer water jacket. This area just needs to hold fluid, not withstand a lot of stress.

Old Coes,

I ran accross this site about a year ago. I don't know anything about it, but it sure looks good. Maybe some others will reply here and let us know if it works.

www.muggyweld.com

Mark

Truckernix, you are correct, but you'd be surprised at how much the entire iron block flexes in a race engine. On a street engine, it isn't as much of an issue.

Sometimes welding is successful and other times the crack never ends. Here's some info on stitching:
http://www.locknstitch.com/

I had to have a flywheel welded on my 1929 Fairmont Railroad engine. It was a castiron flywheel that cracked at the locating keyway. I had a local high tech welding shop do it. They could only braze it due to the poor quility of castiron. I would bet your block is of equal poor quality.
It may seem like a lot of work, but you might want to JB Weld those pieces back in and pressure check the rest of the block. Plus like the above post suggested, check the cylinder walls in that same area. If it all checks fine, remove the broken parts and sandblast the area before heading to the repair shop. You wouldn't want to speed a lot of money for a repair, just to fine it broke on the other side! Joe

Joe H,

Hey....a speeder!


Stuart

I once patched a hole in a transmission with a piece of sheetmetal and JB-weld. I didn't give it 2 days, but the darn thing lasted years! JB-weld is amazing stuff!

JB weld was also used successfully @ the machine shop I worked at, if the break was in an unpressurized area it was used almost exclusively. Grind a Vee, rough area w/80 grit & JB away. Brian

i must admit i used jb weld on both sides of a 305 in a 89 chevy 4x4 that was allowed to freaze. ran great drove it a year and when i traded the truck it still ran fine and did not run hotat all .that quick steel also works well

I've heard of this method from a very old timer ... Preheating is not necessary. Clean area to be welded, drill small hole at start and and end of where the weld will be (along the crack) I guess drilling the hole will stop the crack, because the crack will just get bigger when welded if you don't. Use a rod suitable for cast iron. And here's the tricky part... only run about a 1" bead at a time. Immediately after you put the torch down, use a hammer and tap on the weld until it is cooled down. I forget exactly what that does, but it's necessary. Inch by inch and tapping on it is what the old guy said to do. He also said that he repaired a block on a tractor one time- it was about a 8" crack and took all day!

I have mig welded a 6 inch crack two years ago in a 50's car engine block using the mig welder with stainless wire, an have had no leaks as yet over 6000 miles on the repair now.

Albert is right with the MIG. I have MIGed two broken exhaust manifolds that are still going strong (69 292 engine in 59 truck, and 47 cj2a) and I even redid the rear shock mounts on the rear axle of the 59 truck. 2 years, and a couple of 3000 lb loads ago. All still working good. Becuase of the localized heat of MIG its supposed to do well.

And as for the JB weld side, I even fixed an alternator mount on a phjord 302 in a MK VII. I didn't give it long, lasted the 5 years I had the car!

Main ting is to assembey the parts as tight as possible, try to pre heat a bit, use proper rods for cast iron, go only 1" at a time and tap w a ball hammer while it cools down a bit. For about a minute or so. This to prevent metal to schrink after beeing heated localy. It is realy tricky, and rods exspencive, but absolutely possible.