Welding freeze-cracked engine block

[Vtnewbie]

GM V8 engine block cracked down above/along bottom skirt due to water in the block last winter. Prior to welding, do I need to drill the ends of the cracks (as for stress cracks) to stop the cracks propagating? I'm concerned about the amount of heat I'd be introducing to fill full-depth holes, rather than just covering the v'd out cracks.....

 

[Shield Arc]

Ever do this before?

 

[ak9]

Quick answer is yes ....... But b4 you put any electric to it ...there is the prep.....pre heat to 500 F ish slowly then the electric weld with high nickel rod then the slow cool down to 200 F ....best to mag flux or other means to determine the Very end of the cracks tho . I've found to enlist a pair of "other" hands to hold the pre-heat torch and the no contact themo to be most helpful in doing this type of repair

 

[Vtnewbie]

Thank you sir!

 

[stuckmotor]

Ak9,
How far from the sides and ends of the crack should the pre heat extend? I'm just curious.

 

[flusher]

GM V8 engine block cracked down above/along bottom skirt due to water in the block last winter. Prior to welding, do I need to drill the ends of the cracks (as for stress cracks) to stop the cracks propagating? I'm concerned about the amount of heat I'd be introducing to fill full-depth holes, rather than just covering the v'd out cracks.....

I recommend this rod:

Super Missileweld | The Harris Products Group

I've used 1/8" rod to a weld broken flange back onto the engine block of my Farmall Cub using my Hobart Stickmate LX welder. Works fine. Just follow the manufacturer's recommendations for polarity and amps for the rod size you select.

I didn't use preheat. Just made 1" long stringer welds. Measured the temperature with an inexpensive IR thermometer from Harbor Freight. Kept the temperature below 400F and let the block cool down to 100F or so between stringers. Peened the welds with a pointed air chisel during the cooldown to relieve stresses.

Good luck.

 

[Shield Arc]

We used Super Missile Weld for quite some time, trying to keep cast steel pile driving equipment together. Then we switched to 312 stainless steel.

 

[arkydog]

look under repairing dodge cummins diesel 5.9. engine block #57 cast on block side. there is a company the makes a insert that you drill along the crack and use their tool and insert and side by side you repair the cracked block. its a fix for the block that cracks because it was made too thin.

 

[yomax4]

Super Missile Weld Is 312 Stainless. I prefer Spray Powder on any cast under 1/2" thick. ( Nickel Iron powder ) Never Fails. On the thicker material I recommend short 1" stich welds. One at one end and one at the other after drilling the ends, Let it cool while peening the bead to relieve stress and repeat the steps again. Buy premium rod like MG 289. Just my opinion. I used to sell maintenance and repair alloys and have burned a lot of nickel and spray powder. There are some very good Nickel Free synthetic Nickel rods out there too. Good luck..

 

[pmsmechanic]

I've had good results using ArcTeck 223 welding rods for cast. I've never welded a block though. I'll learn something here.

 

[Arc weld]

Arctec 223 is similar to 8018.

 

[Norm W]

I used to do this with JD "M" blocks as they are made out of unobtianium. We strip the block down and set it on the wood stove. The stove is hot enough to raise the temp in the shop from 32* to 80*. You could throw a cat through the walls, so it is a rather hot stove. Weld short beads with high nickel rod. You can't weld for long because the stove is that hot. We used a needle scaler to peen the welds. When the weld is finished let the fire go out with the block still on the stove. Never had a problem with further cracking.

 

[Texasmark]

I know this is a "half fast" cure, but years ago I bought a boat with a Chevy 4 block Mercruiser engine. It had about a 2 " crack along the middle of the block. I cleaned it up real good with a grinder, wire brush and acetone and then gave it a good dose of JB weld. I had it for 7 years and sold it to some younger friends that had it when I left the area. Guess I was lucky.

Why the glue? Didn't have the money, equipment, nor expertise to do it right. Had it not held I'm not sure what the next step would have been. One thing that may have helped was that a marine engine without a recirculating freshwater system has essentially no water pressure....couple of psi or so and that may have been the secret when thinking about some of the radiator pressure caps I've seen up to 16 psig. Other thing was that it probably ran cooler. Don't remember if I had a thermostat in it or not and if I did it would have been around the 160-180F mark.

 

[davesl708]

I know this is a "half fast" cure, but years ago I bought a boat with a Chevy 4 block Mercruiser engine. It had about a 2 " crack along the middle of the block. I cleaned it up real good with a grinder, wire brush and acetone and then gave it a good dose of JB weld. I had it for 7 years and sold it to some younger friends that had it when I left the area. Guess I was lucky.

Why the glue? Didn't have the money, equipment, nor expertise to do it right. Had it not held I'm not sure what the next step would have been. One thing that may have helped was that a marine engine without a recirculating freshwater system has essentially no water pressure....couple of psi or so and that may have been the secret when thinking about some of the radiator pressure caps I've seen up to 16 psig. Other thing was that it probably ran cooler. Don't remember if I had a thermostat in it or not and if I did it would have been around the 160-180F mark.

It's funny. I had the exhaust manifold water jacket crack in several places on my Volvo Penta (GM) engine. For some reason not all the water drained and it froze. I was on the water when I noticed the leaks. Cleaned the paint with Acetone and applied JB weld. Has held for four years now. Note the boat does not get to 15psi like some liquid cooled engines.

 

[muddstopper]

I used to do this with JD "M" blocks as they are made out of unobtianium. We strip the block down and set it on the wood stove. The stove is hot enough to raise the temp in the shop from 32* to 80*. You could throw a cat through the walls, so it is a rather hot stove. Weld short beads with high nickel rod. You can't weld for long because the stove is that hot. We used a needle scaler to peen the welds. When the weld is finished let the fire go out with the block still on the stove. Never had a problem with further cracking.

I used the old wood stove trick to weld up a water pump once. I remember I could only stand welding for a couple of minutes before I had to back up from the stove. I had a friend weld up a small block chevy engine once using regular mig wire, ground out a vee and did short welds. Engine ran for several years. While I am certainly no pro, I have repaired several cast items using mig. I have one of those propane weed burners I like to use for preheat. The wide flame just seems to work better at spreading out the heated area. I will preheat to about 600degrees, weld a inch, peen using a needle scaler, preheat to maintain the 600degree heat and weld another inch, repeating until I'm done. I havent had the weld crack yet using this method. On a old sauage press, I repaired, after welding, I sanded the weld smooth to hide the weld. The rest of the press had the ruff cast look. To make everything match, I took some coarse sand paper and just laid it over the sanded area, grit side down, and started pecking it with a small hammer. This left a ruff finish that was hard to tell from the original cast look.

 

[drizler]

It's funny. I had the exhaust manifold water jacket crack in several places on my Volvo Penta (GM) engine. For some reason not all the water drained and it froze. I was on the water when I noticed the leaks. Cleaned the paint with Acetone and applied JB weld. Has held for four years now.
Note the boat does not get to 15psi like some liquid cooled engines.

I did the same thing on mine with a 2 " hairline on the side of the head just weeping. Somebody on a boat group was kind enough to give me something better than but similar to Jb. THey used it in his town job repairing busted drains and things like that he said. I prepped it with a dremel just like for welding and put it on. He had run the same problem 7 years earlier and put it on as a temp fix till it fell off . He said it just never did. Well mine went on in 2004 and now has around 300 more hours and is tight as a drum.

 

[crazyal]

Years ago I was doing NDT and we had to do some work at a large valve company. Often I would find cracks in castings that would require welding. They would often give me a guy to grind the crack out before it could be welded. The process usually went like this. I would mark the crack, use the overhead crane to lift the valve body up and out of the inspection booth, move it to his work station, let him grind the crack out, then reinspect it. Often it would take 4 or 5 times before the crack was fully removed. One day I showed him how magnetic particle testing was done (I was doing fluorescent testing which requires a dark rook) and showed him the crack. Before then I think he was just going through the motions thinking that the crack was gone even though I said it was still there. After that i was able to get the company to let the grinding be done in the same booth so grinding and testing could be done with in a minute of each other. They used die grinders with carbide bits.

If you have the means I would remove the paint and see if I could find someone who could map out the crack for you. Then grind the crack out. Otherwise you could have rust and/ or glycol in the crack which will weaken the weld.

 

[Bill Stecik]

I am a firm believer in arctec prouducts . 223 works good but unichrome is the best for cast , i think. Having said that , I have used JB weld to repair the liner seats in a D6 cat engine and it hasn’t failed in 10 years or so .