any1 ever weld a engine block?

[yogi09]

Just bought a truck off a guy that said it needs a new radiator,, paid $200 bucks for it, so I didnt really check it out to much.. Brought it home and checked it out,, coolant ran right out the back of the block was hoping it was a blown out freeze plug,, dropped the tranny and found the engine block has a crack in it,, thats what happens when you run water during the winter in Ohio... anyways,, before I try to track down a new 2.5 I thought about trying to fix it myself,, anyone ever done this before and if so,, what was your process,, ,, ahh yeh,, its split on flat surface,, so this may be possible,, I think,,,

[Buddy T]

engine block

I never welded a bloke but I rebuild grand pianos I had a harp (the cast iron part) that was cracked the welder preheated the harp with a torcha long way around the crack and used a nickel rod he also locked all the doors in the shop said any sudden air movement would crack the weld and kept the heat on the harp after welding slowly cooling it a piano harp has 40,000 ponnds tork on it when brought up to pitch I am happy to say it held and the piano is still working fine hope this might help you in some way.

[aametalmaster]

Yes i have welded them. Where are you in Ohio i can help...Bob

[yogi09]

Yes i have welded them. Where are you in Ohio i can help...Bob

Thanks Bob, I appreciate that,, I live in Chillicothe,, about 45 miles south of columbus... How far away is this for you...

[aametalmaster]

Prob 4 hours to the north east. I am below Youngstown...Bob

[Jeffw5555]

I have welded a number of blocks, both cast iron and aluminum. Every job is different, and can react differently. I haven't had any fail (yet.....)

By your brief description, a crack on the side of the block that is not "bounded", i.e. has a lot of flat area on either end of the crack, is the easiest to weld.

The problem is truly understanding the true length of the crack. You want to isolate the start and end points, but often it is tough to find out where those start and end points really are. (I think that most failures of welded block cracks come from cracking on the ends of the welds that have been there from the start....)

I try to find the start and end points, lightly grind and look under magnification, put some water or alcohol on the crack and heat with a heat gun, these are ways to find the start and end points.

Once I find the start and end, I drill a small 1/8" hole at the ends. Then clean the heck out of it. I use a flap grinder and dremel to clean, alcohol, and repeated heating with a MAPP torch to make sure no oils or other nasties are present in the crack.

I have never heated the entire block; don't have a good way to do it. I just use a MAPP torch around the general area to heat it up some. Once heated up, I clean again, then use a nickel rod that is rated for cast iron, with short stitch welds. (put a short stitch weld on the one end of the crack over the drilled hole, then immediately jump to the other end of the crack, back and forth ending at the middle of the crack....) Then let it cool, keeping it from drafts. Then go!

I'm sure you will get other opinions as well......

[Portable Welder]

JeffW555,

Here are a couple of things I'd like to add to what you said.

I prefer cleaning with wire wheel and a carbide, when your done welding go over the outer weld area with the torch and take a chipping hammer and peck at the weld ( Peening it ) This will give you some added stress relief for the area.

It is not recommended to grind on Cast Iron if you plan on brazing it because the metal will smear to a certain degree and using a carbide will leave the area roupher with texture giving the braze a better surface to bond to.

[Miller Swartz]

Both JeffW555 and Portable Welder give excellent advice.

Just Like PW, I would like to add a bit as well.
Torch heating the block in a localized area is quite acceptable. Obviously heating the whole block to a uniform temp is preferred, but few of us have that capability. Typically I recommend approximately 12 inches on either side of the crack (if possible). The goal really is to minimize the temperature gradient between the heat effected zone ( HAZ) and adjoining material to prevent additional cracking. In the repairs that I’ve seen fail on CI, rarely do they fail in the weld itself. It is usually in the area just adjacent to the weld. For this reason, the pre-heat temp is also key. Slow preheat up to 500 F is recommended and you should maintain this as your interpass temp until the repair is complete. Like Jeff, I also recommend a slow cool. The use of a welding blanket over the part also helps this process.

Another common error is failure to remove the entire crack. All too often I've seen people follow all the proper procedures only to sabotage their efforts by only going half way on the crack removal. If you leave any of it there, there is a good chance that over time it will propagate out again. When removing the crack make sure to “U” joint the grove. “V”ing out the area creates a stress riser at the bottom of the grove and isn’t recommended on CI. You can also drill both ends of the crack if you would like, but this isn’t a must. It does help prevent propagation of the crack because a round hole has no stress risers and thus the crack has a difficult time spreading.

I also recommend peening, but there is an old adage for cast iron repair that goes, “Don’t peen if you don’t know the peener!” Peening is done to counter act the contraction of the weld material as it cools helping to prevent stress cracks in the surrounding base material. In the repair failures I’ve seen that were the result of improper peening, the person used a sharp pointed end of a chipping hammer. This is great for slag removal in joints, but it again creates a pointed indentation in the weld material or stress riser. Actually a ball end of a ball peen hammer would be perfect if you can get at the weld with it. Think about the surface of a golf ball but on a bigger scale. Also, you don’t have the beat the tar out of it either. A nice tapping motion is enough to counter the contraction. In some cases, peening incorrectly can actually be worse than not peening at all; hence the saying.

All in all, CI repair is not as hard as people think and with all the good recommendations on here so far you should be fine.

[BMS]

for the holes at the end of the cracks I assume you drill all the way through the material?

[abprt]

repairing a cast iron motor block

Just bought a truck off a guy that said it needs a new radiator,, paid $200 bucks for it, so I didnt really check it out to much.. Brought it home and checked it out,, coolant ran right out the back of the block was hoping it was a blown out freeze plug,, dropped the tranny and found the engine block has a crack in it,, thats what happens when you run water during the winter in Ohio... anyways,, before I try to track down a new 2.5 I thought about trying to fix it myself,, anyone ever done this before and if so,, what was your process,, ,, ahh yeh,, its split on flat surface,, so this may be possible,, I think,,,

Sometimes cast iron blocks will continue to crack with preheat and get worst while welding. To eliminate continous welding problems repairing motor blocks, I would suggest to use the pinning technique. You can check it out on the net. I have a boat motor that needs repaired tomorrow while in the boat and the motor won't have to be taken out as long as you can get to it to use this precedure. I live about two hours from you in S/east Ohio.

[jeffd]

Many people may have had success with welding cast iron and it may hold if you have experience with welding this material. But, my money is on the pin method. I have not done this myself but have seen a couple different items repaired using this system and it works, one thing was a cummins engine block from a pickup that had a crack in it and was leaking coolant to the outside of the engine, the crack was about four inches long and repaired using a system called lock-n-stitch check it out