I found a crack in an odd place while pressure testing
 

The crack is between the forward exhaust port and the water pump mount on the passenger side of a 37 block on the outside of the block.

The opposite bank seems tight, it has been holding 25 lbs for a day and a half. this side leaks down to zero in a half hour. I haven't found any other leaks, but without it holding over time I can't be sure it's crack free.

How would YOU fix this? would Lock N Stitch pins be the best?

I couldn't take a decent photo of it bubbling with one hand while spraying with the other hand, so here's a video. Anyone else see a crack like this? Seems like an odd place to crack without other damage, so I'm concerned I'm missing something.

https://www.youtube.com/watch?v=O1AL...ature=youtu.be

Re: I found a crack in an odd place while pressure testing
 

drill a hole at each end of the crack, grind out and weld with a mig

Re: I found a crack in an odd place while pressure testing
 

To have a crack, that's a pretty good spot to have it.

I would use a high quality epoxy such as Belzona or the like. You should be able to get at it from both sides. May need to make a tool of sorts to get it from inside, but I think you could reach around and down in from the water pump cavity.

Mechanical means (lock and stitch, welding, etc) will work as well.

Re: I found a crack in an odd place while pressure testing
 

Thick& thin, bad place for welding. Braze, maybe, Stitch probably. Yep! Good place to have one.

Re: I found a crack in an odd place while pressure testing
 

I had a very similar crack in an otherwise very solid block. Paid a lot to get it welded by a very proficient welder who heated it in a furnace first then slowly cooled it. I think he used high nickel SS rods. Weld was good but I then I found another big crack inside the exhaust port that couldn't be reached. That's what can happen when you get freeze cracks I guess. Sold the block cheap to a drag racer who was going to fill the water passage with cement. Expensive lesson learned on my first flathead.

Re: I found a crack in an odd place while pressure testing
 

I think MIG welding cast iron is as bad idea. Epoxy probably won't last and will eventually leak. Stitching is the way to go. Check out Irontite. I bought my kit (drill bit, tap and plugs) on eBay but the company will sell directly to you. The cost is pretty reasonable and I found that they are very helpful if you email them and explain your situation.

Re: I found a crack in an odd place while pressure testing
 

try Devcon, it hardens like steel.

Re: I found a crack in an odd place while pressure testing
 

Belozna is the only epoxy that can be used on Caterpillar engine and still retain the warranty on the engine.

It is expensive, but the best out there. All epoxies are not equal and any epoxy can fail. Its the prep work to the surface that makes all the difference.

Re: I found a crack in an odd place while pressure testing
 

The problem with that particular area is that it is very thin. MIG cast iron, NO. I would find someone that is a proficient TIG welder. Pre heat and use nickel rod as a filler after drilling holes on each end of the crack. Stitching would work if the area was thicker.

Re: I found a crack in an odd place while pressure testing
 

Real small tight grain inclusions in cast iron can be sealed with sodium silicate or water glass. Brazing works well due to the lower heat that is required to solder a small spot and then let it cool slowly so it doesn't crack on you. Pin it with cast iron pins or put an NPT plug in it if it's not too large. All are acceptable methods for repair of small cracks or pin holes. I've seen leaks where the core wire didn't meld in with the cast iron during the pour. It will leave a pin hole that would be easy to plug.

Re: I found a crack in an odd place while pressure testing
 

I just got off the phone with a friend that has a welding shop. He recommends, drill holes on each end of the crack to relieve the stress and stop the crack from traveling. "V" out the crack lightly, and clean the area around the crack. Pre heat the area and TIG weld and use a filler rod called Phosphor Bronze. What you are doing is basically brazing with a TIG machine.

Re: I found a crack in an odd place while pressure testing
 

I would not stitch an area less than 1/8" thick. Access is great, so I would drill the crack ends and "v" the crack slightly then your choice of proven epoxy like Belzona or JB. That will likely hold longer than you. Can be repeated in the distant future, though I would not expect it to ever be a problem again. Looks to have stayed away from the exhaust port...your lucky!

After reading the above post, just my opinion, but I would avoid a heated solution. I have seen braze jobs crack on cooling. Especially thin areas that cool pretty fast.

Re: I found a crack in an odd place while pressure testing
 

The military uses DEVCON on diesel engine cracks like yours.......works great and lasts a long time. I have used it with excellent results.

Re: I found a crack in an odd place while pressure testing
 

Which Devcon? There are quite a few.


If this was a running vehicle, I'd wipe it off and apply a glob of PC-7, which is about the same as JB weld but thicker, and drive on. Since this is a fresh build and have other options, I'd like to make it as optimum as possible.


I'm definitely not going to MIG weld it.

Re: I found a crack in an odd place while pressure testing
 

Devcon steel V it out and grind the area around it a bit and CLEAN CLEAN CLEAN. you can even match the surface . JMHO

Re: I found a crack in an odd place while pressure testing
 

Whatever you decide to do, drill the ends of the crack first. That is the only thing that will stop the progression of it.

Re: I found a crack in an odd place while pressure testing
 

This is a 37 block in my stash I have had for a long time & was supposedly running well before I got it. The repair had obviously been done many moons ago with good success. Appears to be stick welded with a nickel rod.
Cheers Left front.
Tony

Re: I found a crack in an odd place while pressure testing
 

I am often a wild man.I had a car that I hated and I let the antifreeze get weak.It froze up and split the block on both sides from heads to pan. I V’d out both sides and stick welded it using nickel rod. I drove it for years afterward and had no problem with it. 90 Olds 307. I did not remove the heads or pan.

Re: I found a crack in an odd place while pressure testing
 

Poking around a little more through the lower pump hole, the crack ends real close to the wall of the exhaust port, so close that a drilled hole at the end of the crack might hit the outside of the port wall. That makes me wonder how hot an epoxy repair would get right there. JB weld isn't great for high heat. Devcon plastic steel is rated for 250°F. Belzona 1111 is rated for 396°F. Just feeling it with my fingers I estimate it at about 1/8" thick, no more than 3/16".

Re: I found a crack in an odd place while pressure testing
 

Most of the recommended repairs stated above are certainly very good . I performed this type of crack repair many times which has proven to work and never has failed after many years when the customer didn't want to spend a lot of money on high hour dozers as well as many other expensive engines in heavy off road equipment where labor and down time was a valuable commodity and repair costs would exceed the worth of the machine, This is how I done them and have had zero failures ,some of these repairs are still in service after 20 plus years on farm tractors etc. . Set cracked area horizontally (flat ) as to avoid run off, drill small holes at ends and plug if desired , vee out and clean with a solvent that dries without an oily residue ( I have used denatured alcohol or M.E.K etc.), blow dry with compressed air down into crack, seal off all water passages except for one,( MAKE SURE WHAT EVER YOU USE IS NOT FLAMABLE) and safe to use with an electric vacuum, take a shop vacuum and have assistant apply vacuum to the open water neck or fitting of water jacket, with a mix of suitable cold weld compound, epoxy , Belzona 1111 SUPER METAL , Devcon , J.B weld etc. have assistant apply vacuum to water jacket then feed the compound into the crack until it penetrates as deep as possible into the cracked area, let off vacuum ,smear liberal amount to the area over the cracked area while blending with the compound already fed into the crack, allow to dry the time needed to fully cure,(I allow atleast 24 hours), then refill and return to service. I done this 40 years ago on a flathead the machine shop said had core shift but was actually a freeze crack , after it was machined assembled and installed the crack became evident , when coolant was added it began to leak ,rather than dis -assemble, I done this and the present owner still hasn't had any issues with the crack repair ,I came up with this many years ago while traveling ,when a sand hole in my new 454 motor home reared it ugly head , being miles from a dealer I had to think of a temporary fix . we later done this to a junk block and cut it apart to see how it worked and the compound permeated the pores of the cracked cast iron . hope this helps.