I found a crack in an odd place while pressure testing

[Yoyodyne]

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

[alanwoodieman]

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

[Tim Ayers]

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.

[Ol' Ron]

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

[30Murray]

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.

[Eagle43]

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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.

[marko39]

try Devcon, it hardens like steel.

[Tim Ayers]

Originally Posted by Eagle43

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.

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.

[woodiewagon46]

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.

[rotorwrench]

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.

[woodiewagon46]

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.

[Russ/40]

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.

[hotrodart]

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

[Yoyodyne]

Originally Posted by hotrodart

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

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.

[jimvette59]

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

[JSeery]

Originally Posted by Yoyodyne

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.

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

[KiWinUS]

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

[Andy]

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.

[Yoyodyne]

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".

[Fordestes]

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.

[GB SISSON]

Fordestes, I love that kind of solution. Mechanical but with the twist of the suction I really understand that it would work. I have seen way too many jb weld and marine tex repairs that didn't hold up due to poor prep work. If your vacuum could pull a blob into and just past the crack it would be a great repair for pressure pushing out. Gonna find me some belzona 1111!

[Yoyodyne]

Originally Posted by Fordestes

hope this helps.

Thanks, great idea! I can use a vacuum pump.

[Yoyodyne]

Originally Posted by GB SISSON

Gonna find me some belzona 1111!

If you find a source of small quantities, please share. I found 1 KG for $400.

[Tim Ayers]

Originally Posted by Yoyodyne

If you find a source of small quantities, please share. I found 1 KG for $400.

Yes, expensive. 1111 is not sold in small quantities any longer. This is why I used 1212. Sold in smaller quantities and designed to be used for metal that is not surgical clean.

My advise would be to call Belzona. They have local field reps that work your area. In the mean time, send me a message. I have an offer for you.

[glennpm]

I'm a fan of JB Weld but have also used Blue Magic Extreme. Both have very high temperature products. I used the Blue Magic QuikSteel Extreme on pin holes in an exhaust header a couple of years ago and the repair is still fine.

We used Belzona in the power plants I've worked on. It makes sound permanent repairs.

https://www.oreillyauto.com/detail/b.../37901/4388157

https://www.quiksteel.com/brands/QuikSteel.html



Get the surface very clean. I would use acetone for the final cleaning.

[Fordestes]

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Check with your local welding shop , we found a cold weld compound at a welding supply, we had a Dozer with a cracked radiator tube, I used the same process to repair the damaged tube and within 24 hours it was and still is running , the labor to repair the machine was over $5000 ,the construction company had a deadline and a week of down time was out of the question . I have used regular J.B. Weld in a high heat area without issues, I wont use J.B quick for a high heat area, I personally would try the regular J.B. weld in your case, I have used regular J.B to repair a damaged 3208 Caterpillar block deck at the fire ring area ,the repair lasted me over 6 months while being driven700 plus miles in a week till the new replacement truck arrived, I Designed an injection tool to force the compound into the crack and then built up the deck surface around the top of the cylinder fire ring area, I have used Marinetex on lower water jacket cracks (low heat area) and none have failed. Mabe you can find a sample size from the manufacture or a dealer, check with a caterpillar dealership ,some mechanic may have a bit left over from a previous repair ?

[glennpm]

Yes good point on not using the J-B Weld Kwik version. It has poorer properties than the "regular"


From https://www.jbweld.com/product/j-b-weld-twin-tube


"J-B Weld™ is The Original Cold Weld two-part epoxy system that provides strong, lasting repairs to metal and multiple surfaces. Mixed at a ratio of 1:1, it forms a permanent bond and can be shaped, tapped, filed, sanded and drilled after curing. At room temperature, J-B Weld™ sets in 4-6 hours to a dark grey color. A full cure is reached in 15-24 hours. J-B Weld™ has a tensile strength of 5020 PSI and sets to a hard bond overnight. It can withstand temperatures up to 550ºF when fully cured."


For a vertical surface like yours, you will want to dam the J-B to keep it where you want. It helps to let it setup for a little while before putting the final coat on. For vacuum or injection in the crack, apply it right away.


I find that blue masking tape is good for the dam. You can also keep moving it up with a pop-sickle like stick for a few hours after you apply it. check it every fifteen minutes or so.

[Fordestes]

It looks like the engine is on the stand , so tilting it horizontal as I stated above would be the best.as the compound is vacuumed in you should see a pattern of the crack slowly sinking into the cracked area, that indicates it is working and allows you to see what portion is being treated, remember to smear a little over the area after the vac. is removed and make sure it does not keep seeping in during the cure time as to avoid a pin hole in the crack surface. I had it seep overnight and had to redo a small area, that was a large cracked though.