Did I do this right ?

[capthook]

I was taking out all the seats and stuff in my boat so my wife can reupholster them, when I found a crack in my block. This is a 1973 gm 3.0 inline 4. I noticed water rust marks running down the block. I got down there and looked and seen the crack. I ran my finger across it and it seeped just a little. So I put the muffs on and started the boat. I watched it very closely and seen it weep for a few minutes then just stopped. The boat has never been over 140 degrees and has never showed any signs of wanting to over heat. My guess is that it has been there a while and I have just never noticed it. So I got my drill out and drill a little into the block on both ends of the crack. I then got some JB weld and spread this on evenly over the crack. I have been letting it cure since about 5 pm yesterday. What experience has everyone here if any had with block cracks and getting away with this? Thanks everyone.

 

[Windykid]

Re: Did I do this right ?

The problem is you have to drill all the way through on both sides to keep the crack from walking.

You seem to be experiencing the lucky crack, as when the motor heats up the metal expands and tightens the crack instead of expanding the crack.

You may get lucky with the JB weld but I dont think it will last. Maybe you can get through this season. But I thing you will have to pull the motor and have it welded professionaly or replace the block.

 

[capthook]

Re: Did I do this right ?

Thanks. Do I have to be extra careful when drilling through the block? I don't want to drill to deep and hit something. I am hoping that this cures the problem, not that it ever really seemed to be the problem. Thanks again.

 

[capthook]

Re: Did I do this right ?

anymore suggestions or ideas?

 

[Windykid]

Re: Did I do this right ?

Take it slow when drilling through. You should put some greese on the drill bit so you dont put any shavings in the passage.

 

[capthook]

Re: Did I do this right ?

I will give this a try. I already put the JB Weld on so I will have to grind this back off. Hopefully I am in good shape. The oil looks as good as it did the day that I put it in.

 

[Windykid]

Re: Did I do this right ?

let us know how it works out!

 

[MRS]

Re: Did I do this right ?

I did what you did to yours I also wire brushed with a drill that was four or five years ago still holding. Good luck with yours.........

 

[capthook]

Re: Did I do this right ?

Well it turned out fine. I have no leaks from the crack. The jb weld seemed to do the trick. now I have another issue. My crank case oil has a very little hint of water. This was not there when I repaired the crack. I think that I have a gasket going bad letting in water because I also have a small oil leak where the manifold meets the head back by the riser. Hopefully this is all. Thanks.

 

[capthook]

Re: Did I do this right ?

one more thing. I am still not sure if my engine is the 153CI or the 181CI my engine serial number is 3437004 and the tag says mercury. Any help would be great

 

[cheburashka]

Re: Did I do this right ?

I've been going through a similar problem with the same engine. You need to do a leakdown test. The easiest way to do it is to fit an old car valve stem into a section of hose that's attached to the intake junction at the thermostat housing, and block the hose that goes into the manifold. Then use a bicycle pump to pump it up to 15 lbs. You get a feel for how many pumps it takes to get it to 15. Do it dry first and wait, then check the pressure after ten minutes or so. There should still be pressure. In fact, the pressure should hold for a lot longer than that. Next step is to fill the system with soapy water, all the way to the top. Then pressurize it again and listen/look for leaks. On mine, there was a crack in the cylinder head which seeped out a small amount of water, but it put the water out under the valve cover gasket and it found its way into the oil. You may have a similar problem. Another thing to check is the exhaust manifold. Mine cracked from the freeze and allowed water to seep into the intake.

I don't know if the internal side of the water jacket is vulnerable to freeze damage on these engines, and I've heard from a lot of people who were able to patch external cracks and still keep the engines running. I do know that the head is vulnerable. I've also learned to have more respect for ice. It's some powerful stuff!

The irritating thing is that the water always leaks out of the biggest hole, but that doesn't ensure that the ice didn't make more holes that you just aren't seeing yet. I'm getting very tired of saying "well, it looks like I dodged a bullet" every time I find something else destroyed by last winter's freeze.