93 Mercruiser internal & external engine block crack can it be welded or just junk it

[saltybutwet]

93 Mercruiser internal & external engine block crack can it be welded or just junk it

93 mercruiser 3.0 engine blocked cracked. It took me months to trace the root cause of my milky oil . I found that I had an internal engine block crack, and an external hairline crack that someone tried to do some jb welding on.

my question is: can this internal engine block crack be welded, inside and out, or just junk it? it is in the water jacket below cylinder 2

I have already removed all internal parts, and I just have a block on the stand, and not sure if it will be coat effective to have this welded by a professional, provided it can be done.
thanks for any input

 

[alldodge]

I would junk the block. JB weld on outside cracks are fine but I personally have never found anyone which can weld cast iron and have it last

 

[saltybutwet]

thanks for the input

 

[saltybutwet]

I have been told a professional can weld the the block, and it would be better than new, but I haven't taken the block into the shop to conform

I will keep asking around

 

[NHGuy]

It would require too much cost to weld correctly. I did some research on this a few years ago. Apparently to weld cast metal correctly requires the casting to be at very high temps. Can you get to the source of the water jacket crack? If so, and if this motor is OK otherwise, JB weld it.
Drill the ends of the cracks to stop the crack moving. Clean the area perfectly. Use a solvent cleaner and wipe it all away once clean. Apply your epoxy, then while the JB is setting warm it with a heat gun. That liquifies the JB and fills the repair area better than just laying it over the top.
You can also stitch it. With stitching you drill and plug the crack, it's a project but folks do it to save otherwise lost parts. The benefit to stitching is it would hold pressure well. We don't need that in boats because they flow very low pressure cooling water.

Since your crack is so far down in the motor wait a couple of days after the repair for a complete cure and do another pressure test before putting it back together.

Or find a block...might be the thing to do

 

[saltybutwet]

It would require too much cost to weld correctly. I did some research on this a few years ago. Apparently to weld cast metal correctly requires the casting to be at very high temps. Can you get to the source of the water jacket crack? If so, and if this motor is OK otherwise, JB weld it.
Drill the ends of the cracks to stop the crack moving. Clean the area perfectly. Use a solvent cleaner and wipe it all away once clean. Apply your epoxy, then while the JB is setting warm it with a heat gun. That liquifies the JB and fills the repair area better than just laying it over the top.
You can also stitch it. With stitching you drill and plug the crack, it's a project but folks do it to save otherwise lost parts. The benefit to stitching is it would hold pressure well. We don't need that in boats because they flow very low pressure cooling water.

Since your crack is so far down in the motor wait a couple of days after the repair for a complete cure and do another pressure test before putting it back together.

Or find a block...might be the thing to do

thanks for the input and advice
I have the block disassembled at this point so getting to the crack is no problem. The crank and rod bearings have been oil starved so it will need new ones, cam bearings look good but will replace them also, if I think I can use this block

I went to a reputable Machine shop who does work for the county I work for. I explained to the owner about the cracked block issue, he wants to look at the block, crank, cam pistons, rods ect. The owner thinks it can be repaired with block filler, he gave me a estimate of 400 - 600 for tanking the engine, possible crack repair without pinning, bore cylinders, checking crank, can, new bearings and over sized pistons and rings, mill deck and I may need some miscellaneous other parts

This engine has excellent compression on all 4 cylinders 180-178 so I wonder if the cylinders can just be honed and new rings on the original pistons
here are a few pics of the engine block
cylinder #3 crack just below the black marker

cylinder #4

cylinder #2

Cylinder #1