Abrupt and Massive Inflow of Water Into Oil

[Marian Claire]

After removing the water jacket cover and digging around some. The leak is in located the forward part of the "floor" of that chamber. This matches what I found when looking up thru the top of the crank case. The cylinder walls and the other parts of the chamber look to be in good shape compared to some of the pics we have seen on the forum. I did poke around some trying to find bad spots.
The shape of the leak makes me wonder if this area froze at some point. Possible many years ago. I am not that familiar with freeze damage other than frozen copper water supply lines. Man that brings back some memories.
As best I know this A-4 has always been RW cooled and in the brackish water of the lower Neuse River. I believe it is a MMI rebuild and I need to contact Ken and see if he can date it with the block #. Seeing how good the A-4 looks in general and the good compression #s I bet it is not that old. A freezing issue has no sense of time.

Dan
S/V Marian Claire

Edit: "There were recently several blocks with a crack on the floor of the cooling chamber above the crankshaft (freeze damage?)." Post # 25.

[Surcouf]

Edit: "There were recently several blocks with a crack on the floor of the cooling chamber above the crankshaft (freeze damage?)." Post # 25.

I would recommend to read that whole thread, block got repaired

https://www.moyermarineforum.com/forums/showthread.php?t=10561&highlight=cracked+block&page=4

Another block with a crack on the bottom of the block, likely freeze damage, look at post #15 for the crack

https://www.moyermarineforum.com/forums/showthread.php?p=124528#post124528

[Marian Claire]

After cleaning out the area around the leak this is what I found. Looks like the crack was repaired/stitched and the repair material failed. The block seems to be intact and retains the shape of the drill holes. Also it looks like some repairs below the open section. I think they are in the area where the cylinder wall/block/water jacket wall all come together. I wonder if those "holes" did not go all the way thru and where not exposed to the cooling water. ???
Everything else on the motor is in such good shape I want to explore any repair option I can before writing off the block. Pipe dream??

Dan
S/V Marian Claire

[Surcouf]

After cleaning out the area around the leak this is what I found. Looks like the crack was repaired/stitched and the repair material failed. The block seems to be intact and retains the shape of the drill holes. Also it looks like some repairs below the open section. I think they are in the area where the cylinder wall/block/water jacket wall all come together. I wonder if those "holes" did not go all the way thru and where not exposed to the cooling water. ???
Everything else on the motor is in such good shape I want to explore any repair option I can before writing off the block. Pipe dream??

Dan
S/V Marian Claire

Very impressive... I can't believe somebody did all that prep work and did not finish the work, or that ALL the repair material could fail. Was there some material in those holes before you cleaned? This would have been a major leak, not a minor one like described before...

I am not sure it is still suitable for a stitch repair with these holes already drilled like these.
I would recommend to call Don / Ken, and try (won't be easy) to find a block repair shop who knows what they do. It indeed looks pretty clean. Do you have more pics of the outside of the clean block?

[Marian Claire]

"Was there some material in those holes before you cleaned?"
Yes. But I could easily poke thru with the sharp end of a chainsaw file. It was not until I accessed the water chamber, flushed out the little bit of goop and cleaned off the crankcase side that I could see the shape of the drill holes.
"Do you have more pics of the outside of the clean block?" I can try and take some today.
I can say that compared to what I have seen firsthand and in pics on the forum this A-4 is in good condition. Not counting the leak.
When I first found the leak I assumed that the block itself had rusted thru and there could be other places just as bad. Considering the solid and well defined edges of the holes I think the block may be fine and it was just the plug/filler material that failed.

Dan
S/V Marian Claire

[Dave Neptune]

Dan, sorry to hear you found some cracks. It does sound like it has been repaired before. If you are fresh water cooled, I'd take it to a good automotive/marine welder to see if they think they can stitch back together. Also ask them what they think of the "stitching" that was done before. If the block is in good shape as far as the material remaining your good to go for another stitching.

A fresh water cooled "stitched properly" block should yield many more year of service.

Dave Neptune

[ronstory]

Makes you wonder if the steel they used for stitching was off a bit from the galvanic voltage of the cast iron block. With our block and pan supposedly are 'high nickel', which gives it a "lower" galvanic voltage then the typical cast iron of detroit style engine block. The galvanic voltage of mild steel and typical cast iron are effectively the same.

Since the stitching plugs rusted away, it lead me to believe it was greater galvanic voltage and those plug became the 'sacrificial anode' for the block. Add in brackish RW cooling to the process... that does not help.

Perhap the corrosion additives in the coolant for FWC would have protected it... but we may never know.

OK, that was my random musings for the day.