Help! Cracked block from freezing

[Dan Crenshaw]

I have an '83 Chris Craft with a 350 V-8 that I have been rebuilding for a year and when I winterized it I missed a freeze plug and just got back from the lake for the first test run of the year and water is pouring out of a crack on the left side of the engine just above freeze plug. I have had 4 different boats over the last 20 years and don't have a clue how I missed one. I checked the oil and there doesn't seem to be any water in the oil. Is there a difference in a crack that is only on the outside and only pouring water out the side of the engine like mine but not into the oil compared to a crack that is also allowing water into the oil? Or does it not really matter because the required repair is the same? I think it is a GM 350 V-8. Can I get a automotive repalcement block and everything off mine will bolt right on or does it have to be a marine engine?

 

[Don S]

Re: Help! Cracked block from freezing

It may be pouring water through the outside crack because an inside crack is smaller. You could patch the outside crackes with things like JB weld, and marine tex, to find out if then it leaks internally.
Personally, I wouldn't go out on a boat on any body of water that was patched like that. But many do and most eventually get towed back to the dock by a good samaritan that took pitty on them and use is off time for towing.

 

[danond]

Re: Help! Cracked block from freezing

Just for clarity's sake - I don't think you weren't opening freeze plugs - those are drains.

If your heads aren't cracked you can use a new marine short-block. The cam is typically different as are the head gaskets and the casting plugs. You can also use any matching 350 but it probably will need a marine cam and brass casting plugs.

Also - yes, you can JB weld or whatever the crack in the block, but it's a very temporary fix, and I'm with Don. I wouldn't go on anyone's boat with a cracked block. It can sink awfully fast.

 

[Dan Crenshaw]

Re: Help! Cracked block from freezing

I agree, I don't want to patch it. I want to replace the block but I want to do it as inexpensively as possible. Will it be better to just buy a marine short block instead of trying to get a deal on an automotive block from a junk yard then having to install a marine cam and brass casting plugs? It has been a long time since I did any major engine work but I think I am up to it.

 

[harleyette]

Re: Help! Cracked block from freezing

I agree, I don't want to patch it. I want to replace the block but I want to do it as inexpensively as possible. Will it be better to just buy a marine short block instead of trying to get a deal on an automotive block from a junk yard then having to install a marine cam and brass casting plugs? It has been a long time since I did any major engine work but I think I am up to it.

Ray's Crack Repair in Hodgenville KY repairs cracked marine blocks without welding, he pins them. Highly recommended. Phone 270-358-0934 if not there leave message, he may be on the house boat

 

[harleyette]

Re: Help! Cracked block from freezing

Ray's Crack Repair in Hodgenville KY repairs cracked marine blocks without welding, he pins them. Highly recommended. Phone 270-358-0934 if not there leave message, he may be on the house boat

 

[Dan Crenshaw]

Re: Help! Cracked block from freezing

I assume this option is only able to be done if there is no water in the oil. I ran the engine for 2 or 3 minutes and even loaded the boat back on the trailer under its own power but was that long enough to know if it is only a crack in the water jacket or do I need to put muffs on it (so I don't have to drive back down to the lake 45 min away) and run it for a whileto see if it spews creamy oil out of the carb? if I run it til that happens and I then know I have no choice except to replace the block, will that cause any damage to other parts that I could have reused had I not run it til the milk spewed?

 

[Dan Crenshaw]

Re: Help! Cracked block from freezing

Update on cracked block. I ground it down and cleaned it up then JB Welded it. It has been doing fine for 2 seasons. I will update this post if the repair fails. Maybe I'll get lucky and it will last 3 or 4 yrs.

 

[scoflaw]

Re: Help! Cracked block from freezing

Similar kudos for jb weld