Cracked Block-Freeze damage

[airloans]

1988 OMC Cobra 5.0 V-8, early freeze one night and the block is toast. 4 inch crack in side of block 2 - 3 inches above oil pan lip. <br />1. If (and I know this is a big if) damage is limited to the external area of the bock can it be repaired? What do repairs of this type cost.<br />2. If block is history, how many hours of labor would it take to R & R engine and overhaul (boat shop). Been many years since I overhauled an engine, but it shouldn't be that much different than an auto engine.

 

[Capt Ken]

Re: Cracked Block-Freeze damage

The block may not be your only problem. The exhaust manifolds may have also been damaged internally. If you're inclined, you can find another good block that still has a standard bore and rebuild it using your internal parts. Time to rebuild can depend on alot of things like, doesn't the carb need rebuilding, grinding valves, removing and reinstalling engine and such. So what's with the airloan? Ya into financing planes or selling air?

 

[airloans]

Re: Cracked Block-Freeze damage

I do finance aircraft, that is what the name is about.

 

[Trent]

Re: Cracked Block-Freeze damage

Since Ken is looking for a plane...Hmmm maybe yall two could work out a deal??

 

[Capt Ken]

Re: Cracked Block-Freeze damage

Boy have I got a deal for him.

 

[SS MAYFLOAT]

Re: Cracked Block-Freeze damage

There is a way that the block can be repaired cheaply with a drill, 4" grinder, pipe tap, pipe dope, and pipe plugs. The process is called "Lacing". If there is no internal damage (water in the oil), and a straight line crack (not around a corner) the repair can be done with the engine in the boat and no need to tear down. You may have to remove the exhaust manifold to gain access.<br /><br />If you are interested in this process, E-mail me at SSMAYFLOAT@neo.rr.com.<br /><br />I have successfully done numerous blocks like this caused by freeze damage. It does not weaken the integrity of the block, but will maintain its strength. Good Luck

 

[flashback]

Re: Cracked Block-Freeze damage

hey mayfloat, i have read about lacing and it sounds good. question, whats the grinder for?

 

[SS MAYFLOAT]

Re: Cracked Block-Freeze damage

The grinder is to grind off the top of the pipe plug once it is place. After the plug is flush with the block, you then drill into the crack overlapping into the plug you just installed. Then repeat the cycle until the crack is laced up. Make sure that the plugs you use are solid ones.

 

[Mumblerone]

Re: Cracked Block-Freeze damage

SSMAYFLOAT...years ago, we had an early freeze while trailering our race car (Corvette) to Lime Rock, Conn...neadless to say it cracked the block as described above. We thought we were going to make a temporary repair that might work. Drain the water and blow dry the area. We carefully ground down the area (an into the crack) with a small grinder/sander, drilled a small hole(1/8th inch) at each end of the crack. We then smoothly put epoxy over the crack, about 1/4" thick. Hit it with some paint (orange). We got lucky...that motor lasted for several rebuilds until it finally 'blowed-up'; for other reasons. Might this not be worth a try first? There is no engine stress in that area.

 

[Capt Ken]

Re: Cracked Block-Freeze damage

That lacing sounds like a real labor intensive job. Can you imagine how long you would have to lay under that engine to drill and tap say a 6 inch crack with each plug overlapping the last plug.

 

[SS MAYFLOAT]

Re: Cracked Block-Freeze damage

It doesn't take that long. I use 1/2" black iron plugs. If your crack is 6" long (say 7" to allow a half inch overlap at each end of the crack) That is 14 plugs = 14 holes. I can do that in about 2 hours or less. Of course I do lots of fabricating and service work, so its not that big of a deal for me. No matter what a project is, the first time will always take longer for anybody.<br /><br />What is nice about this type of repair, is once it is ground down smooth and flush with the block. It then can be painted and nobody will know that the block was ever cracked.<br /><br />This is the type repair that the old timers used before epoxy and JB Weld. In fact it is something that I had learned from my father. It is a practice that has saved me money as well as my friends. I have known several shops that do this procedure and charge for a new block. Of course I don't recommend these shops to anyone.<br /><br />I do suggest that a casting port (freeze plug) be removed to flush out any metal from the drilling/tapping. Second tip is use a good quality pipe tap. Broken taps are a pain in the butt to remove.

 

[Walt T]

Re: Cracked Block-Freeze damage

I should point out that it's possible a repair like that will leave you stranded on the water with possible safety problems should a storm come up.

 

[SS MAYFLOAT]

Re: Cracked Block-Freeze damage

DieselWalt, How do you figure? When the plugs are installed with proper overlap, with the threads interlocking, it works similar to the keystone in an arch. <br /><br />I know I have performed this procedure on a dozen or so blocks. Nobody has ever come back with a problem of leakeage or damage from the repair. I know two of the engines that were done in the early 80's is still in my buddies boats. Both have even been pulled and complete overhauls performed. If they thought for one minuet that the repair was questionable, they would have not rebuilt them. I even suggested to them that they should get new blocks, but said they were confident with the repair.<br /><br />This method is a cheap reliable and proven way of repair. Just don't do it if you don't feel confident in your work. IMHO those that use JB Weld or other epoxies for cracks on cast scare the crap out of me.

 

[ODDD1]

Re: Cracked Block-Freeze damage

I gotta throw my 2 cents in here...have never been confident of a frozen, cracked and repaired cylinder block...most cylinder blocks crack horizontally along either the lower edge of the deck [were the cylinder head bolts on] or along the bottom of the water jackets just above the oil pan rail...the outer wall of the block is as important as the cylinder when you think about holding the main bearings in place under the cylinder heads...these 2 items are trying VERY hard to get away from each other, and the cylinders and outer wall of the block are what's holding them together....you crack a block externally and lose 25% of that blocks strength...internally and externally and its half gone...do I want such a thing in my my boat? no freakin way.....

 

[geriksen]

Re: Cracked Block-Freeze damage

I agree with ODD1. You should pull the intake and look for cracks on block in the valley. That is where they are usually the worst. Get another block and trasfer the guts. Anything else is a patch and if you sell that boat, you will get sued, even if it manages to hold up.