M_norrick

I recently purchased a 1994 powerquest 257 with the drive tore off of it. This boat looks incredible minus the missing bravo1. I immediately pulled the engine, replaced transom assembly, etc etc. Five minutes before reinstalling the 502 I noticed something. A SIX INCH CRACK IN THE BLOCK!!! Talk about a bad nite! I notices the petcock valve on the block was closed on that side. I opened it up and water came out ofcourse. I didn't see any oil in with the water. I then drained the engine oil and seen no signs of water in the oil. So I am "assuming" it simply cracked the water jacket. Has anyone ever repaired anything like this and what is the cheapest and most reliable route to take? I have read about "lock n stitch" methods but not sure how good it is. I have also done research on nicel welding the crack. Any insight is greatly appreciated! Looks like I won't be boating next weekend as planned

sr73z

if the crack is near the deck, then the block is most likely scrap. yes it can be welded, but reliability will be a problem with heads torqued down and heat cycles etc. if crack is down by oil pan rail, may be ok. best bet to take to a machine shop you trust and ask if it can be fixed. a good shop won't fix if they know it won't hold up.

Budman II

iTrader: (1)

Cast iron can be difficult to weld, and my understanding is the whole piece has to be heated up super hot to get the weld to hold. That would mean that it would have to be stripped down to a bare block anyway. You would want to have it examined closely and magnafluxed to make sure there is not also a crack on the inside. If the engine had not been run, there might be a hairline crack inside that was not allowing water to get in while it was just sitting. Also, if a very small crack were to extend down into the main journal webbing, the structural integrity of the block would be compromised.

It may be repairable, but it is probably a long shot.

M_norrick

What exactly ar you calling the "deck". The crack is a right above the freeze plug and is around 3" roughly from the bottom of the head. It runs horizontally.. Thus parallel with the head. I think I am going to try a weld first. If it fails I will pull engine again and tear down to block. A place here in town said they could cast fusion weld it and magnetite for 400 bucks. They said they heat to 1400 degrees F and actually fuse the crack together... Then Re-magnaflux it.

cubicinches

The Lock N Stitch method, or any other type of pinning repair is best for a crack in that area. If the person performing the pinning is experineced, you can get an excellent repair. Welding a crack of that size will typically result in a mediocre repair at best, and the rest of the surrounding area is compromised from the heat... Deck warpage, etc. Cast iron was never meant to be welded. Cast spray welding does work well for certain repairs, but in an area that large, the heat becomes an issue. Find someone to pin it.

DMOORE

For the price of a good used block.. I wouldn't even think about messing the a cracked cast iron block. There are plenty of good used blocks out there that will do the job for you.



Darrell.

cubicinches

That's true... If only it stopped at the cost of the block.

Add in the cost of teardown and reassembly by someone competent, cleaning of parts, rings, bearings, gaskets... at the very least. Unless you're going to tear it all down and re-use the old suff... which is probably a bad idea. Pinning can be done with almost no disassembly of the engine, other than possibly some external components to gain access to the area.

Of course, if it's not getting water in the oil, you could always run it the way it is and let it leak water into the bilge, or smear some JB weld on it and call it a day... I've seen both done before. Might not be the perfect scenario, but the price is right...

tinman565

Did the place in town say they would give you your money back if it doesn't hold ? Take the $400 and find another block sir. If you don't....I see you spending the money for the repair, and then spending more later for another block. Be smart...not cheap.

M_norrick

After doing a ton of more research and examining the area, taking in consideration of transportation issues, and even more research. I have came to the conclusion of trying the putty method. I plan to drill a small hole at the ends of the cracks to make them stop. Then plan to use a die grinder and grind an ever so small valley in the crack. Then use an epoxy putty.

I will put e everything back together and run it. Then ofcourse check the oil for tell tell signs of water. From what I have read and talked to others, there is little or no pressure on the water jacket of the engine in a marine engine due to the fact it gets blown out the exhaust ( in my case). In an automotive application, there is pressure, and would not even try this. I wish I could afford new block with teardown and reassembly but unfortunately I am boating on a budget.. Lol. Thought I would give this a shot first and see how it goes. Who knows.... May permanently fix it thanks again for all of the information!

Ted G

iTrader: (1)

You could try epoxy or JB Weld but understand it is definitely under pressure. My HP500 runs almost 25 psi at 60 and around 15 psi at 35-40. I would not spend money on shaky repairs like welds, epoxy it and if it fails you know what you need to do.