Fixing a cracked block? 4.3 liter freeze damage

[Chass]

I just traded into an 88 Seaswirl 18' Sierra Cudy with an OMC 4.3 liter I/O. Its a nice boat and it runs great. Unfortunately I didn't notice the freeze plug in the bottom of the boat when I ran it. There is no water in the oil thus far. I put the freeze plug back in and it doesn't leak anymore. I've run it for half an hour with the water on it.

I noticed that it has a crack in the block on the drivers side on the outside water jacket of the middle cylinder. It leaks a fast steady drip from the crack. If the cracking is isolated to the visible external crack couldn't I continue to use this engine?

I figure I have three options:

1) Replace the engine/block

2) Run it like it is. Whats a little water in the bottom of the boat? Thats what a bilge pump is for right? I've seen Cummins 53 blocks and old jeep engines run for years with cracked blocks.

3) Clean it up really well and grind it to bare metal. Then JB Weld or use some other metal bonding agent to seal it up. Since this is not a closed system like a car, it shouldn't build a lot of pressure correct? Is it possible that the JB Weld will actually keep it from leaking indefinitely? What are the risks to running it this way?

Anyone have any experience with this sort of thing?

Thanks,
Chass
ct

 

[Fishermark]

Re: Fixing a cracked block? 4.3 liter freeze damage

Given that it is an 88 OMC... I would go for door #3. Grind it down, slap some JB Weld on it and go boating.

 

[chiefalen]

Re: Fixing a cracked block? 4.3 liter freeze damage

I saw a straight 6 with jb weld on it for 10 years. Ran great no problems old pos. Got to be perfectly clean use some acertone after grinding it down. I have also seen magnafluxed blocks last for years.

 

[danond]

Re: Fixing a cracked block? 4.3 liter freeze damage

Slightly unrelated to marine but my dad's '89 Ranger has 100,000 plus on a jb-welded camshaft drive gear.

It's not a guarantee, but it only takes time to give it a shot. Cost is next to nothing, so why not? Go for it!

Keep oars in the ski locker.

 

[bomar76]

Re: Fixing a cracked block? 4.3 liter freeze damage

I have also seen magnafluxed blocks last for years.

?????
That made zero sense.....well I guess in some twisted way it could, as in saying " I have seen blocks painted green last for years".

Magnaflux is method of DETECTING cracks ....here is a little info from Wikipedia on it:

"Magnafluxing, developed originally by Carl E. Betz, is a method of testing ferrous metals for surface and subsurface flaws. The component being tested must be made of a ferromagnetic material such as iron, nickel or cobalt, or some of their alloys. This test is often used on industrial tools, and engine parts during maintenance inspections. It can also be used to diagnose failure, as in crash investigations.

It works by applying a magnetic field to the component under test, using e.g. a permanent magnet. This will cause a high concentration of magnetic flux at surface cracks, which can be made visible by dusting iron powder or a similar magnetic material over the component.

Parts can be tested using one of two methods. The wet method consist of bathing the parts in a solution containing iron oxide particles. The wetted part is then placed in a magnetic field and inspected using a black light (ultraviolet light). The iron oxide particles are attracted to surface discontinuities or cracks, where the magnetic field is discontinuous. The particles flux around the imperfections and the patterns are visible under the black light.

The dry method is based on the same principle. Parts are dusted with iron oxide particles and charged using a yoke. The particles are attracted to the discontinuities and are visible by black light."


...so, magafluxing a block (or any other ferrous metal) doesn't have a thing to do with repairing cracks, it is a method of detecting cracks, and since most marine engines leak like a sieve where they cracked due to poor or no winterization I can't see a whole lotta use for the process in this or any other ice crack situation.

 

[Bondo]

Re: Fixing a cracked block? 4.3 liter freeze damage

it shouldn't build a lot of pressure correct? Is it possible that the JB Weld will actually keep it from leaking indefinitely?

Ayuh,.....

Even with an open cooling system, there's the potential for up to about 15psi.....
But,...
I've seen,+ done quite a few blocks with Epoxy, that held for Years....

Like anything else,... Proper preparation is the Key,.....
That,+ it only works if there's No internal cracks......

 

[chiefalen]

Re: Fixing a cracked block? 4.3 liter freeze damage

Of course bomar is correct as usual.

I misspoke, powder welding also known as flame spray welding is what I meant to post. Been around for 40 years or more. Mixed results, but last 10 years or so been more reliable.

I regret using the wrong terminalagy.

However there is also furnace welding. Can't be done in the boat.

 

[Chass]

Re: Fixing a cracked block? 4.3 liter freeze damage

Thanks for the input. I got an overwhelming "give it a try, you've got nothing to lose" answer from this forum and my local forum so I did it.

I pulled the hoses and wires necessary to get to the crack with my die grinder. I cleaned it up to bare metal and mixed up some standard JB Weld. I massaged it into the crack as someone suggested and then put a good layer on. My only problem was getting it to stay in place because the crack is down low and facing down. The JB weld kept dripping off until it had just began to set up. Anyway after it set up just a little it was fine.

I let it sit for 36 hours and then ran the boat with water on it. No leaks and still no water in the oil so I headed up to the lake.

We put the boat in the water and warmed it up. Then headed up the lake a little ways. I checked on things periodically and never had a leak or any water in the oil. I ran the boat at full throttle for a little while just to load it and still never had any problems.

I'm pretty pleased that its working out. I'll keep an eye on it when I use the boat but I'm confident that its fixed.

Thanks everyone!

Now, where do you have a prop repaired?

Chass
ct

 

[Chass]

Re: Fixing a cracked block? 4.3 liter freeze damage

Ok, you've got me there!

Chass
ct

 

[Silvertip]

Re: Fixing a cracked block? 4.3 liter freeze damage

Cracks can continue to expand if not stopped. One way to do that is to drill a small hole at each end of the crack. If you do that, why not tap the hole at each end of the crack, fashion a plate to cover the crack. Grind the crack out, pack it with JB weld, epoxy or any other similar product and bolt the plate and a hand cut gasket over it. It has been done many times before and I've seen it done on a tractor engine that had a hole in the block the size of ones fist where a rod came through. Obviously it took many more bolts and a bigger plate but a little time and effort can turn a so-so fix into a more permanent and very inexpensive fix. Access is the key factor in a repair of this nature.

 

[Chass]

Re: Fixing a cracked block? 4.3 liter freeze damage

I'm pretty sure I'd have to pull the engine to get that kind of access. Plus this isn't a crack caused by continuing stress. It was a one time freeze. If it ever froze again, I would expect it to crack the JB weld but not unless that were to happen.

I did consider that type of option but I'm not sure that this crack is in any danger of continuing. I hope I'm right!

Chass
ct

 

[hard-3]

Re: Fixing a cracked block? 4.3 liter freeze damage

you know the best way to test it for longivity is to invite a few friends to go for a day out to ski if it does not bust wide open then murphy was not in law school the day you fixed it!!!

 

[Chass]

Re: Fixing a cracked block? 4.3 liter freeze damage

I spent the afternoon running around on the lake again yesterday. Boat ran great and still has no water in the oil. I had a big load of people and put some pretty hard stress on that engine.

Thanks to JB Weld!

Chass
ct