22v / Marine Power 340 Cracked Block Advice

[co99tj]

Hi All -

Got a dilemma I need some advice on from this great group. I just took my boat to be summerized and they discovered that the mechanic that winterized the boat forgot one of the plugs and left water in the motor over the winter. The "freeze plug" in the casting popped out and was sitting in the bilge - but there was indication of a small crack on the outside of the block. They told me it would most likely require a new motor - but there was a chance that the freeze plug "did it's job" and saved any significant damage...although they said that was a rare possibility.

Long story short - it turns out that the motor ran just fine on a hose for a good hour with no indication of leaks or water in the oil. They put the freeze plug back in the motor and said to just keep an eye on it for the first few times on the lake with a load on it to make sure there aren't any issues.

The mechanic that winterized the boat has been very accommodating and took responsibility and offered to replace the motor if it did indeed fail. However - now my dilemma is that the motor seems to be running fine and they think perhaps the crack is small enough that it's not causing any problems or is not cracked all the way through and could be fixed with JB Weld, etc.

My concern is that now I have a low-hour boat with a potential cracked block that I'm going to stress about for the next 5 years every time we are out...checking the oil after every session, looking for water / oil in the bilge, etc...and just generally not enjoying my time on the boat. With repeated heating and cooling cycles of running, stopping, etc. I'm wondering if this could become a bigger issue over time and eventually the motor fails and who knows if the mechanic is still around or in business - leaving me to take a huge risk (not to mention a hit to resale if I decide to sell the boat).

Could use some advice from this group as I'm by no means a mechanic and don't know much about freezing blocks, other potential issues, etc. If the block is indeed cracked, is it possible that it will worsen over time? Or if it runs perfect now does that mean most likely any significant damage was avoided and JB Weld on the crack would prevent any further damage?

What would you do in this situation? If the engine failed on the first test, it would be an easy answer...replace the motor. But since it runs, it seems like the mechanic got lucky but I'm the one holding the short end of the stick now and not sure what to do?!

Thanks for any advice!

[chpthril]

Crack = new engine on their dime, end of story.

[co99tj]

Well that's an easy answer

So no shades of gray to this situation? They said it was a small "hairline" crack - and weren't sure if it was all the way through. Is there any way to gauge the severity of the crack or does it not even matter?

[chpthril]

Small crack this year, large crack next year, then they say, So sorry, you signed away your chance to fix right. They admitted to the winterizing mistake that resulted in a cracked block.

[co99tj]

What does "new engine" mean in this case - would that be a motor with similar use going in the boat or a new block with everything moved over from mine into the new one, etc.? Is that MP340 a pretty common / easy to find replacement?

Would it be an opportunity to make lemonade out of the situation and possibly put more HP in the boat with a bigger / newer engine or does it not work that way?

[sandm]

Small crack this year, large crack next year, then they say, So sorry, you signed away your chance to fix right. They admitted to the winterizing mistake that resulted in a cracked block.

I would side 100% with chp on this one and as you pointed out, every time you take it out you'll be worried about block failure until it happens. I'd push for a new longblock and for the sake of simplicity, stick with same engine that comes out. start messing around with a larger block and you might get programming issues and timing/fuel issues from the engine using more fuel than the ecu is programmed for.

I'd be prepared to pay a few hundred for some misc things like new impeller, starter if yours is original, things like that. their culpability should end at the engine block RNR.

that's my .02. makes it a much easier story with them admitting the mistake.

[KoolAid]

Freeze plugs are not there to keep the engine from freeze damage, they are there for sand casting of the part. If factory plugs ever pop out from freezing, the block is damaged in my opinion. Don't get me wrong, you could run one for years with a cracked block. If it was my mistake, I would drill a hole at each end of the crack to stop the crack from spreading. Tap the holes, grind down the area and then attach a steel plate to the block with gasket sealer and hold it in place with two bolts. I saw a guy do this about 15 years ago and it worked for years.

[TeamAllen]

I would have it replaced. The thought of it having issues anytime during the peak season would be the difficult part. They will be busier and engine replacements take some time. Better to take the loss of time now then July 4th IMO

[co99tj]

I would have it replaced. The thought of it having issues anytime during the peak season would be the difficult part. They will be busier and engine replacements take some time. Better to take the loss of time now then July 4th IMO

That was my concern as well. I was thinking if it runs okay even on the lake (vs. the hose), I might try to make it through the season as-is and maybe have the engine replacement done at the end of the season. Doesn't really seem like there's a good answer here though...unfortunately.

[co99tj]

I would side 100% with chp on this one and as you pointed out, every time you take it out you'll be worried about block failure until it happens. I'd push for a new longblock and for the sake of simplicity, stick with same engine that comes out. start messing around with a larger block and you might get programming issues and timing/fuel issues from the engine using more fuel than the ecu is programmed for.

I'd be prepared to pay a few hundred for some misc things like new impeller, starter if yours is original, things like that. their culpability should end at the engine block RNR.

that's my .02. makes it a much easier story with them admitting the mistake.

Thanks - I agree - was just wondering if there was any point to upgrading anything given the amount of labor that needs to be done anyway - but my main goal is reliability, so hopefully an identical replacement would lessen the likelihood of any maintenance issues down the road.

It's a bummer and my bad luck - but the good news is that the mechanic that did the work is about as stand up of a guy as you can get. When I called him to deliver the bad news, he said "you need a new motor and I'll put one in for you" without hesitation - and he has a legendary reputation in the area, 30+ years of experience, and is trusted by everyone "in the know" around these parts. What complicated the entire thing is when the motor ran fine on the hose...now it's a question of does it or doesn't it have a problem, what's the right fix, etc.

[co99tj]

Thanks everyone for all the input and advice. Just out of curiosity - anyone know the ballpark costs for engine replacements with the different options - long block, short block, bare block, etc.? I talked to the dealer and they said around $6K-$7K which actually sounded a bit low to me - but I'm not sure if that was a brand new complete motor or what. I see a complete Marine Power 340 engine online and it's over $10K alone - so curious what we might be looking at here.

[chpthril]

At this point, all you need a marine short block. Does not need to me "Marine Power", as its just a GM 5.7L Just needs to be the correct generation.

I would consider that you spent the coin and get the heads done, while the engine is out and torn down. The rest of the labor and parts, is on their dime.

[SONIC]

I agree here, the engine may be fine but it may not be. Your chances of getting it fixed go down by the day IMO. If you wait until the end of the season who knows if they will still be willing to replace it.
IMO have them swap it now.
It's mostly labor, a shortblock isn't that expensive.

[USWaker]

I would also recommend in the future, before draining your block/cooling system, flush it thoroughly with marine antifreeze. It’s cheap and offers some peace of mind in the event that your block didn’t drain entirely. Living in a cold environment, I’ve done this with both of my boats even when I store them in a heated shop. You never know when the heater might fail etc.

[UNSTUCK]

It is the shops responsibility to make this right. They caused the crack, so they need to fix the crack. That's all they really need to do though. As long as the crack is 100% fixed once they are done and you should feel as being made whole. KoolAid is on the right track here with potential options. There are proven crack repair methods out there that a competent machine shop or knowledgeable mechanic can perform. Drilling out the crack is the first step. One the crack is gone, it can no longer continue to grow. Then the block needs to be filled back in to regain any lost strength. There are a few different methods for doing this. All proven and will make the block at least as strong as before.
There is no reason to ask for a new motor. There's lots of parts there that they didn't damage. If they wanted they could replace the block and swap over all the internals and bolt ons, for example. Again, that would make you whole and the issue would be fixed.
If they are offering a new motor though, I would jump on it now while that is still on the table. Take the boat back to them and just tell them to make it right. How ever they do that is up to them, as long as it's 100% fixed.