Why do you have to replace engine, if block is cracked?

[Fordiesel69]

I notice a lot of boats go dirt cheap as they should due to a cracked block. This may sound dumb, but what is the big deal if it is cracked and water is leaking into the bilge while the engine is running? I imagine the amount will be small and the pump would be able to handle it in most cases. Of course this would increase transome rot and such, but for folks who want a cheap boat, is this really as big of concern as it is made out to be?

 

[JB]

Re: Why do you have to replace engine, if block is cracked?

The real problem is that water is probably not leaking into the bilge, but into the cylinders and oil sump.

Can you say, "BOOM"?

 

[Aviator5]

Re: Why do you have to replace engine, if block is cracked?

Everyone has the right to do whatever he wants with his boat, that includes running with cracked block and, even water in the oil, or no oil.

 

[SuperNova]

Re: Why do you have to replace engine, if block is cracked?

I notice a lot of boats go dirt cheap as they should due to a cracked block. This may sound dumb, but what is the big deal if it is cracked and water is leaking into the bilge while the engine is running? I imagine the amount will be small and the pump would be able to handle it in most cases. Of course this would increase transome rot and such, but for folks who want a cheap boat, is this really as big of concern as it is made out to be?

You're right, as long as the cracks are on the outside, it's pretty much just a water leak. I did it on two boats when I was younger, dumber, and broker. Didn't do it for long before I was better educated, but long enough to know it'll work. The problem is, the blocks usually crack on the inside before they crack on the outside, for some reason. So chances are very good, if you see cracks on the outside, it's very probable that it's also cracked inside and that will allow water to mix with your oil, with the resultant shortened life expectancy of the engine. Thus the cheap price of the boat.

 

[Stachi]

Re: Why do you have to replace engine, if block is cracked?

You're right, as long as the cracks are on the outside, it's pretty much just a water leak. I did it on two boats when I was younger, dumber, and broker. Didn't do it for long before I was better educated, but long enough to know it'll work. The problem is, the blocks usually crack on the inside before they crack on the outside, for some reason. So chances are very good, if you see cracks on the outside, it's very probable that it's also cracked inside and that will allow water to mix with your oil, with the resultant shortened life expectancy of the engine. Thus the cheap price of the boat.

the reason they crack on the inside first ,is because thats where the major amount of heat is...how long you can use it for..... uhm ,till it quits ??......baby it and keep yer fingers crossed, check what is on your dipstick often....if it looks like choclate milk....it won't be long till you are repowering....I would start looking now...in the off season....

 

[Triton II]

Re: Why do you have to replace engine, if block is cracked?

The reason most engines crack through the water/oil galleries inside before any external cracking is evident is that the wall thicknesses inside tend to be thinner whereas the external part of the block has to have extra material for reinforcing around the engine mount areas and for trying to contain major blow ups, i.e preventing "legs out of bed". As a previous poster stated, if there's an external crack in the block that's leaking, then you can guarantee something inside will be in major trouble. Also cracked blocks tend to affect cylinder heads so continuing to run an engine with a cracked block will do far more damage in the long run and isn't worth it.

 

[Stachi]

Re: Why do you have to replace engine, if block is cracked?

The reason most engines crack through the water/oil galleries inside before any external cracking is evident is that the wall thicknesses inside tend to be thinner whereas the external part of the block has to have extra material for reinforcing around the engine mount areas and for trying to contain major blow ups, i.e preventing "legs out of bed". As a previous poster stated, if there's an external crack in the block that's leaking, then you can guarantee something inside will be in major trouble. Also cracked blocks tend to affect cylinder heads so continuing to run an engine with a cracked block will do far more damage in the long run and isn't worth it.

agreed.......sounds lke a throw away engine to me already...drive it till it blows, and save for a new one...

 

[windsors03cobra]

Re: Why do you have to replace engine, if block is cracked?

I boat on lake Michigan if there is any chance of it "blowing" leave me at the dock.

 

[elpirata76]

Re: Why do you have to replace engine, if block is cracked?

Fix the problem or dont buy it. You are setitng yourself for failure.A cracked block is always trouble. The engine losses compresion lossing power. You'll probally get really bad gas millage. Damage to cylinder walls and piston heads is very possible. The list ,continues you'll end up spending more money. If you got it good luck if you dont have think about it.

 

[slasmith1]

Re: Why do you have to replace engine, if block is cracked?

Why do you go to the doctor when your skull is cracked?

 

[oceansbreeze]

Re: Why do you have to replace engine, if block is cracked?

why do we see so many cracked blocks in boats anyways? You don't see many cracked blocks in cars.... you've got the same mechanics... water cooling. 4-6-8 cylinders, nothing superbly special.... higher rpm's I guess, but... if there is oil in the pans, I don't see why they crack so much - or why so many are cracked to begin with

 

[lowkee]

Re: Why do you have to replace engine, if block is cracked?

why do we see so many cracked blocks in boats anyways? You don't see many cracked blocks in cars.... you've got the same mechanics... water cooling.

That water cooling is mixed with anti-freeze (hence the name) in cars. Most <30' boats are cooled with pure water, which freezes. Frozen water expands.. a lot.

 

[smokeonthewater]

Re: Why do you have to replace engine, if block is cracked?

yep 99% of the time they don't crack when running... they crack for the same reason that ice cubes bulge up out of the ice tray and for the same reason you get pot holes in the road in winter.... water expands when it freezes but iron does not..... if you doubt it drain the antifreeze from your car and fill with water.... get a couple 15 degree nights and you will be a believer..... if you want to see a cheaper example fill a milk jug with water, wrap a string around it and tie it.. slip it off and freeze solid.... then try to slide the string back on..... won't go

 

[piper_chuck]

Re: Why do you have to replace engine, if block is cracked?

I notice a lot of boats go dirt cheap as they should due to a cracked block. This may sound dumb, but what is the big deal if it is cracked and water is leaking into the bilge while the engine is running? I imagine the amount will be small and the pump would be able to handle it in most cases. Of course this would increase transome rot and such, but for folks who want a cheap boat, is this really as big of concern as it is made out to be?

When I go boating I want the experience to be as trouble free as possible and I when I leave the dock, I want to be reasonably sure I will be able to return under the boats power. Knowing there is water leaking from, or worse, inside the engine would put me on edge. Knowing there is a problem that will cause the engine to die without notice at some point is a no launch condition.

 

[Fordiesel69]

Re: Why do you have to replace engine, if block is cracked?

Luckily none of my engines are cracked, but I have seen some real nice boats go so cheap I would have rather bought them and put new engines in them. Some owners say they have been using them the entire season like this so the leaks must be external.

Fingers crossed I did my winterizing correctly.

 

[Philster]

Re: Why do you have to replace engine, if block is cracked?

In many ads, owners will claim they used the boat, and it just needs someone to spend a little time on it if they are handy. Or "it leaks, but all you have to do is blah blah blah..." and "...my family used it all year yada yada yada...".

 

[H20Rat]

Re: Why do you have to replace engine, if block is cracked?

Luckily none of my engines are cracked, but I have seen some real nice boats go so cheap I would have rather bought them and put new engines in them. Some owners say they have been using them the entire season like this so the leaks must be external.

Fingers crossed I did my winterizing correctly.

that or the owners will tell you pretty much anything to sell the boat. They have been using it the entire season... To hold all the crap that was piled on it in the garage maybe.

wait until the spring if you want to pick up a nice boat with a cracked block. All the new owners from 2009 that didn't know you have to take special precautions to winterize an I/O will suddenly learn what they did wrong.

 

[jeeperman]

Re: Why do you have to replace engine, if block is cracked?

Any water cooled engine block can crack. Antifreeze or not.
From freezing
From excessive heat
From stress
From a bad casting
If you really want to you can live with and limp along with an external crack that only leaks water to the outside and not into the oil.
I would suggest a SeaTow membership.
Heads can crack for the same reasons above.
But if you have water leaking into the oil from a cracked block, you can reuse/transfer virtually everything except bearings if you change to a new/used block soon enough.
Running with a cracked block invites the potential that you will ruin the heads and all rotating internal parts due to water in the oil and/or overheating.

 

[lrlima]

Re: Why do you have to replace engine, if block is cracked?

I bought my first boat from a guy that sold it to me with a cracked block. worked for one season, then lost compression in one of the cylinders and ran rough the next year. Got to learn how to pull an engine and do the swap....thanks to iboats.

 

[Silvertip]

Re: Why do you have to replace engine, if block is cracked?

Engine blocks crack for two reasons. 1) overheating which usually cracks a cylinder head or blows a head gasket but the block itself can crack as well. 2) Freezing. Water expands with tremendous force as it freezes and the block can then crack on the outside, inside, or both. What are commonly referred to as "frost plugs" are not really frost plugs -- they are core plugs which is a method to get casting sand out of the block. Engine blocks freeze because their owners are clueless about the importance of winterizing or just don't give a hoot and take their chances. I don't mean to sound overly critical regarding this but come on folks, water freezes at 32 degrees F. Cold temps and snow should not be the trigger for winterizing.