H shaped Freeze crack, please help

[Maddness038]

hello,
I have Larson Senza with a Volvo Penta 5.0GL and I'm going to start off and say that i have 2 really big cracks on each side of my engine block, in the shape of an H. I did a little bit of research and concluded that these are freeze cracks. They gush water every time the engine runs. I read a few forums and wondered if I could repair these with some good 'ol JB wield, and if not could you give me some advise on how to fix it? Money here is pretty tight

 

[Capt21]

Re: H shaped Freeze crack, please help

Welcome to iboats. Not winterizing properly will do that every time. Gotta replace the block. Might check the manifolds while you at it as they may be cracked too. In my short time here, I have read countless threads all with the same outcome. The guys here are great and can help you with whatever questions you may have for the replacement.

Adam

 

[bhammer]

Re: H shaped Freeze crack, please help

Do you get any water in the oil? If so, you have to replace the block. If not, you can try to repair with JB weld. I myself am not a fan of that method and if it were me, I would not do it. I however do know some folks that have done this. Plus, with a big crack, you may have thrown some internal tolerances out of wack and casue some other issues. For me, it is just too much of a chance of being out in the middle of the lake and a crack starting to leak again.

The best method is to find a used block and swap out all the accessories. If you buy used, you can have it rebuilt. This is the way I would go....

 

[Maddness038]

Re: H shaped Freeze crack, please help

Thank you. Can anyone help me find a replacement block? I'm going to sound stupid when I say this but how can I check if I got water into the oil? keep in mind I'm only 18 and trying to help out my father so i don't know a whole lot about engines.

 

[bhammer]

Re: H shaped Freeze crack, please help

That's what these forums are all about. hey, at least you know what oil is.

A quick way to check for water in the oil is to check the oil level with the dip stick. If it is higher than it should be, there is a good chance you added volume with water. The sure fire way is to drain the oil and see if it looks milky or anything different than regular oil, it is leaking into the oil.

 

[Maddness038]

Re: H shaped Freeze crack, please help

Ok, thank you so much, this means a lot to me. I will check the oil levels first thing tomorrow and check the manifoldsand see if they are cracked

 

[jtmarten]

Re: H shaped Freeze crack, please help

If the oil looks milky or like a choc shake, you have internal cracks as well. If they're only external cracks, you may be able to get them welded.
If you need to replace the block, check local salvage yards, or even craigslist.

 

[Maddness038]

Re: H shaped Freeze crack, please help

Thanks again, now when i go to the salvage yards/craigs list do i have to stick to a Volvo penta block or can i just use any 5.0L block?

 

[bhammer]

Re: H shaped Freeze crack, please help

Thank you. Can anyone help me find a replacement block?

You have options here. You can check local salvage yards. You can also google for marine rebuilt block. www.rapidomarine is a pretty popular place for marine blocks.

If you get one from a salvage, you will need to replace the casting plugs, (freeze plugs) head gasket and I think you need an engine from a truck as the Cam is setup a bit different. Some folks that have gone through a swap will chime in.

If you go with something like rapido, you get a warranty.

 

[Maddness038]

Re: H shaped Freeze crack, please help

Okay. I get it and thank you so much for you time and help. how much does a used block and all of those things you usually talked about cost?

 

[Bondo]

Re: H shaped Freeze crack, please help

Okay. I get it and thank you so much for you time and help. how much does a used block and all of those things you usually talked about cost?

Ayuh,... Several Thousand dollars...

 

[ENSIGN]

Re: H shaped Freeze crack, please help

Engine block,possibly heads and manifolds

 

[jtmarten]

Re: H shaped Freeze crack, please help

My former jetboat had a cracked block when I bought it. I sourced a 4-bolt 454 block for $200, had to have 2 cyl sleeved, then had all bored 0.020" so I could re-use the pistons. Entire rebuild cost me $1600.
If you end up having to replace the block, no reason not to bump up to a 350.

There is no such thing as a Volvo Penta block, its just a Chevy V8 with brass freezeplugs. I didn't even bother with brass plugs since I only boat in fresh water.
If you assemble the engine yourself, you'll want a slightly looser tolerance on the main bearings, and a high-volume oil pump isn't a good choice unless you run a larger capacity oil pan.

 

[dannyual767]

Re: H shaped Freeze crack, please help

Back to the "water in the oil" issue. All you have to do is pull the dipstick and take a look at the oil on it. Is it normal looking? If so, then you don't have water in the oil. If it looks like a chocolate/vanilla milkshake, you've got big problems.

jtmarten, when you had your BBC bored .020 to reuse your pistons, I'm going to have to assume that your pistons were .020" oversize. Or did you mean that you had the block honed .002" to reuse the original, stock pistons??

 

[Don S]

Re: H shaped Freeze crack, please help

Back to the "water in the oil" issue. All you have to do is pull the dipstick and take a look at the oil on it.

Doubtfull that there will be any water in the oil yet. IF there is, it would only be a very small amount. The engines normally crack in the lifter valley. With the external cracks, as the ice melted, the water would run down and out of the outer cracks, not up and into the oil.
Even running on muffs with 2 very large outside cracks would probably not put a lot of pressure on the internal leak.
What most people find is that after repairing the outside leaks with JB weld, they then head for the water and after a while running on the water with a warm engine that the water gets into the oil and turns it milky and the level goes up.

 

[bhammer]

Re: H shaped Freeze crack, please help

If the OP can google engine pressure test and leak down test, I think those would answer his question. I go back to what I said though... At this point, with two cracks, he is going to be better off pulling the block and swapping with a rebuilt or for cheaper, a truck engine from the junk yard.

 

[jtmarten]

Re: H shaped Freeze crack, please help

Back to the "water in the oil" issue. All you have to do is pull the dipstick and take a look at the oil on it. Is it normal looking? If so, then you don't have water in the oil. If it looks like a chocolate/vanilla milkshake, you've got big problems.

jtmarten, when you had your BBC bored .020 to reuse your pistons, I'm going to have to assume that your pistons were .020" oversize. Or did you mean that you had the block honed .002" to reuse the original, stock pistons??

The pistons in the cracked block were 0.020" oversized. The replacement block was standard bore, but had thrown a rod and broke the base of 2 of the cyl. The machinist did hone match the pistons after boring.

 

[jtmarten]

Re: H shaped Freeze crack, please help

Doubtfull that there will be any water in the oil yet. IF there is, it would only be a very small amount. The engines normally crack in the lifter valley. With the external cracks, as the ice melted, the water would run down and out of the outer cracks, not up and into the oil.
Even running on muffs with 2 very large outside cracks would probably not put a lot of pressure on the internal leak.
What most people find is that after repairing the outside leaks with JB weld, they then head for the water and after a while running on the water with a warm engine that the water gets into the oil and turns it milky and the level goes up.

+1
Would be a good idea to pull the intake and have a look. Then a realistic, economically feasible game plan can be developed.

 

[Maddness038]

Re: H shaped Freeze crack, please help

ok everyone, i looked at the oil and its the normal color, as i am typing this im about to take the manifolds off and inspect those. if i put pictures up would that help in any way?

 

[Don S]

Re: H shaped Freeze crack, please help

ok everyone, i looked at the oil and its the normal color,

So ??????
Have you taken it out on the water and run it for a while? If not and you only ran it on muffs for a short time, then you know nothing.
One thing I will tell you, is water in the oil is NOT caused by cracked exhaust manifolds. That puts water on top of your pistions.