Replace cracked block 1985 mercruiser/Chevy 305

OK, assuming my cracked block isn't worth trying to fix with some JB Weld type stuff, what's the least expensive solution to replacing the block? I have read that i can use an automotive block (need to change the plugs, correct? with my other current engine parts and it will be marine OK. Correct or not?

Is there a time period I need to get to match the rest of my 1985 engine?

Mine is a 305 2bbl 200hp. I think it's just cracked externally. The mechanic said the engine at least idled fine but was leaking water like crazy out the crack. Does this mean there is a likelyhood that just replacing the block will be fine?

Thanks.

Re: Replace cracked block 1985 mercruiser/Chevy 305

Without seeing the engine, anything is possible.
The only way to find out is to do it.

Re: Replace cracked block 1985 mercruiser/Chevy 305

Yeah. Have whoever is doing the replacement take the block apart and find out what parts are bad.

I did exactly what you're doing a year ago, and I've learned a lot since then. Looking back on it now, I'd say the best cheap solution for someone with my mechanical skills was the one I found... buy a reman long block and bolt on my old accessories. Cost was about $1800. But, I now have a boat with a 350 in it, a nice upgrade.

Here's the thing you don't want to hear: This isn't a cheap repair. You've broken what's usually considered the most expensive part of a boat, and what you have left may be nearly worthless, or at least worth a lot less than you think.

Minimally, assess whether the boat's worth (to you) spending at least several hundred dollars on and a lot of time to get back on the water. It won't be perfect at the end of that, but it'll float and run. That's using a junkyard block, replacing the gaskets and freeze plugs, and spending the time to bolt it all back together and re-install it.

Otherwise, you can get a running boat on craigslist or similar for less time and money than you'll pay for a replacement engine for this one.

I suggest that if it's worth it to keep it, it's worth it to put in a reman engine, unless you like doing engine work a lot.

Edit: If this boat is the Mark Twain in your profile, I think it's probably worth it to get a reman... nice boat

Erik

Re: Replace cracked block 1985 mercruiser/Chevy 305

tmh said:

OK, assuming my cracked block isn't worth trying to fix with some JB Weld type stuff, what's the least expensive solution to replacing the block? I have read that i can use an automotive block (need to change the plugs, correct? with my other current engine parts and it will be marine OK. Correct or not?

Is there a time period I need to get to match the rest of my 1985 engine?

Mine is a 305 2bbl 200hp. I think it's just cracked externally. The mechanic said the engine at least idled fine but was leaking water like crazy out the crack. Does this mean there is a likelyhood that just replacing the block will be fine?

Thanks.

Click to expand...

Your best bet is to rebuild. Have your crank/rods machined add new pistons and bearings to a prepped block. (get a junkyard core)
You could find a block that has the same bore diameter as your pistons but your still going to need new bearings and rings. Things will need to be measured very carefully when swapping internals.

Re: Replace cracked block 1985 mercruiser/Chevy 305

tmh said:

OK, assuming my cracked block isn't worth trying to fix with some JB Weld type stuff, ....


I think it's just cracked externally.

Click to expand...

Actually IF it is just cracked externally you might be okay with some JB Weld type product. I have heard of those who have done that repair successfully.

That's IF it is only cracked externally.

Having said that, I've never done it. But others have posted that they have successfully done so.

Re: Replace cracked block 1985 mercruiser/Chevy 305

Ayuh,.....

You're Not going to use this motor,.....

Just Part the danm thing Out........

By the time you swing some sort of Repair,....
You'll have Way More into it, than you'll Ever get out of it....

It's a 305........

Everybodyelse does the Same thing you're doing.....

Junk it,+ Drop in a 350..........

Re: Replace cracked block 1985 mercruiser/Chevy 305

yeah, Bondo, you're probably right. I guess i'm just trying to minimize the pain by talking about other options.

It's a 23 yr. old engine and it's done. It ran so well, I feel bad for having killed it!