Go Flames Go (Cracked Block?)

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Martin Leaney

Seaman
Joined
Jan 5, 2003
Messages
71
Hockey season is now over for the Calgary Flames and so boating season is here (finally).<br /><br />I have just brought my boat (25' Chris Craft) back from it's first outing of the year. I decided to take it to a small lake first for a short trial run. I had done the winterization work myself as I had the Mercury manuals for the engine and for the I/O. I "thought" I had done it as per the manual. The boat has a late 80's GM/Merc 305cid V8.<br /><br />When I got on the water the boat did not run too good (wouldn't get up on plane easily) and then the engine died. It started a couple of times but then refused. I pulled up the engine cover to find about 10 + inches of water and the bilge pump not running.<br /><br />After getting a tow back to shore and getting the bilge emptied I started the engine and found that water was gushing out from under the exhaust manifold. A further inspection revealed a 'I' shaped crack in the block. <br /><br />I got the manual out (which still had the bookmark in the winterization section from when I used it in the fall) and found out that I had mistakenly opened the petcocks on the exhaust manifold instead of the ones on the block. Doh!<br /><br />Now the question(s). <br />Is there such a thing as Frost Plugs?<br />What can be done to repair the crack? <br />Can it be welded?<br /> Is epoxy good enough on a marine engine?<br />Do I need reading glasses?<br />Should I limit the # of glasses of beer when I'm working on the boat...?<br /><br /><br />over...
 
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Catchem

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Re: Go Flames Go (Cracked Block?)

Yes there is a such thing as frost plugs.Check them out.<br />Not sure about epoxy on block but there may be something out there,but,if the crack is on the outside of the block you should be able to get someone to weld it up.<br />"Glasses"Maybe LoL<br />Save the beer for after the job.
 
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Martin Leaney

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71
Re: Go Flames Go (Cracked Block?)

Getting access to the area that needs welding may be an issue - I don't want to pull the engine unless I can't fix it any other way.<br /><br />If I do end up pulling the engine I am thinking of upgrading to the 350. Another question is whether the carb is big enough for the extra cubic inches.
 
flashback

flashback

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Re: Go Flames Go (Cracked Block?)

capt, IMHO repair of cracks in the block is risky at best, check your oil and see if you have any water in it. many times you will get cracks on the inside of the block as well. in any case, i think you would be best off getting a new engine or at least a short block...
 
Bondo

Bondo

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Re: Go Flames Go (Cracked Block?)

Your Only real Choices are Epoxy, or Replacement.......<br />The Block would have to be Removed,+ Stripped to Weld it Right......<br />Is there Water in the Oil ????<br />V-motors tend to Crack just under the Head, in the lifter valley Also..........<br />In a Light Freeze, the Core Plugs(Frost Plugs) Might save the Block,<br />But in a Heavy Freeze, Well, You can See what Happens.................<br /><br />Stepping up to the 350cid Is the way to Go.......<br />Your Carb, Might need to be Rejetted.......<br />But it Should work just Fine.........
 
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yoced

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Re: Go Flames Go (Cracked Block?)

And no, there are no such things as Frost Plugs. The brass cup plugs are there to fill holes which are used in the casting process. It is only an accident that sometimes these plugs get pushed out rather than (or at the same time as)the block cracking.<br /><br />And yes, you probably have more repairs to make than that one exterior crack.
 
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Martin Leaney

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71
Re: Go Flames Go (Cracked Block?)

The engine has about 800 hours on it and the compressions are a bit low but consistent on all cylinders. I will have to do some more checking to see how extensive the damage is.<br /> This, unfortunately, may be the best time to rebuild.<br /><br /><br />Thanks for all the input.
 
Boatin Bob

Boatin Bob

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Re: Go Flames Go (Cracked Block?)

I got the manual out (which still had the bookmark in the winterization section from when I used it in the fall) and found out that I had mistakenly opened the petcocks on the exhaust manifold instead of the ones on the block. Doh!<br />
Click to expand...
Just wanted to point out that next time you need to do both of these, the manifold and the block. It's not a case of doing the manifolds instead of the block but both. You were half done :confused:
 
M

Martin Leaney

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Messages
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Re: Go Flames Go (Cracked Block?)

Just did some more checking and the block is cracked on the inside as well ! Time to rebuild... <br /> :rolleyes: <br /><br />The engine is a 1986 Merc/GM 230 hp in a Chris Craft '260' (same as 253) cabin cruiser. We will go with a rebuilt 350 short block of the same year. <br /><br />Since we are rebuilding what are the best specs for the new motor? We want decent fuel economy but would like more power than we have/had. 270-280hp would be good if we can get that without a rough idle (and changing carbs etc).
 
flashback

flashback

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Re: Go Flames Go (Cracked Block?)

I had the same problem a few years back(bought boat knowing the block was trashed) I went to a local machine shop who rebuilds most of the marine engines for the dealers around here and picked up a rebuilt 350. It is basicly a stock engine, with the exception of the pistons, the builder said I should see about 275hp. I like dealing with the local guys for this sort of thing cause I can meet with them and shake a hand. good luck which ever way you go. I notice Bondo is in on this one, he is a gm guru so your in good hands..........
 
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Martin Leaney

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Re: Go Flames Go (Cracked Block?)

Thanks Flash - what pistons did you get that were different from stock? Higher compression?
 
flashback

flashback

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Re: Go Flames Go (Cracked Block?)

Capt. I had them put in flat top pistons, which as i understand, is a little higher comp...If I had it to do over tho, I would go with a vortec setup which I have heard, will produce about 300hp. doesn't cost that much more but at the time, I didn't have that much more... :D
 
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Martin Leaney

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Jan 5, 2003
Messages
71
Re: Go Flames Go (Cracked Block?)

What side is the dip stick on for the different years? Mine is on the left (looking at the engine from the front).
 
M

Martin Leaney

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Messages
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Re: Go Flames Go (Cracked Block?)

I have been looking into engines. I want a rebuilt 1985(?) 350 short block. <br /> Is there any reason I can't use a standard GM engine? <br />What makes a V8 a "Marine" engine as opposed to a auto engine?
 
D

DJ

Guest
Re: Go Flames Go (Cracked Block?)

Several things.<br /><br />1. Camshaft.<br /><br />2. Stainless steel or brass core plugs.<br /><br />3. Different water pump.<br /><br />4. ALL the accesories (fuel pump, carb, distributor, alternator, starter)
 
M

Martin Leaney

Seaman
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Jan 5, 2003
Messages
71
Re: Go Flames Go (Cracked Block?)

I think the camshaft is a mild hi-perf rise and duration so that isn't a problem. The core plugs aren't a big deal either and I am just replacing the short block so I will bolt back on all accessories from the previous engine.<br /><br />Looks like everything will be ok... (famous last words)<br /><br />Thanks all
 
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