So close....oh so close.... Mercruiser 350 5.7 starter mess.

walrus133

Recruit
Joined
Jun 20, 2011
Messages
1
This morning I woke up proud of myself. Last night I successfully drilled out a broken off starter bolt. It was the inside, tough to see (or reach) one and somehow I managed to pull it off. The broken part of the bolt came out beautifully.
As I was starting to reattach the starter with new bolts I noticed something that made me wince: the spot on the engine block where the OTHER starter bolt hole needs to be screwed in had a crack, and a nasty crack at that. Maybe it had been overtightened or maybe it was just stress and wear and tear. I decided to see if it would hold the bolt and quickly received my answer. A snapped off a piece of the engine- leaving me with the threaded hole half exposed. Nasty problem.
It's been a long afternoon. Anyone have any ideas? Anyone been there? Thanks in advance.

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scv76

Seaman Apprentice
Joined
Jun 17, 2011
Messages
33
Re: So close....oh so close.... Mercruiser 350 5.7 starter mess.

Not much help here..had the same thing with an auto 454 and had to weld a nut to the block for the starter bolt to grab
Sorry not much help
 

cruzin1a

Cadet
Joined
Jun 12, 2011
Messages
25
Re: So close....oh so close.... Mercruiser 350 5.7 starter mess.

Would something Like JB Weld work to attach the piece that broke?
 

mikethepike

Seaman Apprentice
Joined
Dec 15, 2010
Messages
42
Re: So close....oh so close.... Mercruiser 350 5.7 starter mess.

easy out. You drill a hole in the middle and the easy out has reverse threads to grab it and ease it out
 

Stamey

Petty Officer 1st Class
Joined
Aug 7, 2010
Messages
286
Re: So close....oh so close.... Mercruiser 350 5.7 starter mess.

JBWeld is probably not the way to go. Your best hope, without actually pulling the block, is brazing it with brass. Cast iron doesn't weld easily. If you want to weld it the block will have to come out and be stripped of all internals so that it can be heated, the entire block, then welded and cooled off VERY slowly, otherwise it will crack even more. This will have to be done by someone who knows how to weld cast iron. From what I understand you have to use Nickel rod.

And if you're going to pull the block to weld it you might find it feasible to replace the block so you don't have to worry about it again.

Same kind of thing with cast aluminum. I tried that on a gas grill once. After I was done welding, MIG, I watched it cool off and crack around the edges of where I welded. Repeated the process multiple times. Every time I welded a crack, 1-3 more would appear, radiating from where I had just welded. Once I started peening it though, it was a different story, no cracking. What I had to do was start beating it with the "peen" side of a ball-peen hammer all around the weld site, and on the bead itself, as it cooled off. As long as I beat the crap out of it while it cooled the cast aluminum wouldn't crack. Have not tried this with cast iron though.

Chris
 

cruzin1a

Cadet
Joined
Jun 12, 2011
Messages
25
Re: So close....oh so close.... Mercruiser 350 5.7 starter mess.

Short of the extensive measures just mentioned (which require the block to be pulled and completely stripped) and the other option of replacing the block... We all know how easy it is to get to the starter bolts on a 350 in a boat... not. So why not try JB Weld? I have seen it do some amazing things.
 

81 Checkmate

Lieutenant
Joined
Jul 20, 2010
Messages
1,360
Re: So close....oh so close.... Mercruiser 350 5.7 starter mess.

I would have to agree with Cruzin1a

Why not give the JB Weld a try before pulling the motor.

I would clean it real good with acetone and get off all grease and try it, Let it cure to recomended time before drilling any holes.

Just my thoughts!
 
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