84 chris craft 3.8L mercruiser

Joined
Jun 23, 2009
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27
I recently acquired a '84 chris craft scorpion with a 229 cu.in. 3.8L Mercruiser. I was happy to get it for free but knew there had to be a catch, I was told the boat had sat a while but was unsure of any specifics of why it was no longer used. I took it home and started tinkering to find water dump out of every spark plug hole of a seized engine!!! I removed the motor to start a total tear down to see how bad the damage actually was. Water was everywhere, I think the culprit was a stuck open water baffle in the exhaust the last time the boat was ran. Any hoo, I was able to get the pistons free(with the help of a lot of PB Blaster and some coaxing). The cylinder walls seem to be very clean even where the pistons had rested for the past years. The heads on the other hand are pretty bad, valves stuck open and rust and corrosion all over. Are they able to be rebuilt should I even bother with any of the motor?? I am having a hard time finding parts and gaskets for this motor. I know it is a gm based 3.8 but are any of the parts interchangable, like the heads or gaskets, or do they have to be mercruiser specific.

Thanks for any help
 

Howard Sterndrive

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Nov 5, 2008
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4,603
Re: 84 chris craft 3.8L mercruiser

the basic long block (Block / Heads) are same as car 229. The cam is marine specific, but the Edelbrock 2112 has the same grind.
Any rust streaks down the sides of the galley in the thin area behind the lifters? I'd look seriously for freeze cracks there.

water shutter issue possible, but not most probable cause.

freeze cracked block most probable. Heads usually survive but should be checked.
are the exhaust manifolds cracked along the sides/bottom?
 

Bondo

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71,082
Re: 84 chris craft 3.8L mercruiser

Ayuh,... I'd Junk it,+ go back together with a 4.3l motor...
 
Joined
Jun 23, 2009
Messages
27
Re: 84 chris craft 3.8L mercruiser

Ayuh,... I'd Junk it,+ go back together with a 4.3l motor...

I was hoping nobody would say that. It was a thought in the back of my head, just don't have the money for a whole new engine. And the reason I thought the water shutters is the flex hose that goes to the L/U was off. So water was just free to flow and the shutters were stuck open when I pulled it apart. I'm hoping the block is still good:confused: I know the heads are screwed
 
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