Differences in Mercruiser 3.0 blocks over the years?

synergy141

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Hi, I have an 07 Bayliner with the Merc 3.0 engine. I bought it with a cracked block. I have found a bottom end from an 1989 Mercruiser 3.0. Would these be interchangeable? Or what differences would the blocks have?

Thanks.
 

Bondo

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Hi, I have an 07 Bayliner with the Merc 3.0 engine. I bought it with a cracked block. I have found a bottom end from an 1989 Mercruiser 3.0. Would these be interchangeable? Or what differences would the blocks have?

Thanks.

Ayuh,... I believe the motors went from a 2 pc. seal, to a 1 pc. seal in 'bout 2000, so, No, they're not the same,.....

With the right flywheel, a Complete motor from earlier could be dropped in,....

By bottom end,..?? ya mean a Short Block, no head,..??
 

synergy141

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What I want to do is. Strip down the 80's Short block and add all the components from the 07 to it. Or Maybe keep the whole bottom end of the 80's block if its good and add the 07 head to it and all the rest of the parts.
 

Bondo

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Ayuh,... Thanks Bruce,..... I guess a decade makes quite a difference,.... :rolleyes: :D
 

bruceb58

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Ayuh,... Thanks Bruce,..... I guess a decade makes quite a difference,.... :rolleyes: :D

I am not super familiar with the difference. I know you can buy new turn key engines that fit all years so the difference must just be the flywheel.
 

Bondo

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I am not super familiar with the difference. I know you can buy new turn key engines that fit all years so the difference must just be the flywheel.

Ayuh,.... Flywheel, 'n rear main seal,.....

Old crankshaft bolt pattern was 3, 1/4", 'n the one pc seal motors are 3",....
 

dozerII

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Just ordered one of these newer 3.0 to replace an 80's 140, the fly wheel and coupler have to be updated, as well as an adapter plate for the intake/exhaust manifold. I'm pretty sure you won't be able to mix and match the two.
 
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