94' 454 magnum efi 20ft ski boat
08-25-2009 | 01:25 AM
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94' 454 magnum efi 20ft ski boat
Long story short. I cracked a piston and had to tear my engine down. Looks like I need a bore so I'm going .030 over. I think I'm going with .095 dome top pistons because that is the closest I can find. looks like the mercruiser ones are like .120?I searched cams and I keep coming up with .510/.510 220/220 is that a carb lift and duration?? i thought MPI/efi had a high lift shorter duration? Basically I need a cam and pistons so I'm doing a full rebuild. but this is in a ski boat so I need 0-2000 rpms in a useable fashion thanks in advance.
I'll post pics of my carnage as soon as I host them.
I'll post pics of my carnage as soon as I host them.
08-25-2009 | 01:28 AM
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Where should I get a cam?? What are my options?/ I dont want to recalibrate my ecu if at all possible. I have EMI manifolds and an aftermarket fuel pump/regulator with return system on the boat but thats it for upgrades. also was thinking about roller tip rockers/sportsman style.
08-25-2009 | 03:07 AM
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I don't think those are the correct specs for the 1994 efi cam. Those are the specs for a carbed 454mag cam. The merc part numbers are different for the 1994 efi and carb cams. The stock cam for your engine is still available from mercruiser for about $250. You can look it up on www.mercruiserparts.com
Maybe rmbuilder will chime in. If anybody knows the specs, he will.
Maybe rmbuilder will chime in. If anybody knows the specs, he will.
08-25-2009 | 10:29 AM
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It gives me part number 431-4734 for the cam shaft? But no Specs. My boat is a direct drive with a center mounted engine is it a reverse rotation? I didn't think it was? Anyone? It's a Malibu 1994 Echelon. I would like to get a cam for it if it's available.
08-25-2009 | 11:35 AM
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I Looked it up it's a standard rotation.. Only correct craft has a R/H rotation prop because the reduction drive turns it around?? Anyone have the specs on the 454 Magnum MPI cam? I can get it cam Dr. checked but It's kinda messed up.
08-25-2009 | 01:17 PM
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Merc never has the specs except in the repair manual for the engine. If you look at a 1994 carbed 454 mag, you will see it is a different part# for the cam. I know for sure that the carbed specs are .510/.510,.220/.220 on a 115 lob sep. and since yours has a different part number, the specs will be different. I think that cam is still available from GM.
