5.7 litre merc, reliable engine builders?

C

chadr

Member
Hey guys, long story short my boat sank tied up to the dock at the lake last weekend. Still in with insurance and waiting on that, but I think my main engine will be toast, they are saying they won't cover my two year old 9.9 merc kicker. I am a diesel engine mechanic by trade and would look into rebuilding the main myself if it it salvagable. Kicker has already been run and I'm sure it will be fine with a carb cleanout. Just wondering about buying the whole thing back from insurance and going from there. Lots of options for drop in engines on line, just wondering if anyone has experience with good or bad rebuilds or drop in's? Engine was a 1994 carbuerated, just before they went fuel injected. I would look at both options, fuel injected or not. Thanks for any input
 
rebuild it if it not been run. salt is whats going to kill the wiring
but dry it all out you may find it all salvageable.
would invest in shore power and at least two bilge pumps
dead batts, no bilge pump
feel for you ....
had water in mine but not totally under but past the crank
had to flush oil twice and diesel it ....
 
I would buy a crate motor from GM. They are brand new not rebuilt and work beautifully in a boat. I put a 330 horse in my bosses boat and he loves it.
 
IMG_0860.JPG If you do decide to rebuild it "Scat Crankshaft" rotating assembly's are really nice and more affordable than buying rings and bearings and come with new bearings, rings, Pistons, connecting rods and crankshaft. Going to a 383 stroker over 350 if you want is very noticeable however keep your compression ratio around 8 to 8.5/1.
You can have your heads rebuilt however there are lots of options for aftermarket in both aluminum and cast iron with option regarding combustion chamber volume to fine tune your compression ratio to piston volume.
Weak link for a rebuilt engine in a boat is usually the stock valves, good stainless valve like "Ferrea" are the best investment you could make.
Heads in pik are "RHS" Racing Head Services new cast iron designed for torque with "Ferrea" stainless valves. Factory rockers are preferable to roller rockers in a boat imo!
 
Had a couple 350's in a 24' Searay (fairly heavy boat with a deep vee). At much above 3500 RPM temp would go up & oil pressure would go down. Goose the HP & IMO the problem will only get worse. My neighbor used to run 454's in bow pickers - said roller rocker are were a HUGE improvement - could go roller cam as well.

For a marine motor you want the proper valves, freeze plugs, pistons & cam lift/timing. IMO it will still be a POS compared to an outboard; run them WOT & still touch the block with your hand.
 
ericl said:
Had a couple 350's in a 24' Searay (fairly heavy boat with a deep vee). At much above 3500 RPM temp would go up & oil pressure would go down. Goose the HP & IMO the problem will only get worse. My neighbor used to run 454's in bow pickers - said roller rocker are were a HUGE improvement - could go roller cam as well.

For a marine motor you want the proper valves, freeze plugs, pistons & cam lift/timing. IMO it will still be a POS compared to an outboard; run them WOT & still touch the block with your hand.
Click to expand...

If your operating temperature goes to high you need to improve your cooling system.
Roller tips on rockers are great as they reduce valve guide wear. I have had roller fulcrum rockers seize up, row back home.
Competition cams makes a ball fulcrum roller tip rocker you can buy for the same price as Oem replacement and I prefer the reliability.
Roller cams are the only way to go imo, check your block casting number as if Merc used a 1994 block it should probably have a roller cam in it already.
I didn't see anything special inside my Indmar 454, factory cast flat top Pistons, passenger car rods, cast crank, factory steel valves. I installed BBC Vortec heads on it, almost 10/1 CR ratio now and need to run premium, nice solid lifter cam I had laying around, about 450 HP now and no overheating or oil pressure issues.
Brass freeze plugs are $15 a set for the complete engine.
 

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chadr said:
Hey guys, long story short my boat sank tied up to the dock at the lake last weekend. Still in with insurance and waiting on that, but I think my main engine will be toast, they are saying they won't cover my two year old 9.9 merc kicker. I am a diesel engine mechanic by trade and would look into rebuilding the main myself if it it salvagable. Kicker has already been run and I'm sure it will be fine with a carb cleanout. Just wondering about buying the whole thing back from insurance and going from there. Lots of options for drop in engines on line, just wondering if anyone has experience with good or bad rebuilds or drop in's? Engine was a 1994 carbuerated, just before they went fuel injected. I would look at both options, fuel injected or not. Thanks for any input
Click to expand...

If the motor was raw water cooled I wouldn't touch it..
Buy a new crate engine
 
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