SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Luckie Stiff on September 03, 2007, 05:31:27 PM
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I have a line on a good, low mileage 460 complete engine, is there anything special that needs to be done to stuff it in the boat?
Thanks
Skip
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Well, I guess I'll start. Basically an auto engine is designed to run at a lower rpm than a marine engine(because it has a transmission). A marine engine is usually built to withstand higher rpms and more extreme conditions. In short, marine engines typically have better components in them to withstand the higher rpms, hotter oil temps, and uphill like resistance constantly on the engine.
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Guess I'll ad, depends on what you want your boat to do. Like lilrick said, these motors are a higher rpm/high load type motor (typically)
So if high speed, more hp is your goal, cam, head work, lifters, valves, roller rockers, pushrods. In your case, botom end (crank) will do stock well up and over 500hp,
but you might want to change pistons and rods too. Plus to match it all... intake, carb, headers... the list grows... just ask anyone here how much they have spent to reach 60-80 mph ;D
typical Marine motor is overbuilt compaired to car/truck ;) but depending on what you want... simple changes can make it work!
Performance costs :-[
Rebel
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And there are some differences in tolerances, so be sure to tell the machine shop doing the bore that it is for a jet boat application.
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You can put your engine in a boat , it just won't live as long and won't push the boat very fast.
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And there are some differences in tolerances, so be sure to tell the machine shop doing the bore that it is for a jet boat application.
Cylinder temps are a lot higher in a marine application which is why ::)
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You need the pistons looser in the bore, much like a motor set up for nitrous.
The ring end gaps need to be about 2x the clearance of a normal passenger car.
This all has to do with the temps that build up inside the chamber at high load for extended periods.
The other thing is the freeze plugs, they need to be brass so they don't corrode in salt. If you are riverbound only, you may be able to get by without, however, the engine is still lacking antifreeze so there still may be corrosion issues (but it will take much longer to show up).
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What impeller are you turnin? If it's a "AA" and the motor is well broke in I'd say drop her in and go fer it. I doubt you'd see too much over 4300 R'S.