5.7 conversion to closed cooling, fuel injection?

[rogair]

These may sound like simple/stupid questions, but here goes....thanx 4 help
'91 Bayliner 3555, 2 dead 5.7's, dead alpha 1's... in California / ocean only
I'm replacing both motors w/ rebuilt auto 350's(R.V. cams??). ASE master & aircraft mechanic. Looking for cheap, but operating costs a concern..

1. How easy/cost to convert to closed cooling? Salt water still runs to heat exchanger AND exhaust risers? (I have new aluminum intake manifolds, need 4 exhaust man/risers)

2. cheap conversion to auto fuel injection? - GM multiport F.I.?
Fuel savings considerable or not really? (I can easily rebuild the quadrajets)

3.used/rebuilt/knockoff alpha 1's or bravo upgrades? (I need gimbal/transom mounts also)

4. install used generator? Don't need a/c, but many 2-3 day weekend trips to islands planned

 

[JustJason]

Re: 5.7 conversion to closed cooling, fuel injection?

First... Don't use automotive blocks... Get marine shortblock (or long if your heads are toast) Also... you need to carry everything "marine rated" over from your old blocks. The fuel system, the ignition system, the chargeing and starting system... Everything.

then on to your questions....

1. Its fairly easy to do... but its 800 bucks in parts per motor.
2. NO AUTOMOTIVE... It wouldn't last anyways... you'd toast the motor in no time. Automotive EFI and MEFI use 2 completely different stratagies.
3. might as well go with the SEI drives that are sold here on Iboats.... pretty good for the money.
4. better than being stuck someplace with dead batteries... But your going to have to wire up some 110 lights and switches.

 

[rogair]

Re: 5.7 conversion to closed cooling, fuel injection?

thanx...
marine short blocks? other than brass freeze plugs, the difference?
do u think closed cooling worth the effort? I understand no auto accessories / i will rebuild my starters, alternators, etc...

o.k. quadrajets prolly the way to go..

boat has shore power & nice big electrical panel already...just no generator. cost?

 

[JustJason]

Re: 5.7 conversion to closed cooling, fuel injection?

usually 4 bolt mains, high volume oil pump, marine water curculator pump, and especially marine head/intake/and exhaust gaskets.

Is closed cooling worth the effort??? In the long run... usually.

generator us up to you. beats charging batteries all the time. no idea on cost... coudle be a few hundred to a few thousand.

If this boat was moored in salt have a good look at the outer transom plates for rot. (especially around where the bellows mount)

 

[gcboat]

Re: 5.7 conversion to closed cooling, fuel injection?

Here's a little read on the differences between auto and marine powerplants:http://www.boatfix.com/how/marineeng.html

Closed cooling on NEW engines, in a salt water environment is a blessing to the motor. There are two kinds available - a half system and a full system. A Google search will easier answer the differences than I could. Do remember that there are major differences between the two engines.

 

[rogair]

Re: 5.7 conversion to closed cooling, fuel injection?

other than raw water pump, good to go...

transom plates are trash, looking for complete drives/hsgs...

how much better are the bravo's than the alpha 1's ?? worth the diff $?

 

[JustJason]

Re: 5.7 conversion to closed cooling, fuel injection?

its not that bravos are better or worse. Its what the drive is rated at. Alpha's are rated for up to 300HP. Although when you get close to 300 most people say you should baby them a bit more... ie no slamming into gear and then into full throttle.
Bravos are rated for well over 300.