Engine swap

jr chapman

Recruit
Joined
Jul 14, 2010
Messages
1
Can you use '93 4.3L car engine in '95 boat with 4.3L. If so, what changes need to be made? Any help would be appreciated.:)
 

PS94

Petty Officer 1st Class
Joined
Aug 1, 2009
Messages
293
Re: Engine swap

I think this should be made a sticky.

So far, from reading iBoats, you'll need to swap to brass frost plugs, and then change most of the internals, cam, crank, etc.. as it would seem the boat motors have forged internals, whereas most automotve don't.

If you cracked a block, use the auto one, with all your marine parts..
 

adeneo

Petty Officer 2nd Class
Joined
Jul 7, 2010
Messages
107
Re: Engine swap

I've done this several times without issue.

If the engine is saltwater cooled you will need to replace the following:

Freeze plugs
Head/manifoil gaskets
Circulation pump
Camshaft
Distributor, starter and alternator
Carb
Exhaust
Raw water pump
Thermostat and housing

Those are the main things.

Some say the marine engines have forged inernals and a different cast, I've only rarely seen this on any of the engines I've worked on, and as there is no saltwater anywhere the oil goes, the only reason for forged parts would be to strengthen the engine, wich is fine, but not really necessery to make it work. Same with stainless valves.

If the engine is freshwater cooled there's no need for new frost plugs, gaskets or circulation pump (unless it has connections for heater), as saltwater will not enter the engine.
Camshaft, distributor, starter, alternator, carb and exhaust would all need to be replaced, and heat exchanger would be added.
 

CapnMorgan

Cadet
Joined
Jul 9, 2010
Messages
13
Re: Engine swap

I have put motors straight from the bone yard in boats. I have a mercruiser 383 stroker motor and it has forged pistons but cast crank and rods. All of my boats have been standard rotation also, yet quite a few have had rev. rotation markings on the distributor cap.

and just to give an idea, I own a used car dealership and learned about 4 years ago the markup on a boat is way higher than a car lol, I buy every boat that comes through the auction. The first boat I sold, I put a 2.3l from an 88 ford t-bird 4 years ago, My buddy said it still runs great. I have noticed that the cams in boat engines fit under the radical category when compared to hot rod cams.
 

cr2k

Captain
Joined
Mar 19, 2009
Messages
3,730
Re: Engine swap

I hope you changed the carbs, starters, alternators, etc to marine or you are way out there liability wise when NOT IF one of those boats blows up.

Marine engines, salt of fresh water have a lot of differences, including the circulation pump in most cases. water+steel=rust, automotive blocks have steel core plugs.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,241
Re: Engine swap

Ayuh,.... adeneo, 'n cr2k have it Right,...
PS94 is Wrong,....
And,..
CapnMorgan,..?? "I have noticed that the cams in boat engines fit under the radical category when compared to hot rod cams."
What the 'ell does That mean,..??

Marine cams are otherwise known as an RV/ Truck cam... Nowhere near Radical....
 

sully73

Cadet
Joined
Jun 21, 2008
Messages
24
Re: Engine swap

several years ago i help a buddy put a blazer motor in his crownline. two day swap and all i remember needing to add to the long block was the vibration balancer off the marine engine. still runs great and he claims its the best motor hes ever had and still running strong. use the auto long block, and swap over the marine parts from your boat motor and you should be fine so long as the donor engine is in good shape.
and by balancer, i mean the camshaft balancer thingy amjob in the lifter valley, not the harmonic,although im not sure if there is a diff in the harmonic either. we just pulled the donor down to a long block and swapped over the parts. very easy swap in my opinion.
;)
 
Top