Fresh water cooling conversion ?
Moderators: BeaconMarineBob, Moderator, BeaconMarineDon
Fresh water cooling conversion ?
hello again,
I recently purchased an F 28 as some of you already know, which is in need of some engine work,
here is the situation
the engine on the starboard side is in and working, fine, raw cooled
the engine on the port side has been removed at the v drive ,
when I purchased the boat the previous owner supplied me with a "freshly rebuilt" engine, I did run it in my driveway with life support and it sounds good and runs smoothly
here is my question,, the replacement engine is Fresh water Cooled, the one in the boat is raw cooled,
my plan is to install the fresh cooled engine and then add a fresh cooled kit to the one already in the boat
has anyone done a conversion, is it a straight forward convert? any info would be appreciated.
engines are small block gm, v drive
I know the gaskets at the risers have to be upgraded to block off types,,
and I plan on purchasing a complete kit
oh one more thing, the engine in the boat is serpentine belt, the replacement is v belt , he did supply me with the original engines serpentine set up, so I suppose it would make sense to do that as well
my previous experience tells me its always better to have a fresh cooling setup , the past two boats I had,, had raw cooled and that really kicks the crap out of the engines,, my boating is done in brackish to salt water.
I recently purchased an F 28 as some of you already know, which is in need of some engine work,
here is the situation
the engine on the starboard side is in and working, fine, raw cooled
the engine on the port side has been removed at the v drive ,
when I purchased the boat the previous owner supplied me with a "freshly rebuilt" engine, I did run it in my driveway with life support and it sounds good and runs smoothly
here is my question,, the replacement engine is Fresh water Cooled, the one in the boat is raw cooled,
my plan is to install the fresh cooled engine and then add a fresh cooled kit to the one already in the boat
has anyone done a conversion, is it a straight forward convert? any info would be appreciated.
engines are small block gm, v drive
I know the gaskets at the risers have to be upgraded to block off types,,
and I plan on purchasing a complete kit
oh one more thing, the engine in the boat is serpentine belt, the replacement is v belt , he did supply me with the original engines serpentine set up, so I suppose it would make sense to do that as well
my previous experience tells me its always better to have a fresh cooling setup , the past two boats I had,, had raw cooled and that really kicks the crap out of the engines,, my boating is done in brackish to salt water.
- prowlersfish
- 2025 Gold Support
- Posts: 12724
- Joined: Sat Nov 05, 2005 6:56 pm
- Location: Lower Chesapeake Bay ,Va
Re: Fresh water cooling conversion ?
The issue you may have , the engine in the boat has years of rust built up and deposits . If you install fresh water cooling the coolant could turn rusty in no time and all the flushing won't fix it . If was a fresh water boat you may get away with it , salt water boat forget it . I would run one fresh water cooled and the other raw water until its time to repower . Remember the raw water cooled engine must run cooler ( uses a 140 degree thermostat ) then a fresh water system .
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat

-
- Ultimate User
- Posts: 1876
- Joined: Mon Sep 28, 2009 5:08 pm
- Location: Canton, TX Boat on TEXOMA
Re: Fresh water cooling conversion ?
I have an f28 that is going to be sold with new engines, when I put her together would like to used serpentine belts, any idea where they came from? I have a good raw water cooled reverse engine (starboard) that has only been in fresh water if interested.
Larry Eddington
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
Re: Fresh water cooling conversion ?
Larry, maybe its me, I dont understand what your saying?? sorry
Re: Fresh water cooling conversion ?
Prowler,, I dont quite understand, what will happen if I convert the engine,,? I forgot to mention that the engine in the boat has a documented 50 or so hours , and new manifolds and risers, dosent seem to be that dirty. So is what your saying that the coolant circulating through the engine instead of the raw water will damage it or dislodge rust and sediment?
- prowlersfish
- 2025 Gold Support
- Posts: 12724
- Joined: Sat Nov 05, 2005 6:56 pm
- Location: Lower Chesapeake Bay ,Va
Re: Fresh water cooling conversion ?
Yes , all the crud rust will be stuck in your cooling system . Was it salt water use ?
Larry to go to serpentine belts you would need to replace all the pulleys if you could find any to fit the 318 marine
Dante do you have a photo of your belt set up ? Never seen a 318 marine with a serpentine belt , OPPs That's assuming you have 318s You could have Mercs I just knew Larry has Chryslers what engines do you have ?
Larry to go to serpentine belts you would need to replace all the pulleys if you could find any to fit the 318 marine
Dante do you have a photo of your belt set up ? Never seen a 318 marine with a serpentine belt , OPPs That's assuming you have 318s You could have Mercs I just knew Larry has Chryslers what engines do you have ?
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat

Re: Fresh water cooling conversion ?
I dont have Chryslers,, I have Merc small block general motors engines as I mention in the beginning of this thread,
Ill snap some pics,,
the previous owner did give me the serpentine set up for the engine,,
and prowler, I dont know the history , but I am assuming its salt water,,
is there anything that can be done to clean the block?
Ill snap some pics,,
the previous owner did give me the serpentine set up for the engine,,
and prowler, I dont know the history , but I am assuming its salt water,,
is there anything that can be done to clean the block?
Re: Fresh water cooling conversion ?
not to go off topic, and Ill start a new thread if I have to, but I was told by several people that the direction of prop spin is determined by the V drive, not the engine, because as you can imagine I was concerned what engine was purchased for the port side,
I was told the direction is done in the trans,, on THIS type of set up
I was told the direction is done in the trans,, on THIS type of set up
-
- Ultimate User
- Posts: 1876
- Joined: Mon Sep 28, 2009 5:08 pm
- Location: Canton, TX Boat on TEXOMA
Re: Fresh water cooling conversion ?
That is true in my f28, but if you turned the engine to a normal, not v drive, the port engine would still need to twist the prop over the top to the outboard or normal rotation. In other words my v drives are exactly one to one and it does reverse the direction and has to as the engine is facing backwards. It gets confusing but rest assured on my two experiences with f28 the starboard engine is the reverse rotation engine. I am not saying in every other instance that is true but in my two v drive boats it is. We have all been down this rabbit trail before.Dante D wrote:not to go off topic, and Ill start a new thread if I have to, but I was told by several people that the direction of prop spin is determined by the V drive, not the engine, because as you can imagine I was concerned what engine was purchased for the port side,
I was told the direction is done in the trans,, on THIS type of set up
My f28s Starboard is reversed rotation engine and port is normal rotation.
Now newer v drive who knows but my old Paragon PV31s the engine drives a large gear that drives the out put gear voila spin is reversed, but engines are the same as other normal type straight through drives.

Larry Eddington
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
- prowlersfish
- 2025 Gold Support
- Posts: 12724
- Joined: Sat Nov 05, 2005 6:56 pm
- Location: Lower Chesapeake Bay ,Va
Re: Fresh water cooling conversion ?
Dante D wrote:I dont have Chryslers,, I have Merc small block general motors engines as I mention in the beginning of this thread,
Ill snap some pics,,
the previous owner did give me the serpentine set up for the engine,,
and prowler, I dont know the history , but I am assuming its salt water,,
is there anything that can be done to clean the block?
Flush flush and flush some more .Then run it and maybe change the coolant a time or 2 I read and read your post and I did not see GM I saw small block but missed the gm . took 2 times to see it when I looked again ...... Its hell getting OLD


Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat

Re: Fresh water cooling conversion ?
I know, when I get the fresh cooled engine in, Ill decide what to do with the one that is raw cooled, maybe its best leave it alone until I replace it. you make a good point prowler
Re: Fresh water cooling conversion ?
i left mine alone, I put a good/used FWC engine in my F32, port side, plug and play basically, starboard is RWC, wasnt worth the hassle or expense to convert to FWC IMO