Converting from closed to raw water cooling

[Tail_Gunner]

A while back I wrote just about exactly what is on that website (I have never seen it before BTW)... 84EdH may remember where it is... Ed?

Chris......

EDIT: Found it... http://forums.iboats.com/mercruiser...outdrives/overheating-633114.html#post4432663

Nice you have one of those fancy smancy diag's for a 87 454 mercruiser going to cold water...

 

[achris]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

Nice you have one of those fancy smancy diag's for a 87 454 mercruiser going to cold water...

Nope... They only ever used the 'warm' system on the 454 in '87.... The upside is that the cooling system for a 454 is exactly the same as one for a 350. So you can change your 454 to cold manifolds by following the diagram of a later model 350... Something like 1994.

Try manual #17, page 23, section 6A.... (need a link to that manual?)

Chris.....

 

[Tail_Gunner]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

Is that boatinfo library?

 

[achris]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

Is that boatinfo library?

Either there or HERE

 

[Tail_Gunner]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

That's a WAG..pretty much the village idiot when it comes to marine plumbing...and i intend to stay that way...:laugh:

 

[achris]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

Those are 'warm' manifolds TG.... Are you after warm or cold? (Less plumbing with cold)... BTW, what's a WAG?

Chris...

 

[Tail_Gunner]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

Wild... A##...Guess...WAG

Below is what i have somewhat....there is no thermostat housing just a tube connected to a tank.. reservoir... sitting in front of the engine,,,there is another tank or reservoir sitting on the back of the engine. The exhaust was up graded to to stanless marine marine manifold riser's

And thats seems to be the cooling system type.....

Overheats above 30 mph...3000rpm 1987 454 alpha one combo.....bought the boat from a old guy cheap....i now know why the luv of his live was messed up and he had given up on her...the boat that is..


Yes after cold i am going to take that cooling system and..... well the engine bay will have a much cleaner look.

 

[achris]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

Ahhhh, closed cooling... You need to run a few checks. First I would check the output of the seawater pump in the drive (if you're still running with the drive pump).

The argument of 'warm' vs 'cold' manifolds is completely out the window with a closed cooling system.... With full closed you will have the manifolds in the 'engine' side of the system, making them 'warm'. If you change the closed cooling system to a semi or half system then the manifolds will be cold...

The next thing I would do is to pull the heat exchanger off and have it professionally cleaned by a radiator specialist...

I had closed cooling on the engine before the current one... Wish I'd put it on the new engine....

Chris....

 

[Tail_Gunner]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

Gonna dump the closed system...running in freshwater...and i dont even like the way the system looks on the bilge. I like the clean look and simple systems...going to do some yellow plug wires's though...I cant imagine cleaning up a 27 yr old radiators that are plain but ugly...:laugh:

 

[achris]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

To go back to raw water cooled there are going to be quite a few changes... Different thermostat housing, change the manifold/elbow closed gaskets to either full flow (for cold manifolds) or restricted (for warm manifolds), a few new hoses.... You'll also need a new thermostat... The closed cooling t'stat should have been 160 degree, the raw water needs to be 140 degrees.

Chris..

 

[Tail_Gunner]

Re: Cooling System Question(s)

Re: Cooling System Question(s)

To go back to raw water cooled there are going to be quite a few changes... Different thermostat housing, change the manifold/elbow closed gaskets to either full flow (for cold manifolds) or restricted (for warm manifolds), a few new hoses.... You'll also need a new thermostat... The closed cooling t'stat should have been 160 degree, the raw water needs to be 140 degrees.

Chris..

Going to go cold...there is...no thermostat housing now just a tube that bolts to the intake and then routes into the tank..already using a 140 as to the thermostat housing can i pickup any modern 7.4/ 454 housing....the older styles dont seem to be avaible.