Multiple Heat Exchangers

[pcmpete]

Has anyone experimented with using multiple heat exchangers in their setup?
I am in the process of rebuilding a Mercruiser 470 which are known overheat problems and heat exchanger upgrades etc.... Would adding a second exchanger help with cooling?
Here is a diagram of what I am planning, so would like to hear the pros and cons of this idea. I currently have 3" exchanger and WILL have a buy the 4" one OR if this concept works get another 3". (or 4" as the second one)

 

[zbnutcase]

Re: Multiple Heat Exchangers

I have a customer with a B&M blown 454 in his 21 footer running dual heat exchangers and it works great. I wouldn't hesitate to do it
if you have the room.'nutcase

 

[pcmpete]

Re: Multiple Heat Exchangers

I have a customer with a B&M blown 454 in his 21 footer running dual heat exchangers and it works great. I wouldn't hesitate to do it
if you have the room.'nutcase

Do you know what order the heat exchangers are in?
E.g. does the coldest raw water go to the coldest coolant
or
coldest raw water go to the exchanger that comes from the engine (warmer coolant) (i hope that makes sense)

 

[achris]

Re: Multiple Heat Exchangers

I PMed you this, but for the benefit of other readers I'm post it up here too...

The water flows must 'oppose' each other... Otherwise you'll get too little temperature gradient in some part(s) of the circuit.

 

[Don S]

Re: Multiple Heat Exchangers

Nice job on the drawing Chris, I'm impressed.

 

[HT32BSX115]

Re: Multiple Heat Exchangers

I currently have 3" exchanger and WILL have a buy the 4" one OR if this concept works get another 3". (or 4" as the second one)

There's no reason why a second heat exchanger would not work. You're doubling the heat exchanger area.

 

[bhammer]

Re: Multiple Heat Exchangers

I had a 470 with a 3" and a 4" exchanger on an old boat and it was set up like the drawing Chris supplied. It worked fine. The 4" was the last exchanger for sea water and the first for coolant but not sure if it matters.

 

[pcmpete]

Re: Multiple Heat Exchangers

I had a 470 with a 3" and a 4" exchanger on an old boat and it was set up like the drawing Chris supplied. It worked fine. The 4" was the last exchanger for sea water and the first for coolant but not sure if it matters.

What side of the motor did you install the second exchanger?
I am thinking about using one of each side using the second mount fixture on the block.

 

[bhammer]

Re: Multiple Heat Exchangers

They were mounted right next to each other. The PO had made a steel bracket that allowed it to mount right next to it.

 

[pcmpete]

Re: Multiple Heat Exchangers

They were mounted right next to each other. The PO had made a steel bracket that allowed it to mount right next to it.

Any photos?