How many run a recirculating water pump?

[kevnmcd]

As I get ready to redo my motor this winter (stock 502 mag EFI), I was just wondering how many of you have gotten rid of the recirculating water pump (the one that is attached to the front of the motor) and added a by-pass? What are the pros and cons? Thanks.
Kevin

[Beer-30]

As I get ready to redo my motor this winter (stock 502 mag EFI), I was just wondering how many of you have gotten rid of the recirculating water pump (the one that is attached to the front of the motor) and added a by-pass? What are the pros and cons? Thanks.
Kevin
Ya know, one of the things I was going to suggest was closed cooling. Right about the time you mentioned salt water, I was going to mention it. If you have an extra $800-1000, you could keep the re-circ pump, put in the thermostat of your choice and run regular anti-freeze/coolant. The only thing that would touch salt would be the seapump and heat-exchanger.
Other than that, I would continue to run it, myself. Simpler plumbing and pretty fail-safe - as well as fairly stable temps. Less chance of shock-cooling.

[kevnmcd]

Ya know, one of the things I was going to suggest was closed cooling. Right about the time you mentioned salt water, I was going to mention it. If you have an extra $800-1000, you could keep the re-circ pump, put in the thermostat of your choice and run regular anti-freeze/coolant. The only thing that would touch salt would be the seapump and heat-exchanger.
Other than that, I would continue to run it, myself. Simpler plumbing and pretty fail-safe - as well as fairly stable temps. Less chance of shock-cooling.
Don't forget about the exhaust. ;) I might do that down the road if I start spending more time in the salt, right now it is only a couple of times a year and it's only for a couple hours at a time. Not to mention the additional $$$. :(
The only reason I was looking at removing it was for the couple of hp I might gain and one less mechanical item to maintain.

[Beer-30]

Oh yeah. And the exhaust too.

[paradigm shift]

On an EFI motor I would run the recirculating pump. Keeps engine temp warm with a thermostat so you do not run in enriched mode. I would seriously look at closed cooling if you run in salt.
If you go the cross over route be sure snd check you block water pressure. You would be suprised how much they can very from set up to set up.
I took the recirculating pump off of a 502 MPI and went to a cross over with a thermostat. I ended up going back to the stock set up after a year of trying to get temperature to run even and warm at idle during the cooler months. I have the crossover somewhere in the shop still.
Just my.02 and expierence
Oh yea you will not notice any difference in prefomrance. You might gain a couple HP but you will not notice it.

[kevnmcd]

On an EFI motor I would run the recirculating pump. Keeps engine temp warm with a thermostat so you do not run in enriched mode. I would seriously look at closed cooling if you run in salt.
If you go the cross over route be sure snd check you block water pressure. You would be suprised how much they can very from set up to set up.
I took the recirculating pump off of a 502 MPI and went to a cross over with a thermostat. I ended up going back to the stock set up after a year of trying to get temperature to run even and warm at idle during the cooler months. I have the crossover somewhere in the shop still.
Just my.02 and expierence
Oh yea you will not notice any difference in prefomrance. You might gain a couple HP but you will not notice it.
Thanks for the input. That is what I was looking for.

[Randy De Pirate]

I removed mine and went with all stainless steel hose. I am very happy with the results. One less thing to fail. I agree check you water pressure. I checked with Rex Marine since they been aorund a long time in the performance solution. They assured me there are no cons, just postives going to a crossover solution.

[C-2]

On OSO this topic has been discussed numerous times.
I'm also about to plumb my motor, will be looking at doing this, seems to be a good setup according to quite a few people:
http://www2.***boat.com/image_center/data/520/1132cross2.jpg
http://www2.***boat.com/image_center/data/520/1132crossover1.jpg

[paradigm shift]

C-2 the Rex is a good set up in my opinion. Exactly what I have in the garage with the single hose by-pass or 3 ports. Nice set up but it did not regulate temperature as even as with the recirc pump is all. Temp gauge seemed to hunt some as thermostat opened and closed. If I ran a real small bleed hole to get temperature up in the cold months and cold water it seemed to hunt a little more when running.
If you guys go the cross over route just be sure and check your block pressure prior to adding cross over and after. The stock set up with thermostat has a built in by-pass in the thermostat housing and it can make a difference in your block pressure. I reccomend checking before or you will not know if the cross over addition is the difference or it has always been at that pressure.
Guys I am not trying to sell you one way or the other just trying to make sure you understand these are not always just a bolt on and go process. Some never check things but I do. Not sure if that is a good thing some think I am just too picky at times. Some just call me a pain in the $ss. :rolleyes: :rollside:

[Randy De Pirate]

What should the water pressure be on a 454 merc? Or where do you find that information?

[Red Horse]

Hey Kevin, on my boat with no recirc pump and after I have been running, I have to let the boat idle for a while to cool. Running get plenty of water and then all that heat and reduced water. Have had run on problems because of it. I would keep the pump.

[kevnmcd]

Hey Kevin, on my boat with no recirc pump and after I have been running, I have to let the boat idle for a while to cool. Running get plenty of water and then all that heat and reduced water. Have had run on problems because of it. I would keep the pump.
Yeah...I will be keeping the pump. Thanks, Ken.

[paradigm shift]

What should the water pressure be on a 454 merc? Or where do you find that information?
Pressure will vary with set up. Ideal would be like your car 15-18 psi. Main issue is you do not want any steam pockets since you are dealing with water remeber boiling temperature. I have seen some run as low as 2 or 3 pounds at idle and you really do not want over 21psi maximum in my opinion. I believe mercury reccomends 16 - 17 psi max on an open colling system.