Regulating water pressure

[Big Inch]

The thread leading up to this one is here http://***boat.com/forums/showthread.php?t=160051 if you care to see what led up to this.
Does anyone know if it is possible to reduce water flow or pressure on my boat. I have a Bravo one drive leading to a Mercruiser seawater pump and am looking for a way to reduce the water pressure to my motor so I can effectively increase my motor temperature. I tried running a t-stat but I need a better way. The motor runs better at higher temps but I'm afraid of creating too much pressure in the block/heads. I have a water pressure gauge and oil temp gauge on order. Regardless of what my pressure reads at rpm I still want to find a better way to raise my temps then using a t-stat and the only thing I can think of is finding a controlled way to reduce the water pressure or intake.
Please help :)

[BrendellaJet]

this is what we use on jet boats...
http://www.***boat.com/image_center/data/500/Rigging_001.jpg
You could also use a different volume of line for the exit water which would raise pressure(within safe limits) and increase temp also.

[BrendellaJet]

what block pressure are you using? What kind of head gasket? Im seeing 20-23 lbs of block pressure as read at the thermostat housing(cometic gasket). Again, this is on a jet boat but the engine doesn't know what its turning...

[Havasu Hangin']

I don't believe lowering pressure will increase temps. Some pressure in the block is good- it lessens the chance of steam pockets.
Maybe you want to reduce flow? To reduce flow, most I/O's are setup with a t-stat and recirc pump.
However, almost all the high performance guys I know just run a bypass and keep it cold. My motor temps never even register on the guages...but they seem to be very happy.

[Big Inch]

You could also use a different volume of line for the exit water which would raise pressure(within safe limits) and increase temp also.
I don't want to raise pressure by increasing the pressure at the exit line. This is essentially almost exactly what the thermostat is doing in my setup and is what I am trying to avoid.
what block pressure are you using? What kind of head gasket? Im seeing 20-23 lbs of block pressure as read at the thermostat housing(cometic gasket). Again, this is on a jet boat but the engine doesn't know what its turning...
I'm not sure yet of the pressure. I have a water pressure gauge on order but I probly won't have it before the weekend so won't be installed for a couple of weeks.I want to make sure it is under 25 psi. I honestly am not sure of what head gasket was put on the motor. It was just rebuilt and I have not gotten a spec sheet on the build yet.

[Big Inch]

I don't believe lowering pressure will increase temps. Some pressure in the block is good- it lessens the chance of steam pockets.
Maybe you want to reduce flow? To reduce flow, most I/O's are setup with a t-stat and recirc pump.
However, almost all the high performance guys I know just run a bypass and keep it cold. My motor temps never even register on the guages...but they seem to be very happy.
You are correct I am not trying to find a method to lower pressure. I temporarily installed a t-stat to test the motor at higher temps but this runs the risk of creating dangerously high pressure in the block. I am looking for an alternative way to reduce the flow prior to the water entering the block as a way of raising my temps. I am also open to other suggestions that would raise my temps.
Without the t-stat my motor is sluggish and overly rich to the point of fouling plugs and backfiring through the exhaust. When I raise the temp I get much better performance out of the motor and also raise the oil to proper operating temperatures.

[cfm]

With a cross over system, to increase water temps you want to restrict water after the engine - ie: at t-stat housing - with restrictors (those big washers with holes) or a t-stat itself.
These may create more water psi than you want - therefore you have to check this. If you find the correct restrictor and it causes more psi than you want, then you need to run a psi regulator just before the restrictor or block that will dump the excess water over the transom.
Some people successfully use threaded brass plumbing water psi regulators and many pony up and buy the cheap but of course expensive Mercury Racing water psi valve.
I would start the cheap and easy way. Get a Moroso or other water restrictor kit. they are cheap and come with a handful of restrictors that vary in orifice size and fit where a t-stat would on intake manifold. Watch your temps and watch your water psi. If both are where you want with no more mods needed, then your all set. If either or both aren't where you want than it's time to run a t-stat with bypass and water psi valve.

[cfm]

this is what we use on jet boats...
http://www.***boat.com/image_center/data/500/Rigging_001.jpg
You could also use a different volume of line for the exit water which would raise pressure(within safe limits) and increase temp also.
Do you have a manufacturer name + part # for that ? Where to buy ? I'd like to check one out. Thanks.

[don johnson]

I have seen your previous threads and ask why you want to increase the water temps? I have had both Pfaff and Teague motors and they like to run them as cool as possible. I currently have twin 1,100 HP 572 CI blower motors and they run right at 95- 100 degrees....
I suggest you consider a different approach. Look at the tune on the motor. Sounds like it is off. I have run many big HP, big inch N/A motors and when the tune is right they ran great at low water temps....

[ck7684]

You need to be sure the oil is heating up enough to boil out any moisture...

[Big Inch]

With a cross over system, to increase water temps you want to restrict water after the engine - ie: at t-stat housing - with restrictors (those big washers with holes) or a t-stat itself.
These may create more water psi than you want - therefore you have to check this. If you find the correct restrictor and it causes more psi than you want, then you need to run a psi regulator just before the restrictor or block that will dump the excess water over the transom.
Some people successfully use threaded brass plumbing water psi regulators and many pony up and buy the cheap but of course expensive Mercury Racing water psi valve.
I would start the cheap and easy way. Get a Moroso or other water restrictor kit. they are cheap and come with a handful of restrictors that vary in orifice size and fit where a t-stat would on intake manifold. Watch your temps and watch your water psi. If both are where you want with no more mods needed, then your all set. If either or both aren't where you want than it's time to run a t-stat with bypass and water psi valve.
Thank you once again Cfm. I will be trying the restrictor kit once I get the pressure gauge installed.

[Big Inch]

I have seen your previous threads and ask why you want to increase the water temps? I have had both Pfaff and Teague motors and they like to run them as cool as possible. I currently have twin 1,100 HP 572 CI blower motors and they run right at 95- 100 degrees....
I suggest you consider a different approach. Look at the tune on the motor. Sounds like it is off. I have run many big HP, big inch N/A motors and when the tune is right they ran great at low water temps....
You may be correct about my tune being off. I am quite certain that I could tune the motor to run efficiently at these colder temps. The reason why I am not doing this and moving on is because I believe it is of utmost importance to get the oil temps up higher then they are reaching when I let the motor run at 95 degrees.

[Big Inch]

You need to be sure the oil is heating up enough to boil out any moisture...
You also want to make sure that your oil is hot before you run the motor hard. In my boat even getting on plane the motor is running hard. If it is not up to temperature the oil is essentially too thick and this reduces your flow through your motor and I believe leads to premature wear throughout the motor.

[don johnson]

You may be correct about my tune being off. I am quite certain that I could tune the motor to run efficiently at these colder temps. The reason why I am not doing this and moving on is because I believe it is of utmost importance to get the oil temps up higher then they are reaching when I let the motor run at 95 degrees.
I suggest an oil cooler thermostat kit to maintain oil temps at the desired range. These are readily available.

[Havasu Hangin']

I suggest an oil cooler thermostat kit to maintain oil temps at the desired range. These are readily available.
Yep. Oil temp is very independent from block temp.

[BrendellaJet]

Do you have a manufacturer name + part # for that ? Where to buy ? I'd like to check one out. Thanks.
Its a watts regulator. Try some searching in the jet forums. The part # is mentioned in those threads. Pretty sure the part has been discontinued but it is still available(found mine at a True Value Hardware store). Pressure range is adjustable from 25 psi-75 psi,300 max inlet. You can alter the pressure the block will see by altering inlet & exit line sizes. I think this one has a 3/4 inch pipe thread on it. Lots of guys running this setup with big HP NA deals.

[Big Inch]

I suggest an oil cooler thermostat kit to maintain oil temps at the desired range. These are readily available.
I have heard of people using these but I don't see where it would be installed on my cooler. You can see pics of the cooler in the linked thread. I believe it is a Dan Olson cooler. I honestly haven't researched these coolers only because someone told me that they limit the flow past the cooler until it reaches temps and if you run in cooler water this can take some time. I think the only downside of this is higher temps on the exhaust tips until it opens. All things considered this may be worth looking at if it is applicable to my cooler. Still going to try the restrictor plates first since it may be a simple fix.

[uLtRADeNniS]

Maybe a bad gauge??....
I run a 554ci N/A, 802hp. The motor runs much better a cooler temps. I would think its optimal to let it run cool; especially in that desert. The 115+ degree heat can really effect your performance especially when you run less water to the motor.
Anyways.. this is what I run(available at Grainger). ....I also run a Oil Cooler.
http://aycu05.webshots.com/image/25164/2003221120106219612_rs.jpg

[Big Inch]

Maybe a bad gauge??....
I run a 554ci N/A, 802hp. The motor runs much better a cooler temps. I would think its optimal to let it run cool; especially in that desert. The 115+ degree heat can really effect your performance especially when you run less water to the motor.
Anyways.. this is what I run(available at Grainger). ....I also run a Oil Cooler.
I have mechanical gauges hooked up temporarily to insure accuracy.

[Panic Button]

Merc PN 863208A3
Bypass valve set for 25#
http://www.offshoreonly.com/forums/attachment.php?attachmentid=33992&stc=1&d=1057954986

[DUCKY]

You do not under any circumstances want to restrict inlet flow to achieve desired temp. The jet boat guys run those regulators because a nice tight pump can make in excess of 100psi in the block which will kill head and intake gaskets. The Mercruiser raw water pump will never do that. You need to maintain a minimum of 15-18 psi in the block at speed for proper cooling. Although I would suggest sticking with a t-stat, if you are dead set against it you can use the restrictors that were mentioned above, but you must keep the pressure up.

[Boostedballs]

You don't want to reduce flow. Steam pockets can warp heads etc.
You could install a liquid-to-liquid heat exchanger on the water inlet and outlet. It should help preheat the incoming water and cool the water that will go into the exhaust. A win / win

[Boostedballs]

I bought one of those thermostals and housing with 4 ports on it. Now my water pressure is around 7psi with no loss of flow. It was $115 from JP or JC or something marine. Polished stainless, looks bitchen.
Now my water temp is solid at 180psi. Or at least it was before my engine ate some rod bearings...