StrikinLightnin

Took the boat out for a shakedown run and found that my water pressure was pegging the gauges when running over
4k and around 30-35lbs cruising in the three thousand rpm range.Engines also have crossovers instead of a water pump.I have thru-hull water pickups on the boat.My question is will I be able to adjust water pressure/flow by sliding or closing the pickup more?
Probably have to put a regulator setup on it.

Thanks,
Dennis

Bad Girl

I have thru hull pickup on my 42 and was able to adjust water pressure by how much the pickup was below the bottom.

however it is best to have plenty of flow and then adjust. you need more control over the water dumping through the exhaust or through a thru-hull off the exhaust pipe to make sure your exhaust is full of water as well and about 10 psi at the end of the pipes.

point is control the end of the loop rather than the beginning. you will starve the motor when coming out of the water. you could dump some water from the rear of your intakes on each side of the motor and plumb it into your exhaust as long as you have large enough water dumps.

hope it helps as a start.

MOBILEMERCMAN

Bad girl is right but, It is also a balance of water needed for the motor versus how much drag your making and speed your loosing. Gauge doesn't know if its water or air mix. There are many ways to test and adjust pick ups, Be careful and make sure your not passing air through motor. 23- 25 lbs is ideal.
Jim

monstaaa

agreed as stated above. as well you can bleed off some of the excess water/ air pressure as it enters the water system at the strainer, which will get rid of alot of air in the water as it enters the water system as fountains ride on a small cushion of foamed water.
in our application we have purges in our 3 gallon water tank as well as engine dumps and exhaust dumps all designed to control water pressure AS WELL AS VOLUME. dont forget about volume.

StrikinLightnin

I don't believe that I have lack of water to the engine when I'm out of the water as I have the large Harden Swirl Away strainers.Water temp runs 150* with Summit SS 160's drilled out to get coolant up top for startup.Cooling the block doesn't appear to be a problem.I have Dart intakes which I'm not quite sure how to tap water from them for the exhaust dump.The tails seem to be very warm so I would definately like to put more water through them.The CMI's have a fitting but with the Dart intake I'll have to figure out how to tap into. Oil temp was up there @220-230* with an Eddie 3" cooler and a Perma-Cool t-stat.I'm getting rid of the thermostat and going to run oill lines directly into the cooler.

Dennis

monstaaa

drill and tap the back of the intakes. there should be a cast in "boss" or "landing" on both sides of the rear of the intake manifold.
usually they get drilled to accept a 3/4 pipe thread fitting and then get bushed down to regulatye the volume of water they allow to purge. this will only be evident thru testing. but for say a single four barrel 700 + h.p application that runs around 100 you end up with a -8 fitting or dump.

as for the oil temps 220 is not bad. actually you need atleast 220 to steam any water out of the oil that may enter the oiling system. not to say that it should remain constant at 220 - 230.

hardin strainers have a 3/4 pipe bung in them that can be used to purge the strainer. this will also help rid it of air and excess pressure v.i.a a thru hull fitting that is below the water line until on plane. and/ or equip the water system with a spike pressure relief valve to avoid pressure spikes.

i have experienced situations where high water pressure had negative effects on the cooling system from a saturatiojn stand point. exiting too fast. by regulating the volcity in which the water enters and exits the entire water system you end up with a truly efficient cooling system that will cool, exit, and extend engine life with out scrubing speed.

35 White Lightning

It fixed my over water pressure issue by installing the valves and thru hulls to dump it over the side. I could peg the gauge all the way back to 0 lbs

StrikinLightnin

When you say "valves" do you mean a regulator or just a hand valve?

Rebel_Heart

I was initially having some water pressure issues, but purchase the Merc relief valves. Only have 12 psi at WOT. My water temp is below 150 and oil temp never is over 190.

35 White Lightning

Here is a thread that has the part number a little pricey $305 apeice but they work before you blow a head gasket or an intake gasket http://www.offshoreonly.com/forums/s...ad.php?t=54216