First my set up. I have an NA 540, closed cooling, full dry CMI's, Imco SC -2 lower, using the drives water pickup.
Unknown to me, I had a blockage in my gimbal keeping my water pressure at reasonable levels. Last weekend, I overheated the rubber hoses on 1 header. After checking everything out I discovered a blockage in the gimbal, where the 1 1/4" hose attaches. Now that I cleared it up, I have way to much water pressure. I have 30 psi at 40 mph. The gauge is pinned, who knows what it is at WOT. Being that I have closed cooling, I dont have to worry about blowing gaskets in the engine. I am a bit concerned about popping a hose off the raw water side at speed. I want to run a pressure relief valve, but also want to hook up a seastrainer. I have found a strainer that has a pressure relief valve option built into them, such as Hardins. I have heard of some that work well and some dont. Who has one or knows of one that works well? Do you think I even have to be concerned with water pressure being that the pressure is only in the heat exchanger, oil coolers and headers? I dont like the idea of closing up the low water pick up in the drive some, to lower the pressure. I prefer keeping the extra flow for when it is needed and just regulate it via dumps.



Thanks.

Stainless Marine has a nice unit, and Fred @ Trick carries them.

You probably need a pressure relief or gate valve before the sea pump ...Then again, you may not....One test might be to plumb into the plugged end of each header distribution tube....Then connect those two lines with a "T" and dump the flow overboard....The flow can be regulated with a gate valve,pressure relief,hose diameter or washer orifice....Further,the installation will improve pressure and volumne balance between both headers.

Let us know what you do.