jeffg

Just got engines back from being rebuilt, kept all stock, replaced Gils with KE headers, water pressure at idle about 7 , at 3500 rpm and up the needles get pegged at over 35 psi, some water leaking out of hose as if under high pressure, help what should I check for, HP500s carbed, normal water and oil temps.

MIKEHTMSR24

the header restricting water flow out

jeffg

I will try to figure out some way to check headers for restrictions. Could some thing be hooked up wrong, maybe wrong gasket? This occured on dyno also. The boat is an Outelimits and when doing a search someone mentioned OL putting pressure relief valves in- could they have left it off, where would I look?

candyman35

jeffg
What kind of pressure did you have before the rebuild? To check the headers for the restriction you need to make up some tees and install them in the two water hoses that go to each header. I used the plastic tees that are used in underground sprinkling systems. Off of the tee install a gate valve and then some rubber hose running over the transom. While running have some one open up the gate valves at 3500 rpm. Try to open each equally until you have reduced the pressure to 20lbs. If you open both valves fully and the pressure won't drop then that rules out the headers.

Did you install a water crossover to replace the circulating pump? That has been known to cause pressure problems also.
Dan

Cord

iTrader: (2)

You'll be needing some type of a dump valve. There are several threads on this in the tech section. I used a 3/4" valve and it's not bleeding off nearly enough pressure. My dealer has a propritary dump valve that uses a 1-1/2" port. That's my next step.

BTW-your engine might survive at 30psi, but it won't at 35. Don't run it up there or you'll be reparing it.

fountain27ho496

Just curious, never had a water pressure gauge before.
Stock power, was out last night it gets close to the
max on the gauge. Thanks JC

WETTE VETTE

If the correct type of valve is used 3/4" is more than enough to lower the pressure. There are several guys using the dump valve system I came up with with great success and some of them were seeing 40 plus PSI. 30 PSI is ok but still overkill. Shoot for 18 to 22 psi at WOT. Send me a PM if you can't get it figured out.
Craig

Cord

iTrader: (2)

Wet-I have your system on my boat. By 60mph I'm seeing 35psi! However, I do have an unusual application that is probably the cause for the high pressure. It seems to work well, but is simply overwhelmed in situation.

WETTE VETTE

Cord,
What valve are you using and is it overwhelmed while being all the way open? Are you running an offshore style pick up or through the drive? Is the dump on the inlet or outlet side of the seawater pump? On most boat the 1/2" valve is adequate to relieve 10 to 15 PSI at WOT. Sounds to me like you may need the inlet and pressure side system. I would hate to see you have to use a huge 11/2" valve if it isn't necessary and will not eliminate spikes. If you have a lot of ram on the inlet side you may need to dump some water there at 5 PSI through a 1/2" check then the 3/4" valve will keep up. Just a thought. I run the 5 PSI inlet check on my inlet just to eliminate spikes before the sea strainer. Then I run a small 1/2" valve on the pressure side to dial in my max pressure.
Later,
Craig

Cord

iTrader: (2)

It's the 3/4" McMaster-Carr valve. It's installed after the pump, before the oil cooler. The pickup is in the drive and is a single 3/8" hole. I have a crossover and have flow restictors that control the waterflow through the engine. I believe the water pressure is comming from a combination of the crossover and the flow restrictors. I'll be adding a transom pickup this weekend, so we'll see how much control I have over the water pressure.

What is this 5psi check?