Pressure relief with Cross over with bypass
#1
Getting ready to install my Cross over with Bypass (Hardin Marine) and my question is will I need a pressure relief inline as to not make a milkshake, and if so where do I install it?
Thanks
Bryan
Thanks
Bryan
#2
Registered
Joined: Aug 2007
Posts: 1,038
Likes: 2
From: St.Louis MO
http://www.hardin-marine.com/p-13357...th-bypass.aspx
Is this the one you installed?
If so I just installed one on my 502...why would you need a pressure relief in the water lines??
Is this the one you installed?
If so I just installed one on my 502...why would you need a pressure relief in the water lines??
#3
Registered

Joined: Jun 2004
Posts: 1,949
Likes: 37
From: Omaha, Nebraska. Boat on the Mighty Mo! Longest river in the USA!
Yes you will need one. Also install a water pressure gauge. My valves are located right before the input to the cross over. I would buy the adjustable relief valve, not the expensive merc plastic one.
#4
http://www.hardin-marine.com/p-13357...th-bypass.aspx
Is this the one you installed?
If so I just installed one on my 502...why would you need a pressure relief in the water lines??
Is this the one you installed?
If so I just installed one on my 502...why would you need a pressure relief in the water lines??
#7
Registered

Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
16-18psi at 85+mph.
People assume the crossover somehow adds pressure to the system. High water pressures can be from transom pickup variations, style, depth, etc. Or, restrictive flowing exhaust manifolds, or small water lines feeding manifolds, etc. Every boat is different.
Buddies 38 Cig, had high water psi. 25psi just cruising. would peg the psi gauge with hard running. The solution wasnt relief valves, it was trimming down the water pickups on the transom. They were too deep. A little goes a long way on that. Plus its scrubbing uneccessary speed off. I also recommend running dumps off the rear of the intake manifolds, at the water jacket on a siamese block like a 502. Helps cool those rear cylinders down, and can be used to fine tune the water psi by playing with hose size on them.
People assume the crossover somehow adds pressure to the system. High water pressures can be from transom pickup variations, style, depth, etc. Or, restrictive flowing exhaust manifolds, or small water lines feeding manifolds, etc. Every boat is different.
Buddies 38 Cig, had high water psi. 25psi just cruising. would peg the psi gauge with hard running. The solution wasnt relief valves, it was trimming down the water pickups on the transom. They were too deep. A little goes a long way on that. Plus its scrubbing uneccessary speed off. I also recommend running dumps off the rear of the intake manifolds, at the water jacket on a siamese block like a 502. Helps cool those rear cylinders down, and can be used to fine tune the water psi by playing with hose size on them.
#8
Having taken the boat out only once and realizing the current issues (no t-stat),this is great information that I will use, My previous crossover didn't a t-stat because if there was one installed the manifolds wouldn't see nay water until the t-stat opened, now I have that problem fixed but was/ am concerned with over pressurization but with the information you have given me I need to get it out on the water and see what is happening.
Thank you
Thank you



