Block Pressure too Great?

[455Olds]

Just bought a new/rebuilt pump for my boat... 12JG 9-vane with a droop snoot and A impellor. Also added basset OT headers. Went from a turn key boat to a water hose blowing machine...
The large hose off the water pump housing has blown the last two times out... causing the blatant miss-use of four letter words, a sinking feeling, and a well earned work-out for the bilge pump. This had never happened before the new pump, and has now happened twice in three days.
Was my old 12JC just old and tired, and now the newer pump finding all the weak links in my system? What kind of pressure relief valve should I be running to reduce the block pressure? Any other reasons this would continue to blow?
If I replace the rubber hose with a piece of aluminized exhaust pipe what would blow next? All comments are greatly appreciated....

[sleekvino]

contact duane at htp marine his got the perfect fix and it works great on my boat.had water in the oil and was a constant battle .now i run all day at 4500 plus with no froth.its the 100 dollar fix again.:D

[MudPumper]

You need to run a pressure reducing valve between the pump and motor. The kind you have on your house. My bolck pressure at WOT is about 26psi. Do a search and you will find some threads on this. ;)

[Wally_Gator]

Rex Marine also has them...
Here is the link to Rex's site.
Pressure Regulator (http://www.rexmar.com/page184.html)

[djdtpr]

I use the one that Rex sells works great!My buddy on the other hand tried to save a little time and money went and bought one at a hardware store and has a hell of a time getting it set properly.$60.00 at rex.

[455Olds]

Found a few notes on using a pressure relief valve from a hardware store... tried it, can't get it to work...
The relief valve as purchased was set at 75lbs... adjusted it to 25lbs by unscrewing the stop inside the valve and watching the guage I had installed as I gave the engine gas. One problem... the valve only allows water past when the pressure exceeds the 25lbs generated when I step on the throttle, at idle no water gets by and my engine temp rises.... haven't tried, but think the block temp would rise to overheating range if I didn't shut it down.
What am I not seeing? The valve was installed between the pump intake and the water pump housing on the block. I need a valve that allows water to enter at any pressure not to exceed 25-50lbs, but this valve allows water only to enter when pressure exceeds 25lbs...? Help....

[MANIC MECHANIC]

By definition a relief valve opens only when the set pressure is exceeded, what you want is a pressure reducing valve.
Tim

[Rexone]

You tee the pressure relief valve off the intake line and dump it overboard. That way it bypasses water pressure only in excess of the set pressure of the valve. For example if you have it set at 20 lbs, only when the pressure exceeds 20 lbs does the bypass pressure relief open.
You don't run the intake line through the valve. Someone had a good pic posted awhile back but I don't remember where it was.

[Jeanyus]

Pressure reducing valve, sold by HTP
http://www.hi-techperformance.com/images/Water_Bypass_Kit_DCP_0726.jpg
Z

[455Olds]

Thanks everyone. Seems like everything's running good now...
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