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I need some help with my jet boat w/ ford 460 berkeley jet. it is still building too much water pressure at 3,000 rpm after install pressure relief valve. It builds 20 psi plus even with the valve all the way open. I used -8 stainless hose through out the whole system. Off the pump I have a tee installed with the pressure relief valve then from there goes to the front to another tee then goes into front cover. Off the intake manifold one port goes to another tee then dumps out of the transom exhaust. the other port on the intake manifold goes to the water injection on the headers. ??? I don't know what to do ???
 

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pressure

Put a gate valve in front of the pressure relief valve, then you will cut down the volume of water going to the relief valve.
 

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B1 Racing
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Put a guage on the block and see what pressures your getting.

A regulator will solve the problem. They do make them for industrial use and work great on boats, look for somethng that can take some good pressure, like 375-400 to be on the safe side, the more power you have the more pressure you are likley to make. Cars and trucks run at around 15 psi. from what Im told (not a car mechanic)
 

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Are you sure water is coming out your water dump that comes off you relief valve????


the way my 460 in my tahiti was plumbed

pump to gate valve

gate valve to the T that had the relief valve on top with water dump

from front of T to the water pump cover

water pump cover to thermostat housingr

then one hose off each side of thermostat housing to exhaust manifolds
 

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cs19 how much pressure you run at WOT? I know that a car is suppose to run at some low PSI but i was told that since we run a open system that we want more pressure to helo push out steam pockets. Ive been running mine at 25 PSI for a few years now.
25-30. Never had any issues
 

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I need some help with my jet boat w/ ford 460 berkeley jet. it is still building too much water pressure at 3,000 rpm after install pressure relief valve. It builds 20 psi plus even with the valve all the way open. I used -8 stainless hose through out the whole system. Off the pump I have a tee installed with the pressure relief valve then from there goes to the front to another tee then goes into front cover. Off the intake manifold one port goes to another tee then dumps out of the transom exhaust. the other port on the intake manifold goes to the water injection on the headers. ??? I don't know what to do ???
20-30 psi is fine. I think your just being paranoid. Most stock jet boats dont run a bypass or a presure regulator. If your not blowing out the intake manifold gaskets or head gaskets...just run it. A closed system runs at about 12-16 psi before it pops the cap.

higher HP levels require a regulator or a bypass because of the inceased water volume thru the pump at higher rpm's.

One question though? why are you runing a T in your dump line? I understand the T before the water injection before the headers, but not on the dump line. I run a -10 in off my reg to a T that goes to 2 -8's into the front and a sinle -10 to the dump. I run my headers dry.

Also, if your running the regulator all the way open its not doing anything. You need to close it down before it will work properly. I dialed mine in with air pressure and it was off by 2 psi when i checked it with a gauge on my manifold running it at the river. You cant set it with the hose!!!!!
 

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your bypass line (one going overboard)needs to be larger then the other lines:)bulb
Why?
He has a -8 T'd to probably 2 -6 lines to the headers and then a -8 dump line. That "should" be plenty. 2-8's are larger than 1 -10, no? Also he says its above 3000 rpm's and the header Spring and ball should be open if its working right. Now if the problem was at idle or just off idle then i would agree with you somewhat. If your running a single -8 inlet and only running "ONE" dump line the same size it could create this problem.

Dont know if he is using the ball and spring T though. if i has a busted spring or is hung up it could cause so issues, but he didnt say if water was coming out the headers or not either....
 

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Agreed. I ran mine straight through with all -8 line and fittings and a wide open gate valve for years without issue.
thousands of other people do too, works fine for alot of people, Its when they get into more HP they get issues. You can build some serious pressure with a big motor and good jet-drive.
 

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Discussion Starter #14
I hope I'm being just paranoid. This is my first jet boat let alone my first time building one, so I just learnas I go. I've gotten alot of information through this site. It's just that I spent ALOT on the engine. It's a ford 557 about 700 hp. So I'm pushing alot of power to the jet and just thought 20 psi plus would cause mechanical failure and possible blown gasket or water in the oil or hydrolock. at 5400 rpm its about 30 psi at idle its about 5psi. heres a sketch of my setup
 

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Why?
He has a -8 T'd to probably 2 -6 lines to the headers and then a -8 dump line. That "should" be plenty. 2-8's are larger than 1 -10, no? Also he says its above 3000 rpm's and the header Spring and ball should be open if its working right. Now if the problem was at idle or just off idle then i would agree with you somewhat. If your running a single -8 inlet and only running "ONE" dump line the same size it could create this problem.

Dont know if he is using the ball and spring T though. if i has a busted spring or is hung up it could cause so issues, but he didnt say if water was coming out the headers or not either....

Sounds like he is using a water bypass kit and with that kit you need to run a larger hose on the valve that goes overboard BEFORE it goes to the motor or it will not work the way it should.

So from pump to gate valve then pressure relief valve then relief side goes overboard larger hose -12 and -8 goes to a T under motor then to front plate (waterpump holes) then out T stat one line overboard -8 and one line into header T ball valve then to each header......right?
 

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Konaboy71

It looks ok and yes I see you have a 3/4 line on the bypass:thumb:


12volt soliniod after T stat? Are you running a Banderlog box for the headers?:)bulb
 

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Sounds like he is using a water bypass kit and with that kit you need to run a larger hose on the valve that goes overboard BEFORE it goes to the motor or it will not work the way it should.

So from pump to gate valve then pressure relief valve then relief side goes overboard larger hose -12 and -8 goes to a T under motor then to front plate (waterpump holes) then out T stat one line overboard -8 and one line into header T ball valve then to each header......right?
No not really. I run a -8 from the bowl to a 1/2" ball valve and then to the presure regulator. I run a -8 dump off of the reg and the other -8 line to the T to 2 -8 to the front of the engine. That dump line off the reg only dumps what wont pass through the reg. At idle i wont get anything out the regulator dump. At about 3000 water starts to flow pretty good out the reg dump. Just saying how i have done it and it works. You can go bigger with no problems cuz more is always better. I was just saying his dump lines off the T stat dont need to be bigger because he is already bigger on the exit wqith the 2 -8's than the intial "1" -8 supply hose is all.


Aww through transom headers. Now i know why your running A T at the rear and into the headers.
 

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I hope I'm being just paranoid. This is my first jet boat let alone my first time building one, so I just learnas I go. I've gotten alot of information through this site. It's just that I spent ALOT on the engine. It's a ford 557 about 700 hp. So I'm pushing alot of power to the jet and just thought 20 psi plus would cause mechanical failure and possible blown gasket or water in the oil or hydrolock. at 5400 rpm its about 30 psi at idle its about 5psi. heres a sketch of my setup
That should work just fine.

What fonz said, you running a banderlog valve to the headers?
 

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Discussion Starter #19
I'm running a mallory ignition box that has an internal rpm switch. i have it set at 2200rpm to activate and have it going to a relay that activates the solenoid. Also the boat runs at 150 degrees which is okay but I've always been told more heat more hp. that engines are designed to run around 190 for optimum performance???
 

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Discussion Starter #20
also why do you install a gate valve right off the jet. is that to control the flow??? can you use a ball valve or does it have to be a gate.
 
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