455 Olds has no water pressure
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455 Olds has no water pressure

  1. #1
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    Default 455 Olds has no water pressure

    I hoping that someone can help me work out some of the bugs in a 455 olds packajet that has just been installed in a 19 foot jolly rodger-----I have put a pressure guage on the intake manifold which is a edlebrock performer---its up near the front next to the thermostat housing --is this the right place for it?At idle I dont have any water pressure reading and at 2500 I only have 11 pounds--this is with the bypass which is an old T handle type screwed down all the way.Shouldnt the pressure be a lot higher with it screwed down all the way? Should I go to the newer type of bypass? Is the pump not putting out? Supposedly the pump has been rebuilt, so I hope thats not the problem. The fitting on the pump is a 3/8 pipe thread --are newer pumps a bigger fitting.When we first ran it it was overheating at 2500 rpm so we took the thermostat out and now it runs cooler but still no pressure at idle up to 1800 or so. Can somebody help thats seen this before. Not stumpedd but getting close.

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    AKA OhOneWS6 Last Mohican's Avatar
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    Post some pics of the water hose routing and exhaust. Usually with log style exhaust there is no water pressure in the block to speak of. The exhaust is restrictive enough the block never build pressure. You really do not want more than 16 PSI in the block. Does your setup have a car style water pump?

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    Thanks Mohic---No we junked the car type pump, and went to the direct water from the pump--water splits and goes to two Ts in the front of the block and then one side of each T goes to the therm housing and then comes out the top of the therm to the logs---berkeley logs only have one fitting in the front unlike Hardins----id post pics but the boat is not in my garage

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    AKA OhOneWS6 Last Mohican's Avatar
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    Typically you see the water routed to the logs first then out of the logs to the motor then out of the motor to the snails. I know there is diagrams floating around. I'll try to find one. Is there not a fitting in the rear of the logs? You want the water to enter the low point of the log and exit the high point. Then it enters the motor where the water pump would be and exits the motor where the thermostat would be. Then to the snail and out the back of the boat through the exhaust. If you have a marine thermostat it changes a little with the bypass in the thermostat housing. How many water line are on the "Thermostat housing"? If it is only 2 it is a splitter and not a thermostat housing. If it is 4 it is actually a marine thermostat setup.

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    Senior Member Oldsquirt's Avatar
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    Quote Originally Posted by bentshaft View Post
    Thanks Mohic---No we junked the car type pump, and went to the direct water from the pump--water splits and goes to two Ts in the front of the block and then one side of each T goes to the therm housing and then comes out the top of the therm to the logs---berkeley logs only have one fitting in the front unlike Hardins----id post pics but the boat is not in my garage
    First off, if you were running the complete thermostat kit it would have had a t-stat, a spring and a poppet valve inside the housing. Were all those parts installed?

    Second, assuming all the parts were correctly installed in the t-stat housing, you have the hoses plumbed to it incorrectly. The two lower holes are for the exit water. The top two are for the "bypass" lines from the tees at the front of the block.

    If you were missing the spring and poppet, your setup would have allowed most/all incoming water to bypass the block.

    Check this page at Rex Marine for details of the t-stat kit plumbing and internal parts-->> Page 160

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    Quote Originally Posted by bentshaft View Post
    Thanks Mohic---No we junked the car type pump, and went to the direct water from the pump--water splits and goes to two Ts in the front of the block and then one side of each T goes to the therm housing and then comes out the top of the therm to the logs---berkeley logs only have one fitting in the front unlike Hardins----id post pics but the boat is not in my garage
    The Pack-A-Jet was designed specifically to work with a water pump- If you removed the pump and are just running the Pack-A-Jet logs, you're probably not able to keep enough water IN the engine since the logs have like 1" hose fittings on each log! (since I don't have a picture of your existing configuration, I have no idea what was done at this point). Why did you stray from the proven Pack-A-Jet design?

    Personally, I think the water pump on the Pack-A-Jets makes for better flow and more consistent temperature throughout the motor than the designs that run without. My Glastron has never had an issue with pressure (too high or low) or maintaining engine temperature (never exceeds 160 with a 160 thermostat) regardless how hard I run it.
    Go back to the original Pack-A-Jet configuration and I bet you find everything will magically fall into place.
    Just my .02
    Elm

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