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Thread: temperature ?

  1. #1
    fire on the water
    Hey guys, what is the optimum temp to run a 454? Any suggestions?
    Thanks, Tyler

  2. #2
    The MarinePower Engine Owner's Manual that came with my brand new Ultra 21XS, which I picked up yesterday (woo hoo!), lists an operating temp of 160 degrees. My boat is equipped with their 454 magnum, or "premium" as they call it, but the operating temp is listed as the same for all 454 engine types offered.

  3. #3
    Hey Ultra
    that MarinePower Engine it fuel injected? if so how does it work?

  4. #4
    Run it at about 180. It'll run better, faster, and use less gas.

  5. #5
    Just make sure you buy a bypass valve. Don't run that motor with a thermostat and no bypass valve.
    Also, don't rely on a water gate valve to get your temp to your desired level. The water temps will be significantly higher at idle than at cruising RPM's. The temp fluctuations will cause potential valve breakage.

  6. #6
    Can you explain the bypass valve a little more, this sh... is hurting my little old brain! I think my bomb on water is setup with a gate valve to regulate the temp. I have noticed that at idle the temp rises and the temp lowers when Im running moderately fast or simply fast. Sounds like I should check for a thermostat and put one in if not there. Plus I should open that damn gate valve all the way? But whats the story with this bypass valve? where should it be located or plumbed too?

  7. #7
    If you run a thermostat without a bypass system, the water pressure coming into the engine block from the jet creates way too much pressure (until the thermostat opens). What usually ends up happining is you blow gaskets and overheat the rubber exhaust hose (which eventually fails). Most through transom exhausts are at or below the water line. Blow the rubber hose and your boat could sink! With a bypass valve, the excess water pressure (before the thermostat opens) get routed through the exhaust. With this system, your engine temps will be much more stable (only varying about 10-20 degrees).
    The bypass valve mounts on top of your intake manifold water inlet.
    I think you can get these systems from distributors like Rex Marine or Eddie Marine. If you can't find one, call GS Marine. I think they install these all the time.

  8. #8
    Do you use a special thermostat housing that has two hose connections on top? Or do you have some sort of tee fitting in the hose going to the thermostat housing? I see that IMCO has a SS polished housing that may as well be gold plated for the price they want.
    I like the housing setup but dont need anything that fancy, a cast housing works fine fo

  9. #9
    What's the proper operating temp. for an old 460 Ford? I have read in other sources that you want temp. at 160 because any higher forms metal deposits in engine. Also heard that higher temp is better for mileage, emissions, but Lower temp. makes more power. New Chev 496 is closed cooling, assume its for emissions.

  10. #10
    Lower AIR/FUEL temp makes more power and higher engine temp(to a point) makes power. Running above 160 isn't going to form metal deposits unless "above 160" means 240. Metal deposits will be the worst of your worries. Think about the temp thing. How well does your car run right when you start it on a December morning. For full effect pretend you live someplace that gets cold in the winter. RC was right about too much block pressure. Normal engines are designed to operate at <20lbs of pressure. Too much and you will blow gaskets. 180 is my story and I'm stickin' too it!

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