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Thread: Engine running cold. Problem???

  1. #1
    Nostalgic Spectra
    Was wondering if anybody ever had problem with their engine running cold.... temperture wise. Here's the scoop. I run a 477 BBC,single carb in a Spectra day Cruiser. I blew the engine 2 summers ago. Had it rebuilt with new cam,new roller valve train, heads, pistons. I run CMI water jacketed headers as well. Since then the highest temp it has hit was just over 100. Most of the time it barely registered. I put a restrictor in the water neck to keep the water in the engine a little longer hoping it make some heat but nothing. I do run a engine and tranny cooler also, but before the blow up, it ran around 150-160 with both coolers. I did check the mechanical temp gauge by boiling some water and sticking the sending unit in it, and it definelty registered. I have only took the boat out 4 or 5 times since the blow up. The heads do warm up, but not enough that I have to pull my hand away from them.
    I guess my other question is should I be concerned with way how cold the engine runs. If so, what can I do to get some temp.
    Thanks Guys:idea:

  2. #2
    twowheeledfish
    Was wondering if anybody ever had problem with their engine running cold.... temperture wise. Here's the scoop. I run a 477 BBC,single carb in a Spectra day Cruiser. I blew the engine 2 summers ago. Had it rebuilt with new cam,new roller valve train, heads, pistons. I run CMI water jacketed headers as well. Since then the highest temp it has hit was just over 100. Most of the time it barely registered. I put a restrictor in the water neck to keep the water in the engine a little longer hoping it make some heat but nothing. I do run a engine and tranny cooler also, but before the blow up, it ran around 150-160 with both coolers. I did check the mechanical temp gauge by boiling some water and sticking the sending unit in it, and it definelty registered. I have only took the boat out 4 or 5 times since the blow up. The heads do warm up, but not enough that I have to pull my hand away from them.
    I guess my other question is should I be concerned with way how cold the engine runs. If so, what can I do to get some temp.
    Thanks Guys:idea:
    If anyone could answer this, I'd appreciate it too. My jet runs quite cool as well... never breaks 100, heads only warm to touch, etc. I'm usually running in 55-60 degree river water. I considered closing the valve coming off the jet pump to restrict the flow of cool water a bit. Any info would be appreciated.

  3. #3
    Moneypitt
    If you are running log type exhaust, plumb the incoming water thru the exhaust, then into the engine. Some jet boats were originally set up that way. As for the v drive, what changed? Plumbing the same? Same w/pump? Same water dumps?..........MP

  4. #4
    Nostalgic Spectra
    If you are running log type exhaust, plumb the incoming water thru the exhaust, then into the engine. Some jet boats were originally set up that way. As for the v drive, what changed? Plumbing the same? Same w/pump? Same water dumps?..........MP
    Plumbing, pump is all the same. No changes.

  5. #5
    Racey
    Are you running a thermostat? or like moneypit said preheat the water by running through your exhaust first then into the motor.

  6. #6
    Nostalgic Spectra
    Are you running a thermostat? or like moneypit said preheat the water by running through your exhaust first then into the motor.
    No thermostat, goes from pump to the coolers,to the engine, then out the headers. Like I said ,up until the rebuild, it ran around 150 with the same setup.

  7. #7
    WannabeRacing
    This is pretty heavy in the opinion point, but here goes.
    As long as the oil has temperature, and the chamber of the head has temperature, then your goal for making the most power is to freeze the engine. Like Warren Johnson stated, "If I could get 60 degree water temp, I would."
    I am sure you have seen the NHRA broadcasts where pro stockers are putting ice cubes in their radiator. They run transmission oil heaters, rear end oil heaters and engine oil heaters. They want all those oils hot without having to get excessive heat in the engine by running it too long. We have the advantage on the water. Unlimited cool water. When you are designing an engine trying to keep your water temp way down, you always want more clearance piston to block, as the block will not heat up as much, and not swell as much, but after that, freeze the thing. You can then run more timing, more compression . . .etc. without detonation. More power.
    If your oil temp is staying way light, it is a real problem. Something you will need to look at with restrictors, thermostats, etc. But if you have oil temp and heat in the chambers, freeze the rest for the most power. Especially on gasoline. Alcohol likes a little more heat than gas, but that is another story.

  8. #8
    Moneypitt
    Ditto, what he said. You seldom hurt them cool or fat, but hot and/or lean will make a mess.............MP

  9. #9
    WVspeedfreak
    Run too cool and the moisture in the engine will not get warm enough to "escape".....hence making a nice sludge of the oil in do time. Ask me how I know......Thought for sure I had cracked block, head , etc. Turned out that I was running it way to cool. Just some food for thought.

  10. #10
    Junior Member
    Join Date
    Jul 2011
    Posts
    594
    Run too cool and the moisture in the engine will not get warm enough to "escape".....hence making a nice sludge of the oil in do time. Ask me how I know......Thought for sure I had cracked block, head , etc. Turned out that I was running it way to cool. Just some food for thought.
    Go back read the post, IF THE OIL HAS TEMP!!!!!!!! the run the motor as cold as you care. Watch the vast majority of the circle boats and they are putting water thru them as fast as the can. WVspeed problem is he is running the water thru the exhaust last. FIX IT. We run our deal as cold as we can get it, but the oil runs at 250*. You can't make sludge at that temp. P.S. change your oil more often.

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