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Thread: Water temp

  1. #1
    Big Inch
    I'm curious what everyone's thoughts are on acceptable low water temps. I just had my motor rebuilt and after getting it together my temps were a little bit high. The impeller that was in it fell apart when it was first started up. I guess it got dry sitting around. So anyways it was replaced but apparently back flushing it did not remove all the debris. When I pulled off the first inline cooler it was packed with rubber and after removing it the motor runs extremely cold. 95-100 degrees under load. I have always thought this was too cold and would not allow proper combustion in the chamber and that the temp should be brought up. I purchased a 160 degree thermostat, drilled two 1/4 inch holes around the edge of it so it would have consistent flow and reinstalled it. I spoke with the guy that installed the motor for me and asked him if there was a better way to control the temp on the motor and he stated that I should remove the thermostat and just let it run at 95 degrees. He said that the belief of this being too cold is an old school way of thinking and that the motor benefits from the additional cooling and will create more power. That as long as it is not so cool as to create condensation in the oil that it is fine and actually preferred. I'm sure he has way more knowledge in this area then I do but I just wanted to get some more opinions before I remove the thermostat.
    thanks for your help

  2. #2
    HALLETT BOY
    as long as oil temp gets above 212 degrees, you should be fine . as the oil gets
    that hot, it creates steam from any moisture in the oil and it goes out the breathers or into the pcv...

  3. #3
    Big Inch
    Unfortunately I don't have an oil temp gauge to measure this. I am not seeing any signs of condensation in the oil but I'm not sure what to do about installing a temp gauge. Don't you have to tap into your oil pan to read this accurately?

  4. #4
    Senior Member
    Join Date
    Dec 2009
    Posts
    648
    That Sounds Way Low To Me. 95* I Know Jet Boats(with Out Therm. Kit) They Have To Set Your Temp At Idle And When You Go Then It Drops Way Down. I Guess What I'm Askin Is What Does Any OnE Else Run ?(temp Wise?) . I Have A Jet Thats Fairly High Compresion And On 110 And It Hates To Be That Cold. Seems Much Happier Around 140-160*

  5. #5
    cfm
    as long as oil temp gets above 212 degrees, you should be fine . as the oil gets
    that hot, it creates steam from any moisture in the oil and it goes out the breathers or into the pcv...
    Yes, oil temp is more important than water temp.
    We need to make sure oil is at min of 180 before we get hard on throttle. 212 min to keep water out of oil, and 250-260 max for oil and motor longevity.
    The cooling system effects the oil temp big time. A too cold coolant temp may make your oil temp too cold or take too long to warm up. All applications react different so we must check if this is not a 100% OEM engine and 100% OEM cooling and oil system.
    Most marine engines that do not use t-stat will have oil cooler with t-stat so that oil will climb to proper temp faster. However, I've seen in colder water this can take a long time to get there too.
    =======================
    Do you have a pic of your cooling system ? If not, can you describe it especially if uses recirculating pump or a crossover system.

  6. #6
    centerhill condor
    I only run a stat in the non summer months.
    CC

  7. #7
    Big Inch
    Cfm I will do my best to describe my set up. First of all the motor is not oem nor is any part of the cooling system except for the seawater pump. It is a 598 ci merlin block,heads,intake manifold and is normally aspirated with about 10.2-1 compression. I run about 75% pump gas 92 octane and 25% 110. The cooling system is plumbed in this order. It draws water from my bravo 1 drive and goes directly into the mercruiser seawater pump (no sea-strainer.) It goes first to the aftermarket steering fluid cooler then to the aftermarket oil cooler. It has a remote located HP-1 oil filter. After the oil cooler it is routed to a T fitting that feeds the lower section of my Imco exhaust manifolds, entering at the rear of the manifolds. Exiting the front of the manifolds it goes through braided lines into the front of the motor on it's corresponding side. So essentially there is no crossover. There is an individual line going from the left side of the exhaust manifold and entering the left side of the block and 1 from the right exhaust manifold into the right side of the block. From there the water flows through the block and up into the manifold and exits there from the thermostat housing and splits again to each riser and out the tips.
    Please let me know if you need anything explained in more detail. I would post pictures but the boat is at the river and I am at work looking forward to the weekend

  8. #8
    Big Inch
    Found some pictures that might be of help.
    Power steering fluid cooler circled in red.
    http://img528.imageshack.us/img528/7070/coolerzc7.jpg (http://imageshack.us)
    Oil cooler and lines circled in red.
    http://img113.imageshack.us/img113/6...rlines1fv5.jpg (http://imageshack.us)
    Side view of motor
    http://img69.imageshack.us/img69/7509/engineie9.jpg (http://imageshack.us)

  9. #9
    Big Inch
    Yes, oil temp is more important than water temp.
    We need to make sure oil is at min of 180 before we get hard on throttle. 212 min to keep water out of oil, and 250-260 max for oil and motor longevity.
    The cooling system effects the oil temp big time. A too cold coolant temp may make your oil temp too cold or take too long to warm up. All applications react different so we must check if this is not a 100% OEM engine and 100% OEM cooling and oil system.
    I forgot to comment on this earlier. I have no way of measuring the oil temps at this time. I'm open to suggestions. As of now I know that I was getting steam out of the breathers when it was running hot, obviously. To recap, it was running hotter due to the plugged cooler. I will have to check on that this weekend now that it is running cooler. While running at the low temps of 95ish degrees the oil pressure was consistent with what I believe it should be making. 55ish pounds at constant throttle around 4000 rpms. I am running Kendal 50 wt oil. I believe this indicates at least fairly warm oil temps because if the oil was not heating up enough I believe I would be seeing much higher pressure at higher rpms due to the cooler/thicker oil. It is not showing signs of overheating the oil ie.... losing pressure at rpm or under load. I have a mechanical oil pressure gauge hooked up temporarily so that I can get a reliable picture of what the oil is doing. This was done because I do not have a oil temp gauge and I am open to suggestions on how to better measure the oil temps.

  10. #10
    HALLETT BOY
    Why so many adapters on that oil cooler ????

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