Page 1 of 3 123 LastLast
Results 1 to 10 of 25

Thread: BB temps and cooling?

  1. #1
    Drunk tank
    In some other threads I've heard it mentioned that most of these BB in boats have an issue of running too cold, is this true? isnt it better for an engine to run cooler? i would really appreciate an explanation of this stuff since its got me rather confussed. Also, is there a device that cuts off water flow to the block based on RPM's? I'd like to keep my engine running in great condition for as long as possible, so if this would be a mod that would help by keeping the engine at an ideal running temp, I might be interested in doing it in the near future.
    Thanks for your input
    Ryan

  2. #2
    fourspeednup
    An car engine is designed to run between 180-200 degrees. In my boat it runs 120-130. At the lower temp it will make less power because....well shit I don't really know why but I know it losses efficiency at colder temps. New cars/trucks run much hotter. Fuel distribution sucks when a motor is cold...that's why carbs have choke's, to richen the air:fuel ratio.
    I run a valve between the pump and block to control water flow but it doesn't do much good. I can have the thing almost completely shut and it still runs 130 at the river. Pressure regulators are used on some jets to prevent too much water from entering the block and seeping past gaskets. There was a thread on here not too long ago on that topic...may have been in the v-drive forum. do a search

  3. #3
    victorfb
    im sure there are engine gurus on here that can and will explain it better, but running an engine too cold in a marine application can spell dissaster. you have a hot combustion chamber heating the heads, valves and seats, ect. and running cold water through the head and block can cause cracking, exhaust valve seats popping out, and more. the best way (especially on a jetboat) is too run it hot then adjust it to cool down slowly. of course not too hot. but you get the picture. as for cutting off water flow to the block? i have never heard of that, nor would i recommend it. there is a device that cutts off water flow to the wet headers (Banderlog valve) and is rpm sensitive. at idle to 1500 or 2000 rpm it will shut the water flow off so there is less chance of reversion. (water entering the exhaust port). hope any of this helps.

  4. #4
    victorfb
    hey fourspeednup.
    130 seems preety damn cool to be running that thing. its just my opinion, but i think you better try and get that motor to heat up a bit more. 180 would be nice.

  5. #5
    fourspeednup
    An entire replumb is in order...the ****tard who had it before me just used it to ski behind. Since joining up here at the end of last season, I've learned sooo much. Can't wait to get back on the water and try some of the stuff out. Step one is definately gonna be to get it to run warmer.
    victorfb-is it 180 while cruising? if so, what's it like idling through a marina? I go through the Havasu channel and that's a good 15-20 min at idle

  6. #6
    LakesOnly
    By way of design, the internal combustion engine utilizes heat in its favor, and is to some degree dependent on heat for a good portion of its power output.
    The more heat (by way of the combusted and expanding gases) that can be kept in the engine and utilized to force the piston downwards (and rotate the crank), the greater the power output.
    Thermal efficiency can be lost by way of the absorption of the cylinder head and block, engine oil, etc. The cooling system takes away heat, and even the uncompletely combusted gasses escape out the exhaust port, etc. Much of this heat is "useful" but is not taken advantage of. (To some extent, different types of cooling are certainly necessary.)
    Cooling an engine to an operating temperature that is less than optimum reduces the capabilities of that engine's maximum thermal efficiency. Simply stated, if you allow your engine to run at 180* instead of 130*, a lesser amount of heat will be lost to the cooling system and instead remain where it can make useful power.
    LO

  7. #7
    fourspeednup
    Originally posted by LakesOnly
    By way of design, the internal combustion engine utilizes heat in its favor, and is to some degree dependent on heat for a good portion of its power output.
    The more heat (by way of the combusted and expanding gases) that can be kept in the engine and utilized to force the piston downwards (and rotate the crank), the greater the power output.
    Thermal efficiency can be lost by way of the absorption of the cylinder head and block, engine oil, etc. The cooling system takes away heat, and even the uncompletely combusted gasses escape out the exhaust port, etc. Much of this heat is "useful" but is not taken advantage of. (To some extent, different types of cooling are certainly necessary.)
    Cooling an engine to an operating temperature that is less than optimum reduces the capabilities of that engine's maximum thermal efficiency. Simply stated, if you allow your engine to run at 180* instead of 130*, a lesser amount of heat will be lost to the cooling system and instead remain where it can make useful power.
    LO
    Yeah, yeah, what he said

  8. #8
    cheech
    engine oil needs to be 180 degrees to do its job correctly. i believe most of your engine clearences are for the 180 to 210 engine temps also. if you are dead set on running your motor as cool as possible have your machinist set the clearences accordingly, no sence of having the pistons slapping around in the hole.

  9. #9
    screamdreambrad
    rex has the best part available. it is a real bypass thermostat, and it works awesome. 160 degrees all the time! can't beat it. buy one of these and you will kick yourself in the ass for dickin around so long. go order one tomorrow! you won't be disappointed. brad

  10. #10
    fourspeednup
    screamdreambrad-At first I thought I was taking tech advice from Mrs. Flyin Vee lookin at the avatar! That part sounds like a must have for this summer. Thanks

Page 1 of 3 123 LastLast

Similar Threads

  1. Water Temps???
    By Garucci in forum V-Drives
    Replies: 13
    Last Post: 05-11-2005, 01:54 PM
  2. EGT Temps
    By SJ Valley Dave in forum Gear Heads
    Replies: 7
    Last Post: 03-04-2005, 04:55 PM
  3. Oil Temps
    By Wet Dream in forum Gear Heads
    Replies: 4
    Last Post: 06-03-2004, 04:43 AM
  4. how hot is to hot? (oil temps)
    By MoparSanger in forum Gear Heads
    Replies: 5
    Last Post: 08-30-2003, 05:24 AM
  5. EMI temps
    By lovemyultra in forum Gear Heads
    Replies: 5
    Last Post: 04-16-2002, 07:11 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •