New motors Hot on Test stand ...
07-29-2007, 02:33 PM
#1
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New motors Hot on Test stand ...
I have built 2 MIV 496's and trying to get them in the boat ...I cant get them to run cool on the test stand ... I am running a mercruiser Style thermostat housing with 140* stat ... Stainless Marine Crossovers ... 500HP style oil coolers across the back of the motor ... I have a large ~40 Gallon Garbage can with a 1.25" outlet at the bottom with the standard hard wall 1.25" hose feeding the sea pump ....
I have a Test Box with standard Gauges ...volts,oil pressure,oil temp,water temp and a tach ... I added a mechanical water temp gauge also ...
If you run the motors they run for 5 mins or so.. usually 1500 to 2500 rpm ... after 5 minutes you can feel the heat coming from the motor .. Elec temp gauge reads zero ... then mech gauge comes up steadily ... it will go to 200-210+ if you let it ... during all this the elec guage will rise ..seen 190 or so on it and then you can tell the thermostat opens ...when it opens the mech guage will go to zero .. steam pocket? Then back up ... shooting the front of the heads with IR shows about 190-195 .... The mech gauge is taped into the intake port and the elec on the thermostat housing ... I can go on but hoping someone will have a clue ....m
I have a Test Box with standard Gauges ...volts,oil pressure,oil temp,water temp and a tach ... I added a mechanical water temp gauge also ...
If you run the motors they run for 5 mins or so.. usually 1500 to 2500 rpm ... after 5 minutes you can feel the heat coming from the motor .. Elec temp gauge reads zero ... then mech gauge comes up steadily ... it will go to 200-210+ if you let it ... during all this the elec guage will rise ..seen 190 or so on it and then you can tell the thermostat opens ...when it opens the mech guage will go to zero .. steam pocket? Then back up ... shooting the front of the heads with IR shows about 190-195 .... The mech gauge is taped into the intake port and the elec on the thermostat housing ... I can go on but hoping someone will have a clue ....m
Last edited by offthefront; 07-29-2007 at 02:41 PM.
07-29-2007, 02:45 PM
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I have never ran an engine like this off a container of water before but could it be because you are reusing the same water and as it runs the water is heating up and recirculating the same "hot" water and not pumping in cold water as it would if the boat in in a lake or ocean or running through a radiator that is being cooled by a fan ? Just an idea. I would try and see if you can hook a water hose up to it instead and see if your temp guages read lower. Good luck.
Brandon
Brandon
07-29-2007, 02:52 PM
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I have never ran an engine like this off a container of water before but could it be because you are reusing the same water and as it runs the water is heating up and recirculating the same "hot" water and not pumping in cold water as it would if the boat in in a lake or ocean or running through a radiator that is being cooled by a fan ? Just an idea. I would try and see if you can hook a water hose up to it instead and see if your temp guages read lower. Good luck.
Brandon
Brandon
07-29-2007, 02:55 PM
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I am definitely not an expert of any kind on this one, but it seems like your plumbing may be wrong. I don't see a mechanism to circulate the water through the engine. The water can bypass the block straight to the exhaust in that configuration. Without the crossover, the water pump (if you had one) would force the water through the block. Just a guess,
Rene
Rene
Last edited by oldandtired; 07-29-2007 at 02:59 PM.
07-29-2007, 05:05 PM
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with the thermostat closed ....the water's path from the top of the intake is back into the same chamber where the water comes into the thermostat housing (1.25") from the sea pump,and also the 1.75" line that exits to the crossover ...plus you have the bypass from the intake to the crossover ..... Without a thermostat the water has a straight path to the exhaust ....m
07-29-2007, 07:49 PM
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The water needs to come from you sea pump to your crossover. The therm. housing that you have needs to be changed. You will need to dump the water from the new housing into the exhaust. They make different type housings to run with a crossover with therm and w/o therm.
