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Old 09-03-2012, 04:55 AM
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lodilobo
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MASTER JOURNEYMAN
 
Join Date: Sep 2007
Posts: 40
Default sbc cooling problem...

I have a '71 Vega with a 439 c.i. 18 degree motor, which dyno'd at 755 h.p. It has 14.7 :1 compression and is a low 9 second race car. The motor is a new build this year, and due to limited room in front of the engine, because of the necessity for a vacuum pump, I had to go with an electric water pump. I had always used an Edelbrock mechanical pump before the new motor. In the past, the car always stayed around 175 - 180 degrees. The car now runs extremely hot.....it gets to 210 - 220 after 3 passes, and takes forever to cool down. Here are the different things I've tried to correct this problem...180 thermostat....160 thermostat....no thermostat...restrictor in place of a thermostat....changed from CSR pump to Mezziere. Yesterday, I did a pressure test on the cooling system, to see if there might be a blown head gasket, even though there are no other indicators of it. It held at 15 lbs. for over 5 minutes, so I'm pretty sure the heads / gaskets are not the problem. The only other thing I can come up with is the radiator. It is a new aluminum unit, that I bought form a vendor on RJ, and it measures 27"w x 17" h x 3" thick.....2" shorter than my old radiator. Once again, I needed the clearance after relocation. I'm considering removing the new radiator, and going back to the old one, but it will not be an easy swap, so I don't really want to do that. Anyone with ideas on why this motor runs so hot, please reply. I must be missing something here, but can't come up with it. I forgot to mention earlier....the electric fan is mounted in front of the radiator, and is wired correctly to pull air through toward the engine.
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