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| Running hot after rebuild/upgrade https://www.slantsix.org/forum/viewtopic.php?t=14999 |
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| Author: | sandy in BC [ Fri Nov 11, 2005 6:03 pm ] |
| Post subject: | Running hot after rebuild/upgrade |
The Valaint runs smooth and strong since the recent rebuild....but it runs hot. This is not a thermostat or rad problem. I raised the CR to 9.25:1 added a Comp 264 cam and Chev valves,(172/150) radiused the combustion chambers, bored 40 over. I changed the vacuum advance to a 5r ,,,thinking about less mech advance. I wonder about the water pump I used, Are they all the same? Is my CR too high for regular? |
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| Author: | Lars [ Fri Nov 11, 2005 6:55 pm ] |
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Whenever I've rebuilt an engine they have always run hotter for a little while because the motor is still real tight. I imagine after a couple thousand miles it oughta start running cooler. |
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| Author: | SlantSixDan [ Fri Nov 11, 2005 8:10 pm ] |
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1960-model water pumps were different for 170 (3-1/4" impeller) vs. 225 (3-1/2" impeller). For 1961 and later, the 3-1/2" impeller was used on all slants. So unless you happened upon a NOS 1960 170 pump, no, it's probably not the pump. |
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| Author: | steponmebbbboom [ Sat Nov 12, 2005 7:05 am ] |
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Someone recently was telling me about a water pump with a plastic impeller, which broke loose from the shaft and stopped pumping. I think all the replacement water pumps are steel or bronze now. |
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| Author: | SlantSixDan [ Sat Nov 12, 2005 8:38 am ] |
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The original impellers were cast iron, then after a few years a phenolic impeller with a cast iron insert was phased in. These work fine for many decades and miles, but yeah, eventually the phenolic part can slip on its cast iron hub. Never seen a bronze impeller on a passenger car slant water pump (only marine); since the '70s just about all the replacements have had a regular stamped-steel impeller. |
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| Author: | argentina-slantsixer [ Sat Nov 12, 2005 12:44 pm ] |
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sandy, i know it seems dumb but check the bypass hose from the head to the waterpump (the one that takes care of pressure buildup relief when thermostat is closed) |
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| Author: | mcnoople [ Sat Nov 12, 2005 3:42 pm ] |
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I know it's stupid to suggest but you have a real guage in the proper location? How hot are you talking 190,200,210? |
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| Author: | sandy in BC [ Sun Nov 13, 2005 12:12 pm ] |
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I have the same old stock gayuge in the stock location. The guage is fine,,,the rad is fine. What has changed is the motor has been rebuilt. The car cooled fine before the rebuild. The WP was changed at the time of the rebuild. We are talking hot enough at 70 mph....bt too hot on grades(and Man do we have grades here) The rad boils. I wonder if the CR is too high for regular fuel. |
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| Author: | Dart270 [ Mon Nov 14, 2005 7:10 am ] |
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Seems like the motor might still be tight as others said. 9.25:1 should not be too much for pump gas. Have you tried premium to see if there's a diff? Total mech advance should be 30 deg MAX. Are you driving faster up those grades? My 64 Dart with all it's motor mods was fine on a 3-core OEM rodded-out rad out of a 63 V wagon, but got hot on serious road course duty. A universal Afco or Griffin radiator is an inexpensive and wonderful thing... Lou |
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| Author: | sandy in BC [ Mon Nov 14, 2005 7:34 am ] |
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Now that regular gas has gone down to $3.64/usgal from $3.90 it may be time to try a tank of premium. It may be the BBD is not keeping up and things get lean. Yeah we always drive it hard. I hope the motor is just tight. The car always cooled really well before. |
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| Author: | skraecken [ Mon Nov 14, 2005 11:56 am ] |
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When I changed from 8 btdc to 15 btdc the temp dropped about 8 degr. celsius. |
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| Author: | Dart270 [ Mon Nov 14, 2005 1:14 pm ] |
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My bet is that it's now lean. Might try drilling out jets a little or get a bigger carb for that beast. I was getting 22-23 mpg out of a Holley 500 2bbl, so size is not a big issue. Tuneable TBI in the works? Lou |
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| Author: | sandy in BC [ Mon Nov 14, 2005 1:25 pm ] |
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It may well be lean...the car ran very well with this carb on a stock motor. The carb shriek is impressive at full throttle now. The carb is a stock 318 BBD on an aluminum Super 6 manifold. My GF just bought an Eagle Talon TSI awd,,,the Valaint is just a little slower to 70 mph. The Talon weighs the same and is 200hp. The tunable TBI is next but probably not until the summer,,,too cold and too busy now. A 400 cfm throttle body sounds about right. |
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| Author: | sandy in BC [ Sat Dec 10, 2005 2:09 pm ] |
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Well!,,,the winner is...whoever suggested the motor is still tight. 3 weeks of daily commute (50 miles/day)and the thing runs as cool as before the rebuild. Still just a tickle of ping on full throttle on regular fuel. Smells just a tad lean. Next I need to reset the valves....reset the idle mix and drive the ever livin hell outta it! |
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