65 ss 409 4speed ss convert - Impala Tech
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post #1 of 7 (permalink) Old 10-13-2012, 10:11 PM Thread Starter
Join Date: Jun 2012
Location: alberta
Posts: 11
65 ss 409 4speed ss convert

I am doing a ground up on this car up in western canada Frame is done body is mounted with new mounts engine and trans installed no doors or fenders on yet but the body and all related pieces are painted red. I have owned this car for a long time it has a habit of getting hot when idling engine was hot tanked and put together rad was cleaned installed new fan clutch circulation looks good but the longer it idles the hotter it gets and it is not really hot outside either Help
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post #2 of 7 (permalink) Old 10-14-2012, 02:29 AM
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Welcome to the Team Dundas!

You didn't mention your fan shroud or the number of blades on your fan. Shroud is required and your blades should number five not four.

A modern seven blade fan off a big block will also fit and pull more air through the radiator at idle. Modern cars also had a thermostatic fan clutch that turns the fan off (cuts the horsepower draw by 80% when motor is going down the road at speed and the fan isn't needed because motor is at operating temp). As far as that goes a modern aluminum water pump uses a larger diameter shaft to drive the fully enclosed water wheel that moves the water. Yours is smaller unless you have the Corvette pump, but either way the impeller inside is open allowing water to spill off the blades just like paddles or oars in the water when rowing.

Big Dave
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post #3 of 7 (permalink) Old 10-14-2012, 08:19 AM
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Location: Lewisburg, Ohio
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Welcome Dundas, I would consider a new aftermarket radiator and a high flow water pump. The shroud and fan Big Dave talks of are good advise also. Was the engine ever bored out oversize?
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post #4 of 7 (permalink) Old 10-19-2012, 05:23 PM Thread Starter
Join Date: Jun 2012
Location: alberta
Posts: 11
Yes it has the factory shroud and a 5 blade fan. The water pump is a 409 or 348 date 1959 but I had it rebuilt. I had the rad cleaned they said it was fine It is the original 4 core rad still has the 65 date metal plate on it. When I start the car it seems to warm up fairly quick then the 160 degree themostat opens the water comes through the rad I have the hood off when standing the drivers door stepping on the gas you can feel the air from the fan I installed a new thermostatic fan hub and I can hear it cut in and out. But the temp just keeps coming up. You can feel the air coming through the rad. The engine is a std bore std crank 400 hp with a Kurt harvey Isky step 2 solid lifter cam. Then I shut it off before it gets to hot.
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post #5 of 7 (permalink) Old 10-19-2012, 05:53 PM
Join Date: Jan 2006
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Ignition timing will also cause a motor to run hot if too far advanced in search of a few extra ponies. As far as that goes running on the lean side will also cause it to run hot.

When they rebuilt the water pump did they use the stock cast iron paddle wheel impeller?

A fully boxed water pump will constrain the water from spilling off the blade of the paddle wheel (just imagine pulling an oar through water and noting the vortexes at each edge of the oar in the water caused by the water that isn't being pushed back rolling off the edge of the oar's blade).

You can upgrade your original date code correct water pump casting internally to use the larger diameter Corvette water pump shaft with it's associated larger bearings, and a steel closed scroll impeller pressed on the end of the shaft to move the needed amount of water. This mod not only moves more water, but it does so with less wasted horsepower which shows up as heating the water as the water is just spinning around in the pump.

Big Dave
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post #6 of 7 (permalink) Old 11-01-2012, 01:35 PM
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Location: Alberta, Canada
Posts: 224
What do you consider hot? Do you have a temp gauge or heat gun that you use to check the temperature?

Two things:

1. You may want to try a 185-degree thermostat, as it's a misconception that having a cooler thermostat will make your engine run cooler. Especially with a big block.
2. How long is it running for when it gets "hot"? Even with the fan running, cars aren't meant to sit idling and are meant to have air flowing through the rad from going down the road. Does it run hot when you're driving too, or just when it's idling?
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post #7 of 7 (permalink) Old 11-08-2012, 07:25 PM
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Location: Surrey, BC
Posts: 141
Over heating

Had a couple of instances where I overheated. New thermostat AND 50/50 antifreeze mix made a big difference.
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