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Discussion Starter #1
I finally got the motor done, new gauges installed, new carpet too. But I can't keep it from overheating. I changed the radiator from the stock one to a long, aluminum with twin cooling fans. Removed the restrictor and used the old thermostat (minus the guts). And still keeps on climbing up to 210+ right away. I checked the flow(looked in radiator) and it's flowing. It's a new Weiand aluminum water pump, so I don't thing that could be it either. The block was FULLY machined, boiled and looked new when I started. I'm using World heads ported w/205 intakes, they looked new when I got them from machine shop also. I'm lost, ANY HELP, IDEAS????
 

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From the picture, it looks like the fan will only pull air through half or a little more of the radiator.
 

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are you seeing any bubbles in the flow?

and like Ironman... Fans look small....

I would try a 7 blade fan with a shroud... if that works.............
 

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Discussion Starter #5
I checked fans, flowing like they should. I thought about the fans being short. I'll try using a single full sized fan I had on the stock radiator in the morning. When I was test driving it, I sped up to 55 and it didn't help at all. I even tried bringing the timing down to 12 initial, didn't help.no bubbles
 

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Are you running the carb's fuel mixture really lean?? That could be generating a lot of heat. Based on your 55mph heat issues, this leads me to believe that it's not an air flow issue.
 

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Discussion Starter #7
Well, murphy's been working on me alot lately. This morning, I switched radiators, then started her up, was running like ****. Couldn't figure it out, changed plugs and wires, didn't help. Then noticed the carb gurgling when I turned on the fuel pump. The secondaries were flowing gas. So I put on a 910 CFM vac sec. I had, that was it, ran fine. I haven't tried tuning that carb yet. I am running 110 gas, 13:1 compression. I would have thought that retarding timing would have helped with heat, but it didn't. I'll pull the plugs in the morning and see what they show.
 

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Does it over heat both sitting at an idle and steady cruising? I tried using a gutted thermostat and going back to a good hi flow thermostat helped control temperature slightly. First glance, I'd say the fan.

I'm using a stock 3 core radiator to cool a 421, nothing fancy. But...if the ambient temperature is no higher than 85 I can keep temperatures under control, no problem. Over 90 outside and I can not control temps with my current set up. I am sure my problem is two fold and it starts with the radiator. The second for me is the fan I use does not draw air across the complete radiator.
 

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Are you using a vacuum advance?

Retarding your timing will actually make the motor run hotter. It can be as bad or worse as too much timing. It's an incomplete or late burn sending hot gases out the pipes and heating up the exhaust ports. The most efficient way to run your motor and keep it cool is with (gasp) a vacuum advance. At idle your 12° centrifugal can become like 24°-30° total with vacuum advance. Cruising you can be at like 50° to 52° total.

I know folks are probably sick of me preaching about it but why not use it on a street driven car and exploit those benefits and keep your cool? It does not not hurt performance, conversely it helps with part throttle response and efficiency of the motor. On a drag only car it's not needed. Keep those race distributors in race cars.
 

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Discussion Starter #13
Hmmm, I have a mechanical advance MSD. It seems to gain about 15 or 20 degrees at 3,000 rpm. Initially, I had it set to 20 base, it would advance to about 35-40 total. It doesn't mind the 12 degrees though. from an idle, the throttle response is fantastic. I was overheating before I retarded to 12. I might put it back to 20 then. It's all messed up, all the time I spent tuning the other carb, timing, etc.
So, in the morning, I'm gonna switch to the large single fan, remove the thermostat, advance timing, and pray REAL hard!
 

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Is the block filled? how about crank and W/P pulley sizes. The crank pulley should be at least as big in diameter. You might want to look into a northern fan shroud setup for your electrics or think about a nice mechanical.
 

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Discussion Starter #17
I have a Weiand Hi volume pump, pullies are about the same size, I'm gonna check it out. Also, wondering if the lower hose might be caving in, it's the one that draws the water. It was in poor shape and maybe has a bit of a kink. With the condition of the hose, it might be collapsing with the hi volume suction. Going to Autozone firsy thing to get a new one. I don't think it an airflow issue, but still gonna mount the big fan (ellec.) before I try an go with a mechanical fan. No, the block isn't filled.
 

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What is the cfm rating on those fans? I'm betting you are not moving enough air. Definetly make sure the lower hose is not collapsing
Tg
 

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I had the same promblem lso with my 406.Then I put a tauras fan,and then it runs 190 all day long.I have a iron headed 406,summit brand alum rad,summit brand high flow alum water pump,and a tauras fan wired on high.
 
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