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Old Aug 4, 2020 | 11:23 AM
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Default Minimum Operating Temperature

what is the minimum operating temperature for a 67 327 engine?
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Aug 5, 2020, 08:13 AM
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Originally Posted by Spowell637
I guess my initial question wasnt very clear. After cold start, what is the recommended temperature before driving. Thanks again.
There will be many opinions. Here is mine:
You should drive off at a normal pace just as soon as engine starts and idle is stable so that it is unlikely to stall. Best not to put a hard load on it until it comes to temp, a few minutes on the road at speed. Thats it. Dont overthink it. The engines are tough. Idling with the choke on in belief this is happiness for the engine is wrong. They don't like slow warmups with rich mixtures. Start it and drive normally.

Dan
Old Aug 4, 2020 | 11:54 AM
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They'll operate below zero, but after the thermostat opens the minimum would be the thermostat rating. I never run below 180 degree thermostats because once any lower rated thermo opens you'll get the cooling efficiency of the system no matter if it's a 160 or 180. If you're car normally runs at 195, it will still do that with either thermostat. The 160 would open a little sooner and under the right circumstances with outside temp and cooling efficiency could make it run cooler for a short time than the 180.
If your car normally runs at 170, a 180 would raise that, but 160 is too cool for long term operation in my opinion. There are plenty of guys on here that will tell you how much greater their car runs and cools with a 160 thermo, so take your pick.
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Old Aug 4, 2020 | 12:12 PM
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Originally Posted by 65GGvert
They'll operate below zero, but after the thermostat opens the minimum would be the thermostat rating. I never run below 180 degree thermostats because once any lower rated thermo opens you'll get the cooling efficiency of the system no matter if it's a 160 or 180. If you're car normally runs at 195, it will still do that with either thermostat. The 160 would open a little sooner and under the right circumstances with outside temp and cooling efficiency could make it run cooler for a short time than the 180.
If your car normally runs at 170, a 180 would raise that, but 160 is too cool for long term operation in my opinion. There are plenty of guys on here that will tell you how much greater their car runs and cools with a 160 thermo, so take your pick.
It is a common misconception that a thermostat regulates engine temperature. It does not. The thermostat opens slowly beginning at around the specified temperature. It closes again, slowly as the engine cools after shutdown. As for running temperature, it is important that engines not run over-cooled. Efficiency falls off and wear can increase. The oil depends upon sustained operating temperatures, typically 180 degrees on old cars, to boil off the water which is a byproduct of combustion and the fuel which winds up in the crankcase of any carburetted motor from fuel condensation on cold manifold walls aided and abetted by use of the choke. If your cooling system is up to snuff a 180 degree T-stat will be all you need.

Dan
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Old Aug 4, 2020 | 12:43 PM
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What Dan says is 100% correct as it applies to our older pre-smog era cars. Many (falsely) believe that running at 150 or 160 is optimal....it is not. Engines are more efficient at higher temps and need to burn the condensation out of their internals. I've torn down lots of old engines that ran really cool that ran non-pressurized cooling systems, and the gunk and sludge was truly impressive. The newer engines run at 220-240 degrees for 300,000 miles without a hiccup. I get a kick out of guys who post on every forum who think their car is overheating because it is running 200-210 on a 100 degree day. No worries.
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Old Aug 5, 2020 | 08:05 AM
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I guess my initial question wasnt very clear. After cold start, what is the recommended temperature before driving. Thanks again.
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Old Aug 5, 2020 | 08:13 AM
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Originally Posted by Spowell637
I guess my initial question wasnt very clear. After cold start, what is the recommended temperature before driving. Thanks again.
There will be many opinions. Here is mine:
You should drive off at a normal pace just as soon as engine starts and idle is stable so that it is unlikely to stall. Best not to put a hard load on it until it comes to temp, a few minutes on the road at speed. Thats it. Dont overthink it. The engines are tough. Idling with the choke on in belief this is happiness for the engine is wrong. They don't like slow warmups with rich mixtures. Start it and drive normally.

Dan
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Old Aug 5, 2020 | 10:15 AM
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on the flip side what temp would you consider the engine overheating?
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Old Aug 5, 2020 | 10:31 AM
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Originally Posted by Jake Morgan
on the flip side what temp would you consider the engine overheating?
The temperature upon which coolant is forcibly expelled from the radiator overflow, which is when the pressure cap rating is exceeded. Until that happens it is not technically overheated.

Dan
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Old Aug 5, 2020 | 02:18 PM
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Originally Posted by Jake Morgan
on the flip side what temp would you consider the engine overheating?
At some point over where the excess heat was causing percolation problems with the gasoline. The rubber hoses, wires and other soft parts on these old cars weren't designed for today's temperatures.

They were designed to run around 180-185 and that's where they should run in my opinion.

Doesn't matter what new cars/engines do. That's irrelevant.
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