Agreed.
 

I'll be going back to a 180 for sure, with a drilled steam hole. There is just too much difference at how my motor runs at say 163 vs. 180-185. Much better at 180.

Thanks to all for your replies and Brainstorming on this...

Some very good points made..
 

The important thing in my choice of a 180 over a 160 is that it helps my motor reach critical oil operating temp a teeny bit FASTER, on a cold start. This means less wear and quicker "get your motor running" factor.

Chopper, my 4 x 4 Scout II HAS a tractor motor.. (258 AMC/Jeep/originally a tractor motor design) so the study is relevant :3DSMILE:

I guess it's interesting that this subject has come up again at the end of the summer, just like last year. I just recently went through this process again, myself. I have chronicled my trials of upgrading my radiator to resolve the persistent overheating problem elsewhere on this forum, and to summarize the results, I found that changing from a brass to an upgraded aluminum radiator (1.5 inch double row vs the original brass 1.25 double row) and using straight distilled water with two bottles of Water Wetter resolved the overheating problem. Note here that I was not using any thermostat; just a restrictor plate (this was on the advice of the builder). However, I found that in the cooler weather, the engine would not heat up properly, and this was reflected with a decrease in performance and an increase in oil consumption. As an example, I went to another member's summer home up in the cooler area of the state about a month ago. On the way home, with the outside air temps around 60 or 65 degrees, I found that, on the road at 75 mph, the engine would not heat up over 140 degrees until I got back down into the warmer (90 degree) weather of the valley. Based on the results of the various studies I have seen on the effects of running the engine too cool, I opted to install a 180 degree thermostat and now the engine runs at the proper temperature with better performance. These are my results; YMMV.

Does all this info just relate to the FE's?

What am I looking for as far as operating temps for a 351W?

I think between 140 and 170 on the freeways depending on outside temps. and it shoots up to 210 in traffic almost anytime.

it's a very interesting thread...

Monster,

I agree with Buzz, thermostats ensure that the engine temperature stays above the the temperature value. If you are running significantly above that temp you need to increase air flow over the radiator or increase the radiator size (or effectiveness with Water Wetter for example).

To keep the temp AT the thermostat value, you need a thermo switch on the fan, it needs to go in the bottom coolant line and be set to a temperature below the thermostat value. Otherwise, there is no "reserve" of cooler water to reduce the engine temp and the temp will wander up above the thermo switch temp.

In a nutshell, the themostat sets the minimum temp, the thermo switch on the fan sets the approximate upper limit IF the radiator and fan are adequate.

Jim

pretty much all domestic V-8's want a 180 thermostat, except new EFI, they run 195's.

casaleenie, your problem is not enough airflow, you need a better puller fan and shroud.

Wow,
I posted this thread just about a year ago. I've learned a great deal on cooling systems over this time due to cooling problems I was having with my Cobra and another car that I'm restoring and from info on this site.

Some important system basics:
Cooling = the systems ability to disapate heat

Disapation=Coolant flow and a radiators ability to transfer heat

Anything that affects this disapation WILL have an affect on the temperature.

ie; reduce the coolant flow and the coolant will absorb more heat.
The radiator disapate's at a fixed rate at a given coolant flow at a given air flow (Xgal/min / XCFM = X degrees cooling).
Conversely, accelerate the coolant flow and at some point you will also affect the ability of the system to disapate heat ( the coolant needs to reside in the radiator long enough to transfer heat) This a why you need a TSTAT or restrictor.

As has been mentioned in this thread by others, too cold also has an affect on performance. I believe that the trick is to identify and maintain your optimum temperature over the range of changes in the factors that affect the system. For FE's a 180 appears in many cases to be the sweet spot.


Bryan FYI, I'm running a Flex-A-Lite Black magic fan with 2800CFM flow. The bad thing about this fan is that the "autoswitch" has a minimum setting of 190. I like the fan & the shroud design but the switch should offer more range. In addition it measures the surface temp of the rad. with the probe sensing the temp of air through the rad. (I would prefer a more accurate measure with the probe in the coolant and adjustable below 170.

Thanks all,
Mike

This one's for you decooney- My scj with adjustable valves acts exactly as you described, I did go back to the 180 it runs best between 180-200 valve train noise sounds sweet and throttle response is way better.

Cool...
 

Ed Cougar,

Thanks for your reply. The additional confirmation is helpful and good to note. Once I started to focus on it while driving in the cool/warm/cool conditions, only then did it start to make sense as to what was really going on. Also, I don't care for the more irratic behavior of the engine when it runs cooler. 20 degrees makes a big difference to me now that I understand what was happening on cooler days... it's even worse and more noticeable with aluminum heads than my previous iron heads for sure!.