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These tests kind of reinforce my own results; regardless of what value thermostat you install, the engine temp winds up pretty much the same once the running engine is stabilized. All a lower value thermostat does is open sooner, not wider, so your stabilized engine temp is about the same. The thermostat acts as a temp-controlled check valve, constantly opening, then closing a little, them reopening as engine loads change. This changes water flow to the radiator. But even wide open, a thermostat is a large restriction to flow- as it was designed to be.

Leaving the thermostat out completely WILL radically drop engine temperatures because the 'check valve' is gone and water flow is unrestricted. I remember a GT-5 that could NOT get its heater & defrosters to work 'cause the engine temp stabilized at 140F on hundred-mile highway runs. It only went to 170F during a hard driven open track event. Later, the owner found NO thermostat in there at all. Adding a 351-C thermostat allowed the heater & defrosters to work for the first time since he'd owned it.
Steve "Do you know which degree thermostat you have in your car? Is it a 180 degree?"

I have no idea.....I probably changed it at the same time, but that was the 80's!

Bosswrench "The thermostat acts as a temp-controlled check valve, constantly opening, then closing a little, them reopening as engine loads change."

I was able to observe exactly those slight temp. fluctuations when lasering that pipe directly above the thermostat.
quote:
Originally posted by Bosswrench:
These tests kind of reinforce my own results; regardless of what value thermostat you install, the engine temp winds up pretty much the same once the running engine is stabilized. All a lower value thermostat does is open sooner, not wider, so your stabilized engine temp is about the same. The thermostat acts as a temp-controlled check valve, constantly opening, then closing a little, them reopening as engine loads change. This changes water flow to the radiator. But even wide open, a thermostat is a large restriction to flow- as it was designed to be.

Leaving the thermostat out completely WILL radically drop engine temperatures because the 'check valve' is gone and water flow is unrestricted. I remember a GT-5 that could NOT get its heater & defrosters to work 'cause the engine temp stabilized at 140F on hundred-mile highway runs. It only went to 170F during a hard driven open track event. Later, the owner found NO thermostat in there at all. Adding a 351-C thermostat allowed the heater & defrosters to work for the first time since he'd owned it.


So if you were running a 351C in a race car, would you suggest leaving the thermostat out all together?
Thermostats



180°F (82°C) thermostat: The thermostat starts to open between the temperatures of 173°F and 180°F; the thermostat plugs the bypass orifice between the temperatures of 185°F and 192°F; and the thermostat is fully open between the temperatures of 198°F and 204°F.

192°F (89°C) thermostat: The thermostat starts to open between the temperatures of 185°F and 192°F; the thermostat plugs the bypass orifice between the temperatures of 197°F and 204°F; and the thermostat is fully open between the temperatures of 210°F and 216°F.

Thermostats are not ultra-precise devices, which is why it is necessary to write they open and close within a small range of temperatures, rather than at one precise temperature. Notice the Robertshaw 333 thermostat must open about 50% before it plugs the bypass orifice. If a cooling system is healthy proper thermostats (Robertshaw 333) of different ratings will regulate at different temperatures.

If a cooling system is stabilizing at the same temperature regardless of thermostat rating then one of two problems exist: (1) wrong thermostat or (2) the cooling systems heat removal capacity is marginal, the thermostat is operating wide open and not regulating anything.

I believe the Panteras cooling system has been marginal at low engine speed for 40 years. The SACC 4.9" pulley will help matters quite a bit. I think it will eventually be recognized as one of those "must have" type of parts.

-G
after watching the forums discussions on cooling issues , I of course wanted to solve all these issues before driving my car. having worked in the hot rod/racing industry for 35 years I contacted howe racing for a radiator stewart racing for a water pump and I wanting to use a serpentine belt on my engine , I bought a march pulley set ,5.5'' crank and water pump pulley, which is a 1:1 drive on the water pump. I bought a Stewart water pump and asked them about pulley ratio's . they recommended for the street 15-20% overdrive w/6500 rpm limit . I purchased a 4.75 '' water pump pulley from jones racing products. I did the swirl tank/surge tank mods , Robert shaw 195 thermostat, howe racing16X24 double pass radiator ,full shroud w/16'' spall puller fan. the shroud has 8 rubber flaps with about 45sq'' of area for cruise speeds.a/c condenser in front of radiator. the car has been driven 1100 miles this summer in Tucson, mostly on the street in 100-115 temps , runs on the thermostat at 195 and the fan cycles when idling. hiway driving 75-100 at 195* also. attached is a photo of the belt arrangement. with all the input from my sources I am happy with their advice plus I have a pantera with no cooling issues! p.s. the extra belt straddling the water pump snout is for the whipple supercharger drive.

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  • 351serp
I know I am really really late to this party but I finally got my SACC Fast Water Pump Pulley installed a couple of weeks ago. I did a full coolant flush to remove the 50/50 glycol mix that was in it. I replaced the coolant with plain water and two bottles of No-Rosion along with the fast pulley. I am noticing a 8-10 degree reduction in temperature when I drive in city traffic. Now it runs no hotter that 193 or so. Big improvement to the +200 temps that I used to get prior. The big test will be this summer I guess. Thanks Scott and George for your advice.
quote:
Originally posted by ItalFord:
I know I am really really late to this party but I finally got my SACC Fast Water Pump Pulley installed a couple of weeks ago. I did a full coolant flush to remove the 50/50 glycol mix that was in it. I replaced the coolant with plain water and two bottles of No-Rosion along with the fast pulley. I am noticing a 8-10 degree reduction in temperature when I drive in city traffic. Now it runs no hotter that 193 or so. Big improvement to the +200 temps that I used to get prior. The big test will be this summer I guess. Thanks Scott and George for your advice.


Better late than never right? lol Wink

10 degree reduction is a pretty awesome result. We're glad it worked well for you!

Chris
I installed one of these last week with favorable results on my 71. I've done the cooling mods but it still ran a bit warm on the occasional drive home from work in silicon valley commuter traffic. By the temp gauge (moderately scientific) it lowered it by something like 10-15 deg at 0 to 10 MPH.

For me well worth the ~$100 and 20 minutes to install.

Thanks Scott!
quote:
I installed one of these last week with favorable results on my 71. I've done the cooling mods but it still ran a bit warm on the occasional drive home from work in silicon valley commuter traffic. By the temp gauge (moderately scientific) it lowered it by something like 10-15 deg at 0 to 10 MPH.

For me well worth the ~$100 and 20 minutes to install.

Thanks Scott!


That is AMAZING!!! Thanks for the post!!!

Folks,

We have be out of stock on this pully for some time now.

To date, I have done 3 production runs of this pully and I figured that was going to be about it since sales slowed down after the third run. (By the way, we sold many pullys to non-Pantera owners running the 351c in other vehicles.) 

Anyway, Over the last 6 months I have had repeated requests for this pully so it is now back in stock and available for immediate shippment.

You too can enjoy the AMAZING results this pully has offered to many very happy customers.

Take care all, Scott

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