[DeTomaso] Bleeding the cooling system

Kirby Schrader kirby.schrader at gmail.com
Fri Apr 5 10:55:23 EDT 2013


That would be found here.

http://www.spacecitypanteras.com/Technical/Pantera_Cooling-JTaphorn.pdf



On Fri, Apr 5, 2013 at 8:29 AM, Jim Gray <grayjim at att.net> wrote:
> Maybe I will re-read John's article on your website about a cooling system redo.
>
> Jim Gray
>
>
>
> ----- Original Message ----
> From: Kirby Schrader <kirby.schrader at gmail.com>
> To: MikeLDrew at aol.com
> Cc: "detomaso at POCA.com list" <detomaso at poca.com>
> Sent: Thu, April 4, 2013 8:47:50 PM
> Subject: Re: [DeTomaso] Bleeding the cooling system
>
>
> Yes, but I believe you're missing the important bit….
>
> 'We' are using a remote thermostat. (We meaning all us guys using the Mike
> Trusty/John Taphorn modification)
> Which, by the way, is how most modern cars work these days…
>
> The downside of the stock Pantera cooling system is that damned swirl tank and
> pressure cap on the HIGH pressure side of the system.
> When stock, a 24psi cap would not even keep the coolant in my car when I backed
> off the throttle at 7000rpm.
> Yes, I had the right cap for the neck I was using.
>
> With the current system, there is a bypass all the way from the engine to the
> thermostat and back again. No 'thermal shock'.
> The overflow tank is on the low pressure (suction side). How much simpler can
> you get?
>
> I am certainly no cooling expert, but I see no reason to bypass once the engine
> is warm until it gets cool enough to shut off the thermostat and then you have
> the bypass again.
> The larger volume keeps the temperature more stable.
> I used to watch my GT40 block coolant temp swing 12-15 degrees C when the
> thermostat opened and closed. I don't see that anymore.
> Is 12-15 degrees C a thermal shock?  :-)
>
> Why would you want to keep recirculating hot coolant back through the engine
> when it is at operating temperature?
>
> Especially when you have a mid-engined car which seems to keep everyone
> re-inventing the cooling system.
>
> Yes, one could argue that the engine doesn't warm up as fast, but it's at
> operating temperature before I get out of my estate and to the first stoplight…
> Which is about the same time as a 'from the factory' GT500 or CLK350 operates.
>
> Otherwise, I agree with you completely!
> :-)
>
> Still being a heretic in Texas,
> Kirby
>
>
>
> On Apr 4, 2013, at 7:15 PM, MikeLDrew at aol.com wrote:
>
>>
>> In a message dated 4/4/13 7 57 19, kirby.schrader at gmail.com writes:
>>
>>
>>> With this plate in the block, you can use any thermostat you want in
>>> place of the Cleveland type.
>>
>>
>> >>>This used to be 'the thing to do', but it's not a popular modification
>>anymore.  Among other things, it creates cavitation, as there is essentially no
>>water movement in the cooling system until the thermostat opens, so the water
>>pump just churns and churns away.  It also leads to hot spots inside the engine,
>>as the coolant near the combustion process is heated up, but the coolant near
>>the thermostat is still too cold to allow the thermostat to open.
>>
>> JC Christian took me to school on all of this some time ago and I learned a lot
>>from him.  Among other things, the 'hat' in the Cleveland thermostat doesn't
>>completely block off the orifice in the block, by design.  A certain amount of
>>flow through the engine (instead of through the radiator) is always desired.  If
>>you look at the other Ford engine familes, i.e. Windsor, or FE, they have a
>>bypass hose at the thermostat outlet that permanently routes a certain amount of
>>coolant internally, bypassing the radiator, when the thermostat is fully open.
>>When the 351C thermostat is closed, there is a larger amount of water bypassed,
>>and when it closes, it partially blocks the orifice, and the remaining area is
>>about the same as the area of the bypass hoses on the other Ford engines.
>>
>> Also, if you block the thermostat orifice, the block suffers from thermal shock
>>when the thermostat finally opens.  It is incredibly hot in the hot spots, and
>>then that hot fluid moves forward, and ice-cold fluid from the radiator takes
>>its place.  WHAM!  That's really hard on the engine.  A functioning bypass means
>>that the engine warms up uniformly and properly, and when the thermostat opens,
>>the cold water coming from the radiator mixes with warm water circulating inside
>>the engine to ease the temperature transitions until the system stabilizes at a
>>set temperature.
>>
>> The executive summary to me was:  Bypass good.  Blocked passage bad.
>>
>> At least, that was my takeaway from the discussion.
>>
>> Mike
>
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