[DeTomaso] More on Cooling

Mad Dog Antenucci teampantera at yahoo.com
Mon Sep 7 01:50:12 EDT 2009


I agree Tony.

Shock effect?  

Pleeeze. 

JT is gay ;-]>

 
Mad Dawg Antenucci 
Team Pantera Racing 
The 1st & still the only vintage race team in open road racing 
www.teampanteraracing.com




________________________________
From: Tony DiGiovanna <tonydigi at optonline.net>
To: detomaso at realbig.com
Sent: Sunday, September 6, 2009 5:06:30 PM
Subject: Re: [DeTomaso] More on Cooling

The wax actuator in the thermostat is always in a bath of coolant returning
from the radiator.  I don't think it will create the shock effect
anticipated here.  If there was a sudden opening and a rush of cold water
into the engine, wouldn't the thermostat close right away?  If there is any
small bypass thru the thermostat (which there usually is and should be,) it
won't open until the returning water approaches the rated temp.

Although in theory the thermal shock thing is less than ideal, I've never
actually seen, 1st or 2nd hand, an engine system do identifiable harm to
itself in this way.

Remote thermostats should be on the return leg, right?

What do all the Windsors and Chevys do without their Cleveland-style skirt
and bypass?

-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
Behalf Of John Taphorn
Sent: Friday, September 04, 2009 11:48 PM
To: detomaso at realbig.com
Subject: [DeTomaso] More on Cooling



Hey guys, I heard from one of our precious informational resources today who
was monitoring the list, but unable to post.  His name is John Christian
(JC), a Pantera owner who worked as an engineer for Roush Racing over many
decades.  JC is a humble gentleman who knowledge of anything automotive
certainly eclipses mine by at least a power of ten.  When JC speaks, I
listen. He called me at work this afternoon to chime in on the ongoing
cooling thread that has been discussed recently.



He wanted everyone to appreciate the importance of retaining the by-pass
feature in the Cleveland engine.  Without the bypass during warm up, coolant
pressure is high in the block as the pump spins pressurizing the vessel.  At
start up heat energy, via conductivity, eventually migrates through the
coolant to the thermostat and it begins to open.  Not all the way at first.
Although in short order, very hot coolant surrounding the combustion
chambers reaches the thermostat and the thermostat recognizes the need to
open fully.  When fully open the thermostat probably allows about 25 gallons
per minute to flow.  In a matter of seconds, the block is emptied of hot
coolant and displaced with cold coolant.  This thermally shocks the engine
causing dissimilar metals to contract at varying rates.  Our cast iron
blocks are very durable and can tolerate this abuse for a while; however, it
is less than an ideal scenario that eventually may create complications.
The diffent
expansion/contraction rates are is tough on gaskets; especially when they
are sandwiched between aluminum and iron.  This may accelerate leaks at the
aluminum water pump and aluminum heads.



In contrast, utilizing the bypass allows coolant to circulate through the
system prior to the thermostat opening allowing the coolant on the low
pressure side of the water pump to rise in temperature and reduce the
temperature differential and resultant thermal shock to the engine when the
thermostat opens.  This would make a case against using a Weiand type water
pump that eliminates the by-pass feature when not redesigning the system to
accommodate a separate bypass or bypass thermostat housing.



As an aside, JC estimated that while flow exiting the block through an open
thermostat may be about 25 gals/min, without a thermostat it may be 60 - 90
GPM.  For those of us that have incorporated a remote by-pass thermostat and
eliminated the conventional thermostat in our cooling systems, that in an
impressive leap in flow circulation during start-up. 



JT
_______________________________________________

Detomaso Forum Managed by POCA

Archive Search Engine Now Available at http://www.realbig.com/detomaso/

DeTomaso mailing list
DeTomaso at list.realbig.com
http://list.realbig.com/mailman/listinfo/detomaso

_______________________________________________

Detomaso Forum Managed by POCA

Archive Search Engine Now Available at http://www.realbig.com/detomaso/

DeTomaso mailing list
DeTomaso at list.realbig.com
http://list.realbig.com/mailman/listinfo/detomaso



More information about the DeTomaso mailing list