[DeTomaso] More on Cooling

wkooiman at earthlink.net wkooiman at earthlink.net
Sun Sep 13 17:02:37 EDT 2009


The bypass on a Windsor is accomplished with a 1/2" hose that goes from the water neck (thermostat housing) to the water pump.

When the thermostat closes, water is free to flow from the intake manifold to the water pump.

I don't think the 1/2" hose ever closes.  In this respect, a Cleveland is superior.  (in my opinion)

The wax actuator is bathed in water from the engine, not from the radiator.  Water enters the block in the front, travels to the back, and then into the heads and back to the front.  Once it reaches the front, it goes back into the block (or the intake on a Windsor), and THEN hits the wax actuator.  In other words, water doesn't hit the wax actuator until it has made a complete pass through the engine.

There are steam holes in the head gaskets, but they're pretty small.

Without a warm up passage, the engine will warm up, the thermostat will open, and then cold water will enter the block.  By the time it hits the thermostat, it will be warmer, but still probably cold enough to cause the thermostat to close.  Once it heats up enough, it'll open again, and the whole cycle will repeat - until the whole system stabilizes.

I doubt this will cause the head gaskets to fail, though.

Personally, I'd rather keep the warm up passage, either with a proper Cleveland thermostat or with a remote bypass thermostat.


-----Original Message-----
>From: Mad Dog Antenucci <teampantera at yahoo.com>
>Sent: Sep 7, 2009 1:50 AM
>To: Tony DiGiovanna <tonydigi at optonline.net>, detomaso at realbig.com
>Subject: Re: [DeTomaso] More on Cooling
>
>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
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