in the TR4 comp manuel Kas said to break the bellows and re-install the
thermostat. "You must have a restriction in the system or the water pump
will force the coolant through the radiator too fast for proper cooling to
take place, and the engine can overheat very quickly." His advice in the
TR6 comp manuel is similar.
bruce
----- Original Message -----
From: "MARK J WEATHERS" <markjwea@email.msn.com>
To: "Bill Babcock" <BillB@bnj.com>; <WEmery7451@aol.com>;
<fot@autox.team.net>
Sent: Tuesday, March 04, 2003 6:19 AM
Subject: Re: Head Cooling Problems
> I have seen several conflicting documents on fluid speed vs. cooling
> ability...one of those eternal debates I guess. Within the practical
limits
> of our pumps I am guessing faster flow has little effect, but the lack of
> pressurization without a restriction does sound like more of a culprit.
>
> I put an aluminum radiator from a 944 into my TR6 when I got tired of
having
> the stock one re-soldered. It is a little shorter and wider but overall
> frontal area is comparable and it is lighter of course and cross-flow. It
> came with the expansion tank (ugly) which allowed putting the cap on the
> suction side. I blocked the bypass, fit a spiral impeller and closed up
the
> impeller to housing gap, reduced the impeller speed 10% and removed the
stat
> completely. So far it has worked well although I don't have a lot of
> competition miles on it yet. It is fully shrouded and runs one electric
fan.
> I think I will try a restictor plate.
>
> Mark Weathers
> 72 TR6
>
> ----- Original Message -----
> From: "Bill Babcock" <BillB@bnj.com>
> To: <WEmery7451@aol.com>; <fot@autox.team.net>
> Sent: Monday, March 03, 2003 9:53 AM
> Subject: RE: Head Cooling Problems
>
>
> > I'll have to read the link. The thing engineers worry about (especially
> > nuclear plant engineers at pressurized water reactor plants because
their
> > systems are designed to operate without boiling the coolant--same as a
car
> > only bigger) is actually "departure from nucleate boiling" which is the
> > transition to bulk boiling. Bad for cars and nuke plants because the
steam
> > shrouds the heat transfer surface and dramatically reduces the heat
> > exchange. Compared to flow considerations (which until I read the
article
> > I will still regard as small) lower static and dynamic pressure in the
> > engine will have a huge effect. The seven pounds from the radiator cap
> > gets added to five to 15 pounds from the water pump if it's exit from
the
> > block is reasonably restricted to keep the bubbles small.
> >
> > The easiest way to put the cap where you want it is to add an expansion
> > tank, then you can keep the radiator and cooling system full. If you
have
> > a return line plumbed to the cooling system high point it will be
> > self-venting. Peyote has a simple tank, made from a section of large
> > diameter tubing. You can get a pretty aluminum one from Pegasus.
> >
> > -----Original Message-----
> > From: WEmery7451@aol.com [mailto:WEmery7451@aol.com]
> > Sent: Monday, March 03, 2003 7:16 AM
> > To: Bill Babcock; fot@autox.team.net
> > Subject: Re: Head Cooling Problems
> >
> >
> > In a message dated 3/2/03 5:14:12 PM Pacific Standard Time,
BillB@bnj.com
> > writes:
> >
> > << It's probably more about the reduced pressure allowing bubbles to
> > form--something engineers call nucleate boiling. I don't know about this
> > "water moving too fast through the radiator" notion. Usually rapid flow
is
> > good for cooling because it keeps the boundary layer thin. >>
> >
> > I agree that probably ninety percent of the engine overheating problems
> > result in the coolant flashing to vapor due to the loss of block
pressure.
> >
> > We were doing some NRC smokescreen calculations directed at optimum flow
> > rates in heat exchangers, trying to avert massive expenditures in plant
> > modifications at the Happy Valley Nuclear Plants. We also had Kas
slowing
> >
> > down coolant flow using larger pulleys.
> >
> > The talk of the times (60s), when many TR-3 drivers would show up at
> > Nelson
> > Ledges, would be optimum flow rate and restrictor washer size. I
remember
> >
> > when ten to fifteen TR-3 would start a race, and we were all having
> > similar
> > problems. I seem to now be the last of them. This isn't to say that
> > everyone couldn't have been wrong at that time. I am now taking
Randall's
> >
> > "Stewart Components" seminar.
> >
> > Next questions for the cross flow radiator experts:
> >
> > 1) I assume that I could go to a radiator shop and have a cross flow
core
> > installed that will fit in the existing TR-3 radiator space.
> >
> > 2) How do you plumb the thing to put the radiator cap on the suction
side
> > of
> > the system (from seminar)? This might not be possible with the tractor
> > blocks.
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