Re: [FWDLK] '59 runs a little hot...Higher flow water pump?

[David Homstad <dhomstad@xxxxxxxxxxx>]

Bill,

2 reasons an engine can run hot at idle: 1. Slow airflow at low rpm. 2. Slow
water flow through the radiator.
If the water moves too slowly through the radiator, it gets cooled off, but
once it is cool, it can shed no more heat as it completes the trip through
the radiator.

To quote from a cooling system expert, Stewart Components, at:
http://www.stewartcomponents.com/html/tech_support/techtip3.asp

"A common misconception is that if coolant flows too quickly through the
system, that it will not have time to cool properly. However the cooling
system is a closed loop, so if you are keeping the coolant in the radiator
longer to allow it to cool, you are also allowing it to stay in the engine
longer, which increases coolant temperatures. Coolant in the engine will
actually boil away from critical heat areas within the cooling system if not
forced through the cooling system at a sufficiently high velocity. This
situation is a common cause of so-called "hot spots", which can lead to
failures.

Years ago, cars used low pressure radiator caps with upright-style
radiators. At high RPM, the water pump pressure would overcome the radiator
cap's rating and force coolant out, resulting in an overheated engine. Many
enthusiasts mistakenly believed that these situations were caused because
the coolant was flowing through the radiator so quickly, that it did not
have time to cool. Using restrictors or slowing water pump speed prevented
the coolant from being forced out, and allowed the engine to run cooler.
However, cars built in the past thirty years have used cross flow radiators
that position the radiator cap on the low pressure (suction) side of the
system. This type of system does not subject the radiator cap to pressure
from the water pump, so it benefits from maximizing coolant flow, not
restricting it."

One of the rules of thermodynamics is that the rate of heat transfer between
2 masses (air and radiator/water) is proportional to the temperature
difference. The hotter the water in all areas of the radiator, the more heat
it will dump into the air. A higher water flow will get hot water to the
lower areas of the radiator and improve cooling.

Dave Homstad
56 Dodge D500

-----Original Message-----
From: Forward Look Mopar Discussion List
[mailto:L-FORWARDLOOK@xxxxxxxxxxxxx]On Behalf Of Bill K.
Sent: Monday, March 08, 2004 6:28 PM
To: L-FORWARDLOOK@xxxxxxxxxxxxx
Subject: Re: [FWDLK] '59 runs a little hot...Higher flow water pump?

That makes sense actually.

In traffic you move slower and generally your engine is at a lower RPM.  So
the fan pulls less air through the radiator.   So it runs hotter.  Put an
electric fan on, it runs the same all the time regardless of RPM.  So you'd
get more airflow in traffic and run cooler.

My rat car the fan actually isn't working in.  It's been cold and I didnt
feel like changing it.  The car runs cooler when I go fast with it b/c the
air is blowing into the radiator.  If it gets too hot, I turn the heater fan
on full blast.  Sitting at idle made the hot light come on one day when it
was below zero out.  Which kind of proves that airflow is what makes the
difference in coolant temp.

Putting more coolant through the radiator might actually hurt more than
help - it would give the coolant less of a chance to exchange the heat and
be cooler when it enters the block.



Bill K.

----- Original Message -----
From: "C. B. Kidder" <60Saratoga@xxxxxxxxxxxx>
To: <L-FORWARDLOOK@xxxxxxxxxxxxx>
Sent: Monday, March 08, 2004 7:07 PM
Subject: Re: [FWDLK] '59 runs a little hot...Higher flow water pump?


I don't know what to tell you, Lou. My 60 is the same way--if I sit in
traffic too long it gets hot. My 57 Studebaker used to do the same thing
until I put an electric fan in. Now it always stays right between 160-180.
Maybe you could do that.

Brion Kidder
  ----- Original Message -----
  From: Lou
  To: L-FORWARDLOOK@xxxxxxxxxxxxx
  Sent: Saturday, March 06, 2004 1:40 PM
  Subject: [FWDLK] '59 runs a little hot...Higher flow water pump?


  Last year, I had my radiator recored (3 or 4 row...can remember which),
and upgraded to a 6 blade fan, but the temp gauge starts to creep up pretty
high and pretty quickly on a hot day in slow traffic.  I hesitate to go from
a 180 to a 160 degree thermostat.  The shop used a laser pointing temp gauge
which shows that the thermostat housing area is indeed staying right around
180 degrees, but when you point the thing a little farther back, and on the
intake, and areas near the temp sender, sure enough the temp is in the
200's.  Dunno what it should be in those areas, but it just  makes
uncomfortable thinking that it could be running hot.

  Timing is OK, new cap, etc.   I see that Summit Racing sells  "FlowKooler
Mechanical Water Pumps."  Anyone have any experience with these?  Wondering
if they work and are really any good.  Here is the narrative from

http://store.summitracing.com/product.asp?d=5&s=614&p=293&searchtype=ecat

  Get 30 percent extra coolant flow.
  FlowKooler water pumps solve low-speed heating problems by doubling the
water flow rate at low RPM and idle. At 3,500 RPM the flow rate returns to
normal to prevent too much water flow at high speed and they last longer
than a stock replacement. These pumps use a specially designed steel plate
on the impeller that traps water, eliminates cavitation, increases flow, and
reduces engine temperatures.

  Lou