perf-list-digest Thursday, August 20 1998 Volume 01 : Number 064

Ford Truck Enthusiasts - Performance
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In this issue:

FTE Perf - Cooling
Re: FTE Perf - Cooling
Re: FTE Perf - Cooling
FTE Perf - Re: Temps
FTE Perf - RE:cooling
FTE Perf - ADMIN: Truck Driving Schools (2 of 2)



Date: Wed, 19 Aug 1998 10:47:40 -0700
From: Keith Srb
Subject: FTE Perf - Cooling

Forwarded for "Chris Samuel"

I fail to see the convection current theory in the internal engine cooling
system flow.
IME The pressure in the block can easily reach past 60 PSI (MOROSO Pump)under
3000 RPM. That kind of pressure (or any) when combined with flow will c*ancel
out the convection flow. The pressures in the head over the combustion
chamber and around the exhaust port can reach multiple hundreds of PSI if
the coolant should flash to steam; which can and does happen even on street
The head gasket controls the coolant flow. Notice that the holes in the
gasket are smaller then the holes in the heads and block. This is how the
"even" flow through the engine is generated.

The Ford radiator or "Top Flow" is a vary old design and has a minor
problem. The outlet of the pump/engine is connected to the header tank
that has the radiator cap (top). This subjects the cap to the full outlet
pressure which can easily exceed a 25 PSI Cap. This is often misinterpreted
as over heating, when actually it is pressure overriding the cap. The "Cross
Flow" design moves the cap to the other side of the radiator or the suction
side, thereby eliminating this problem. There is another fix and that is too
use a non pressure relieving cap on the radiator and plumb in a "Puke" tank
and moving the pressure cap to that tank.

The water pump design is critical to the cooling and the best ones are made
by "Drake" and are a positive displacement type (but they don't make them
for all engines). The pump must be driven off the crankshaft as unless you
are intending to run a 5 or 10 horse motor to drive it your kidding
yourself. Yes that is a lot of power but the superior cooling capability
that it gives allows you to build more power and will offset it easily.
There are some applications where the electric can be desirable, drag racing
comes to mind, and perhaps Sleddog. But virtually anywhere else and...
well... you do what you want. Regardless every effort should be made to
avoid a negative pressure on the inlet side. Cavitating the water pump is a
bad thing.

Ideally we would want a vary high pressure in the engine. This will
certainly raise the boiling point but more importantly it will hold the
coolant against the head/block casting, if we can keep them wet we can cool
them. We would want the coolant to be moving through the engine at just the
exact flow rate for the BTU's generated. On a Ford or any Race engine the
thermostat should be in place. It should be preferably of the full bypass
type. But the stock type with several 1/8" holes drilled in it works well.
The Cooling System: Hoses and Radiator should be at a lower pressure and the
flow rate should be high for both the coolant and the air over the radiator,
this will provide the maximum cooling efficiency.

If we are looking for maximum cooling we could inject coolant directly off
the pump to points aimed at the exhaust valve pockets in addition to the OEM
system. We can also promote the cooling of the heads by taking coolant out
of the back of the heads. This is often done by pulling it out at the intake
manifold face and running it back to the radiator side of the thermostat.
The lines need not be large a set of AN-6 will do the job in most cases.
Some engines can have the heads drilled and tapped for 3/4 or 1" Pipe and
then run a AN -12 but this is not as common a practice.

The concept of cooling the heads first or "Reverse Cooling" was all the rage
several years ago, GM even jumped on the band wagon with their little block
for a time. But the fad has passed and even GM has moved back to the old
standard system layout. Reverse Cooling still looks like it should work but
there are a bunch of casting issues that must be addressed; besides the
standard system works quite well.

The cooling system is one of the least understood of all the systems in
Internal Combustion Engines. I certainly am no expert by any stretch; but
I'm learning.


We are all victims of our education.

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Date: Wed, 19 Aug 1998 14:00:32 EDT
Subject: Re: FTE Perf - Cooling

Just a suggestion. If you would like to see convection flow at work, look at
an early model T. They didn't have waterpumps. they needed convection flow.
73 F-250 RangerXLT Camper Special
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Date: Wed, 19 Aug 1998 14:18:47 +0000
From: "Gary, 78 BBB"
Subject: Re: FTE Perf - Cooling

Date sent: Wed, 19 Aug 1998 10:47:40 -0700
From: Keith Srb
Subject: FTE Perf - Cooling

> I fail to see the convection current theory in the internal engine cooling
> system flow. IME The pressure in the block can easily reach past 60 PSI
> (MOROSO Pump)under 3000 RPM. That kind of pressure (or any) when combined
> with flow will c*ancel out the convection flow. The pressures in the head

All very nice info Chris and I can't find any fault in your reasoning or info but
my main point was that the convection works in conjunction with and
enhances the pump flow. In spite of all the theory it wouldn't surprise me at
all to discover the reason reverse cooling didn't work or at least provide the
expected results is because it had to buck the convection currents or at the
very least was no longer enhanced by them. Being a non engineer with only
high school physics to base my assesments on I have to defer to the more
knowledgeable ones but I still queston the total canceling of the effects of
convection :-) Household water heaters use this to good advantage, engines
make a lot more heat a lot faster so I'm not convinced yet, sorry to be such a
bone head :-)

One other question/differance of opinion I have is that in an open system
pressure is equal in all directions so how would the top of the radiator have
more pressure than the bottom?
Since I have no test data to substantiate my claim I'll shut up now :-)

78 F-150, 2wd, 460, C-6, 235's
78 Bronco 351M, Np 435, Np 205, 33's
78 LIncoln Town Car, 460, C-6, 19.5' long!
9000#, in ground vehicle lift, Woooo Hoooo!

- -- Gary --
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Date: Wed, 19 Aug 1998 11:27:03 -0700
From: Vogt Family
Subject: FTE Perf - Re: Temps

On Tuesday, August 18, 1998, Gary, 78 BBB[] wrote:
> From: Sleddog
> Subject: RE: FTE Perf - Re: Temps
> Date sent: Mon, 17 Aug 1998 16:47:22 -0400
> > i myself can't see how when an engine gets hot there could be anything
> > even remotely close to "even" cooling. the water enters the block and
> > exits in front, with bottom to top circulation.
> If I understand it right the coolant flows from the bottom of the radiator
> (which is always open to the block) to the block to the heads and back to the
> radiator via the top hose. what this does is create a convection current in the
> engine even without the water pump so the pump doesn't have to work very
> hard. Since all the water jacket areas are open vertically to the heads and the
> heads are open to the intake manifold there should be vertical as well as
> horrizontal flow all along the block unless some #$$%%$# filled up some of
> the jacket with some immovable material of course :-)
> Since the imputus will be closer to the pump the rear of the block won't see
> as much activity but the convection current helps there. Not sure how
> running a line to the front cross over would help except to make the path a
> bit larger to the front..........gosh, that might actually work depending on
> exactly where the water pump gets it's return input for the top of the radiator.
> :-) On the 460 that would be the front of the intake manifold.........Duhhhhh!
> Making more sense all the time :-) Going to need a pretty big line though,
> maybe 1" or so eh?

Gentlemen, please excues me if I am missing something important here,
but it appears that the intake manifold on my 429 can be installed
backwards as there are water exit ports on both the front and back of
the heads, one set of which is blocked by the intake manifold depending
on which way it is installed. If you were to do this, and run a hose
from the nipple on the intake manifold back to the water pump, and
install the thermostat housing backwards, and run a long hose, then you
might have a solution.

The other thing I think about this situation is that you absolutely need
an oil cooler here, and a very large one at that.

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Date: 19 Aug 1998 19:26:16 EDT
Subject: FTE Perf - RE:cooling

I don't know about racing, but it is not a good idea to drill holes in a
thermostat on a street driven car. I tried that once. The car didn't
run any cooler, but took alot longer to reach operating tempeature
(about 20 miles). This was with just one hole with the smallest drill
bit I had.

I concede to your point about the crossflow being more efficient than a
downflow, but there was never a crossflow made with the class or
character of an early to mid 60's bucket header Ford radiator. More
modern doesn't automatically mean better around my place.

Just my opinions. I'm not a cooling system expert, just a guy who has
messed with my share of cooling problems, and I solved alot of them.
Buck Shoff

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Date: Wed, 19 Aug 1998 21:31:11 -0400
From: Ken Payne
Subject: FTE Perf - ADMIN: Truck Driving Schools (2 of 2)

Dear Ford Truck Enthusiasts list members:

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We would like to you to let Alan know you heard about his service
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Now returning you to our regularly scheduled program... (thanks
Keith, didn't mean to intrude!)

Ken Payne
CoAdmin, Ford Truck Enthusiasts

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