Cooling systems I:

[h-bot]

From: Monzabudd_REMOVE_227075_THIS_@yahoo.com


A restrictor is doing the same exact thing as an
open thermostat. It goes where the thermostat goes. it
looks like a washer sized to fit the thermostat
housing. It restricts the coolant flow,just the same as an
thermostat in the open position.(hot).
The difference
is,with a restrictor,the coolant is never held in the
engine (like a cold closed thermostat) untill it heats
to 195.
It can take its time and warm up
evenly,until the balance is met between coolant flow.
If
an engine is going to run hot,(besides for the
reason of the thermostat stuck shut) its going to do it
with a thermostat or a restrictor.

Heres
something you can try at home,for a car that likes push its
temp needle up..
Take your thermostat,and boil it
to see that its working properly.
If its good,
drill 2 3/8 inch holes,in it, so that water will always
flow through it.
Go and try to make your car
overheat.
If it does, drill 2 more holes,and repeat.

possibly, you'll find that you can drive a greater distance
before,the car begins to produce more heat than the cooling
system and entire chassis can dissipate.
Hows them
apples? :)
marco


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[h-bot]

From: CJBIAGI_REMOVE_474774_THIS_@yahoo.com


Does anyone (Robert?) have any conclusive results
on the effect of blocking the bypass in the water
pump? I have heard a lot about this over the years but
haven't really seen any before and after results. Anyone?
Clyde


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[h-bot]

From: twelve_second_vega_REMOVE_507630_THIS_@yahoo.com


I noticed a big drop in coolant temperature with
the bypass blocked. About 25° overall. I picked this
tip up from Denis78. I think he could tell you more
about the theory behind it, but I'm a believer...Robert


[This is message #29740 by user twelve_second_vega on Yahoo! Club GM HBODY: http://clubs.yahoo.com/clubs/gmhbody ]

[h-bot]

From: cosvega76_REMOVE_118288_THIS_@yahoo.com


Clyde:

I used to have problems on the
highway (70 mph) with my Vega heating up to 210-220*,
using a regular 160* stat. If you remember, mine has a
mid-'60s style Corvette radiator with surge tank as well
the heater still in the system.

I changed to
an Edelbrock aluminum water pump, blocked the
bypass, and installed a "hi flow" thermostat (160*) that
I drilled 4 or 5 1/8" holes in the stat to provide
flow for the blocked bypass.

Now I can go down
the interstate and the temp has never seen the high
side of 210*.

By the way, I have a pair of
pusher fans on the front and haven't gotten around to
replacing the fan shroud after I raised the engine to gain
some draglink clearance.

Chuck


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[h-bot]

From: astreformula_REMOVE_460005_THIS_@yahoo.com


In the hope of solving my cooling problems, I'm
wanting to try all these ideals of blocking the bypass
and installing a restictor. One thing I don't
understand is where is this bypass everybody keeps talking
about?

Al


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[h-bot]

From: twelve_second_vega_REMOVE_174684_THIS_@yahoo.com


It is the extra hole on the passengers side of the water pump outlet on the engine block. Block it in the pump with a 1/8" pipe plug...Robert


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[h-bot]

From: astreformula_REMOVE_829352_THIS_@yahoo.com


I have an extra pump that I looked at and I see what you mean. Thanks for the reply. I hope to have this cooling problem beat this summer.

Al


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[h-bot]

From: denisst78_REMOVE_701286_THIS_@yahoo.com


Yep it`s a good idea to block the hole,
the
reason why GM put it there is simple...quicker
warm-ups,that`s all our car already warm up very fast and every
little bits helps,this hole is letting hot coolant
re-enter the engine where only cold coolant should
be....
remember that when blocking off the bypass hole you have
to drill at least a small 1/8" in the T-Stat to
bleed air out
I`d say that with only the bypass hole
blocked and a disc installed on the water pump impeller
you should see at least a 10° drop in
temperature
i did this trick more then once and it does
work...
Denis


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[h-bot]

From: twelve_second_vega_REMOVE_251663_THIS_@yahoo.com


Chuck,
The theory of a thermostat 'slowing
down the flow of water' for cooling may apply to
modern automobiles with their very high efficency
cooling systems. But, it does not apply to the older
copper/brass systems.

In all my years of playing with
cars (and I am not a world expert, just telling you
about my experiences) I have only seen one car that ran
hotter when the thermostat was removed.

That car
was a 1971 Torino with 429 SCJ engine. Every other
engine I have ever worked with would hardly move the
needle off the 'C' when the thermostat was removed.


I did some experimenting with my 302 Chevrolet
and the 2 row Modine Vega Style Radiator. I installed
a 195° thermostat and fired the car up, allowing it
to reach operating temperature at 2000 rpm.


Ambient temperature was about 95° during these
tests.

I recorded a maximum temperature of 225° after 30
minutes of run time. I then allowed the engine to drop
back to idle and allowed it to sit stationary for
another 30 minutes.

I recorded a maximum
temperature of 240° and there was no boiling even after
shutdown. Hot soak temperature went slightly past
255°.

I then re installed my 1" restrictor and allowed
the engine to run at 2000 rpm for 30 minutes.
Temperature stayed at 155° without fluctuation.

Keep
in mind I am using a full shroud and a 17"
Flex-A-Lite Nylon Fan, High Volume Water Pump and Blocked
Thermostat Bypass. Ignition timing at 2000 rpm is 36° BTDC.
Water Pump is 15% underdrive.

I then dropped
the engine back to idle and left it there for another
30 minutes. I recorded a maximum temperature of 185°
and hot soak temperatures (after shutdown) did not
exceed 200°.

The difference in how the engine
felt and the temperature inside the car (without
carpet) was tremendously different. At 155°, I could
actually lay my hand on the bottom of the oil pan sump. I
could not get my hand near the pan at 200° coolant
temperature.

I have experienced the same thing with my 440
Chryslers, 'FE' and '335' Series Ford V8's and Small/Big
Block Chevrolets.


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[h-bot]

From: Phantom402_REMOVE_893101_THIS_@yahoo.com


The reason I will never run a car of any kind
without a thermostat or at least a gutted stocker.
The
engineering reason is to SLOW DOWN the flow of coolant so
that it has time to absorb heat to be realeased into
the atmosphere through the radiator.With out some
form of restriction most engines will over heat and
actually have hot spots and pre ignition do to un-uniform
cooling.
And if anyone can keep an hbody cool without the
airdam is doing good and 200 on a 195 t-stat is excelent
by far.
And some one said that you cant cool big
engines with small radiators. If I can cool a 350 chevy
in a 86 ford ranger with a 4cylinder radiator and
not overheat ,well then tell me it cant be done and
Ill get out my pics of my truck and show you the
stock 4 cyl radiator and I drove it 7 months till I
wrecked it (bad wreck ,hit back of semi).
Good luck to
all,
Lee


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