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Cooling a Stroker

  
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Cooling a Stroker

 
Joevol Joevol
I love my Chevy Chevette! | Posts: 4 | Joined: 11/13
Posted: 11/23/13
05:51 PM

I have a problem with a new build street rod.  Here are the facts:  36 Ford with a GM ZZ383 crate stroker, Edelbrock pro-flo EFI, Aluminum manifold, aluminum radiator, 180 thermo.  Within 5-10 minutes of starting engine heat reaches in excess of 220 in the garage.  Took maiden cruise through the hood yesterday.  Weather was about 60.  Within a mile she heated up again 220-240.  Gotter back in the garage and pulled thermo.  Boiled it on the stove and she opened up.  That said I'll go back with a 160.

So with all of that....what other ideas have you got? Frown  

wayne712222 wayne712222
V-6 Camaros rule! | Posts: 63 | Joined: 11/13
Posted: 11/23/13
09:00 PM

take it from experience..  go hotter on the thermostat..  192/195F..  the last digit will be a 9 in the part number of most of the brands..

last digit a 6 is a 160

last digit an 8 is a 180F..

why... because you are experiencing thermal runaway..

this has been covered a bunch of times... but its been a while..


first.. which way does the water pump rotate... there are conventional rotation water pumps with impellers that rotate right from the front.. \\\\\\\\ pushing the water away from the center inlet of the impeller..

there are reverse rotation water pumps with inverted impeller blades..///////// that are designed for left hand  push the coolant out from the center...

but some... water pump manufacturers have come up with straight vaned impellers that will work in either direction.. a great marketing tool.. except .. |||||||||| they don't pump well in either direction..  they just don't circulate properly and with enough force...

you will also want to install some kind of bypass circuit.. from behind the thermostat to the inlet of the water pump.. or top of the water pump.. some have it returned to the what is the lower radiator tank..  same tank with the lower radiator hose.. this circulates the coolant thru the block.. up the back of the heads.. forward thru the heads and into the coolant crossover.. where its blocked by the closed thermostat..   the mechanical pressure caused by the pumping force on the coolant raises the pressure and pushes the coolant thru the smaller bypass circuit..  where it can go around and around and around..  while it picks up heat from the block and heads to stabilize and equalize the engine temps..  once this flowing coolant picks up enough heat..  its passing past the brass bulb on the thermostat .. the wax expands and pushes the thermostat open.. where the water pump can push the hot coolant  flow into the radiator..  allowing cooler coolant into the engine where it closes the thermostat.. allowing the circulation to collect heat again.. while the coolant in the radiator is totally still so the ram air or fan cooling can take the heat out...


if your radiator is undersized.. or your engine makes a LOT of power/HEAT..  you can overwhelm the cooling system..  but... what happens if you have a 180 or a 160 thermostat in a marginal sized cooling system..

the coolant circulates several times.. but the heat builds faster than the radiator can dissipate it. so the lower temp thermostats eventually hang open.. allowing the coolant to flow faster and faster thru the radiator.. where it is IMPOSSIBLE to cool properly..  

blow on a spoon full of soup..  you can cool it..   blow on the stream of soup as its being poured into the bowl..   you are going to burn your tongue when you try it...

in a LOT of cars.. the heater core is part of the bypass circuit..

in small chryslers of the 80s and early 90s... when the heater core plugged up.. and the bypass style heater control valve was switched to heat.. the lack of flow thru the block heads and bypass prevented the coolant flow past the thermostat .. and caused run away cooling systems and blown head gaskets and warped heads...

with a 50% to 70% coolant to water percentage.. and 13 to 16 pounds of pressure..  the boiling point of the coolant will be around 260/265..   but.. if you calculate the mechanical pressure behind the closed thermostat.. its much higher at high engine speeds..  and this counts where the internal engine is HOTTEST.. around the exhaust ports, valve seats and guides..  this prevents the coolant from boiling in those locations also..

so. instead of going west.. go hot..

look at the corvette C4 models.. they don't turn on the radiator fans till the coolant temp gets to 228F..  and they don't have issues..  unless somebody puts in the wrong thermostat or takes it out.. ..

oh.. also.. if you have a fan clutch.. they don't cycle on until around 185 to 190F.. so if you have a 180 thermostat.. the coolant will not power the thermostatic clutch on until the coolant is above the closing point of the 160 or 180 stat.. and a runaway cooling system will happen..

wow.. i have been typing for twenty minutes...

let us know what happens... stats are cheep.. invest in an infra red temp gun and watch the system cycle..

the higher opening temp of the 192/195 thermostat causes a larger thermal differential between the hot coolant and the ambient air. so its easier to cool ..


please also verify that the cap has a center disc that is spring loaded tight against the rubber seal.. some are loose and are designed to be closed by the flowing coolant.. and won't hold proper pressure in most applications.. allowing the coolant pressure to remain close to zero.. and lowering that 3 degrees increase in the boiling point per each pound of pressure increase...

please don't run a 30 pound race car cap either.. as the extreme pressure changes the oval tubes into a rounder shape.. closing the air spaces between the tubes.. .. might as well leave the cardboard box on the radiator when you install it..  as part way thru a race.. there will be NO airflow around the cooling tubes..  

Joevol Joevol
I love my Chevy Chevette! | Posts: 4 | Joined: 11/13
Posted: 11/24/13
12:31 PM

I'll be back in the garage tomorrow and will start checking things out with an infared thermo.  One piece of info to add is that I'm running a Coolong Component puller fan mounted on radiator between the engine.  It's wired to ignition on position.  Also want to say THANS for taking the time to respond to my question.  Your were good enough to dummy it down and that will help me as I go through the check list.  I'm an amateur relative to most car guys so the through explanation was most helpful.  I'll follow up soon.  Thanks again Wayne....  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 11/24/13
09:42 PM

no problem joe.

i do this because i like to spread my knowledge...

and everybody who reads this will now have an in depth reason behind the where and why and how. it works...

i am trying to work past... where one can tell somebody on the sly.. oh.. see that spark plug in the end of the heater hose.. that's a secret nitrous system.. SHHH!!!

only to have them quietly spread the word about that spark plug..  Wink


please let us know how it helps..

and use a thermostat on the electric fan.. fans that run constantly tend to melt the middle out of the fan blade as the armature shaft gets hotter and hotter and hotter..  seen it too many times..

let us know how it works...  

Joevol Joevol
I love my Chevy Chevette! | Posts: 4 | Joined: 11/13
Posted: 11/27/13
08:49 PM

So here goes.  My 180 tested ok but I swapped it for a 160 any way.  I got under the car with the engine running (don't try this at home) and massaged the hose.  Also had the car on jack stands as the heater wasn't working either (forgot to tell you that).  Radiator took almost a gallon more water/anti-freeze.  Heater now working and the engine is running at 185-190 sitting still or slow cruise (2000 rpm/30mph).  This is a new build so I'm checking other stuff out and therefore only put maybe 3-5 miles on it before I said good enough, let's go home.

Note that it is 30 degrees F here so, I still have a concern of potential heat up in the summer.  You mentioned a number of other things that I'm also going to be looking at once I get the car back from my interior guy who gets it next week.

With all that said, thanks again for the help....I'll be back.... Laugh  

Joevol Joevol
I love my Chevy Chevette! | Posts: 4 | Joined: 11/13
Posted: 11/27/13
08:50 PM

So here goes.  My 180 tested ok but I swapped it for a 160 any way.  I got under the car with the engine running (don't try this at home) and massaged the hose.  Also had the car on jack stands as the heater wasn't working either (forgot to tell you that).  Radiator took almost a gallon more water/anti-freeze.  Heater now working and the engine is running at 185-190 sitting still or slow cruise (2000 rpm/30mph).  I got your point on the lower 160 but it appears to be a quick fix.   I'll probably go back to the 180 to see if it works just as well.  This is a new build so I'm checking other stuff out and therefore only put maybe 3-5 miles on it before I said good enough, let's go home.

Note that it is 30 degrees F here so, I still have a concern of potential heat up in the summer.  You mentioned a number of other things that I'm also going to be looking at once I get the car back from my interior guy who gets it next week.

With all that said, thanks again for the help....I'll be back....  And oh yes, the fan is on a thermo..... Laugh