Can an engine run too cool? - Page 2 - Chevelle Tech
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post #16 of 49 (permalink) Old Apr 5th, 20, 7:30 PM Thread Starter
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Rob
 
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Re: Can an engine run too cool?

Initial at 15 degrees, 30 all in at 3000. I have a very light vacuum can on the distributor. 8 degrees on the distrib, 16 on the crank. Ported to the manifold. 46 total at cruise, 31 at idle. 323 block, 215 heads.ported, bigger valves, stock manifold with a cut down plenum, port matched, stock manifolds, Sean Murphy prepped quadrajet for the build. Do you think the auto trans cooler in the stock radiator kept the coolant warmer? Also, the water pump must move some pretty good volume. I picked up the 180 thermosat and a set of plugs one range hotter. I sky hydraulic roller:

9.5:1 compression
Hyd. Roller
Valve Lift Int/Ext. 0.553/0.578
Valve Lash Hot Int/Ext. 0.000
ADV Duration Int/Ext. 275/284
0.050 Duration Int/Ext. 228/238
Lobe Center 112
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Last edited by RHinkel764; Apr 5th, 20 at 7:37 PM. Reason: Forgot item
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post #17 of 49 (permalink) Old Apr 5th, 20, 8:17 PM
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Re: Can an engine run too cool?

Quote:
Originally Posted by Reelysalty View Post
Thereís a reason engines are dynoed at 160.

Not me, I want it at operating temperature.

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post #18 of 49 (permalink) Old Apr 5th, 20, 8:33 PM
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Re: Can an engine run too cool?

If whatever plugs you have in the motor now are running clean, I wouldn't try a hotter heat range. Definitely try the 180 degree thermostat, you want your oil hot enough to boil off accumulated moisture. And keep that Q-Jet, once setup correctly they're fine.
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post #19 of 49 (permalink) Old Apr 5th, 20, 9:59 PM
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Re: Can an engine run too cool?

I did have a 1982 mustang with inline 6 it had 376,000 miles on it..Winter time (30 degrees or less) was a terrible time to drive that car.
I ended up installing a single core radiator and blocked it all the way off with cardboard.
It was sleeting one evening and I could not build enough heat to defrost the windshield.
I would get out and scrape off the ice while the car was chugging at an idle.
It eventually died on me when I was scraping ice for the 3rd time in 20 miles.

I had to pull the plugs take them inside the car and clean them up with a knife and stick them back in so I could get home which was another 7 miles.
I had a Ford flex fan on it and I had bent the blades pretty straight.

Summer time or above 50 outside was fine and it would get 27 MPG with NO overdrive.

It was so loose I could take my pinky finger and turn the flex fan and the crank would turn with it..with all spark plugs out.
It had 200 PSI cranking pressure..Darn thing did not have enough friction to make decent heat.

I retired the car and buddy took the engine and drivetrain
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post #20 of 49 (permalink) Old Apr 6th, 20, 7:35 AM
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Re: Can an engine run too cool?

Hi
Running cool at a 160f thermostat is to cold . This will give poorer running than if a hotter thermostat is used . Typically a thermostat 180--190F.
Cooling fans should either be thermo-couple//viscous hub or electric .
Always use a fan shroud with both type of above fans
Set electric fan cut in temperature above thermostat opening temp .

Use factory 3-4 core and just cover core in snow /very cold conditions

Many write ups say more power and less emissions when running hot above 200F.

Running dyno engines cold I suspect is either laziness or makes more power cold which is a problem in itself .

!80F thermostat and 1-2 3/16 bleed holes
SBC have a internal bypass water pump passage and BBC have an external hose

Take the car for 20 min drive at least spring weather , park and idle then carefully remove rad cap and insert rad thermometer . Let engine idle should be around 180F
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post #21 of 49 (permalink) Old Apr 6th, 20, 7:55 AM
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Quote:
Originally Posted by RHinkel764 View Post
, I did add the rebuilt high flow impeller water pump..
Is your t’stat a “high performance” or “hi flow” model ? Mr Gasket makes them. If not, hi flow water pump can blow open t’stat.
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post #22 of 49 (permalink) Old Apr 6th, 20, 8:05 AM
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Jeff
 
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Re: Can an engine run too cool?

I would try running 89 octane and see how it runs. That is pretty cool for a engine to run. I experiment with octane, thermostats and timing to get the best for each engine.. Bottom line is an engine burns gasoline, there suppose to be hot..
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post #23 of 49 (permalink) Old Apr 6th, 20, 6:02 PM
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Re: Can an engine run too cool?

"Initial at 15 degrees, 30 all in at 3000. I have a very light vacuum can on the distributor. 8 degrees on the distrib, 16 on the crank. Ported to the manifold. 46 total at cruise, 31 at idle."

Not much common sense in all that.

15 Initial
15 crankshaft for mechanical
30 total, all in by 3K
16 crankshaft vacuum
15 and 16 IDLE on full manifold vacuum
15 Idle on ported
Which one is it, full manifold, or ported vacuum advance?????
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post #24 of 49 (permalink) Old Apr 6th, 20, 6:33 PM Thread Starter
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Rob
 
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Re: Can an engine run too cool?

Sorry, did it in a hurry.

Initial is set at 15 degrees- vacuum disconnected
mechanical adds 18 degrees at 3000 (not 15) so at 3000 rpm I have 33 degrees total- vacuum disconnected
Vacuum can adds 16 degrees to the crank, connected to the manifold.

When idling, I have 33 degrees (no mechanical)
When cruising the initial plus mechanical plus vacuum can is in, I have 49 degrees of advance
When I hit it and manifold vacuum drops then I just have the initial and mechanical to 33 degrees.

Make better sense?
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post #25 of 49 (permalink) Old Apr 6th, 20, 6:40 PM
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Re: Can an engine run too cool?

Quote:
Originally Posted by RHinkel764 View Post
Iím having a tough time dialing in my quadrajet. Itís a 396 stroked to a 440. Iíve followed all the cooling threads thru the years and have a 160 degree thermostat in, there 1/8 holes drilled, a high flow impeller on the original water pump rebuilt by the Dutchman in Oregon, a 4 core radiator, shroud, clutch fan, sealed off the sides of the shroud to the radiator. Iíve got a gauge package which Iím sure is not real accurate but the temp indicator never gets to the first bar- under any conditions.

Hereís my stupid question, is it possible to run too cool? Hereís why I ask. I canít seem to dial in my Sean Murphy quadrajet. Itís set up perfectly, it has great manners, I have Autolite 3924í s for plugs- theyíre in a good heat range and I canít seem to keep them from a slight soot appearance.

I just took a 100 mile cruise, 50 street, 50 highway. 3:73 in the rear so itís spinning good on the highway. I have no black smoke on a flick or a flooring of the throttle. I stopped to fill it up- Iím in So Cal and itís 65 degrees. I can touch the radiator, I can touch the manifolds for a moment, itís very cool under the hood. Would going to a 180 degree thermostat be better? Should I go to the next plug up in heat range?

Iím running a 72 main, 48 b rods, I set the float at .375 from the top as I was getting a wet gasket on carb- that worked. I have an AC pump on with a regulator set at 6 lbs. still running rich as evidenced by the plugs.

Plugs looked great before I converted to a 4 speed from an automatic. Might be something there too? Would love any suggestions and input. Rob
You do know that the 3924 is a resistor plug right?
I'm currently running an AR 3934 plug on my 500 incher and the plugs look pretty nice. It's a pump gas type build.

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post #26 of 49 (permalink) Old Apr 6th, 20, 6:59 PM
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Re: Can an engine run too cool?

As far as engines being run on dynos at 160 deg, I've always suspected that this practice is used as a built in cushion against engine knock for dyno owners to avoid destroying their customers' expensive engines. Just a hunch. BTW, I too usually place a new thermostat in a pot of water on the stove to make sure it opens when the water gets hot, before I install it. I go the extra step of starting off with the stat in the cold water along with a cooking thermometer, and I make sure that it begins to open when the thermometer reads 180 degrees and is fully open before it gets to 190 degrees. I also use Milodon stats. I don't frill any holes in them. IMO that would kinda defeat the purpose of using a stat. The hi-flow Milodon has always worked good for me as is.

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post #27 of 49 (permalink) Old Apr 6th, 20, 8:35 PM Thread Starter
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Rob
 
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Re: Can an engine run too cool?

Thanks Billy. Got one and I did test it out. Opened on temp-180, fully open by 190.
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post #28 of 49 (permalink) Old Apr 6th, 20, 10:15 PM Thread Starter
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Rob
 
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Re: Can an engine run too cool?

Replaced it, now it hits the first line on the temp indicator. The one in 68 has cold, then 3 lines for like a 1/4, 1/2,3/4 then hot indicator. Ideally a thermal gun would be the best. I ran it for 20 minutes, itís about 58 degrees out. It runs good, a little warmer. Then I let it idle for a minute, carefully unlatched the radiator cap and inserted a thermometer. At the top area of the radiator, itís 140 degrees, after 20 plus minutes of riding around. Iíll take it out this weekend for a much longer cruise, report back to see if I have a difference in plug quality, smell etc.. thx everyone for the input.
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post #29 of 49 (permalink) Old Apr 6th, 20, 11:54 PM
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Re: Can an engine run too cool?

Quote:
Originally Posted by RHinkel764 View Post
Replaced it, now it hits the first line on the temp indicator. The one in 68 has cold, then 3 lines for like a 1/4, 1/2,3/4 then hot indicator. Ideally a thermal gun would be the best. I ran it for 20 minutes, itís about 58 degrees out. It runs good, a little warmer. Then I let it idle for a minute, carefully unlatched the radiator cap and inserted a thermometer. At the top area of the radiator, itís 140 degrees, after 20 plus minutes of riding around. Iíll take it out this weekend for a much longer cruise, report back to see if I have a difference in plug quality, smell etc.. thx everyone for the input.
Wow Rob, unlatching a radiator cap [email protected] degrees might be risky. I co-wprker of mine has scars all over his neck from being burned from opening a radiatir cap. Be careful with that practice butha!! I would avoid it.

You might want to get a digital temperature gage. BTW, I always screw the threaded sending unit in the intake manifold water jacket hole. I tried mounting one in the threaded hole on a pair of BBC heads, and the temperature reading were all over the place since it's too close to the exhaust valve. I hope this helps.

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post #30 of 49 (permalink) Old Apr 7th, 20, 2:07 AM
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Re: Can an engine run too cool?

HI
Caution Ö
If the radiator is to borderline sometimes a high flow thermostat flows the coolant to fast . The core cannot dissipate the heat quick enough . Result is u get overheating .
A larger radiator is needed . ALWAYS option the bigger radiator for vehicle .

Items that can complicate situation
High flow w/pump
under/overdrive crank pulleys sbc == 5 1/2 ,,6 1/4 ,, 7 inch similar to BBC ??
Remember street cars are not doing 7000---8000 rpm constantly
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