What Temp should 392 run at normally?

Discussion of the 331-354-392 HEMIs.

Moderators: scottm, TrWaters, 392heminut

hemi4t
Posts: 54
Joined: Thu Feb 10, 2005 11:04 am
Location: Hartland, Michigan

What Temp should 392 run at normally?

Postby hemi4t » Mon Aug 11, 2008 12:23 pm

I've got a 392 in my 40 ford and it is newly rebuilt top to bottom running 10:1 compression, 292 duration cam, BBC water pump, and a griffen aluminum rad with a 16 inch 2700 cfm electric fan, and a 160 degree thermostat. The temp seems to hit 180 degrees within minutes and then hover between 190 and 210+ based on stop and go traffic with temps in the 70 and 80's. The timing is at 6 degrees before and total of 30 degrees by 2500 rpm. The fan is set to come on at 185 degrees. Is 210+ too hot for these engines?

mart
Posts: 536
Joined: Tue Mar 22, 2005 2:06 pm

Re: What Temp should 392 run at normally?

Postby mart » Mon Aug 11, 2008 11:57 pm

hemi4t wrote:I've got a 392 in my 40 ford and it is newly rebuilt top to bottom running 10:1 compression, 292 duration cam, BBC water pump, and a griffen aluminum rad with a 16 inch 2700 cfm electric fan, and a 160 degree thermostat. The temp seems to hit 180 degrees within minutes and then hover between 190 and 210+ based on stop and go traffic with temps in the 70 and 80's. The timing is at 6 degrees before and total of 30 degrees by 2500 rpm. The fan is set to come on at 185 degrees. Is 210+ too hot for these engines?

------------------------------------------------
210 is technically *not too hot*, but if that's were your running normally, it's
a bit scary, because there's not much of safety margin. Under a load it will
probably quickly go hotter and get into the danger zone. Ideally you should
be running at about 180 to 195 degrees under all conditions. Below 180
degrees, you'll lose a bit of power and hurt fuel mileage too. Much above 200
degrees and besides not having have much of a safety margin. you increase
the octane requirements of the fuel and can run into pre-ignition or
detonation problems, forcing you to back off on the timing and thus lose
some power and mileage. The fact that you have a 160 degree thermostat
and you're still running at 210 degrees indicates either the rad is not big
enough and/or you're not getting enough air flowing through it. A few things
to check before you go changing the rad. For incoming air to flow in
through the rad properly, it has to also be able to escape the engine
compartment too. I imagine an early hemi in a '40 Ford engine compartment
is a pretty tight fit. Can the air escape adequately? You might need to
add some additional vents to the hood, or through the inner fender panels
into the wheel openings, to let the hot air out. Also, are you running a
hood scoop of some sort, particularly, one that is not sealed to the carburetor?
Sometimes a hood scoop that's not sealed to the carb can pressurize the
engine compartment enough that it restricts air flowing in through the rad.
Hope some of this helps.

mart
=====================

hemi4t
Posts: 54
Joined: Thu Feb 10, 2005 11:04 am
Location: Hartland, Michigan

Re: What Temp should 392 run at normally?

Postby hemi4t » Tue Aug 12, 2008 9:47 am

I'm running without a hood right now. The radiator is as large as I can get in the car it is a new griffin aluminum two row with the large tubes. I was running about 200 most of the time but being less than 200 miles on a new engine I was thinking it maybe would drop some with breakin miles of around 500 to 1000. My thermostat is not a high flow maybe I need to change it out to see if there is any difference.

budmspeeco
Posts: 133
Joined: Tue Dec 21, 2004 5:35 pm
Location: South Houston, Texas

Re: What Temp should 392 run at normally?

Postby budmspeeco » Fri Aug 15, 2008 7:35 pm

Put a shroud and fan if you have the room. I installed a 460 Ford in a '48 several years ago and it had two of the biggest fans available. I had to squirt water continuously on the radiator to keep the temp down to 190 while running the motor for 30 min. at 2000 to break the cam in. It just would not cool it. I finally bought the shroud Griffin offered for that radiator which did not come with a hole. I could only get a 17" fan on it but now the owner says it never gets over 170 even in traffic. I did install some sheet metal in front to direct all the air into the radiator. I also cut the hole in the shroud to only have 1/4 inch clearance on the stainless steel fan. You also need to have the shroud fit as near to the center of the fan as possible. Hope you have the room because it is probably going to be your salvation to the heat. Good luck, Buddy
'48 anglia

wayfarer
Posts: 77
Joined: Sun Feb 26, 2006 4:16 pm
Location: Central Ory-gun

Re: What Temp should 392 run at normally?

Postby wayfarer » Sat Aug 16, 2008 3:28 pm

Fully Agree. The fan shroud is probably one of the most important and also the most overlooked cooling system components.

hemi4t
Posts: 54
Joined: Thu Feb 10, 2005 11:04 am
Location: Hartland, Michigan

Re: What Temp should 392 run at normally?

Postby hemi4t » Sat Aug 16, 2008 8:09 pm

I have a fan and shroud. Today I had the car out on Woodward for the dream cruise and noticed while I cruised at about 50 mph the temp would rise steadily to 210+ degrees but at lower speeds it would lower the temp to around 185 to 190 degrees. Even in stop and go traffic it was around 190. This is a bit confusing.

stormrunner
Posts: 2
Joined: Sun Mar 22, 2015 9:12 am

Re: What Temp should 392 run at normally?

Postby stormrunner » Sun Mar 22, 2015 11:45 am

I have a 2006 300srt 6.1L hemi,my problem is as im driving down the road I put the peddle to the floor the car takes off like a rocket then it will die till I take my foot of the peddle help even Chrysler so far can fix it.should I take it to GM????and help on this matter would help it all started after dealer changed the plugs coils never changed??? help any one. other then that car runs fine

Hemi Lover
Posts: 7
Joined: Thu Jun 26, 2014 8:09 pm

Re: What Temp should 392 run at normally?

Postby Hemi Lover » Mon Mar 23, 2015 9:38 am

392 motors stock use 195 degree thermostats and large radiator and trans. cooler if automatic.
maybe a 180 thermostat and a electric temp. controled fans will keep it lower than 210degree
all the time.

moparjack
Posts: 9
Joined: Thu Dec 03, 2009 3:19 pm

Re: What Temp should 392 run at normally?

Postby moparjack » Tue Sep 13, 2016 4:21 pm

Verify accuracy of temp gauge?

George
Posts: 627
Joined: Wed Aug 25, 2004 4:12 pm
Location: Fl

Re: What Temp should 392 run at normally?

Postby George » Sat Sep 17, 2016 5:08 pm

This is a Dead Thread from '08 that some guy asked about something totally different to revive it for some reason....


Return to “(LEGACY) 331-354-392 HEMIs”

Who is online

Users browsing this forum: No registered users and 1 guest