How hot is hot?

-
jschodde

jschodde

Member
Joined
Sep 21, 2013
Messages
6
Reaction score
0
Location
Phoenix
In my 67 Barracuda, I have a newly built 340 motor (stroked to 408) with Edelbrock heads, 10:1 compression, champion aluminum radiator with dual electric fans. I took her out last night around the neighborhood and the temperature got up to about 220. I got nervous and brought her home. After I parked, I noticed the electric fans were definitely working overtime to cool it down.

Should I be concerned?
 
Sounds like this is a new build and just completed. Assuming everything else is right, make sure you've got all of the air burped out of the cooling system. Check the heater unless you've bi-passed. Thermostat? How long was it running?
 
Please make sure your gauge works properly before you begin a dismantle. You seem to know what you are doing so I won't mention any of the other really easy stuff, just go thru it one step at a time.
 
Lammio said:
Sounds like this is a new build and just completed. Assuming everything else is right, make sure you've got all of the air burped out of the cooling system. Check the heater unless you've bi-passed. Thermostat? How long was it running?
Click to expand...

Yes, brand new motor. Heater is new but shut off with a valve on the hose.

Here's what's under the hood for reference.

It was running for about 15 minutes as I drove a couple miles around the neighborhood. I just checked water level and it's good.

I'm thinking I should drive it some more (break-in) and just pull over if it get's too hot. What would you do?
 
magnumdart said:
Please make sure your gauge works properly before you begin a dismantle. You seem to know what you are doing so I won't mention any of the other really easy stuff, just go thru it one step at a time.
Click to expand...

Gauges are brand new AutoMeters. I'd hope they are accurate :???:
 
The majority of break in has pretty much occured. 220 is not a disaster but leaves little room for play. If you don't go thru it step by step, and use the ever popular I hope it is ok method, I would add an oil cooler, and possibly a trans cooler, if it's an automatic.
 
magnumdart said:
The majority of break in has pretty much occured. 220 is not a disaster but leaves little room for play. If you don't go thru it step by step, and use the ever popular I hope it is ok method, I would add an oil cooler, and possibly a trans cooler, if it's an automatic.
Click to expand...

Oil cooler? Hmm, I like that idea. Trans is manual.
 
I wouldn't be too concerned at 220, that's pretty much a normal operating temp IMO, but that's just me.

What about timing, where is it at?

If you go for a drive and it does creep up more then you'll obviously need to do some digging.
 
1....Nawhmbah whaon......check accuracy of the gauge. Many ways to approach that. Let it warm up with pressure cap off and monitor with a "candy" or other thermometer, "what have you" Borrow or buy an infra red. Tape a probe to the bottom of the top hose, and insulate it temporarily around the probe with rags and tape

2....Try a different thermostat. 190 is fine but "buy a good brand." I realize that is difficult nowadays

3....Post photos of the setup

4....What specific conditions does it do this, IE highway, idling, low cruise, med cruise?

5...Where is timing set and what have you for a curve?
 
Agree on timing, my 372 ran hot until I recurved and brought in a lot of initall. Also what stat?
 
for evening temps right now, 220 seems hot. Does it slowly creep up and never cool down. Was this idling around or some RPM down the highway. Just some thoughts.
 
Fans shrouded or just strapped on? Strap-ons only cool what they cover, ie. 50% of ypur rad surface unless they are shrouded. Is this that $1400 radiator?
 
jschodde said:
Gauges are brand new AutoMeters. I'd hope they are accurate :???:
Click to expand...

Well I just had to return an oil pressure sending unit (vdo) to summit that was way out of tolerance. Supposed to be 10-180 ohms, was 230 ohms static. Glad I installed a mechanical oil pressure gauge as a backup prior to firing mine up.
 
That's hot but not dangerous. Operating temp on my ('90's) BMWs is 108C = 226F...

Dart273 has a good sequence. First make sure your instruments aren't lying to you. I would put the probe in a cup of boiling water (at the elevation of Phoenix, about 210F) and make sure the gauge reading matches.

If the gauge is right, next take the 'stat out and put it in hot water. If it's a 180F unit, it should be fully open well before boiling.

Then if you still hear hoofbeats, start looking for zebras instead of horses. :)
(such as: electric fans hooked up backwards so they're pushing against the incoming air)...
 
a lot of folks will argue but in our old cars,thats too hot.mine will run all day in the hottest temps at 180.make sure the rad is up to par,the stat is good,you have a shroud,elect fans are always a problem.you always hear of a temp problem with them.granted ive never used them,but ive never had a overheating issue.stock cooling has always worked great for me.i run a spring in my lower hose to prevent colapse.try and verify the guages are correct.
 
DrCharles said:
(such as: electric fans hooked up backwards so they're pushing against the incoming air)...
Click to expand...

I had a friend that did that on his 280Z :D
I walked around the front when he came over and it was blowing out the front.
He said "It only gets hot when I drive, but parked it's fine" :D
Then while he was changing things around and finishing the install he drilled a 1/4 hole all the way through the palm of his hand.
Guy had crappy luck like that.



jdsduster said:
a lot of folks will argue but in our old cars,thats too hot.mine will run all day in the hottest temps at 180.make sure the rad is up to par,the stat is good,you have a shroud,elect fans are always a problem.you always hear of a temp problem with them.granted ive never used them,but ive never had a overheating issue.stock cooling has always worked great for me.i run a spring in my lower hose to prevent colapse.try and verify the guages are correct.
Click to expand...

I run a single 17" electric with a 26 inch radiator in Phoenix with out going over 210 even stopped in traffic.
But I have a basically stock engine too, so I know that matters.
If/when the engine gets replaced with something bigger it'll get a viscous fan clutch and a shroud to match.
 
220 is good operating temperature. Can you give us some more details? Does it cool off going down the road or coming to a stop, or does it get o 220 and stay there? A few more details might help.
 
In my opinion 220 is too hot for operating temp, I don't like to see operating te p higher then 200 on my 360. It normally runs at 190-195.
 
Some of the newer engines run between 220º and 230º. The factory gauge on my Darts pegs at 250º.

It's not uncommon for an auxiliary fan to run for quite a while after shut down, particularly on a cast iron engine. Most aux fans are set to come on around 210º. That means that the fan is working to kill 10º without getting any help from the water pump.

Using a candy thermometer to check water temp is a good idea. Suggest buying one for the shop. I think most women would take a dim view of appropriating their kitchen stuff for automotive repairs. (Trust me, I have firsthand experience. Or, I did it so you don't have to.)
 
Regardless of the possible merits of running at 220 instead of 180, if the cooling system is working properly the temp should be limited only by the thermostat. If you have a properly working 180F stat and the temp gets much higher than that, there is something wrong because the system can't reject enough heat to the air to get the temp back down to the stat opening point. Radiator too small or clogged, insufficient airflow (rarely a problem at speeds over 25 mph), water pump too slow, lower hose collapsing, etc. Let us know what exactly is going on, and when...
 
DrCharles said:
Regardless of the possible merits of running at 220 instead of 180, if the cooling system is working properly the temp should be limited only by the thermostat. If you have a properly working 180F stat and the temp gets much higher than that, there is something wrong because the system can't reject enough heat to the air to get the temp back down to the stat opening point. Radiator too small or clogged, insufficient airflow (rarely a problem at speeds over 25 mph), water pump too slow, lower hose collapsing, etc. Let us know what exactly is going on, and when...
Click to expand...

That's incorrect, sir. The thermostat only regulates an engines minimum operating temperature, not the maximum. The stamped temperature on a thermostat is only that at which it opens. It has nothing to do with the maximum operating temperature. That is a function of the rest of the cooling system.
 
I can see where I was not clear. Obviously it sets the minimum because it doesn't open and allow coolant to the radiator.

The point I was trying to make is that if there is sufficient cooling capacity, the temp will still be regulated by the thermostat because it will not be wide-open and no longer controlling the temp.

A mechanical vehicle thermostat is NOT a simple on-off switch either completely closed or completely open (unlike the wall stat for HVAC in buildings). I've actually heated them in pans of coolant and observed the gradual movement of the valve.

It opens more as it gets hotter, thus increasing coolant flow through the radiator (which of course then lowers the system temp and it closes down partially). Eventually an equilibrium is reached which should be somewhere in the operating range of the thermostat. The time constant of the loop is several seconds.

So, if the thermostat is wide-open it has lost control of the loop, and then (as you point out) the maximum temp is indeed limited by the rest of the cooling system.
 
So tonight I tweaked the electric fan settings to turn on around 170-180. My thermostat is 160. I was able to drive much farther tonight and the temp held around 210 whether I was driving or idling at a light. I think it'll be OK now! Thanks everyone for your advice!
 
That's much better. Good thing, I had a few dozen suggestions for ya, including some fan related stuff. Do the fans ever shut off? What temp.? Keep your eye on it. Now that you are aware I imagine you will monitor this often until you are comfortable that it is solved.
 
You must log in or register to reply here.
-

Back
Top