Go easy on me if this is common knowledge in the Mopar world. I am new to the scene and my 68 Barracuda is the first classic/project car I've owned. Recently did a bunch of intake/carb work and dropped in a new 160 degree thermo. I have been running about 195 and idling at about 210. Took it out a couple times in 30 min increments to see how everything is running and it is sticking at those temps. Are these acceptable or running a little high?
Engine Temp LA 360
- Thread starter Mcfarlrm
- Start date
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Normal- if you want cooler, a bigger radiator is needed.
In Florida stay with the 160° thermostat. As long as it is a high flow style. Also, do you recall the part number of the water pump you have? If it is a 6 vane impeller I would get an 8 vane W/anti-cavitation plate impeller. What type of fan are you running? As long as it doesn’t keep climbing in temperature, and the temps drop when you’re rolling I wouldn’t sweat it for the time being
195 and 210 are perfectly normal and acceptable.
The thermostat ONLY sets the low temperature of the engine.
The radiator, water pump, pulley ratio, fan blades and pitch, outside air temp, driving speed, engine displacement, modifications, etc are what set the normal operating temp.
As stated before as long as the temp stabilizes at 210 or there abouts you are fine.
IMHO as for 160 deg thermostat... It is not going to cool your engine any better than a 190. If you had an excessive amount of cooling capability. Your engine would run at 160. With a 190 it would run at 190.
The engineers designed the tolerances on the engine for a specific temp range. Too cold clearances are too tight.
The thermostat ONLY sets the low temperature of the engine.
The radiator, water pump, pulley ratio, fan blades and pitch, outside air temp, driving speed, engine displacement, modifications, etc are what set the normal operating temp.
As stated before as long as the temp stabilizes at 210 or there abouts you are fine.
IMHO as for 160 deg thermostat... It is not going to cool your engine any better than a 190. If you had an excessive amount of cooling capability. Your engine would run at 160. With a 190 it would run at 190.
The engineers designed the tolerances on the engine for a specific temp range. Too cold clearances are too tight.
If those are acceptable then I will keep the setup as is for now. May look into a larger aluminum radiator and electric fan down the road. Especially once we hit the summer months. Granted, not going to be driving much in FL summers with a no AC car. Current set up looks to be an original Mopar radiator, aftermarket belt driven fan with no shroud (need to watch my fingers). I was going to go the fan shroud route until I realized that there is about an 1/8 inch clearance between the fan and radiator hose so fitment may be an issue. High flow 160 thermostat. Not too sure on the water pump either so will have to check.
mopowers
Well-Known Member
It may be worth verifying that the thermostat is opening fully and at the correct temp on the stovetop.
All I know is my 340 runs like crap close to 200 or above.
All I know is my 340 runs like crap close to 200 or above.
Temps are acceptable, but what style thermostat? Is it a stock standard flow or high flow? It can make a big difference.
Oh did he? I missed it with my blind ***.
then you will have overheating issues. (there are nay sayers to what I just said, but do a search here on FABO looking for "overheating" most say Aluminum radiator and electric fans)
Idling with no shroud!
I pulled into a fast food line last summer, If I kept the engine around 1500-2000 RPM and the temp would drop to normal, let it idle and it would rise, fixed fan, no shroud and an automatic.
My bet is if he installs a factory style shroud he will be fine.
I would be worried if my engine hit 210 just cruising. The temp usually increases if caught in slow traffic & 210 doesn't leave much margin.....
There can be many reasons why the engine runs hot-ter:
- lean mixture
- clogged rad
- fan operation poor
- large gaps around pump impeller blades reducing pump efficiency.
- no shroud or not sealed to rad core
- retarded ign timing
- insufficient timing at idle
- & more
There can be many reasons why the engine runs hot-ter:
- lean mixture
- clogged rad
- fan operation poor
- large gaps around pump impeller blades reducing pump efficiency.
- no shroud or not sealed to rad core
- retarded ign timing
- insufficient timing at idle
- & more
The 74 360 Duster and Dart Sport came with the correct Radiator, and I assume it will bolt right into your 68. Get a Reproduction if you can. You could also get the correct water pump from almost any parts supplier. Then put a 180 stat. Not too hot-not too cold-just right like the Three Bears..
Get an IR temp gun and get it up to temperature. Then, take temp measurements at the top hose going into the radiator and at the bottom hose coming out of the radiator and see what the difference is. That will tell you how much work the radiator is actually doing.
18in flex fan.
66jim
Well-Known Member
Flush the radiator before spending.
Demonic
Well-Known Member
Fill it full of vinegar or Thermocure rad Flush. If your thermostat IS accurately opening fully by 160-165 and the temperature gauge IS accurate showing 195-200, that was an indication of a problem at the beginning. Note that Thermocure DOES require 3-4 rinses after flushing. Don't forget to pull the block plugs.
THERMOCURE™ - Cooling System Rust Remover & Flush | EVAPO-RUST®
THERMOCURE removes rust from your entire cooling system and restores the engine's ability to transfer heat to the coolant allowing engines to run cooler.
www.evapo-rust.com
Get a shroud and a 7 blade clutch fan if it is running hot idling. Make sure your fan is 1/2 in, 1/2 out of the shroud.
Electric fans will likely require bigger wiring, upgraded alternator & give you other issues you didn’t have before. Make sure you understand what it really takes to run an electric fan Before you do it or you will fall into a money pit.
Babyblue66
Cool dude
In all my years of driving and working on old mopars, since 1993, the most consistent I've ever had any engine run was when I ran a 195 thermostat. I've never seen one run at 160 when I installed that thermostat , they just wouldn't stay that cool. Normally I run a 180 and out of 3 cars with a 180 they still stay at about 190. So the next one I install will be a 195.
Last edited:
Babyblue66
Cool dude
And I've had better cooling with a stock mechanical 7 blade fan over a clutch fan. A shroud is a must if you can get one on there.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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My 11/1 367 has been running at 205 to 207 by IR gun since early 2000s when I made it so. The temp does Not vary, because the combination of the big Ford Thermostatic clutch and 7-blade all-steel fan off that same 73 Swinger, does it's thing exactly..
Just so you know, my manual-trans/3.55 geared 68 Barracuda is running an ancient factory rad out of a 1973 Dart with A/C. It is bigger than the core-support which originally housed a 6-cylinder rad. Even the patches on it have patches.
The engine currently runs a 230* cam and makes enough power to run 93mph in the Eighth. It will idle all day at 14*advance timing, and it can often be seen idling around the parking lot at 5* and 550rpm. Why? Because it can, lol.
BTW, you cannot properly tune an engine with a 50 degree temperature variation, so I'm gonna run against the grain here and say that you gotta get a handle on that temp-swing..... else you will be leaving performance on the table.
--------------------------------
Here's my recipe for success; it may be overkill but I can do anything I want to with the gas-pedal, at any time, as often as I want to, without a care in the world as to engine temp; it is rock-solid.
What you do is entirely up to you.
>hi-flow pump (or any 8-blade pump with the anti-cavitation plate)
>hi-flo 195 stat
>up to 50/50 water glycol
>BIG 7- blade all-steel fan
>Thermostatic clutch off an early 2000's Ford pick-up
>molded hoses
>lower hose has the anti-collapse spring in it.
>Fresh cold air into the carb
>Ancient rad as described above, Ima guessing it is a 2-core with
>a factory shroud
>somewhat restricted bypass hose, the inside heater is my bypass.
>Most of the time I run a 7* cap, because; 1) the temp is rock-solid at 205 to 207, and 2) some of my hoses are 1970 original.
>My engine regularly sees 7000 rpm so I run the water pump with a slight underdrive ratio
>I keep the belt fairly tight to keep it on, because I can, because the Hi-flow pump has a large diameter bearing in it. And I keep the alternator bearings in good shape.
>This system was "engineered" in 2000, and has worked flawlessly thru three cams including the 292/292/110 Mopar.
------------------------------
During this endeavor to cure overheating I can tell you exactly what did Not work for me; and
if you have this problem at low roadspeed/low rpm;
Do NOT run a flex-fan
Do not run any flex-fan, period
Begin with the biggest damn 7-blade factory fan that you can find
If you like; set your system up with a direct-drive fan, and after you have confidence in it, then make the switch to a thermostatic clutch. Do not fall for the horsepower-sucking hype of the 7blade fan; on a clutch, your engine will hardly know it's there.
If you have "a bit of a cam" forget running a 5-vane pump, and you gotta run an anti-cav. plate.
You gotta run a shroud, no exceptions. If the big fan gets too close to it, move whatever it takes to get clearance, including jacking the trans up at the mount.
---------------------
In the early stages of "engineering", if you're having difficulty, run the Idle-timing up. Here's the thing about that; your engine will keep on picking up idle-power with ever increasing idle-timing, until somewhere around 30 degrees. You can run as much idle-timing as you want to, until the engine tells you it's too much, by not picking up any more rpm. At that point I recommend taking out 3 degrees.
HOWEVER
The more Idle-timing that you give it, the higher the Idle rpm will get, and it will start to bang the automatic pretty hard on the N/P shift into gear. And so, then, you will want to reduce the rpm with the Curb-Idle screw. When you do, this will begin to close the Transfer ports and to keep it running, you will have to open up the Mixture screws. And now you have set yourself up for a lean tip-in sag or an outright hesitation. So then, even tho the engine likes the extra idle-timing, most carbs are not set up to take very much advantage of that.
BUT
when you do, do this, you are starting the fire in the chamber ever earlier, and so it has time to complete it's burning before the crank drags the cam around to open the exhaust valve. So by the time that happens, the expanding gasses have done their work, and exit the cylinder relatively cool...... and so then, they do NOT heat up the cylinder walls and exhaust ports so much, and the engine runs cooler.
But you gotta draw the line somewhere. And I draw it, when the tip-in sag shows up. You cannot cure a tip-in sag by any method known to me, except by parking the throttle blades up higher on the transfer slots. So then, you gotta quit advancing when:
1) you get a tip-in sag at normal Idle rpm, or
2) the idle-speed becomes excessive, or
3) the trans bangs hard going into gear.
Depending on your convertor, this all comes together somewhere between 14 and say 20 degrees with an automatic. Ima guessing.
Finally; as to the rad, you might want to pay attention to what I am running; if you cure the heat production at the source, you shouldn't need anything more than a properly functioning factory rad and the big 7-blade fan.
To go 93mph at my weight and elevation, the Wallace Calculator says takes 430hp. If you are at less power, you may not need all the mods I did. So once you know what exactly works on your combo, you can downsize.
But I tellya, it sure is nice to have confidence in my system; I haven't even looked at my factory temp gauge IDK for years. For me, it's a non-issue.
As for the fresh air to the carb; yes I cut a hole in my hood. And it broke my heart. The fresh air didn't do much for engine heat, but it made tuning a breeze, as it absolutely killed all the carb-issues I was having, and now the engine will idle all day without boiling the gas in the 750DP, on the AG intake. So, while I highly recommend fresh air to your carb, I get that there are other ways to get it.
And again, my engine, runs pretty warm. So warm that I had to take the engine apart and increase both the ring gaps and the skirt clearance, to reduce internal friction, to idle cooler. If you are at a lesser Power level, you should NOT be having nearly as severe overheat issues.
In any case
Happy HotRodding
Just so you know, my manual-trans/3.55 geared 68 Barracuda is running an ancient factory rad out of a 1973 Dart with A/C. It is bigger than the core-support which originally housed a 6-cylinder rad. Even the patches on it have patches.
The engine currently runs a 230* cam and makes enough power to run 93mph in the Eighth. It will idle all day at 14*advance timing, and it can often be seen idling around the parking lot at 5* and 550rpm. Why? Because it can, lol.
BTW, you cannot properly tune an engine with a 50 degree temperature variation, so I'm gonna run against the grain here and say that you gotta get a handle on that temp-swing..... else you will be leaving performance on the table.
--------------------------------
Here's my recipe for success; it may be overkill but I can do anything I want to with the gas-pedal, at any time, as often as I want to, without a care in the world as to engine temp; it is rock-solid.
What you do is entirely up to you.
>hi-flow pump (or any 8-blade pump with the anti-cavitation plate)
>hi-flo 195 stat
>up to 50/50 water glycol
>BIG 7- blade all-steel fan
>Thermostatic clutch off an early 2000's Ford pick-up
>molded hoses
>lower hose has the anti-collapse spring in it.
>Fresh cold air into the carb
>Ancient rad as described above, Ima guessing it is a 2-core with
>a factory shroud
>somewhat restricted bypass hose, the inside heater is my bypass.
>Most of the time I run a 7* cap, because; 1) the temp is rock-solid at 205 to 207, and 2) some of my hoses are 1970 original.
>My engine regularly sees 7000 rpm so I run the water pump with a slight underdrive ratio
>I keep the belt fairly tight to keep it on, because I can, because the Hi-flow pump has a large diameter bearing in it. And I keep the alternator bearings in good shape.
>This system was "engineered" in 2000, and has worked flawlessly thru three cams including the 292/292/110 Mopar.
------------------------------
During this endeavor to cure overheating I can tell you exactly what did Not work for me; and
if you have this problem at low roadspeed/low rpm;
Do NOT run a flex-fan
Do not run any flex-fan, period
Begin with the biggest damn 7-blade factory fan that you can find
If you like; set your system up with a direct-drive fan, and after you have confidence in it, then make the switch to a thermostatic clutch. Do not fall for the horsepower-sucking hype of the 7blade fan; on a clutch, your engine will hardly know it's there.
If you have "a bit of a cam" forget running a 5-vane pump, and you gotta run an anti-cav. plate.
You gotta run a shroud, no exceptions. If the big fan gets too close to it, move whatever it takes to get clearance, including jacking the trans up at the mount.
---------------------
In the early stages of "engineering", if you're having difficulty, run the Idle-timing up. Here's the thing about that; your engine will keep on picking up idle-power with ever increasing idle-timing, until somewhere around 30 degrees. You can run as much idle-timing as you want to, until the engine tells you it's too much, by not picking up any more rpm. At that point I recommend taking out 3 degrees.
HOWEVER
The more Idle-timing that you give it, the higher the Idle rpm will get, and it will start to bang the automatic pretty hard on the N/P shift into gear. And so, then, you will want to reduce the rpm with the Curb-Idle screw. When you do, this will begin to close the Transfer ports and to keep it running, you will have to open up the Mixture screws. And now you have set yourself up for a lean tip-in sag or an outright hesitation. So then, even tho the engine likes the extra idle-timing, most carbs are not set up to take very much advantage of that.
BUT
when you do, do this, you are starting the fire in the chamber ever earlier, and so it has time to complete it's burning before the crank drags the cam around to open the exhaust valve. So by the time that happens, the expanding gasses have done their work, and exit the cylinder relatively cool...... and so then, they do NOT heat up the cylinder walls and exhaust ports so much, and the engine runs cooler.
But you gotta draw the line somewhere. And I draw it, when the tip-in sag shows up. You cannot cure a tip-in sag by any method known to me, except by parking the throttle blades up higher on the transfer slots. So then, you gotta quit advancing when:
1) you get a tip-in sag at normal Idle rpm, or
2) the idle-speed becomes excessive, or
3) the trans bangs hard going into gear.
Depending on your convertor, this all comes together somewhere between 14 and say 20 degrees with an automatic. Ima guessing.
Finally; as to the rad, you might want to pay attention to what I am running; if you cure the heat production at the source, you shouldn't need anything more than a properly functioning factory rad and the big 7-blade fan.
To go 93mph at my weight and elevation, the Wallace Calculator says takes 430hp. If you are at less power, you may not need all the mods I did. So once you know what exactly works on your combo, you can downsize.
But I tellya, it sure is nice to have confidence in my system; I haven't even looked at my factory temp gauge IDK for years. For me, it's a non-issue.
As for the fresh air to the carb; yes I cut a hole in my hood. And it broke my heart. The fresh air didn't do much for engine heat, but it made tuning a breeze, as it absolutely killed all the carb-issues I was having, and now the engine will idle all day without boiling the gas in the 750DP, on the AG intake. So, while I highly recommend fresh air to your carb, I get that there are other ways to get it.
And again, my engine, runs pretty warm. So warm that I had to take the engine apart and increase both the ring gaps and the skirt clearance, to reduce internal friction, to idle cooler. If you are at a lesser Power level, you should NOT be having nearly as severe overheat issues.
In any case
Happy HotRodding
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