66 Dart, 408 runs hot. HELP PLEASE!

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Evans coolant is a good upgrade. I have been running it in my drag car- 74 Duster with a 416 small block 14.5-1 compression and I can make 5 hot laps in 100 degree weather and it will stay at 180.
 
Your measurement from pump to rad changed from 2.25 to 2.5 during the conversation. A fixed blade fan will certainly fit in there, and if you measure again and get 2.7", the Hayden 2947 clutch needs only 2.7"

With that low a cfm on the elec fans, they will prob become an air dam at 20ish mph as the car speed is having to push the fans, and any kind of flat backed shroud will also be an air deflector/ dam at speed.

As always, the temp at the rad inlet and outlets will tell a lotta the story. .Summers here.
 
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Your stubbornness is part of your problem. drilling holes should never be done.
Use a temperature gun on your temperature sending unit where it screws in the block to see if your gauge is showing the correct temperature.
I had the same problem. put in high performance water pump, a 3 core Champion Radiator plus new temp sending unit, took out the electric fans and went from 200-220 to a solid 190 at any speed. a shroud and the mechanical fan are part of the equation.
 
210-215 is warm, but not over heating.
 
moparman79 said:
Evans coolant is a good upgrade. I have been running it in my drag car- 74 Duster with a 416 small block 14.5-1 compression and I can make 5 hot laps in 100 degree weather and it will stay at 180.
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Yup and that's not hot enough for proper engine operation.
 
fklskv said:
Try running a colder plug? This an excerpt from NGK
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This was my suggestion too.

I use to run extremely high compression on a race boat. While everyone was running High Dollar Race Gas, I was running 93, with 104 Super Octane boost, and NGK 9's instead of 7's. Tried the 8's, but it ran better with the cooler 9's.
 
Not enough fan. I run a Lincoln Mark 8 electric fan on my blower car. I can feel it from behind the rear bumper!
 
BentBow said:
This was my suggestion too.

I use to run extremely high compression on a race boat. While everyone was running High Dollar Race Gas, I was running 93, with 104 Super Octane boost, and NGK 9's instead of 7's. Tried the 8's, but it ran better with the cooler 9's.
Click to expand...
Running better with a colder plug won't effect engine temp much-if at all.
 
As to the bypass system;
It's primary function is to shorten the warm-up period, and secondary function is to prevent dead-heading the coolant circulation, during said warm-up period, when the stat is closed; of the stock lo-po iron headed smogger engine, with the factory WP and fast idle cam at 1200 to 1500rpm..................
Yeah, no, I didn't see that applying any more, even on my little HO367,lol. I installed a Hi-Flo stat,and restricted my bypass to prevent excessive re-circulation of hot coolant.
Once the stat is open,this restrictor forces more of the the hot water to exit the engine and head for the rad.
While the stat is closed, this does force the water to slow down and stay in the engine a little longer. I use a 190 stat to delay full circulation a little longer cuz those aluminum heads take a looooong time to warm up.
I run a lot of timing on the cold engine, instead of a choke. I pull the timing out as she warms up.
I run a Vcan off the spark-port; to augment my lazy mechanical curve at part throttle; which allows me to run 87E10 on 185psi, and more, cylinder pressure.
I run underdrive pulleys to help keep the belts from de-railing at 7000/7200 my chosen WOT shift rpm, with catastrophic results usually following.
Once up to temp,my system runs at 205*F...... ALL the time, with an ancient 26" factory rad from a 1973 Dart 318/AC car.
I'm at about 420hp, your results may vary.
Just offering my success story.

As for your engine; with that much power on tap, I would certainly give up a couple of hp and run a direct-drive 7 blade fan and an anti-cav plate on the HD pump. This will prove where your issue is.
I like the T-clutch from the early 2000s Ford Pick-ups so, if I had to, I would sacrifice rad thickness for rad area, to be able to run it. That thing has been stone-axe reliable for me since 2004.
 
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66durgederp said:
Alright, I'm about at my wit's end with this thing.
Here's the details:
Initial build: 66 dart, MRL 408, ripped off 532 HP and 544ft lbs on the dyno. 11:1 static compression. Aluminum heads. Standard 8 vane Mopar water pump NON shrouded impeller. New Northern radiator PN 205152 26" core, 2 rows of 1" tubes. Spal 10" fans with northern radiator matching shroud. 803 CFM each. 35 degrees timing all in, 91 non ethanol fuel. Standard stant 180 degree thermostat with 2, 3/16" holes drilled in it. Standard bypass hose IS in place. TTI ceramic coated headers AND thermal interior barrier. Stock fender wells (uncut) stock valance in place.

Problem: runs like a scalded dog, but ALWAYS runs at 200-215. never crapped coolant on the ground, doesnt seem to ping (that I can hear). I run Schaeffer's 10W-30 for what it's worth.

What I tried to help the situation, in order.

New flowkooler water pump AND 180* Robert Shaw thermostat with Mopar performance silicone bypass hose. No change.

Cut off the dimples on the shroud and installed rubber flaps. No change.

Chooched down the timing to 32*, no change.

Pulled plugs, changed from champions to NGKs - they looked fantastic color wise and the color change on the ground electrode was dead nuts center on the bend, indicating the timing and flame front/kernel is where it needs to be. No change

Header tube temps are consistent. Within 10-15 degrees variation. 310-325 degrees after a spirited drive. They are NOT wrapped, nor will they ever be.

Chopped a hole in the hood - no change. (I'm installing a scoop later anyway)

The lower hose is NOT collapsing. I confirmed with a go-pro under the hood while driving.

I'm running a stant 16 psi cap with a 2 quart overflow tank.

This friggin thing runs at 200-220 (220 is below 25mph putting around) all the time, putting through town, romping down the highway at 90+, doesn't change much. Might see the occasional 190* but as soon as I drop to cruising speed, boom! 200-210. If I let it sit and idle for 15+ minutes, hood open or closed, it absolutely will not budge below 200-205. Ambient air temp doesn't change either. 50 degree evening or an 80+ degree afternoon, doesn't matter. Radiator fins are clean and clear. Id eat off of em, seriously. I've sealed off the radiator core to core support, and hood to core support, no change.

I know I'm going to get the "install a mechanical fan and be done" lecture. Not going to happen. I have 2.25" from water pump to radiator face. There's simply no room. Period.

I've confirmed my OE and VDO mechanical gauge readings with a thermal temp gun. Stat is 200-205 at idle. heads are 215-220.

So, any of you have any ideas? I'm at a complete loss over this thing. I've read numerous forums in general where people claim 210 isn't a death note, but for me, it just seems too damn hot.

Thanks a million.
Click to expand...
I built and raced 340 engines for over 20 years. You really need a 3 or 4 core radiator. Make it fit. You also need a good shroud. If you don't have these two things, you want keep it cooled off. The 180 thermostat is fine.
 
66durgederp said:
Alright, I'm about at my wit's end with this thing.
Here's the details:
Initial build: 66 dart, MRL 408, ripped off 532 HP and 544ft lbs on the dyno. 11:1 static compression. Aluminum heads. Standard 8 vane Mopar water pump NON shrouded impeller. New Northern radiator PN 205152 26" core, 2 rows of 1" tubes. Spal 10" fans with northern radiator matching shroud. 803 CFM each. 35 degrees timing all in, 91 non ethanol fuel. Standard stant 180 degree thermostat with 2, 3/16" holes drilled in it. Standard bypass hose IS in place. TTI ceramic coated headers AND thermal interior barrier. Stock fender wells (uncut) stock valance in place.

Problem: runs like a scalded dog, but ALWAYS runs at 200-215. never crapped coolant on the ground, doesnt seem to ping (that I can hear). I run Schaeffer's 10W-30 for what it's worth.

What I tried to help the situation, in order.

New flowkooler water pump AND 180* Robert Shaw thermostat with Mopar performance silicone bypass hose. No change.

Cut off the dimples on the shroud and installed rubber flaps. No change.

Chooched down the timing to 32*, no change.

Pulled plugs, changed from champions to NGKs - they looked fantastic color wise and the color change on the ground electrode was dead nuts center on the bend, indicating the timing and flame front/kernel is where it needs to be. No change

Header tube temps are consistent. Within 10-15 degrees variation. 310-325 degrees after a spirited drive. They are NOT wrapped, nor will they ever be.

Chopped a hole in the hood - no change. (I'm installing a scoop later anyway)

The lower hose is NOT collapsing. I confirmed with a go-pro under the hood while driving.

I'm running a stant 16 psi cap with a 2 quart overflow tank.

This friggin thing runs at 200-220 (220 is below 25mph putting around) all the time, putting through town, romping down the highway at 90+, doesn't change much. Might see the occasional 190* but as soon as I drop to cruising speed, boom! 200-210. If I let it sit and idle for 15+ minutes, hood open or closed, it absolutely will not budge below 200-205. Ambient air temp doesn't change either. 50 degree evening or an 80+ degree afternoon, doesn't matter. Radiator fins are clean and clear. Id eat off of em, seriously. I've sealed off the radiator core to core support, and hood to core support, no change.

I know I'm going to get the "install a mechanical fan and be done" lecture. Not going to happen. I have 2.25" from water pump to radiator face. There's simply no room. Period.

I've confirmed my OE and VDO mechanical gauge readings with a thermal temp gun. Stat is 200-205 at idle. heads are 215-220.

So, any of you have any ideas? I'm at a complete loss over this thing. I've read numerous forums in general where people claim 210 isn't a death note, but for me, it just seems too damn hot.

Thanks a million.
Click to expand...




Whats the cam like in the car ... also that fan is to small .... Zirgo makes some kick *** fans ...
 
joemish said:
Your stubbornness is part of your problem. drilling holes should never be done.
Use a temperature gun on your temperature sending unit where it screws in the block to see if your gauge is showing the correct temperature.
I had the same problem. put in high performance water pump, a 3 core Champion Radiator plus new temp sending unit, took out the electric fans and went from 200-220 to a solid 190 at any speed. a shroud and the mechanical fan are part of the equation.
Click to expand...


BINGO!
 
66durgederp said:
Alright, I'm about at my wit's end with this thing.
Here's the details:
Initial build: 66 dart, MRL 408, ripped off 532 HP and 544ft lbs on the dyno. 11:1 static compression. Aluminum heads. Standard 8 vane Mopar water pump NON shrouded impeller. New Northern radiator PN 205152 26" core, 2 rows of 1" tubes. Spal 10" fans with northern radiator matching shroud. 803 CFM each. 35 degrees timing all in, 91 non ethanol fuel. Standard stant 180 degree thermostat with 2, 3/16" holes drilled in it. Standard bypass hose IS in place. TTI ceramic coated headers AND thermal interior barrier. Stock fender wells (uncut) stock valance in place.

Problem: runs like a scalded dog, but ALWAYS runs at 200-215. never crapped coolant on the ground, doesnt seem to ping (that I can hear). I run Schaeffer's 10W-30 for what it's worth.

What I tried to help the situation, in order.

New flowkooler water pump AND 180* Robert Shaw thermostat with Mopar performance silicone bypass hose. No change.

Cut off the dimples on the shroud and installed rubber flaps. No change.

Chooched down the timing to 32*, no change.

Pulled plugs, changed from champions to NGKs - they looked fantastic color wise and the color change on the ground electrode was dead nuts center on the bend, indicating the timing and flame front/kernel is where it needs to be. No change

Header tube temps are consistent. Within 10-15 degrees variation. 310-325 degrees after a spirited drive. They are NOT wrapped, nor will they ever be.

Chopped a hole in the hood - no change. (I'm installing a scoop later anyway)

The lower hose is NOT collapsing. I confirmed with a go-pro under the hood while driving.

I'm running a stant 16 psi cap with a 2 quart overflow tank.

This friggin thing runs at 200-220 (220 is below 25mph putting around) all the time, putting through town, romping down the highway at 90+, doesn't change much. Might see the occasional 190* but as soon as I drop to cruising speed, boom! 200-210. If I let it sit and idle for 15+ minutes, hood open or closed, it absolutely will not budge below 200-205. Ambient air temp doesn't change either. 50 degree evening or an 80+ degree afternoon, doesn't matter. Radiator fins are clean and clear. Id eat off of em, seriously. I've sealed off the radiator core to core support, and hood to core support, no change.

I know I'm going to get the "install a mechanical fan and be done" lecture. Not going to happen. I have 2.25" from water pump to radiator face. There's simply no room. Period.

I've confirmed my OE and VDO mechanical gauge readings with a thermal temp gun. Stat is 200-205 at idle. heads are 215-220.

So, any of you have any ideas? I'm at a complete loss over this thing. I've read numerous forums in general where people claim 210 isn't a death note, but for me, it just seems too damn hot.

Thanks a million.
Click to expand...
Hello I have a
 
I have a similar combo with the same problem and did a lot of the same changes. The fix was cheap I blocked the bypass hose. I used a pipe plug inside the hose. This forced the coolant to go through the radiator rather than the short path. Good luck I believe it will solve the problem.
 
update!

So i dumped some coin into the ol girl. did some things that needed to be done in the first place, and upgraded a couple items. Got myself 2 spal paddle blade fans, +600cfm over what I had before, controlled by a dakota digital pac-2750. one fan on at 185, second + trans cooler fans on at 195.

moved the radiator 2" forward on the top, modified the core support, and purchased a more compact yet efficient trans cooler.

I made a mount that bolted through the existing holes in the bumper to attach the trans cooler to, so now its lower, and the radiator face has more exposed surface area.

redid the shroud as well, with spal flappers now instead of some lowes special random rubber whatnots.

Lastly, because it was a "since you was" deal, I installed my LO23 scoop from AAR fiberglass.

today was the maiden voyage before I go beat the snot out of this thing at the streetcar takeover in Spokane WA this weekend. Its roughly 90 degrees outside and on the way into town, at approx 55mph, she held 190-195 all the way into town, and upon start up, held 185 consistently with no issues.

I have yet to go drive it later this evening to see how consistent it will be, but sofar there seems to be some slight improvement.
 
Ran the car this weekend for the first time at a track, and it did very well! temp was 95+ with roughly 20% humidity. Ran 195 consistently in the staging lines, i hit 200 once while hot-lapping it. id leave the line at 195 and by the top of the track it dumped to 185 and would hold it until i got to the staging lines once again. Ran a 12.41 @ 112 on 225-60-15 street tires. Im happier with it, so Im going to let er rip taterchip! Thanks everyone for the tips and ideas. much appreciated!
 
I live in Fort Lauderdale did someone say hot ,I had Glen Ray build a custom 22" radiator for my 470 its summer 92 degrees plus humid, the engine is new so im still breaking it in, sitting in traffic for 20 mins the hottest it got was 165
I use a stock shroud a 7 blade fan direct fit no viscous so the fan is always turning

20180411_181750 (1).jpg
 
Pitch that 180° thermostat for a high flow 160°, and get rid of the bypass. COMPLETELY.
Just stick a 3/4 pipe plug in the manifold, and tap the pump for 1/2 NPT and stick a plug in that too. NOW 100% of your heated water HAS to go through the radiator. Recirculating heated water is fine for grandma's scamp, in the snow. But is has no place on a hot street car.
Take it to the bank, I've been doing this for 20 yrs.
The pump can be modified too, but I don't know that I would recommend it on a crank driven pump..

BTW, you'll prob run 2-3 tenths quicker if you get your starting line temp down to about 140°.
 
My combo works great, and since a lot of people have issues, i thought i should post it. 408 stroker with a 235/249/107 comp Thumper cam, airgap intake, 1 5/8 stepped TTis, Mopar vacum advance dist with 14 initial and 30 total with EQ heads, 504 hp, 3.55 gears, auto with a tight ten inch converter.
I cut the radiator opening extensivelyly to allow a 26 in 3 core Champion radiater to fit, and modified the radiator core support to move the radiator away from the fan as far as possible so i could use a clutchfan with seven blades, no shroud. I ended up with 1/2 inch fan to rad clearance. It took removing a lot of sheetmetal from around the rad, and i had to weld in flat sheet metal for mounting the radiator further forward. Regular bypass hose in place, a good water pump, but underdriven about 20 percent by polished aftermarket pulleys.
What i ended up with is a system that runs at 160 with a thermostat in place, won't go over 170 to 175 on a good gauge no matter how hard i drive it. I hope this helps someone out there.
 
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