340 demon overheating problem

-
MOPAR487

MOPAR487

Active Member
Joined
Dec 31, 2008
Messages
36
Reaction score
0
i HAVE A 340 DEMON WITH A BUILT 340/450 HP 12.5 TO 1 COMPRESSION. aM RUNNING STOCK RADIATOR W ELECTRIC FAN, hAVE IN ITV NOW A165 DEGREE THERMOSTAT. tHEC CAR WILL RUN 220 DEGREES ON A 60 DEGREE DAY. THINKING ABOUT ADDING A FLEXOLITE OR CLUTH FAN TO ASSIST IN COOLING THE CAR. THE ELECTRIC FAN IS APPROX. 18 INCHES ACROSS. IT PUSHES AIR THROUGH THE RADIATOR . ANY SUGGESTIONS?
 
What was the car origionally? 340?? if its bored out to a 408 or bigger with all that HP then you need a bigger radiator.
 
My 360 had similar issues with a pusher fan.I bought a SPAL 16" fan and installed it as a puller and I ran a Moroso electric w/p. All this with a summit 22" radiator. It got down to 200 with the thermostat so I gutted it and used it as a restrictor. I also used that purple ice additive and the temps came down to 190. In traffic, on a hot day, there was no way to keep it cool after about 30 minutes. But at the strip it worked well. Now with the 318 I am running, I put a 160 stant superstat in it with everything else the same and it runs 170. Go figure!
 
22" original size will work fine! i have about 420hp with 11.2 to 1, 4 core rad, 5 blade 18.5" fan out of a mid 80's diplomat, clutch from Napa ask for a 78 pontiac sunbird one, with a 305ci, an original shroud, plus i run a 50/50 mix. I tried the elec fans, on the street MOST stink.
 
what else could he do to cool it? I dont think a scoop adding air would even be a spit in the wind. you could always move north :D
 
I have a 71 Demon 360 with 10.5 compression runs on 92 octane I run 11.80 113 mph with a factory rad with 7 blade fan, a/c (8 blade) water pump, with anti cavity shield on water pump with factory pully's and the hightest it gets is 200 on a 75 degree day. It really depends on how the cam is degreed in.
 
I'm a believer of the MP 5 blade fan kit. I have one in my 68 dart and it keeps the temps down. 180 thermostat & 50/50 mix with home made shroud
 
I had ovrheating issues w/my 69 Dart... would push 210-220 stopped in traffic

Here is what I changed/added:

radiator re-cored x3
correct shroud
Mopar vicous clutch fan
new radiator cap
new water pump

currently have 165 thermostat- it usually sits around 165-170 and doesnt go over 180 in dead stop traffic.
gonna wait for summer (FLA) and see if I can go up to 180 to let it run a little warmer.

Dont know if water pump/cap were needed- but replaced anyway.
Seems like the shroud/Viscous fan probably made the difference

Good luck!
 
MOPAR487 said:
i HAVE A 340 DEMON WITH A BUILT 340/450 HP 12.5 TO 1 COMPRESSION. aM RUNNING STOCK RADIATOR W ELECTRIC FAN, hAVE IN ITV NOW A165 DEGREE THERMOSTAT. tHEC CAR WILL RUN 220 DEGREES ON A 60 DEGREE DAY. THINKING ABOUT ADDING A FLEXOLITE OR CLUTH FAN TO ASSIST IN COOLING THE CAR. THE ELECTRIC FAN IS APPROX. 18 INCHES ACROSS. IT PUSHES AIR THROUGH THE RADIATOR . ANY SUGGESTIONS?
Click to expand...
I run a HHR fan and Meziere 35 gpm electric water pump...Northern 2 row with 1 inch tubes...this is what mine reads at 96 degrees and hammering on it...I have since stepped up to a PRP-6660 50 gpm water pump but still yet to drive it...

IMG00568-20100731-2110.jpg
 
bremereric said:
I run a HHR fan and Meziere 35 gpm electric water pump...Northern 2 row with 1 inch tubes...this is what mine reads at 96 degrees and hammering on it...I have since stepped up to a PRP-6660 50 gpm water pump but still yet to drive it...

IMG00568-20100731-2110.jpg
Click to expand...

Erik, did you like the Meziere pump? I have a Moroso drive on my stock water pump, but I don't think that even with the optional oversize pulley, that it turns fast enough. I am looking to upgrade.
 
I run a stock 318 2 core rad,7 blade fan,no shroud,no thermostat in my 66 Dart with a 408.It takes about 4 passes running 11.20@118 to get to 180,starting at 140.8)
 
What are you running for a water pump? What do you have for pulleys?

Stock radiator in good shape?
 
go to a bigger rad or put a shroud on the one you got to pull all the air it can and give the rad a good flush will help should nerver run over 210 or you will score you pistonts hope this helps
 
You must log in or register to reply here.
-

Back
Top