Viscous Fan VS 7 Blade Fan

-
jefflock

jefflock

69 Dart 408 10.08 best pass so far
FABO Gold Member
Joined
May 18, 2006
Messages
3,515
Reaction score
110
Location
Kansas
I'm still struggling with my 340 Dart wanting to run hot. It currently has a new 3 core 22" rad, new NAPA water pump, 180 degree motor rad thermostat. It is a new rebuild using the same cam, pistons, heads and intake from before. As suggested I bumped the timing up from 10 BTC to 15 BTC. I did install a 750 Holley vac sec with a proform main body. This replaces a 650 DP.
Currently I'm running a 7 blade fan without clutch and no shroud. Will a viscous 5 blade fan cool better? The reason I'm wondering is because I want to purchase the repo shroud and viscous fan from Mancini. They state the fan is 15" in dia. My current 7 blade is about 18". So I'm guessing the repro shroud will only work with a 15" fan. I've tried making a shroud out of metal. But the fan sticks up above and below the core making it difficult to build. I'm sorry this is so long winded. Thanks Jeff
 
Does it overheat when idling or cruising down the highway? Are you using the stock gauge as an indicator or an aftermarket gauge?

Chuck
 
You can save yourself a few bucks by grabbing a fan from the bone yard and buying a cluch at the local parts store for $30.

All of the fans that mount on a clutch regardless of whether they are Mopar, GM or Ford use the same hub and bolt circle so just find one that is the proper OD.

I am using one from a buick regal and grabbed a shroud from a \6 car (Mount it upsdide down for the proiper ofset) on my Barracuda.
 
Did it over heat before you switched to the Proform body ?

I had a carb I built using a 650 double pumper and Proform body that went extreamly lean on the dyno. The problem was with the 650s metering blocks not working correctly with the Proform body. We swapped to Proform metering blocks and all was well.
 
As far as a mech. fan goes, I have found the MP Viscous fan to be the coolest running fan with the most wind under the hood. You should use it with a shroud. This is important.

Otherwise, I have found electric fans to do very well and reduce parasidic (sp) loss. The engine works less and makes more power.

Coolent level and proper mixture is dang near everything along with actual rad. flow & engine timing.
 
To answer some of the questions. Sitting there ildling it gets hot going down the road isn't as bad. I'm using both the stock and an aftermarket guage to monitor it. Adam, I have never used the carb before. I do have a kit for secondary side. I think I'll go install it. Rumblefish that is what I wanted to hear before I laid out the bucks. Thanks Jeff
 
Mine was fin at idle but at wide open it went so lean the motor wouldnt even rev. My motor is a little more built then your however. I actually ran it on my other 340 and it all ways seemed flat and didnt want to rev well. I never really thought much of it at the time.
 
find a dart or valiant or scamp 69-72 w/ 318 and ac. the fan will be the same as a 340 fan and it will have a thermostatic clutch. grab the shroud while you are there as it is going to be a 22 inch radiator on those cars. this should help alot.
 
Your welcome.
Also the viscous fan is a weird, of balance looking 5 blade fan.
 
If you're getting hot in slow moving traffic and sitting still, you need a factory shroud pronto. Also, make sure you have the seal that attaches to the hood that seals along the top of the radiator core support.
 
Get the Viscious fan.....I was going through similar problems. My car would heat up in traffic and then take a while to cool down even on the highway. I had an aluminum radiator, 180* T-stat and a Napa water pump. I was running two electric fans.....it would get up to 210 or higher in traffic. I put on the 5-blade Mopar Viscious fan....car never gets over 200* sitting in traffic with 90*+ temps and high humidity. I don't even have a shroud on it. Oh and the thing about losing power going to the mach fan over the electric.....it's so minute with the Viscious Fan I have yet to tell the difference other than the temp gauge rides the thermostat now.
 
Okay, I ordered the shroud and fan set up. They should be here Friday. I'll install them and the metering block kit for my 750 Holley vac secondary carb. I hope this will take care of the problem.
How important is that radiator to hood seal? Someone removed it and the cowl seal.
I'm going to a 3 day swap meet this weekend in Springfield Missouri. Hopefully there will be some Mopar parts there.
I'll post when I get them installed to let everyone know their effect on my cooling problem.
Thanks Jeff
 
Dusterdon made a good point with the core support to hood seal, you can lose a lot of air flow there. I run the seal even with my fiberglass hood.
 
My fan and shroud arrived by UPS Friday. I installed the fan and tried to install the shroud. I had forgotten the guy I purchased the radiator from told me the stock shroud would not fit. The upper inlet will need to be moved. Anyway I modified the metal shroud I made out of stainless to fit this fan and radiator. Man does it move a lot of air. The cooling system is working perfectly now. The temp gauge hangs right around 180 to 190. Now I need to decide whether to keep the shroud or send it back. Anyone interested in it? $150 shipped to your door in the lower 48. Thanks guys for all your help and suggestions. Jeff:burnout:
 
I only run one of those universal shrouds....I only have that on there so the top of the fan blades are covered for safety.
 
There are some 80's 318 pickups that have small enough diameter fans to fit inside of the fan shroud on an early 70's radiator. That's what I have on my car and it works great. Definately gained power over the car's stock 7 blade fixed fan
 
You must log in or register to reply here.
-

Back
Top