[70GS455]

That means you must wear Suspenders and a Belt to keep your pants from falling down !? >



The EFan is Blocking Air Flow whether it is Running or Not and if it is in Front of the Rad Core or after the Rad Core/Engine side

and thus can be the reason the Coolant in the Rad Core is not getting Max Air Flow to allow Maximum cooling down of the Coolant

Well actually now that you mention it.... =D

If it is blocking air flow, then there are many tens of thousands of late model trucks that are doing it wrong and we need to tell them to knock it off


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[japete92]

It is on the list as an option

As you decide, consider the added noise fans make as they move more air. It's caused by turbulence.

Ever notice how a household room fans gets louder as it spins faster and moves more air? The car's fan will do the same. The fan clutch will help because it de-clutches the fan when not needed. And typically (I do not know all the attributes of all the clutches) de-clutches at high rpm.

W/o a clutch, the 'high' volume fan will likely not be 'noisy' enough at idle to be a problem. Higher rpm? It will be noisier. The owner's tolerance is the deciding factor.

GM did the system (all factors/parts) design many years ago. The farther one departs from that design, the more they becomes the 'designer'. Or, 'design' via trial and error (can get $$$). Risky?

Simply information for you to give whatever weight you choose.

Pete

 

[70GS455]

So I was looking at these two fans:



https://www.summitracing.com/dom/parts/der-17119



Derale 19" (Derale website lists it at 19.25"). I talked to Derale and they said it has a 27 degree pitch and the blades are relatively flat. Derale said the pitch is more important that the curvature in the blade.



https://www.summitracing.com/parts/flx-6719



Flex A Lite 19.25". I talked with Flex A Lite and they say they run a 32 degree pitch. They also said the difference between Steel and Aluminum is about 1-2 lbs.



The problem is availability. Nobody has the 19 inch fans in stock. Waiting a month is basically useless as by then it will too cold to matter.

Go to your local boneyards and try to fiind a GM 7-blade 19.5" fan off of 70's to 80's trucks and big cars

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[temp2c]

Sorry, but as a member of "Team Camaro and Team Chevelle" I have learned that there is nothing better than the factory setup :

1) a 7 blade fan with the correct fan clutch

2) the factory shroud with the fan tips inserted about 1/2" into the shroud

3) the best way to improve on the factory setup is to use an aluminum radiator with two 1-1/4" wide passes

The factory had the best setup. Copy the fan, clutch and shroud. Improving the radiator is the correct way to go.

Beth, some people like to complicate. They like there engine compartment to be an ego soothing mass of wires, solenoid's and lights.. Where people like us prefer a clean, uncluttered, efficient look that actually works... We're humble enough to admit the factory DID know what they were doing and had the money to do the R&D..

 

[.183953]

Not me. I would love to go Electric fans and a different aluminum rad. I just cant justify the thousands of dollars it would cost to get what I want right now.

Trust me you don't have to spend that much!
I would just add electric fans to your radiator that you currently have.

 

[-SS454-]

Beth, some people like to complicate. They like there engine compartment to be an ego soothing mass of wires, solenoid's and lights.. Where people like us prefer a clean, uncluttered, efficient look that actually works... We're humble enough to admit the factory DID know what they were doing and had the money to do the R&D..

That almost sounds like a jab to anyone that does something different than factory. haha.

 

[Chris27]

Beth, some people like to complicate. They like there engine compartment to be an ego soothing mass of wires, solenoid's and lights.. Where people like us prefer a clean, uncluttered, efficient look that actually works... We're humble enough to admit the factory DID know what they were doing and had the money to do the R&D..

Some of us started with little more than a frame and a shell. If I had a stock cooling system with a shroud and clutch fan, I would probably leave it alone. For me, it was cheaper and easier to go with an aftermarket aluminum rad and a Windstar fan. No argument that engine driven clutch fans work. Look at most diesel trucks designed for towing and you'll see large engine driven clutch fans. But when you start modifying things, that GM designed 50 year old technology may not be enough.

 

[Kirk's67SS]

Sorry, but as a member of "Team Camaro and Team Chevelle" I have learned that there is nothing better than the factory setup :
1) a 7 blade fan with the correct fan clutch
2) the factory shroud with the fan tips inserted about 1/2" into the shroud
3) the best way to improve on the factory setup is to use an aluminum radiator with two 1-1/4" wide passes
The factory had the best setup. Copy the fan, clutch and shroud. Improving the radiator is the correct way to go.

The only problem is that some of us 67 and prior Chevelle Owners do not have the Room/Space
in our Engine Bay for # 1 & # 2 above

I went with a Alumitech DF Rad from Don with 2 Rows of 1.25" Wide Tubes Core that is only 23.5" Wide x 16" Hi
and a Dual 11" Efan/Shroud Unit as it would fit into the Limited Room/Space I have in Front of my BBC
and that is even after I had the engine moved back towards the Firewall

As you can see if there was one big Efan in the Middle the Emotor
would not fit in as the Pulley Nose would not allow it to
Engine runs at 180* or less on the Hwy with only 1 Efan ON or none on
and 180* in city Traffic, plus Back to Back Runs down the 1/4, with 2 Efans on

That is why the 68 and later Chevelle Owners have it so easy/lucky to fit in Bigger/Wider Core Rads
with either the Stock Setup or some really Big Efans/Shrouds

 

[Lew540]

Kirk you have lots of clearance. Here is a clearance shot for us early model guys with long water pumps. I had to cut the fan cage to get the pulley to fit and so I had room to even get the belts off.

 

[Kirk's67SS]

Beth, some people like to complicate. They like there engine compartment to be an ego soothing mass of wires, solenoid's and lights.. Where people like us prefer a clean, uncluttered, efficient look that actually works... We're humble enough to admit the factory DID know what they were doing and had the money to do the R&D..

I disagree with you Jeff

The Auto Makers back then only did what they knew of from before
they did not have the Technology/Knowledge there is/was after 50 years later or less
and I am sure that they did not spend a lot on R&D as it took 80+ years later,
1910s to the 1990s to start looking at other ways than the Mech Fan/Shroud to keep the Coolant
from the Engine to the Rad and Back again Cooled Down enough
so that the Engine could run efficiently and not Blowup from Over heating

As for all the Wires and Lights I do not think my Engine Bay is Over Crowded
with any more Wires than is needed to run my Car's Engine Efficiently

Maybe to many Ram Air Tubing and the Fuel Regulator for the EFI Fuel Tank/Pump though

Also with Limited Room/Space in the Engine Bay I had to go Efans/Shroud as a Stock Setup would not fit in

 

[Kirk's67SS]

Kirk you have lots of clearance. Here is a clearance shot for us early model guys with long water pumps. I had to cut the fan cage to get the pulley to fit and so I had room to even get the belts off.

Lew it is because your Belts are to Wide ! > :thumbsup:

 

[bowtie0069]

I haven't read through all the answers but, check the ratio of your pulleys. I put a small block in a Rambler wagon project a few years ago. This engine had previously been the hottest running engine I've ever owned. Because of the space I had in the car I used a street rod style high mount alternator and had to dig thru my pile of pulleys to come up with something that fit. I ended up with a pulley combo that over drove the water pump about 1.35-1. The car had an aluminum 2 row radiator for a an early Chevelle, a 17" stainless flex fan(not my first choice ever) no shroud, about 2" between fan and core. On a 100 degree day it idled about 40 minutes and never went over 147° I had to install a 180° thermostat to get it up to temp. On the highway at 75-80 it would get just over 180, then drop back down as the thermostat did it's job. When this engine was in my Nova it was hard to keep it under 200° using the same setup that cools my 600+H.P. 410" small block just fine.

 

[-SS454-]

I have been thinking about maybe a smaller water pump pulley to spin the fan faster.

 

[lucifershammer]

On my '72 big block, I have AC - so I have the 3 groove factory lower pulley, and the outer groove is much larger than the inner two, which causes both the water pump and alternator to spin faster.

Which pulleys do you have on it right now? Do you know the diameters? I can measure mine and compare if you like.

I have been thinking about maybe a smaller water pump pulley to spin the fan faster.

 

[-SS454-]

On my '72 big block, I have AC - so I have the 3 groove factory lower pulley, and the outer groove is much larger than the inner two, which causes both the water pump and alternator to spin faster.

Which pulleys do you have on it right now? Do you know the diameters? I can measure mine and compare if you like.

I checked the pulleys and the water pump and crank pulley are both aluminum. The water pump appears to be 6 inches and the crank pulley is 5.5 inches.

 

[Not2Fast]

In your "walk around" video below, you state how the car never gets hot....so, what did you change between then and when you created this thread?

https://youtu.be/2zpcRxu4Cp0?t=312

 

[-SS454-]

In your "walk around" video below, you state how the car never gets hot....so, what did you change between then and when you created this thread?

https://youtu.be/2zpcRxu4Cp0?t=312

I never sat in traffic for long periods of time. Last year was the first time it happened in a traffic jam, bumper to bumper, mostly stopped, but traveling less than 5 mph for about an hour. I kept pulling over when it got around 215F.

Second time was recently during the car cruise, same kinda deal. About an hour of moving extremely slow in neighborhoods.

So I assume it's never been sufficient at idle/slow slow speeds, I just got in that situation. It cools really well as I stated in this thread when moving (20+ mph).

 

[lucifershammer]

Ah! There you go, now you might be on to something.

You are actually under driving the water pump as the crank pulley is smaller than the water pump pulley, so I can see how at idle it just isn't moving enough water and/or turning the fan fast enough.

In my factory setup, the crank pulley diameter is about 7.75" and the water pump pulley is about 6.25".

I checked the pulleys and the water pump and crank pulley are both aluminum. The water pump appears to be 6 inches and the crank pulley is 5.5 inches.

 

[swampy 6x6]

HI
6.25 water pump and 6.25 crank
factory is 7 inch crank which can be run with 6.25 w/pump
high flow w/pump with either of above

5.5 inch ,,crank or/both w/pump pulley ,,many on the web report issues with this combo

 

[japete92]

I never sat in traffic for long periods of time. Last year was the first time it happened in a traffic jam, bumper to bumper, mostly stopped, but traveling less than 5 mph for about an hour. I kept pulling over when it got around 215F.

Second time was recently during the car cruise, same kinda deal. About an hour of moving extremely slow in neighborhoods.

So I assume it's never been sufficient at idle/slow slow speeds, I just got in that situation. It cools really well as I stated in this thread when moving (20+ mph).

Very first post you said 240F. Now 215F. Please explain?

Driving (basically idling) for a HOUR in traffic (behind all the other cars emitting exhaust, and blocking air flow) is extremely hard on the cooling system. There is )in my opinion) a HUGE difference between getting 215F and 240F.

I would accept 215F (during the infrequent occurrence), not 240F.

Wanna spin the fan faster in extreme load conditions for free? Push in the clutch and raise the rpm with your right foot.

Info:

https://durathermfluids.com/pdf/techpapers/pressure-boiling-point.pdf

I don't think I can be any more helpful. Sorry.

Pete