Fans, Shrouds and Other Things

[wedg2go]

My 440 is running a genuine stock Chrysler radiator - 22" wide (3) core - with a stock (6) wide blade fan and stock shroud.

I am entertaining the idea of going with (2) 10" electric fans that will pull 2100 cfm. From what I read, this is enough to handle 800 hp. Not really a fan of electric fans, but if it can be a solution to this possible heat soak, I am experiencing, when idling or slow speeds then Mmmm?

At this point in time the radiator might be another thing altogether. I am considering having it "rodded out" just to verify if it's gunked up or not (good money after bad intentions?).

This morning I hit upon the idea of needing to know what a stock fan will pull - cfm - at an idle. After googling it I found page after page about cfm rating on electric fans, but nada on a typical stock fan. Anyone have any ideas on this? If the electric fans are not enough to add a substantial difference -cfm at an idle - then my next thought would be adding a clutch setup to my stock six blade fan.

Which brings me to this question: Can having a wild, loppy idle cause eventual problems with a clutch fan? I know! Stupid question, but I had to ask.

 

[74Scooter]

For a decent built v8 you will likely need to be pulling 3000 cfm or better. The good fans that can accomplish this kind of flow do it with quite a bit of noise and draw quite a few amps which will put a strain on your charging system if not up to the task.

I'd look into the radiator first and add a good clutch fan, if you have the space.

Not sure if you need to worry about the clutch fan with a lopey cam... worst case you might need to swap it out in 10 years instead of 20??

 

[Cuda Hunter]

make the radiator a 26"
Install a clutch fan
skip the electric fans
Install an electric fuel pump. Heat soak will go away. I've had that problem on multiple cars up here in this altitude and the electric pump fix's it. Fix's it without the other items.
Just go buy one and install it for shits and giggles. They are relatively inexpensive and you can remove it if you decide you don't like it and it doesn't fix your problem.

 

[Chryco Psycho]

I agree , electric fans are a step backwards , a 6 or 7 blade clutch fan with a shroud will do a better job Always !

 

[moparleo]

You never said anything about your engine other than a 440. Stock ? If not, details are always necessary to help to cure a problem. Rod out the radiator ? Is it an old, unmaintained radiator ? Rest of the cooling system age and condition. I agree a 26" radiator and 6- blade thermo-fan clutch and the rest of the cooling system gone through. It is a "system" and rarely does one item determine how efficient it performs.

 

[wedg2go]

You’re right moparleo! Important information about the engine was left out. Apologies for creating a vague post.

The 440: It's bored .060 over with Stage III Mopar Performance heads * Edelbrock Chrysler Six Pack intake manifold * Date code correct Holley Carburetors * MSD Ignition * Comp Roller Cam Xtreme Energy 236/242 Hydraulic Roller Cam* Milodon 7 quart Pro-Touring oil pan * Hooker Super Competition headers.

The current radiator, is a good ole’ copper, 3 core Chrysler unit that is in excellent shape. 16lbs cap and a billet recovery. It runs on a stock six blade fan within a factory stock shroud.

My immediate thought was the .060 over bore creating hot spots since this is what I observe mostly from other 440s running on the “warm side” that have been bored over. A discussion up for grabs.

The weird thing here is, the cooling system never boiled over (it’s never over-heated). I run a mechanical gauge and have seen it hit 212 at slow speeds, but no higher. Even after the engine is shut-off. I recently replaced the thermostat with a 180, but it’s the exact same story as running a 195 (I checked three times if there was a chance I installed the 195 back and…Nope!). Strange? Yes! I did “burb the cooling system” in case anyone is wondering. So zero air bubbles and coolant is filled to the brim.

I have to agree with Cuda Hunter hinting towards my vapor lock problem. A electric fuel pump will be installed this winter. The question is, which electric fuel pump is a good one that runs around 6lbs? More “Buzzing” coming from the back, as I am already running a vacuum pump for the brakes. It will sound like an Pissed-Off SuperBee going through town! LOL! As far as installing a 26” wide radiator?…What needs to de done to replace that 22” wide unit? I’m open for it, but I just don’t see how it would mount when the current bolt hole mounts are 24 1/4” apart?

I am currently tanked-up with some non-ethanol fuel, but haven’t had the chance to give it a really good try.

Addendum edit: The clutch fan is coming! Regardless of it's service length. I just don't see putting that much strain on the alternator after installing an electric fuel pump.

 

[74Scooter]

^^ Might want to consider this:

Holley 12-318 Holley 255 LPH OE Style EFI Fuel Tank Modules

Looking at this setup for if I go EFI in the future. In tank and does not require an additional return line to be installed... the pump self regulates in the tank. Pretty clean setup for an in tank pump solution.

 

[Avalanche]

make the radiator a 26"
Install a clutch fan
skip the electric fans
Install an electric fuel pump. Heat soak will go away. I've had that problem on multiple cars up here in this altitude and the electric pump fix's it. Fix's it without the other items.
Just go buy one and install it for shits and giggles. They are relatively inexpensive and you can remove it if you decide you don't like it and it doesn't fix your problem.

How does an electric fuel pump stop heat soak. If you have a carb, won't the fuel boil over regardless of electric or mechanical.
The fuel is still in the floats of the carb.
Can you explain why it solves the problem. I'm interested in doing a swap, just don't understand the logic.

 

[Cuda Hunter]

Keeps pressure in the line, pushing it to the carb instead of drawing it.
I've never had this issue with any of my pontiacs, but seems a majority of the mopars I've owned have the problem. It's fixed more than one for me.
Sure I can replace the entire cooling system as well, and have. Still had the problem, electrified it and the problem went away.
I'm no mechanic, so maybe I'm just wrong.

 

[Cuda Hunter]

mount the pump on a rubber pad, use nylon washers on the rear of the attaching bolts. This will keep the inside buzz down a ton.

 

[budascuda]

Can having a wild, loppy idle cause eventual problems with a clutch fan?

wedbe2go, I think you have identified at least one of the problems!

The way your cam runs your engine, also makes your fan clutch to slip!

Do you happen to have a hand held digital tachometer? Even though It may not be THE problem, it would be nice to know.

 

[wedg2go]

Can having a wild, loppy idle cause eventual problems with a clutch fan?

wedbe2go, I think you have identified at least one of the problems!

The way your cam runs your engine, also makes your fan clutch to slip!

Do you happen to have a hand held digital tachometer? Even though It may not be THE problem, it would be nice to know.

budascuda - silly of me to over think the lop, of this engine, is a little like starting - stopping and that I have "Never" had the opportunity to ever own/drive any ride, through all the years of car ownership, with a fan clutch. So, it's a little bit of a mystery to me and for what it's worth I'm really not sure what I'm getting into when I go and blindly install a fan clutch. I don't even understand the principal of a fan clutch. Dumb question on my part and hoping it becomes a smart move, on my part, to install one! I'm just tired and embarrassed, stranded on any given street corner in some nameless town in Colorado and looking for a little help here.

Unfortunately, no digital tach. LOL!

With that said, let's called this thread "Solved" and I'll dip into the bank funds and toss everything at it that has been mentioned here. If it still craps out, I just might take up this offer here > WTB - Wanting Classic Mopars

Everyone have a good one and thanks!

 

[DaveBob]

My 440 is running a genuine stock Chrysler radiator - 22" wide (3) core - with a stock (6) wide blade fan and stock shroud.

I am entertaining the idea of going with (2) 10" electric fans that will pull 2100 cfm. From what I read, this is enough to handle 800 hp. Not really a fan of electric fans, but if it can be a solution to this possible heat soak, I am experiencing, when idling or slow speeds then Mmmm?

At this point in time the radiator might be another thing altogether. I am considering having it "rodded out" just to verify if it's gunked up or not (good money after bad intentions?).

This morning I hit upon the idea of needing to know what a stock fan will pull - cfm - at an idle. After googling it I found page after page about cfm rating on electric fans, but nada on a typical stock fan. Anyone have any ideas on this? If the electric fans are not enough to add a substantial difference -cfm at an idle - then my next thought would be adding a clutch setup to my stock six blade fan.

Which brings me to this question: Can having a wild, loppy idle cause eventual problems with a clutch fan? I know! Stupid question, but I had to ask.

I cured my vapor lock problem, but kept my mechanical fuel pump. My setup starts with the installation of a fuel pick up from Mancini Racing, that allows a 3/8" supply line and a 1/4" return line. Stainless lines from Inline Tube connect between the tank and a vapor separator fuel filter from a GM application. Earl's Supply insulation covers the fuel lines near the motor, and a 3/8" thick phenolic spacer is under the carb.

 

[CMC]

I've got a 26" 4 core for my motor.
16" electric fan?? do you think 1 would do the trick?


Culinary Zest Dressing & Marinade - 2 (TWO 16 oz Bottles) w/ FREE Key chain LIGHT GIFT Pack FREE SHIPPING

 

[DaveBob]

I haven't had enough experience with electric fans to answer that. That said, heat soak is usually a condition that occurs when a hot engine is shut off. The carb, and the fuel it contains, (and sometime the lines and filter and the fuel they contain, especially if they are sitting right above a hot intake manifold) have a chance to heat soak. Then, depending on the temperature, soak time, and heat of vaporization properties of the fuel, you may have vapor where liquid should be and the engine is hard to start and keep running initially. Vapor lock happens while the engine is running and a mix of vapor and fuel is entering the carb. The phenolic spacer helps with heat soak in the carb. The placement of the filter away from the top of the motor and insulation on the fuel lines helps with any heat soak and vapor formation which may occur in the filter and lines. The vapor separator and return line prevents vapor lock on the inlet side of the carb.

Although not necessarily applicable to your problem, another aspect of engine cooling often ignored is glycol concentration and ignition advance. Although some antifreeze is necessary in the cooling system for cold weather, and as a corrosion inhibitor and water pump lube, the higher the concentration, the worse the cooling. Water is 1.5 times better than antifreeze at absorbing heat. 100% antifreeze is the worst, but even 50% is overkill. I live where temperatures don't ever get below freezing, so I run about a 35-40% concentration of antifreeze. The rest is distilled water. And, I mix the two before pouring it into the radiator. Also, engines run cooler with advance just shy of detonation. Otherwise, the last of the burn is only contributing heat and not power. Your total mechanical advance should be in the mid to upper 30 degree range. I run about 10 degrees initial to get 35 degrees total mechanical. At cruise, with full vacuum, the total is about 50 degrees advance. Hand-in-hand with ignition advance is octane levels. In short, run the lowest octane that won't detonate at the advance you need. Otherwise, like insufficient advance, the last of the burn is contributing only to heat and not power. Also, check the heat of vaporization properties of the fuel you are using. A fuel with low heat of vaporization properties needs to absorb very little heat to turn to vapor. A lot of the aviation fuel seems to have a low heat of vaporization, which allows cold starts without a choke, which I have heard that aircraft do not use. I used to use aviation fuel to boost octane, but now use race fuel for cars, such as VP racing fuels C12, which has high heat of vaporization properties. It's expensive, but with my mild motor, I only need to mix a little C12 with pump gas to get the results I need.

Lastly, check your float levels. Yes, I know you are running three Holley two barrels and I am running a Cater four barrel, but some things may still apply. It's not necessarily an apples to oranges comparison. Although you can get Carter four barrels to run at nearly an angle in pitch and roll, if the float levels are too high, it will run poorly on the gentle slope of a driveway, if left idling for awhile. When you set float level, the higher the number, the lower the float level, since you set it upside down. For my application, the factory manual said 7/32 (.219). At that level, it ran horrible if left idling in the driveway. I lowered the float level by using a 5/16 (.313) setting and then a 3/8 (.375) setting. I also dialed in lots of float drop, since it's not a critical setting, but allows the needle valves to open further, as needed.

The electric fuel pumps may prevent vapor lock by providing a more constant (not pulsing like a mechanical pump), and perhaps slightly higher fuel pressure, preventing the formation of vapor. Think high school physics. A beaker of water in a vacuum chamber will boil at room temperature and turn to vapor, when the ambient pressure is sufficiently low.

 

[budascuda]

Very very helpful, several important points regarding the evolution of heat and heat control....
Thanks.

 

[Steve340]

Vapour lock occurs because the liquid fuel in the fuel line turns to a gas when heated enough. This causes a rise in internal pressure in the fuel line and sometimes I guess the "bubble" in the fuel line will get right back to the pump. The pump is designed to pump fluid not fluid in a gaseous state. This apply's to any type of fuel pump. Or the "bubble" gets big enough the fuel pump does not pump enough fuel volume to push the bubble up and out. Anyway the end result is no liquid fuel can get into the carburettor or fuel injection and the engine stops.
Heat soak is a totally different thing as DaveBob said.