danglerb

My clutch fan still sort of works, and the Bosch AC pusher fan keeps temps below the top line when it doesn't work, so I am not doing this in a rush, but in the next month an electric fan is replacing the clutch fan. Otherwise the cooling system is in very good shape with radiator and hoses about 3 years old, overflow just replaced.

I've been looking at electric radiator fans for about a year or so, and have developed some opinions on whats good, better, and best, and plan to go with best. Delta Control for the PWM fan controller, and one of the top OEM fans, the Lincoln Mark VIII motorcraft RF64 which is a dual speed 4300 cfm 18" blade fan rated at 35 amps (but the PWM should keep it tame enough for my 90 amp alt.).

All comments welcome, but my main questions are about how the fan should be mounted. I measured the Behr radiator, its 25" across the top, with a tab at 7 3/4" and 17 1/2", and the shroud has an opening about 20" across. The RF 64 comes with its own 22" shroud. Maybe once the clutch fan is off and/or the factory shrouds the way to proceed will be more obvious.

Where should I be tapping in to get the power, which will have its own 35 to 40 amp fuse, plus the PWM controller is internally current limited. Starter post is one place I have heard suggested.

Thanks in advance for any help, and I will post picts and progress as I make it.

http://www.dccontrol.com/

Paul D

Danglerb - I used the 'jump-start' post when I converted mine to electric fans. The post will unbolt to allow a ring lug type connector to slip over the bolt very nicely. Make sure you use at minimum 12AWG wire for your harness and make sure you use a fuse.

j.kenzie@sbcglobal.net

yep. 35 amps might need 10 gauge.

danglerb

Did any of you keep the AC pusher fan on the front side of the radiator? Cheap insurance I am thinking, but what an amp draw if both were on.

I am toying with the idea of removing my clutch fan, which seems to only work half the time anyway, and relying on the pusher AC fan and driving carefully or less or something until I get the new fan installed and working. It would sure make measuring stuff a lot easier. Sooner or later its going to have to come off, but maybe I will wait until its in the shop.

Imo000

I kept the AC fan with a 16" electric right up till the SC install. Then I had to dich it and use the electric only. You can do the smae thing too. Only have to cut and splice the power wire of the AC fan and keep the ground (brown) wire as is. The jumper post is where I and problaby everyone else used to get power to an electric fan. There really is no other suitable and convinient location for a positive source under the hood. I've installed a thermo switch but later learned that this is not necesarry cause the rad already had one built into it. So it should be a very simple setup. All you need it a realy that can handle 2 fans, inline fuse and wiring.

checkmate1996

Can you talk a little more about this? I was using a thermoswitch myself but was kind of a pain to adjust. Plus it kinds of looks fugly mounted on the electric fans. I think it would be a cleaner install to do what you suggested above. So as a recap, looking at the front of the radiator, while radiator is in car, in the lower right hand corner is the temp switch. You are suggesting tapping into that switch to kick on the fans as necessary?

danglerb

Not a Chevy, but 3.8 V6 Taurus from the early 90's, Mark VIII same period, Dodge Ram dual fans. I am talking to a Mustang guy right now about a brand new Mark VIII fan for $110 shipped, nice pliant plastic for trimming etc.

I also thought about the 87+ fans and shroud, but they aren't as good of fans as the later stuff from Ford with the Siemens motors.

The idea with the thermal switch is to use that to control a high amp relay, but that tends to swing the temperatures a bit, so I opted for a Delta Controls PWM box that uses a predictive algorithm to reduce the swing, and eliminate the huge starting current these fans have when switched on/off using a soft start. If it keeps the factory 90 amp alt happy its money well spent (fan should never need to run over 75% of full power, much lower amp draw).

RichS 1986928

Danglerb,

Thanks for this post, good info. I was looking at the electric fan Setup from 928 motorsports
but this looks better.
A few questions:
In your opinion why is the Mark VIII the best? There are a lot of options.

Which Delta control box did you decide on and where do you plan on mounting it?

Have you thought about tying the Fan control circuit into the ignition circuit to stop the
fan from running after the car is off?

jpitman2

I built my own brackets out of alloy angle, designed on a dead rad core I borrowed. To keep the top part of original shroud and air tubes to cleaner, I got a spare top piece, cut just enough off below the mounting holes to clear my fan mounts, amd now from the front you cant tell its not stock. I took main power from the hot post in front, but the relay switching power comes from a point only hot with key at accessory or run.
jp 83 Euro S AT 50k

checkmate1996

J,

That's exactly what I plan on doing. I'm glad you shared that. But why didn't you leverage the existing thermoswitch wiring going into the radiator?

danglerb

Chances are good it isn't going to "look better" 928MS makes a nice clean package, that might be the smart choice for many.

The Mark VIII is hands down the king of CFM, when you see one in person its a monster, 35 amps at full power, with a long track record as being "the" fan to use to fix your cooling problem. Lincoln is the auto industry reference for AC and cooling, and this is the fan from the top model. $400 if you buy it from Lincoln, $200 from discount auto suppliers, Motorcraft RF64, or $70 used off ebay, with no problems reported as long as the fan isn't noisy from junkyard damage or exposure.

The Taurus V6 3.8 fan is smaller and also popular, as is the Dodge RamCharger dual fan which has more clearance for a SC etc. I am not sure I would use any of these bigger fans with just a relay on my 83 with its 90 amp alt. The Delta control has slow start without the big surge from switching on at full power with a relay, and will only run the fan at full power when cooling requires it, which should be never even on the hottest day. AC setting is programmable with a default of 50%.

FK35 with the surge thing 1.5-KS $9.95, my install plan is to hand it to Greg. Pictures to follow in a few days unless it turns out more functional than pretty.

Delta is a one person company, he says 10 business days to ship, but gets very busy at times. I ordered on 1/4/07 and expect it in todays mail. The good side of it being just Mr. Baskin is that tech support is also the chief engineer etc.

The Delta controller has a jumper to work either way, key off, or timed and temp. Unless it causes a problem with the battery I am going to let it run after key off, and even then my solution may be to update the alternator.

danglerb

I considered using the existing switch which is 187F I think, and should work fine to drive a fan relay, but I want a lower temp for turning on the fan, this one is targeted at preventing overheating, not keeping temps in a "more" normal range.

I decided to use a temp sensor with programable settings.

I may leave the factory Bosch pusher fan in place, for emergency cooling, or perhaps to use instead of the main fan for AC, or I may leave it for a bit, and remove it later.

Shane

Check with Carl at 928motorsports...

He has fan kits for replacing both the pusher fan and the belt driven fan.

Shane

Here are the links:

Viscous fan replacement

Auxillary Fan Replacement

RichS 1986928

I was close to buying the 928MS fan. It looks like a good setup.
But the Delta controller makes A LOT of sense. The 928MS
setup cycles on and off at full power. The Delta controller
uses a PWM signal to slowly speed up or slow down the fan.
Easier on the whole electrial system, less power consumption
and keeps the temp almost exactly where you want it.

My only concern would be the temp sensor that comes with the
Delta controller. It basically sticks into the radiator fins. I'm
curious if the contact surface remains consistent. The best
way to know the engine temp is to measure the actual coolant
temp like the 928MS version.

I had an old 4x4 with an electric fan that pressed against the
radiator. Bad system, didn't turn on sometimes.

Does anyone know a solution to this? Maybe putting a temp
sensor into the 928MS inline Billet adapter?