Lincoln Mark VIII Fan Testing
 

This was posted on my FE Facebook group. Its been discussed on here though so I thought I would cross post the info. Not my test, Im sure some of you can dispute the method. But its better than nothing.

Basically this dude tested a factory Mark VIII fan against two Rock Auto type re-pops. I know I have wondered how the re-pops actually perform. Pleasantly surprised if these numbers are to be trusted.

Writeup below is copy/pasted with some bolding to make it easier to read.

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Did some simple flow testing on the 2 speed Lincoln Mark VIII style fan I run on the Dart to see which is the best. Never had heating issues with these 2 speed fans but with new brushless technology out I'm sure there's a ton better out there now.

I used the old radiator from the Dart in front of them to get true flow numbers with the pressure drop of a core in front.
Made sure the testing voltages were the same, and needed a battery to calm the inrush current and maintain current. These pull huge (50+ amps) on high speed when starting.

The stock Ford OEM fan flowed the most, followed very closely with the Dorman 620-118 then the TYC-620950.
Between the Dorman and TYC, the Dorman is made in Thailand and the TYC in China. Thailand seems superior as they revamped the fan blade design and flowed closest to the stock design.

With a higher voltage on high speed I can see these fans getting close to 3800-4000CFM at 14.4V.

Without a radiator in front the low speed amperage dropped 3-5 amps and the full speed only about an amp or so.

Results were as follows


Stock Ford fan :
High speed
3415 CFM
22 amps @ 12.7 Volts
Low speed
2800 CFM
18 amps @ 13.7 Volts

Dorman :
High speed
3355 CFM
22 amps @ 12.7 volts
Low speed
2578 CFM
16 amps @ 13.7 volts

TYC :
High speed
3116 CFM
22 amps @ 12.7 volts
Low speed
2578 CFM
17 amps @ 13.7 Volts

I have the same fan on my 71 lemans. Mine came off a Crown Vic. It works great!

I used the M8 fan too. I have 2nd for a spare. I ran it with DCControl controller.

I know they have been used by lots of people with great fanfare. (Ha!) The interesting part for me in this was that the available new units are at least reasonably close in performance to the venerable original. No matter how good the reviews I’m loathe to trust a nearly 30 year old electric fan.

This is really good info. Would you mind providing fan shroud dimensions?

I dont actually own one. Ive always shied away because I didnt want to use a 20+ year old fan and didnt trust the output of the Dorman. Now if I need one I would probably buy the Dorman.

That said, tons of people use these. Google Im sure would turn up the answer. I know they are pretty deep for an electric. I think you need like 6" of clearance to use one.

I bought a replacement motor for mine and I keep it with me. Been lucky I guess, never had a issue with the one I pulled out of the junkyard.

Yeah I had considered that route too, because I think you can still get replacement motors from Siemans/VDO, which produced the originals.

Or even buying the Dorman and then purchasing a VDO motor so you get a new shroud and blade.

At this point I think I have my clutch fan sorted, but I still like the idea of maybe going electric so you can switch the fan on with the car off.

We have both the single speed Mark VIII fan and the 2-speed fan that came in the T-Bird during the same time period. Lincoln used the computer to control the speed of the single speed fan so it was basically a variable speed fan. My observations are that the single speed fan pulls more amps and definitely pulls more air at full voltage than the 2-speed. Maybe a moot point because the two-speed was in our Firebird and wired where the thermostat controlled low speed and a dash override switch would activate the high speed. In six years there was never a time even on the hottest days that the high speed was needed. The single speed fan in my drag car is controlled by a Flaming River variable speed controller and it has never had to go full tilt to keep temps cool.

Still prefer the total reliability of a manual fan setup on the street. Have friends with a wide variety of electric fans and controllers, and have kept several of them company alongside the road while they waited for the tow truck. Always a fuse or controller issue and never a fan motor failure.

Maybe you should just add a electric fan and use it as a secondary fan.

I mocked up the Ford fan on my 64 Tempest with a Champion 4 row radiator and it is too deep. It touches the water pump bolts. Its a 455 with 11 bolt pump. I could trim the fan shroud down but the blade gets too close to the fins. I am still using the clutch and 19" fan. The original shroud for 64's with AC are steel, not plastic.

The shroud is 22x19

Got 2 UpullIT Elec fans: 1 in GTO, 1 spare. Low setting doesn't help the Summer heat load. So wired for High Speed only.

Manual Turn-on thru Relay. Someday i will automate Turn on with the $11 Head Thermoswitch. Only needed at Stoplights on hot days and Summer highway. No mech fan.

High Setting helps completely; Been a Dozen years, Spare fan on Garage wall for when I turn 65 or so.

I dont want to start another, flex fan vs clutch fan vs Mark 8 battle, but I am curous how well a Flex-A-Lite 7-Blade Fan 116441 flows, if anyone has any idea?

Of course the flow would depend on engine speed, and at some point with blades bending over it would be maxed out. Seems an electric fan wuld be nice when stuck in traffic.

I'm using a two speed Taurus fan in my Poncho powered studebaker. Moves a lot of air.

Made the mistake once of bench testing a fan with it improperly secured. If you want an Accidental Murder Drone, it would be hard to come up with something more unpredictable. All I could think of afterward was how poorly it could have gone, and how embarassing the ER explanation would be.

If you could get away with it an electric fan wired into the brake light switch via relay of course would allow it to only run when the brakes are applied. An override switch would be a good idea also.

Your main problem is the 18" diameter which is a limiting factor in itself. Quite a difference in area between the 18" and 19.5" fans (255 vs 299 square inches). Holding everything else even, that's still a lot of volume gained with the larger fan. That said, I have a Hayden 7-blade 19.5" flex fan up on the shelf that I have run in the past and I'd say it was the equal of the mechanical 19.5" fan and clutch -- but the noise was terrible. It always sounded like there was a helicopter right over my car. Purpose of the flex blades is to have max cooling at idle and less horsepower draw in the upper RPM range when the blades flatten out. If I loose my hearing I would run it again, but until then I'll stay with the standard fan.

Also, it seems like only a 6 blade 19" flex fan is now offered which would reduce air flow with the smaller diameter and one less blade.

I haven't told the story here, but did have that catastrophic accident with a Mark VIII fan when it came loose during testing and my hand was literally eaten by the blades. Had to have three fingers put back together and back on the hand, and spent a week in the hospital. While the event seemed like an explosion, the fan cut through my fingers about every inch until the blades were gone. The fan went into my hand from the radiator side and pulled it in, and neither the fan nor I faired that well. I was very fortunate that one of the best hand surgeons possibly in the world was on duty that evening and he took on the challenge with his surgical team. It was his first night back at the hospital after a three week speaking tour. The emergency room doctor had already told me that they would just clean up the hand and amputate the fingers back to good flesh and bone. Just after he told me that, a couple of young doctors came in and said they were looking for a challenge for their surgical team, and I was definitely it.

The fan blade still hangs over my workbench as a reminder to try and not be a dumbass. It's been a little over 10 years and the arthritis is settling in like they warned me, but I have full use of the fingers. Dropped a lot of nuts and bolts for the first two years but surprisingly have almost full feeling in the fingers now. The X-ray was taken just after we walked into emergency and we had gathered up parts and wrapped them up with the hand in a not-so-sanitary towel, and they just took the X-ray through the wrapped up towel.

I ran a Hayden severe duty clutch with a factory 7 blade fan on my '7s LeMans sport vert with a 9:1 CR 455 and stock 3 core radiator and the car would get to 210 °F idling in traffic with a 160 °F Tstat. I changed to a 7 blade Flex a lite SS fan and the car wont get above 170 °F on a 90+ °F day. I change the T stat to a 180 ° F and now it wont get above 175 °F on a 90+ day.

My wife is an OR nurse and I showed her your xray. She said " what did he get it stuck in". That's a serious injury.