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.

you guys must be tougher than i am. i only drive my GTO when it is below 80 outside. dark car, dark vinyl seats, I am hopping in the Silverado if it is even the slightest bit warm outside. I used to be tough but it was too much work, give me a latte and air conditioning please!

Im even worse. I only have a small range I can drive mine in low and high. Because some idiot (me) forgot to put the heater blower in before they put the fender on. So if the weather will make the windshield fog, it can’t drive it.

i stepped up to a 180 thermostat so I could have warmer heat, and sometimes I even think about adding aftermarket air conditioning.

My 19 year old self would weep at the sight of my 45 year old self.

I'm in the process of an engine swap and adapted a MK8 fan to a 68 shroud

Thats nice work.

OEM fan swaps work well. I have a ford Windstar dual fan in my Firebird and it will hold at 180 in dream cruise traffic. In fox body mustangs Ford Contour fans are the go-to.

That looks fantastic. Did you use an original Lincoln fan or is that a repro?

I have a dual fan setup I bought for $1 off of a dude at a swap meet who didn’t want to take things home on Sunday. Codes out to a G6 if I remember correctly. I’ve been meaning to swap the fans into something usable for an old car. It’s too wide as is.

freebie original with a bad motor. bought a motor on Rock auto. Painted the fan parts with Eastwood plastic renew paint and satin clear coated the original Pontiac shroud. The Lincoln fan I think is ABS plastic while GM used fiber reinforced polypropylene. I couldn't find an economical glue or epoxy that sticks to PP. I used screws and butyl rubber to stick to both plastics. I use aluminum sheet to bridge the gaps and painted inside surfaces and the butyl to keep it from attracting dirt during use.

Also, I will be controlling it with a PWM controller (HF-125) from this guy:

https://www.autocoolguy.com/home

A friend put one of those controllers on his Charger and is pleased with it over the Derale he had.

I've researched as best I could for more economical solutions but this seems the only unit that can handle the amperage and has the reputation as being pretty bullet proof

Which brand motor did you use?

VDO

Like I was sayin, difficult and expensive just to have an electric fan. And not sure how the guy cut his fingers off, but im sure a mechanical fan will do the same, especially with metal fins.
But aside from that, here is a idea for you all. all you need is two 70amp relays ( you can get them from napa for an audi headlight relay I think they are 90amp).

and one two way 30 amp relay(one that sends power to one side not energized and when energized switches power to the other)

i will try to make a diagram(
@= fan
^= power flow
|= connection/wire
⚡= battery
➕= relay trigger
⚓= ground/negative
♻️= alternator post(On) (*NOT*BIG WIRE SiDE)
||= 8 awg wire

````` ``➕@Lo===⚓===@HI➕
````````||``````````````` `||
```off```^````````````````^````off
```➖\ _70A_/➕``````➕\ _70A_/➖
````/```||```\``````````/``||```\
```⚓``⚡```^````````^``⚡```⚓
`````````````\```````/
`````````````^``````^
```````````➖\ _2Way_/➕
`````````````/ ``\^/`` \
```````````⚓```♻️```(clutch@)or(Alt@)switch


Just make sure you use 10 gauge or even 8awg wire
from ⚡ to 70amp relay to @ also ⚓to @.

That will do everything that a special controller will do for a 2; speed fan and save you a few hundred bucks and you can always replace a relay from any autoparts store and you still can jump it to run one relay if you need to. That way your vehicle wont over heat untill you replace it and you dont have to wait to order a whole new controller if it goes out, especially if your out on vacation somewhere
Hope that helps somebody someday.

oh this will work on any car/truck/jeep as I had done this to my XJ and my F150. Definitely pays for itself in the mpg on the gas it saves. pretty quickly. especially only getting 15 to 18 or 19 mpg . That 3mpg every 5 gal=15mpg@1gal $5 saved
So every 20gal fill up is $20 you didn't have to spend on gas sooner. That after 10 or so fillups its only saving/ making you money(as its money you get to keep when you would have had to spend it regardless) plus gain a few ponies as well

I found it interesting that the guy with the 71 'vert/455 went from factory setup (7 blade factory fan and Hayden clutch) to a Flex A Lite fan and it got cooler. I have a GTO with stock setup, air, 455 and it stays cool under all conditions here in Florida. 4 core brass radiator, very old but I had it cleaned. I have a '87 Cutlass with a 500 Cadillac swap and an aluminum radiator. I wanted to use the Lincoln fan but it doesn't fit; it hits the water pump. I used a homemade sheetmetal shroud and a 6 blade SS Flex A Lite fan and it was OK on the highway but not in traffic. It was fixed, no clutch. I switched to a 7 blade GM fan with a new Hayden clutch and according to the temp gauge it ran cooler.

I have a '72 vert with a 8.9 CR 455 that is an original 350 car with a stock 3 row radiator. I originally used a stock 7 blade fan with a Hayden severe duty clutch and it would get hot in traffic and was ok on the highway. I switched to a 7 blade 19" Flex a lite flex fan and the car will not get hot regardless of the outside temp or traffic. On a 95 F day it might get to 175-180 F max. I had a 160 F T-stat in it and I switched to a 180 F because it wasn't getting warm enough. Not suggesting people should use this, set-up just offering my personal experience.

112 here today. My Firebird with AC on is fine while cruising, but any amount of idle time causes serious creep. I am looking at electric now, so this thread was helpful.

I use a Mark VIII fan in my race car with a 75 amp relay and always run it on high speed, works well.

I love a good zombie thread.

Do you have a legit Ford Mark VIII fan or an aftermarket replacement?

IIRC correctly the cool part about the testing I posted was that the Dorman unit actually seemed to run on a reasonable level against the FOMOCO unit. I cant imagine Mark VIIIs had a big production run anyway, so not only are the fans left out there not all that plentiful, but they now have 20+ years of abuse on them. A reasonable off the shelf replacement is welcome.

Ill never not believe that there isn't some level of black magic to keeping old cars cool. There are just so many variables that can go unseen, and so many of these old cars have been cobbled together over decades. Joe Average Car Guy complains that he cant get his car to run cool and follows all the cooling system advice but nothing works. Little does he know his car is running too lean and with too little timing. Or a Pontiac guy who has a WP backing plate way out of wack. Google is probably never going to tell him that he needs to clearance that plate.

My 62 Cat has a cheap three row radiator in it. Strike 1, we all know the big two rows should be better. It has no shroud, just an open clutch fan. Strike 2 we all know that's wrong. And strike 3, it has a bunch of air gaps between the radiator and core support. But that darn thing runs a few degrees under its 160* thermostat (just what I had laying around).

Meanwhile the MUCH better supported engine in my firebird struggles a little if you get caught sitting at idle for too long.

Is it because the turd of an olds 455 in the 62 just doesn't produce enough power to make any heat? Do Oldsmobile big blocks have superior cooling tendencies? Ive always wondered that but never seen a study. When you have differences in design of cooling ports and passages in different engines you HAVE to have differences in cooling capability. So it stands to reason some engines would just stay cooler by design than others. I don't know which ones.

And as mentioned in another thread in the cooling section, most of these old cars just flat out didn't come with big enough radiators. When compared to cars from the 80s and up, radiators started to get more fontal surface area. The radiator for a 3.8 liter 90s grand prix has more frontal surface area than the "big block" sized first gen F body radiator from Cold Case.

Agree totally. I've wondered "WHY THIS? but "NOT THAT?"

Basic principles of heat transfer are immutable.

More flow on any side of the equation is always better. Period.
More surface area for heat transfer is always better.
You can overcome a deficiency in one attribute by engineering in an excess of another.

If you have a small surface area radiator, you better have a lot of airflow thru that radiator to bring down the radiator outlet temp as much as possible. That's what I am dealing with now.

It's funny how first gens have all sorts of baffles to direct air, yet 2nd gens and A bodies had little of that other than a fan shroud. It tells us that the design engineers knew there was a serious constraint related to that platform. 1st Gen radiators are so comparatively tiny. Tiny radiator means that airflow capable of cooling a 2nd Gen is not enough to crutch a 1st gen.

uggh, that's awful, thanks for a cautionary reminder.

Well, thought I would try the route of the Dorman 620-118.

I bought off Amazon so I could have favorable returns. Sure enough, I tried to install the fan behind my radiator, and it wouldn't clear the pump snout. I did some measuring, and if I were to trim the fan shroud to the tiniest clearance between fan and core, I MIGHT just barely clear the fan motor to the water pump snout. This is with a long nose pump. There is a small gap, maybe 1/2 to 3/4", between the rad support opening and the core. This would mean I would have to rework brackets for the radiator, AND radically trim the efan shroud.

Fan is being boxed up and sent back. So the Lincoln Mark 8-ish fan is too thick for a 1st gen.:(

How deep is the Lincoln fan? I would have thought anywhere that could get a clutch fan could get one of the electric fans.

I have this dual on my GTO, don't need 1 big one anymore.

https://a.co/d/fkWjTyZ

This is a copy of the Ramcharger fans from years ago I believe.

Since the first gen birds come with 4” (short) water pumps, would the OEM set up allow clearance for the fan?

This is far too big for a first gen F-body. The core on these things is only 23" wide, and end tank to end tank is in the neighborhood of 28".

I would think so. I have the short water pump and use a Flex-A-Lite Black Magic fan. It's fairly deep and I have about 2" of room to the waterpump pully.

Yesterday I watched an episode of Matts Off Road Recovery (southern Utah) where he was going over his fleet of vehicles and touching on their shortcomings. When it came to his XJ jeep with a inline 6 in it he talked about the fan and the hood louvers. He said that he had tried every electric fan that was highly touted as the answer to a changeover from mechanical to electric, Including the Ford/Lincoln fans that everyone talks up.

He said all the electric fans failed in that application and he kept going back to the mechanical fan for his XJ with A/C. He said no matter the ambient temp he never has to stop and let the vehicle cool down with a mechanical fan like he did when testing the electric fans. I thought it was a good apples to apples test under extreme conditions that in his application he had never been able to use an electric fan without the vehicle overheating. When he switched back to mechanical fans the problem was non existent.

He issued a $10,000 challenge that if anyone had an electric setup that could cool in southern Utah and they could prove it didn't overheat, he'd give them $10,000. Putting his money where his mouth is........;)

Just for an observation, I've never seen any closed course race cars with electric fans used to cool them, always mechanical fans. i did see one autocross car many years ago with an electric fan that failed miserably after only a lap around the course.

Probably a little known trick to cool oval track cars down during a red/yellow flag was a water reservoir using a washer pump to squirt water over the core of the radiator while bringing the RPM up, works very well under extreme conditions. The water and air mixture together, will pull a lot more heat from the core than just air will.

:2cents:

I think this guy is having the opposite problem that nearly all of us have with the under-radiated 60s cars. Unless I am reading it wrong its not really an apt comparison.

I also never have to stop to cool down....I have to start moving to cool down. Its the stopping that's the problem. And that's where an electric fan would benefit me. I don't think anyone would make the argument that a big mechanical fan wont move more air under RPM, including racing like you said. The problem is getting stuck in traffic, or a drive-through etc. I need more air at idle.

My car is pretty well sorted out, Cold Case, big 19" clutch fan with a modded clutch to engage faster (I could probably bend it a little more even). And its fine, but it creeps enough at idle that the thought of getting stuck in a bad traffic jam scares me. And its hard to keep temp down in the staging lanes unless.

Plus I have the Terminator installed and Im not making use of its fan controls, which activates my personal flavor of autism and annoys me. Ive just always had something more important to spend money and time on than moving this one to electric.

There's a reason the 2nd gen f-body has a much larger radiator than the first gen. There's simply not enough frontal area on a first gen factory sized radiator.

Big tubes and additional cores only get you so far. After the air passes through the first set of tubes and fins, most of the cooling that can be done already has. Each subsequent core of tubes and fins is dramatically less efficient as the delta between the air temp an water temp decreases.

This is why you see modern radiators thin with large amount of frontal area. It simply cools better. Of course it helps the modern EFI systems can rotate idle and skip cylinders here and there.

If I was to go back 10-15 years and catalog all of the threads on this forum discussing cooling issues, I would lay odds that the majority of them revolve around first gen F-bodys and early A-bodies. Both notoriously under radiated.

The rads are so small, that with anything much over stock power, you need massive CFM at idle to keep them cool.

My setup works okay. It used to cool fine at idle with my old engine, but I added quite a bit of power with the new engine. Now in temps about 80 degrees it will creep ever so slightly at idle. The fan is rated at 3300 cfm and I've taken pains to make sure the shroud is sealed as tightly to the core as possible and have also taken steps to reduce the amount of underhood air that can circulate back in front of the core between the radiator and the core support. This is actually my only complaint with the Cold Case radiator. The factory AC rad I took out of the car sat up against the core support with about 1/4" of room. The Cold Case has about an inch and a half of room between it and the core support, allowing hot underhood air to circulate in front of the radiator.

First if all if the video wasn't applicable, I would haven't posted about it.

He's driving his XJ on the road, stop and go traffic to pull out stuck vehicles that he lets the engine idle while they're hooking up ropes or winches. All the time isn't running at elevated speed. How much air is passing through the radiator while winching a vehicle out of a ravine that isn't pulled by the fan, I can answer that, zero.

If you're unfamiliar with XJ jeeps the core support has the exact same problem as a first gen F body has, a small opening in the core support that is limited in how much radiator can face forward. He also cut louvers in 2 places in the hood to have less restrictions to exhaust the heated air from under the hood.

What speed is he traveling while rock crawling up embankments? No help from the air being pushed through the grill by vehicle speed.

I guess you'd actually have to watch his recoveries to see how much idling, and being driven at a crawl off road that is done before making a call that I don't understand the problem.

To add to this southern Utah ambient air temps during the summer hover from the 90s to well above 100 degrees much of the time.

BTW, closed course cars do plenty of idling in the pits as well as when they're is a red/yellow flag to re-align the running order before restarting a race. The point is as JL Mounce has stressed, fin area can only exchange so much heat at a given air speed.

Pointed out here already is the best electric fan loses at least 15% air volume over a mechanical fan, that's a fact that you can't overlook if your setup is already marginal.

I realize that you probably haven't spent a lot of time around construction sites, or HD trucks, but none of them use electric fans, all mechanical as well as large radiators. You can't cheat physics and if your system is under designed with little margin for say scale in radiators. or dirt on the fins, you're likely to run over that invisible line, and end up on the wrong side of it, at least occasionally.

After many years of running these cars on the street as well as racing them. I have the knowledge to know what works, as well as what doesn't. Electric fans will not be as efficient as an mechanical fan will for the energy expended.

There is a point that the alternator won't run the fan as fast as what is needed to transfer heat at the worst possible cooling conditions. My 05 GTO has electric fans, but it also is 364 Cu in aluminum block, with a huge aluminum radiator, it still likely wouldn't cool a 455 Stratosteak engine under adverse conditions.

The first gen F body was a chevy design and likely was intended to have enough cooling capacity for a 350 SBC. Add 50 to 105 more inches of engine to cool and you're going to run into a problem, especially at high ambient temperatures, Add A/c and you compound the problem even further. With an automatic transmission you further load the radiator. Stacking auxiliary radiators such as A/C and transmission coolers further dilutes how much heat can be dissipated from the cooling system.

I believe I have a very good grasp on thermodynamics applied to all vehicles, both from a classroom point, as well as a hands on learn the hard and expensive ways of what will cool a problem child vehicle. If you feel my post have little to no merit that's fine, just ignore my post. I was just trying to give some feedback from practical knowledge, as well as classroom physics.

If you want to continue to pursue electric fans as a solution to overheating at low sped or idling in traffic, by all means prove all the others wrong that have been down the road.