I thought I found another way....

Kern Dog · Apr 2, 2018

I am changing over to A/C in my 1970 Charger. Part of the changeover includes a new radiator. These days, the radiators are thicker than our originals. I had a generic Griffin in the car but changed to a Speedcooling 26" unit. My thermo fan clutch was now too close to the core. Oddly, the bottom is about 1/4" from the radiator and the top is about 1 1/4". The car has never been wrecked and the transmission is at the right angle.
I looked through my stash of parts and found 2 original Mopar fan clutches that have a shorter neck/shaft than the one I had on the car. The shortest shaft fit the car great but is ugly and dirty. My understanding is that Originals have holes, aftermarket units have slots. I am certain that they came from late 80s RWD cars, either Diplomats or Fifth Avenue cars. At the local NAPA store, they list a Hayden 2747 as the correct unit but the shaft on it is the same as the one I already had on the car. I had to look online to learn of the Hayden 2947. I ordered one from Summit today.

Don selleck · Apr 3, 2018

thanks, that may come in handy for me i did some measuring off my motor mount from my old motor to my new griffin radiator, i think i have maybe 3/4" to 1/2" to spare. that may solve my future possible problem. now if i ever get my newly rebuilt era correct motor back i may find out.

Car Nut · Apr 3, 2018

hunt2elk · Apr 3, 2018

I am using the Hayden 2947 on 2 of my cars. It is 2.7" tall which is the shortest one that I have found that will work on our cars.

khryslerkid · Apr 3, 2018

Kern Dog said:
Oddly, the bottom is about 1/4" from the radiator and the top is about 1 1/4". The car has never been wrecked and the transmission is at the right angle.

The thing is that the factory radiator's mounting brackets were wider at the top, tilting the top inward towards the engine. That makes it square or parallel with the fan. The replacement radiators just have a straight mounting bracket and don't lean inward at the top. I had to use a spacer at the top of my Speed Cool radiator to make it square with the fan.

5.7 hemi · Apr 3, 2018

The 2947 clutch is a tiny thing, better get some small Asian lady to get the bolts started! Lol!

hunt2elk · Apr 3, 2018

5.7 hemi said:
The 2947 clutch is a tiny thing, better get some small Asian lady to get the bolts started! Lol!

Yeah, it is kind of a challenge. They work good though.

5.7 hemi · Apr 3, 2018

Mine didn’t, hope yours will/does.

Kern Dog · Apr 3, 2018

I'm going to use studs to mount mine. 1 1/4" looks to be right. I test fit a long carraige bolt and cut it to size to use as a pattern for length. With about 1/2" of the bolt threaded into the water pump snout, this leaves 3/4" to account for the fan pulley, fan clutch mounting flange, lock washers and nuts. I should have it done tomorrow.

Kern Dog · Apr 4, 2018

The "fun" continues...
The 2947 fan clutch is a pisser to bolt up. I thought that using studs would make it easier. It did not. At all. Try balancing a heavy fan and clutch on 4 short studs, lay a lock washer on and thread it on.

No, I did NOT like that.
Check out the two common Hayden fan clutches. The 2747 is on the left, the 2947 on the right.

Kern Dog · Apr 4, 2018

Kern Dog · Apr 4, 2018

I test fitted it and got the fan on with bolts that had captive washers. It was a whole lot easier. I threaded one bolt in, set the fan/clutch on and threaded on the other three bolts. Easy. THEN I decided to pull it back off to then install the fan and shroud at the same time.
I had test fitted the shroud to the radiator on the table and they fit fine. I didn't think to measure the FAN though...

Kern Dog · Apr 4, 2018

The fan is close to 20", the opening in the shroud is 20 3/8".

Kern Dog · Apr 4, 2018

So....
I checked a few fans I had in the stash...Four were 20", one was 18". I checked a few other shrouds I had from junkyard trips. 22" seems to be common for the late 80s Diplomat/Fifth Avenue cars with 26" radiators.
This leads me to believe that the 20" fans came with engines & cars that use a shroud with a 22" +/- opening.
What is the size of fan used on my car? 1970 B body, 26" radiator, A/C ??
I could use an 18" fan that I have here. It is dirty but will clean up.

5.7 hemi · Apr 4, 2018

The best way to get the clutch on with the fan is to take 2 of the fan bolts out. Screw one clutch bolt in a bit, slide the clutch under that bolt, pull back, start another clutch bolt, rotate, do another and then the last one. Now you can start to screw them down a little at a time, rotate the fan as needed. Tighten all 4 bolts, now install the 2 fan bolts, tighten.

The fan I used is 18”, the shroud is 20”, so the is some wiggle room for when the engine rotates to the pass. side.

The other fan clutch is Hayden 2765, just a tad bit taller than the 2947 but not as heavy duty.

Kern Dog · Apr 4, 2018

I checked a few other threads here. It looks like an 18" fan and a 20 3/8" shroud opening is a common combination. I thought that seemed a bit too wide of a gap around the fan blades but if it works for other people, I'll try it. The car has always ran fine in hot weather, never been prone to overheating, even without a shroud. This new radiator and factory shroud should at least keep me as cool as before, maybe better?

5.7 hemi · Apr 4, 2018

I think you’ll be fine, I do have a fan if ya need it.

hunt2elk · Apr 5, 2018

2863215 blade is 18" diameter and the 2863216 is 18.5". Those are the 2 popular ones and either will work on your car.

Kern Dog · Apr 6, 2018

Today's update:
I mocked up the 18" fan that I had along with the shorty 2947 Fan clutch. The fan was outside of the shroud more than inside. Add to this the one inch + space around the shroud, I wondered if that would be enough.
Remember, before any parts swapping, I was using a Griffin crossflow radiator, a 20" fan and a 2747 fan clutch. That setup was close to the bottom ridge of the radiator but did have adequate clearance.
The shorty fan clutch is a pain in the dick to bolt up.
I then mocked up the 18" fan on the old 2747 clutch and found that clearance to the radiator was great. The pitch of the blades and reduced diameter allowed more space than I had with the previous setup.
It is all together now. The shroud is centered, the hoses and belts are back on. The only thing so far that I can gripe about is that the nipple for the radiator overflow points to the drivers side. I don't know where the stock location for the overflow jug is but I've mounted my "Dodge Caravan" jug to the right of the radiator for 10 + years. I had to make a U turn from the nipple to run the line to the right and down. Not a problem really, it isn't as if I'm going to enter the car in some Mopar National OEM correct car show.
Tomorrow I'll fill with coolant, fire it up and check for leaks. It has been raining so I doubt I'll get to drive it. The windshield leaks. Damn glass installer guy! He looked "maybe" 25 and surely didn't know the tricks that the old timers know. I plan to pull it and reinstall it myself.

beanhead · Sep 13, 2018

Kern Dog said:
Today's update:
I mocked up the 18" fan that I had along with the shorty 2947 Fan clutch. The fan was outside of the shroud more than inside. Add to this the one inch + space around the shroud, I wondered if that would be enough.
Remember, before any parts swapping, I was using a Griffin crossflow radiator, a 20" fan and a 2747 fan clutch. That setup was close to the bottom ridge of the radiator but did have adequate clearance.
The shorty fan clutch is a pain in the dick to bolt up.
I then mocked up the 18" fan on the old 2747 clutch and found that clearance to the radiator was great. The pitch of the blades and reduced diameter allowed more space than I had with the previous setup.
It is all together now. The shroud is centered, the hoses and belts are back on. The only thing so far that I can gripe about is that the nipple for the radiator overflow points to the drivers side. I don't know where the stock location for the overflow jug is but I've mounted my "Dodge Caravan" jug to the right of the radiator for 10 + years. I had to make a U turn from the nipple to run the line to the right and down. Not a problem really, it isn't as if I'm going to enter the car in some Mopar National OEM correct car show.
Tomorrow I'll fill with coolant, fire it up and check for leaks. It has been raining so I doubt I'll get to drive it. The windshield leaks. Damn glass installer guy! He looked "maybe" 25 and surely didn't know the tricks that the old timers know. I plan to pull it and reinstall it myself.

Yeah, it's an older thread....Kern I was just wondering how this setup worked out for ya, with the extra space around the fan blades. I came across this diagram on flex-a-lite's site. They say this is the optimal fan placement within a shroud

I thought I found another way....

Life is full of turns. Build your car to handle.

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Life is full of turns. Build your car to handle.

Life is full of turns. Build your car to handle.

Life is full of turns. Build your car to handle.

Life is full of turns. Build your car to handle.

Life is full of turns. Build your car to handle.

Life is full of turns. Build your car to handle.

FBBO Gold Member

Life is full of turns. Build your car to handle.

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Life is full of turns. Build your car to handle.

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