Fan Too Big For Shroud

[45Kevin]

Several years ago my original 2F started smoking too much for my liking.
So I had an opportunity to buy a 2F that was taken out of an (IIRC) 1984 FJ60.
I got it and did the swap.

There are several differences in the engines.
1. newer one has an oil cooler, no problem
2. several different bosses in the valve cover and my air filter housing wouldn't fit, easy swap to my original valve cover
3. seem to be a few more sensors my wiring harness doesn't have connections for, I can do without them
4. newer one has a viscous fan and it is about an inch larger in diameter, problem is my shroud won't fit now

So, how do I fix the problem.
My first try was to cut up the shroud from the 60 to fit on my smaller 40 series radiator, it was unsuccessful.

I am having problems keeping the coolant temps down in hot weather, while slow wheeling and on long hills.

Next solution. Could I just shave a half inch of the plastic blades of the 60 fan.
It doesn't look like it would affect the structural integrity of the fan.
I would reduce the air pulling power but by having the shroud installed would mean much better pulling power through the radiator.

I thought maybe running the engine and holding a rasp against the outside edge of the fan might work. Would need proper PPE.
But, being a viscous fan it might not even turn at idle.

Looking for thoughts and ideas.

The FJ60 fan.

 

[45Dougal]

Several years ago my original 2F started smoking too much for my liking.
So I had an opportunity to buy a 2F that was taken out of an (IIRC) 1984 FJ60.
I got it and did the swap.

There are several differences in the engines.
1. newer one has an oil cooler, no problem
2. several different bosses in the valve cover and my air filter housing wouldn't fit, easy swap to my original valve cover
3. seem to be a few more sensors my wiring harness doesn't have connections for, I can do without them
4. newer one has a viscous fan and it is about an inch larger in diameter, problem is my shroud won't fit now

So, how do I fix the problem.
My first try was to cut up the shroud from the 60 to fit on my smaller 40 series radiator, it was unsuccessful.

I am having problems keeping the coolant temps down in hot weather, while slow wheeling and on long hills.

Next solution. Could I just shave a half inch of the plastic blades of the 60 fan.
It doesn't look like it would affect the structural integrity of the fan.
I would reduce the air pulling power but by having the shroud installed would mean much better pulling power through the radiator.

I thought maybe running the engine and holding a rasp against the outside edge of the fan might work. Would need proper PPE.
But, being a viscous fan it might not even turn at idle.

Looking for thoughts and ideas.

The FJ60 fan.

View attachment 3651078View attachment 3651079

Looking at your fan, I'd guess that's exactly what a PO has done on mine.
The ends of my fan have been trimmed down - I'd guess with a hack saw.
I'm pretty sure you could make a nicer job of it than they did, especially if you sand / file them afterwards.
I don't think you need it running - just set up a fixed point or use a template and rotate by hand so they're all the same.

 

[mattressking]

This is simple, get the correct fan shroud or fan combo.

You didn’t clarify what year truck/shroud you have.

Essentially what you need is a 77-84 fj40 (with clutch) shroud and fan.

 

[45Dougal]

Worth keeping the viscous coupling though. If its working.

 

[charliemeyer007]

Making a jig to trim the fan blades evenly is easy enough. I like that guys recent post using like 12 server fans to pull air threw the rad. IMHO faster warm ups with no air flow and better cooling with all the electric fans running full blast.
Correct parts is always a good plan if you can find/afford them.

 

[45Kevin]

This is simple, get the correct fan shroud or fan combo.

You didn’t clarify what year truck/shroud you have.

Essentially what you need is a 77-84 fj40 (with clutch) shroud and fan.

I have the year in my sig line. And the shroud is original to the truck.
I don't know if the fan I have now has a corresponding 40 series shroud. Hadn't even considered it.
Did any 40s later than '78 come with this viscous fan. Perhaps later 40 owners could pipe up for me because that would be ideal.

I'm doubtful though as the viscous van actually extends about 1/2" beyond the edge of the DS side of the radiator.

Worth keeping the viscous coupling though. If its working.

That's my thinking. Even with shorter blades on the viscous fan, it would be more efficient than the non-viscous fan I had originally on the old 2F.

Original fan shroud from my truck.

 

[65swb45]

It’s probably the fan clutch that is the issue Kevin. Not strong enough for the job anymore. Decades ago Mark Whatley did a writeup for TT about adding fluid to the clutch to revive it. There seemed to be consensus that it was a better solution than the aftermarket clutches out there.
Of course things could have changed since then. And it’s not like me to keep up with the times anymore.

 

[mrboatman]

Just use a 2x4 and a BFH and adjust the shroud so that the fan has clearance. I’m running an 84 2F from a 60 with a F engine shroud. The plastic fan is from a 75 40 I think and it clears the shroud fine after some adjustment to it.

 

[45Kevin]

It’s probably the fan clutch that is the issue Kevin. Not strong enough for the job anymore. Decades ago Mark Whatley did a writeup for TT about adding fluid to the clutch to revive it. There seemed to be consensus that it was a better solution than the aftermarket clutches out there.
Of course things could have changed since then. And it’s not like me to keep up with the times anymore.

That may be true Mark. But I really think the important missing part is the shroud. I'd like to keep the viscous fan, but my plan B is to swap my '78 non-viscous fan onto the newer 2F. Then my original shroud would fit just fine.

Just use a 2x4 and a BFH and adjust the shroud so that the fan has clearance. I’m running an 84 2F from a 60 with a F engine shroud. The plastic fan is from a 75 40 I think and it clears the shroud fine after some adjustment to it.

Can't bring myself to molest my original shroud. So that is not an option.
I've had this truck for almost 25 years and I'm the second owner. I still have the original engine and the original drum brakes (along with the original bill of sale). I won't destroy the original shroud.
I would have a clear conscience molesting the fan from an anonymous FJ60 though.

 

[GA Architect]

Fan + Fan Shroud = Win

FWIW - Fan & Size:
16361-61010 (8/76 - 1/79) diameter = 430mm
16361-61020 (1/79 - 8/87) diameter = 450mm

I run the Aisin FCT-049 Fan Clutch, a robust unit which it typically for an FJ80 but can be used for the 40/45/55/60.

 

[Jim S.]

^^^ What GA Architect said. I run the 049 on both my 40s in Southern Arizona. They perform well.