Do I need the fan shroud?

[pigpen4x4]

I just got a new aluminum radiator and am working on getting it installed. The question though is with this new radiator do I still need the fan shroud? I am running into mounting issues and the shroud may have to go. What are the advantages and disadvantages of removing the fan shroud?

 

[CruisinGA]

What engine?

I don't run one in my 40, 6 years, no problems.

 

[pigpen4x4]

What engine?

I don't run one in my 40, 6 years, no problems.

Sorry about that...I'm running a '76 2F.

 

[Degnol]

Yes, I think you need a shroud. Like a ducted fan, it is more efficient. Bailey is smart, like engineer-smart, but for what's involved, get/make a shroud.

GL

 

[CruisinGA]

Ed's right, shroud is absolutely better.

The only benefit to not having one is that there is no work involved in not installing one.

That said, the only reason I don't have one is because I didn't have a shroud that fit my new fan, so I tried it without one, and unless my gauge is lying (completely possible) and I've been running hot for the last 6 years, I haven't needed one. I also have a 7-blade FJ60 fan.

If I was getting paid to engineer a radiator/fan combo for someone, it would have a shroud. Alas, I can't pay myself, so no shroud for me.

 

[fj hunter]

i run an ...

f in my 69, and a 3fe in my 73.

yes, put in a fan shroud. for three reasons.

1) for that one time when your fingers just don't go where you want them to go and then they fly away and you have to run all over the shop dripping your precious life blood looking for them so they can be sewn back on in an 8 hour operation, costing several 10's of thousands of dollars, which your insurance will only cover 80 to 90%, leaving you with a $2794.66 bill to pay in stead of buying lockers for the rear and front, but i'm over it now. then the waiting to know if they will even work again as before, and the praying to God that they will so I can put the lockers in myself. ok, enough.

2) for that one time when you get into water and the fan splash needs to be limited to the area of the front of the engine cabin.

3) for the correct and needed cooling of your engine on a dry and hot and hot day when you need to arrive back as base camp and that fan cooling your engine needs every bit of the directed cooling that the fan shroud employs to do the job to get you there safely and in good heath.

there ya have it. my opinion.

 

[pigpen4x4]

f in my 69, and a 3fe in my 73.

yes, put in a fan shroud. for three reasons.

1) for that one time when your fingers just don't go where you want them to go and then they fly away and you have to run all over the shop dripping your precious life blood looking for them so they can be sewn back on in an 8 hour operation, costing several 10's of thousands of dollars, which your insurance will only cover 80 to 90%, leaving you with a $2794.66 bill to pay in stead of buying lockers for the rear and front, but i'm over it now. then the waiting to know if they will even work again as before, and the praying to God that they will so I can put the lockers in myself. ok, enough.

WOW...ok, that's a good reason to have a fan shroud!! I guess I'm gonna see how I can rig it up!!!

Hope the hand/fingers are all ok now.

 

[Pighead]

Short answer? Nope

A properly running 2F does not need a fan shroud.

My '74 fanshroud got so chopped up after adding the 2F and power steering, that I tossed it. Haven't missed it.

 

[dgangle]

Naw, completely uncesseary.

Toyota, GM, Ford, Chrysler, Honda, MB, BMW, Kenworth, Peterbuilt, Mack, Volvo, Caterpillar, John Deere, Cummins, Detroit Diesel, Komatsu, Case, ......just put them on for the novelty.

Justify it anyway you want.

 

[cjgoode]

You do not need one as long as you keep your vehicle moving. You will be 100% fine while driving, but could have problems if you get stuck in traffic sitting still or do slow rock crawling. It helps the fan pull the air through the radiator which is not needed while moving at 20+ mph would be my guess. I bet most people run without them just because the rig came without it.

 

[GarageRat]

Well, listing out for removal here's what I got:
Advantages: Save weight? Maybe? Like a few pounds? I mean, that counts for something right?

Disadvantages: Fan is less effective as there is no ducting, this in turn reduces the effective cooling surface area of the radiator as well as you have no means of forcing air through all of radiator. Safety, as fj hunter has experienced; mangled hands are no fun.

I have friends that swear that a shroud is not needed, yet both have had overheating issues with aluminum radiators and mechanical fans (a 2F and a SBC) at low speeds at one point or another. Once you're at higher speeds the shroud isn't needed as the air gets pushed through the radiator by the air's resistance to moving with the vehicle. It's up to you, personally if your current shroud didn't fit I'd either look into fabbing a new one or buy a different one. There's quite a few universal ones out there formed out of aluminum, would just have to search for one that'd fit with little or no modification.

 

[CruisinGA]

I'll maintain that I have not had any temperature issues running my modified '74 in any weather the southeast has to offer(including 95 degree heat), in any sort of condition from Atlanta traffic, to tellico rock crawling to pulling a trailer up I-75 in the last 6 years with no shroud.

That's not to say I recommend not running one.

I think what it's going to come down to is that---

It is ALWAYS better to have one than to not, however,
it is not necessarily required for satisfactory operation.

Just have to find out for yourself- if you're willing to take that chance.

 

[GarageRat]

I'll agree to that, if you haven't had any issues then there's no real need to change it. Both friends I mentioned are happy with their rigs and weren't concerned with the times they had overheating issues (hot day with little humidity, very slow crawling, very high load). With the 2F we noticed there was a lot of wiggle room with if the shroud is needed or not, it stays at 195 through 95% of situations and only creeps with heavier crawling, as heavy as you can with a locked rig on 33s at least. The owner simply monitors the temp to determine if it should sit for a little bit to allow to cool. I would imagine humidity also plays a part in how much a shroud is needed as humid air is a better heat conductor than dry air.

 

[rusty_tlc]

In the interest of appendage preservation I finally put mine back on. My truck (2F) runs cold with or with out the shroud. 100°+ temps, stop and go traffic, or rock crawling all make no difference.

 

[Downey]

You may choose to run, or not run a fan shroud for any of the above reasons, but let me tell you what the Society of Automotive Engineers says about the whole thing; During structured test, they determined that an engine runs cooler when there is a fan shroud between radiator and fan blade, BUT!!!!!! the engine runs the coolest when zero percent of the fan blade is inside the shroud. With that said, seems like a fan shroud should not be considered a finger saver.
The best bet for me has always been the mother of all air conditioning fan blades mounted about 1" behind a big rompin-stompin alum. radiator---actually have trouble getting the engine to run warm enough!!!

 

[pigpen4x4]

Well, I've been working on the Cruiser a few evenings this week and as of last night I have the aluminum radiator mounted and in. It "fits" inside the stock mount. I had to shave down the sides of the mount and then moved the two bolts on the bottom of the mount in order to gain another inch of clearance between the fan and radiator. I made some tabs to hold the fan shroud in place and everything looks good. Now, I'm just waiting on my new thermostat housing to arrive. I just hope it gets here before Friday so I can go wheeling this weekend!! I'll post pics later today. Thanks for everyone's input.

 

[GarageRat]

the engine runs the coolest when zero percent of the fan blade is inside the shroud.

I'm just thinking this through while I wait for class to start but I can actually see this being true as long as you have the room to mount everything. If the fan is mounted just in plane with the outlet of the shroud then there is less turbulence as the air has more area to move through while being pulled by the fan and the goal isn't to produce pressure after the fan but to just move the air through. For most applications it's probably overkill since the efficiency gained and increased cooling "power" isn't necessary hence why the fan goes in the shroud to keep people from playing "(try to) stop the fan".

 

[rusty_tlc]

I'm just thinking this through while I wait for class to start but I can actually see this being true as long as you have the room to mount everything. If the fan is mounted just in plane with the outlet of the shroud then there is less turbulence as the air has more area to move through while being pulled by the fan and the goal isn't to produce pressure after the fan but to just move the air through. For most applications it's probably overkill since the efficiency gained and increased cooling "power" isn't necessary hence why the fan goes in the shroud to keep people from playing "(try to) stop the fan".

Yeah but what if the Cruiser is on a conveyor belt?

 

[pigpen4x4]

Here are a few pics as promised...

1) I converted the brackets that came with the radiator in order to use them at the top corners to keep the radiator in the support frame.

2) Two more pics of the brackets I made in order to mount the fan shroud to the radiator support bracket. You can see how I had to cut out part of the support bracket.

 

[pigpen4x4]

1) The radiator and fan shroud mounted to the support frame.

2) You can see the bracket that holds the radiator into the support frame as well as the smaller bracket that holds the fan shroud to the support. Additionally, you can see how I had to mod the fan shroud in order to get the top outlet to fit.

3) Bottom bracket for holding the fan shroud to the radiator support.