Why does fan shroud need to be moved with JKS body lift?

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cmitcham

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finally, nice enough weather to get started on the dpg lift kit. jks 1.25 inch body lift and 1 inch mml to start with. the body mount instructions include this step 5...

5. MODIFY RADIATOR
Locate the four fan shroud mounting holes on the radiator.Measure exactly 1” below the factory mounting holes and mark the location with a center punch. NOTICE: The lower passenger side hole will line up with an existing factory hole and will not require marking with a center punch. Drill a new 1/4” hole through the three center punched marks.

i don't understand why the shroud needs to be lowered since the motor (and fan) is lifting. the body mount instructions do have optional paths when the mml is included, but step 5 remains regardless..

thanks for any thoughts.
 
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cmitcham said:
finally, nice enough weather to get started on the dpg lift kit. jks 1.25 inch body lift and 1 inch mml to start with. the body mount instructions include this step 5...

5. MODIFY RADIATOR
Locate the four fan shroud mounting holes on the radiator.Measure exactly 1” below the factory mounting holes and mark the location with a center punch. NOTICE: The lower passenger side hole will line up with an existing factory hole and will not require marking with a center punch. Drill a new 1/4” hole through the three center punched marks.

i don't understand why the shroud needs to be lowered since the motor (and fan) is lifting. the body mount instructions do have optional paths when the mml is included, but step 5 remains regardless..

thanks for any thoughts.
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Do the work, check shroud to blade clearance. If it isn't roughly centered top to bottom on blade, make it so. Nothing else matters.
 
When you do both a MML and BL there’s usually no need to adjust the location of the fan shroud.

Just loosen it up before you go to work, after you’ve done both lifts check the position. Normally everything is good. Tighten down
 
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JMT said:
When you do both a MML and BL there’s usually no need to adjust the location of the fan shroud.
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Exactly, which is why I think it's silly not to do both of them together.

Without the MML, you're raising the body, so you have to move the fan shroud accordingly, otherwise it will contact it. Maybe there are rare instances where it won't, but on mine it certainly did until I installed the MML.
 
I didn't need to relocate it. Just reinstalled it in its original holes.

But you need to unscrew the shroud anyways until both BL and MML are done because they don't get lifted simultaneously. Jack up the body and you might put the fan through the shroud.

With the JKS BL be very careful not to over torque the fasteners past what the instructions recommend. The pucks are very squishy, and mine permanently deformed after a few months.

The other thing you have to be careful of is the gas tank filler hose. Lift the body too high and something could break. Lift the body only as far as is needed to get the pucks into place.

To make life easier I recommend putting the frame on jackstands. Then you're not fighting suspension flex when jacking up the body
 
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Rob5589 said:
No. The factory cooling system works very well when properly maintained. Why introduce more headache and significant expense in an attempt to avoid drilling a few holes, if it's even needed?
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Yeah, that's the equivalent of rebuilding the motor because it might need a new set of spark plugs. You haven't even pulled one to find out but you're gonna tear down the motor instead. Silly.
 
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Rob5589 said:
Why use an inferior cooling system for maybe a couple hp?
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What couple of hp? Can anyone actually prove that?

The 1-2 hp you MIGHT notice on a dyno before and after an electric fan conversion can be chalked up to nothing more than variables such as engine temp, outside temp, altitude, dyno type / accuracy, humidity, etc.

There is NO measurable difference from switching to an electric fan that anyone can measure with any sort of accuracy in my opinion. You already know this of course, I'm just ranting because I'm so sick of people believing that switching to an electric fan somehow gives them extra horsepower. :rolleyes:
 
Chris said:
What couple of hp? Can anyone actually prove that?

The 1-2 hp you MIGHT notice on a dyno before and after an electric fan conversion can be chalked up to nothing more than variables such as engine temp, outside temp, altitude, dyno type / accuracy, humidity, etc.

There is NO measurable difference from switching to an electric fan that anyone can measure with any sort of accuracy in my opinion. You already know this of course, I'm just ranting because I'm so sick of people believing that switching to an electric fan somehow gives them extra horsepower. :rolleyes:
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Getting to this level of discussion that started as why or when to move a fucking fan shroud due to a body lift (not even one that was installed yet) is obscenely dumb and it needs to stop. Anyone that takes the suggestion to replace the mechanical fan blade, shroud, and fan clutch with an electric over relocating the shroud 1" deserves the pain, suffering, and expense of doing so.
 
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cmitcham said:
i don't understand why the shroud needs to be lowered since the motor (and fan) is lifting.
Click to expand...

I found out (many years later :censored:) that my fan blade was grazing the bottom of the shroud after a BL and MML lift. The shroud was lowered with four self-tappers to clear. You can't take anything for granted with even seemingly easy mods. Check and then double check.
 
Sorry to prolong the agony here, but I wonder if the OEM fan really does take any power when you need it which is on the highway? The air flow through the radiator at 60 mph may actually be enough to freewheel the fan. Sure, it uses power at low forward speeds, but who cares?
 
TurboTJ said:
Sorry to prolong the agony here, but I wonder if the OEM fan really does take any power when you need it which is on the highway? The air flow through the radiator at 60 mph may actually be enough to freewheel the fan. Sure, it uses power at low forward speeds, but who cares?
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FWiW, I only notice the fan clutch kicking in at slower speeds. According to my ODBII, the engine typically runs cooler on the highway when there is already a lot of air moving through the radiator.

A while back, when the original fan clutch was dying, the engine would start to heat up at slow speeds and cool down again as I sped up.

All of that tells me that an electric fan won't do much in the way of HP gains on the highway where the cooling system isn't working hard to begin with.
 
Not to mention that where energy required to spin a fan is concerned, there is no free lunch at the energy food buffet. Converting the fan to run off 12 volts just means the alternator will then be harder to turn which places an additional load on the engine just like the serpentine belt driving the fan does.

And for those who didn't realize alternators and generators require more power to turn the bigger the load that is placed on them, just listen to what happens to the rpms of a generator when the load (like lighting) is switched on. The rpms drop down until the generator's speed governor kicks in to bring the rpms back up again. It takes power to provide power.
 
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Steel City 06 said:
I didn't need to relocate it. Just reinstalled it in its original holes.
...
With the JKS BL be very careful not to over torque the fasteners past what the instructions recommend. The pucks are very squishy, and mine permanently deformed after a few months.
...
Click to expand...

An interesting thing about the squishy JKS body lift...

On mine, I never moved the shroud after the JKS body lift and 1" mml went in. Years later I installed the Savvy skid and the shroud still didn't move. On very rare occasions, I would hear the fan scrape.

Then about a month ago, I switched to the Savvy body lift, regained about 3/8" of missing 1.25" body lift and found that the fan was wedged into the bottom of the shroud and wouldn't spin. That was when I moved the fan shroud.

As far as JKS's "torque spec", go back to the first spacer you tightened to spec and see how tight it still is. Keep going around to double check and watch as the lift height decreases. An inner sleeve or a rigid spacer would prevent that, and allow you to actually reach full torque.
 
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