# sounds like a wind tunnel when i accelerate



## SmashThat (Nov 15, 2005)

does anyone know if i would need a shroud with a 14" electric fan?


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## SmashThat (Nov 15, 2005)

ok, my car is all back together and running good. the only problem is, when i accelerate, my fan sounds like a windtunnel. it spins faster the more i accelerate. anyone had this problem?


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## rogoman (Dec 16, 2004)

The fan clutch has gone bad.


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## SmashThat (Nov 15, 2005)

thats what i thought. thanks


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## SmashThat (Nov 15, 2005)

ok, my next question, is there a trick to taking it off once you get the nuts off? it doesn't seem like it wants to come off at all.


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## SonsofWisdom (Mar 29, 2004)

I've never takin off the fan on the 240sx...but I have many others...I'm guessing it's just...stuck...but..wait for others to reply who'v done it...don't want you to break it on my account

Might I recommend...HIGHLY...going ahead and doing the electric fan conversion? Ubber easy...and done a few times...


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## 93_240_ka (Oct 26, 2005)

SonsofWisdom said:


> I've never takin off the fan on the 240sx...but I have many others...I'm guessing it's just...stuck...but..wait for others to reply who'v done it...don't want you to break it on my account
> 
> Might I recommend...HIGHLY...going ahead and doing the electric fan conversion? Ubber easy...and done a few times...


Yeah, read the sticky on the page before this. It'll help you out.


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## SmashThat (Nov 15, 2005)

good idea, i totally forgot about the electric fan and i was gonna do that anyways. does anyone know if its ok to use a single universal fan? thanks


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## 93_240_ka (Oct 26, 2005)

Yeah, if you're going single, use a 14" fan. it'll take up alot of radiator, but it won't take up too much. Permacool has a 14" that heavythrottle uses on their SR swap guide, it's about 100.00 and from the stats on it, it flows pretty well for a 14 with low amp draw.


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## SmashThat (Nov 15, 2005)

does the fan have to face the engine like the stock one or will it face the radiator?


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## SmashThat (Nov 15, 2005)

will it matter that the shroud won't be there anymore to collect all the outside air?


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## surfer240sx (Dec 15, 2005)

o while u all are on the subject of the electric fan, isnt it bad to take weight off the crank? I heard its balanced perfectly the way it is cuz i asked about lightweight pulleys and they said u can snap ur crank i dont c how but thats wat i heard just looking for some clarification before i make that step.


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## rogoman (Dec 16, 2004)

zellx2004 said:


> Thank you for clearing that up. Where did you search to find out that the KA was an internally balanced engine?


I first ran into this situation years ago with the small block Chev V8 and the small block Ford V8; the Chev is internally balanced and the Ford is externally balanced; the Chev flywheel and front pulley are neutral balanced while the Ford units have offset cast-in balancing weights. 

I looked at the Nissan KA flywheels and front pulleys and found them to be neutral balanced so I figured the motors are internally balanced; to verify this I checked out the Fresh Alloy, Nico and KA-T forums with that question; the reply was 'the Nissan motors are internally balanced'.


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## surfer240sx (Dec 15, 2005)

btw i have a used 14in electric fan, is there a way to test it before i put it in? is it positive to positive neg to neg cuz if it is then it doesnt work lol got it from my sises grandam it looks like a nice fit so why not rite?


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## rogoman (Dec 16, 2004)

It seems that this question comes up all the time in many of these forums so I'll post my standard reply.

The OEM pulley has a built-in harmonic damper not a harmonic balancer. The KA motors are internally balanced. If you look at the back side of the OEM pulley/damper, the casting is uniform meaning that the damper is a neutral balance damper. The same thing should hold true for the flywheel. Externally
balanced engines typically have an extra counterweight that's cast into one side of the harmonic damper.

If the KAs were externally balanced, everybody that runs an Unorthodox pulley would have severe vibration problems because the units have a neutral balance. So running an Unorthodox pulley and a lightened flywheel will not alter the balance of the motor.

However here's a caveat to the story. Both the OEM flywheel and front pulley are designed to act as harmonic dampers. Lightened flywheels and lightened pulleys will cancel much less harmonics causing 'possible' vibrations at certain RPMs. It all depends on how well the motor is balanced; OEM balancing will always have some degree of compromised tolerance because of mass production techniques compared to a custom balance. Some OEM balanced assemblies may be better then others.

So to make a long story short, many folks that run UR pulleys don't have any problems, while others may experience problems.


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## zellx2004 (Sep 30, 2004)

rogoman said:


> It seems that this question comes up all the time in many of these forums so I'll post my standard reply.
> 
> The OEM pulley has a built-in harmonic damper not a harmonic balancer. The KA motors are internally balanced. If you look at the back side of the OEM pulley/damper, the casting is uniform meaning that the damper is a neutral balance damper. The same thing should hold true for the flywheel. Externally
> balanced engines typically have an extra counterweight that's cast into one side of the harmonic damper.
> ...


Thank you for clearing that up. Where did you search to find out that the KA was an internally balanced engine?


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