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Old 05-28-2004, 07:42 PM
LeaUK LeaUK is offline
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Join Date: Feb 2003
Location: UK - South East Coast
Posts: 864
Hi

Thanks for your comments and after reading your #Menu21 I see you've carried out some very valuable experiments yourself too - great stuff.

Yes, I did misinterpret your proposed mod as I skimmed through it and noticed that most of the text points to the fan being engaged constantly
Quote:
This will give you full tilt fan engagement right up to the high speed disconnect around 2,500 rpm. You won't believe the amount of fan noise but the engine runs cool as a cucumber.
and

Quote:
So this modification changes the clutch to lock up at all times.
but you are quite right, the mod will in fact allow more control and adjustment than I originally considered - however TBH, this isn't my question as I'm not doubting your mods or experiments.

I want to know if the clutch should engage if the engine RPM is already greater than 1500. That's my uncertainty.

Quote:
But 2000 - 2500 rpm is about optimum, wouldn't you agree?
Yes, most definitely. 3000RPM does seem a little high - but I've chosen 12,500CST fluid and maybe MB original is slightly lower. However I have canvased several mechanics opinion on how mine feels compared to original clutches and most agree that it has the correct amount of resistance - in fact one said it feels slightly less resistive than he would expect!!

My personal opinion is that Benz/Sachs designed the VF to operate at around 95DegC (being a sensible temperature) ie the strip bends (n)mm releasing x(cc) of silicone fluid thus gripping the fan by (y)N - but as the VF ages the fluid either changes viscosity or the volume of fluid reduces thus the strip has to bend further to engage (ie higher temp is needed to achieve the same cooling). This maybe wrong but this makes more sense to me, rather than poor design.

BTW - have you any thoughts what the black plastic casing's purpose is? Is it there for protection only or maybe some kind of airflow regulation?

Lea
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Last edited by Learoy; 05-28-2004 at 07:47 PM.
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