thought thay were ment to be all balanced up read from fensport? i had to get a new 1 cos the old pully i managed to chip in three places when i took it off

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The OEM and the Fensport lightweight crank pulleys are just simple pulleys. They are not harmonic balancers. Of course in the unlikely event that they are badly made and not symmetrical then this would cause problems with vibrations. The headline is that I wouldn't worry about fitting either of these type of pulleys.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

strange, i have heard that they were harmonic balancers don?

from multiple different places, is this not so?

Proper harmonic balancer pulleys are two piece, an inner and outer, usually joined wit an elastomer

Same principle as dual mass flywheels but on a smaller scale

been told now that its nothing to do with ballancing its harmonics inside the crank it causes crank to break eventually, normally along the bigend journals , the OEM has a big pieces of rubber inside dampen the harmonics
so what do i do? i dont want to brake my crank

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If in doubt don't mess with it

Nibbles posted some youtube videos on Keith Duckworth (Cosworth) a few weeks ago (and they were superb). In that the cossie boys found crank whip in a 4 pot F1 turbo engine. Wasn't nice watching them pour the internals into a bucket

The standard crank pulley is 2 piece with an elastomer joining the 2 bits. I may have one in 2 bits I can photo after applying the pulley puller to the wrong part and separating the outer pulley part whilst still leaving the inner bolted to the crank! It was a scrap engine anyway!

I would be interested in other people's thoughts on this as I understood balancing the engine rotating assembly will do nothing to cut down the Vibration and fatigue caused from the harmonic resonance of the crank?

From my basic understanding of waves and vibration the harmonic is a function of the length/ mass and force acting points for a given item. The driving force I assume is the big bang in this instance and I suspect you will find one particular rpm where the crank resonates badly without a damper.

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

Sounds pretty much spot on JP

Many moon ago I helped design an AV cradle for an optical disk drive. You cannot remove a resonant frequency, only counteract it with other weights and damping. Hence the seperation of the two masses by rubber

I don't recall the stock pulley being two part but I never gave it that much thought

I know the Mondeo has a harmonic pulley for sure

Aye pretty much all Toyota pulleys from the iron block/alloy head era are two part. I guess it was that or balancer shafts and all that guff. Personally I would stick with OEM.

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Caldina Blog

Hi,

use the oem pulley, toyota would not use it just for fun

/Edit

even TTE use them iirc

greetz

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KEEP COOL UNDER PRESSURE

street legal?.....perhaps in tschibuti

OEM = damper indeed. Fyi; CS pulley is just over 2 kg:

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René - Carlos Sainz 2433•5000
Turbocelica.nl | ST185 CS restoration and full rebuild

If it ain't broken.. it soon will be

any 1 got a spair ome pully i can pinch

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As stated above the stock crank pulley is a carefully constructed item.

I believe that as a whole the crank, pulleys, (including cam belt pulley), flywheel and clutch assembly should be balanced first individually and then as a whole assembly.

The stock crank pulley dampens the harmonics aka vibrations present along the crankshaft. Removing the dampener is not good for engine longevity imho.

A better source for snappier engine response is a lightweight clutch, lightweight pistons, rods etc (imho).

Sorry for the unwelcome opinion!

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement

I am not sure we are diss-agreeing Kris.

Balancing the rotating assembly as you describe is indeed a very wise move. I just don't think it has much to do with the main crank harmonic vibration that teh pulley is designed to dampen.

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

Agreed

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement