Stillen U.D. pulleys help.
 

I ordered stillen underdrive crank pulley and belt, after talking to my shop about the install they informed me that it would replace the damper which I didn't know was fluid filled to aid in engine vibration. Is the vibration that serve with the U.D.? Would NST pulley set work with the stillen U.D.? Or should I just try to sell them?

What fuckíng horseshit shop did you go to? Go somewhere else that doesn't shove their head up their own ásses for lunch...

Fluid filled, LOOOOOOL!!! Dampener, LOOOOOOOOL!!! It's a solid piece of cast iron, no fluid or dampener anywhere

Pretty much took the words out of my mouth.

SO they are fudging me around. They told me that I would have serve vibrations using the underdrive pulley, and since it is 20% underdrive my other pulley's couldn't keep up.

How you say......ra tards!

You are going to get more vibration because you are removing the vibration damper .... you may not feel them because they are harmonics at higher rpm.

Whether it is a damper that is fluid filled or just a ring of cast iron, it is no longer present, so the damper effect is actually removed.

Whether this is going to affect your engine is the real issue. If you give the car a spanking every now and then, probably not, but drag it or track it with sustained hi-rpms, it might.

Many years ago, with a race engine based on a Traco-Olds 215, that was all internally balanced and with the crank damper deleted, we kept losing cranks and eventually solved the problem by using an ATL race damper, so I can confirm that revving the engine hard enough for long enough with cause failure.

DD road duties, it "should" last for as long as you own it ...

On THIS car, where is the dampener on the pulley?

Refer page 1679 of workshop manual - is integral/internal to the pulley ... refer snips attached. Also here:
http://workshop-manuals.com/nissan/3...iew/page_1679/

If you reckon there is no damper, knock yourself out ... my workshop manual reckons it is internal to the OEM pulley and with 20K in parts to go into my race engine, I will be fitting a Ross damper.

Like I said to the OP, maybe not necessary on a DD but my bus lives at 6500-7500rpm on regular track days.

Tread your own path ....

I have a stillen pulley no vibration no dampers no fluid all I know it was all fun fun...

thank you all

May I pose the question of... (And I don't mean to be an ásshole)

Does an aftermarket flywheel damage the car? After all the flywheel is on the other end of the crank, and weighs MUCH more than the crank pulley, and is much bigger, so even the slightest vibration has gotta make a bigger difference, no?

It is not vibration per se, it is the harmonics .. I'll find a reference for you and post it here later.

Reference 1: Wikpedia on harmonics: http://en.wikipedia.org/wiki/Engine_balance
Reference 2: Coming .....

In my post I used the word "vibration" but to be strictly accurate, I should have used the word "harmonic vibration".

It is harmonic vibration that destroys OEM oil pump gears in the VQ engine above 7500rpm - I cannot find the actual engine speed as my notes are in the orifice at work - but it is around 7600-7700.

The reason I have reservations about after-market pulley kits is that no-one knows what engine speed the critical harmonics are exhibited ... and these harmonic vibrations are engine killers ...

If you want to know more, take the time to speak to Jackson Stewart at Unitech Racing as I have done several times, or Clark Steppler at JWT and I am sure they can fill you in on the details.

A flywheel is an inertia storage device, not a damper.

The purpose of the damper on the nose of the crank is to either shift the rotational frequency (engine rpm) at which catastrophic harmonics become evident out of the engine operating range, or to damp them such that they are no longer destructive.

Mate, you can disagree with me, even tell me I am a d1ck-head full of sh1t, but 40 years of motorsport and the pain and disappointment of losing 3 cranks in one season taught me a hard lesson about harmonics, and that is knowledge that I respect.

Now, the OP was told by his shop the proceed with care, and all I am doing is echoing those words of advice.

I do not know what the implications for after-market pulleys actually are - they may be totally benign (and probably are) but if the OP wants to use his vehicle on the track or strip, I am simply saying buyer beware.

There is no need to continue this thread .. because we are each accountable to ourselves for our own actions - I am not dictating to the OP, merely providing fact-based information that may, or may not, be pertinent to his post.

He (and you) are always at liberty to ignore the statements and that is your right.

As I said, tread your own path ....

^I like you
Since I have been informed that you Aussie's don't drink Foster's in Australia... If you ever make your way to the states, Foster's on me! Lol :tiphat:

7500rpm with the factory balancer.

So what I;m asking is the Pulley won't hurt the engine at all. I just don't want sh*t to go wrong or dying in the long term.

Yes it would be fine I have my stillen for 24k miles now the car runs as fast as ever. But since its UD I think you need to change the alternator pulley too.

No, you'll be fine unless you have a huge stereo. I have it without an alternator pulley and have no problems

^ If Andrew said its ok then you can take his statement like a good check to the bank and cash it in!

All you need is to get a reputable mechanic to install it!
Have fun with your Z!

So for everyone who's blown their motors, I've always seen them run higher than OEM redline. I've seen the VVEL blow, the bearings blow, and the oil pump blow. I know the high rpm's killed those motors but I'm wondering how many had lightweight crank pulleys installed also. It just seems too risky.

And from holding a bunch of OEM crank pulleys after installing lightweight crank pulleys, they all seem solid but they're not. They all have a tiny rubber section splitting the two halves that you can move back-and-forth even with your own hands. Now imagine what kind of movement back-and-forth that can have at an 8000 RPM shift point.

^ So would you say for a few spirited runs in a week not even through redline is safe?

I redline my car all the time, Stillen pulley has been on for... 20-30k miles?

Oh well lets go redline then. Lol

If my engine blows thats gonna be good excuse to get a C6!

i would never install them on my car on any car i work on . the only damper other than oem ive even used is an ati fluiddamper . there is an reason its there . say you have an alternator starting to go bad at that point your are adding a side load on and off the end of the crank that with a rubber isolator you wouldnt have added to the crank . besides that it is made to remove harmonic vibrations caused by combustion and side loads on the crank at diff angles . hence the name harmonic balancer . the gains you will see from changing this are so minimal its not worth the risk .

risk vs reward = no beuno to me ..

its your car do as you will . ill leave you with this . look up whatever race motors you want you will see a balancer on there not a straight crank pulley . granted most of them are driving dry sump oil systems and or mechanical pumps . most teams use ati balancers in my exp .. very good product .. hell call your local reputable machine shop and ask him the value of the balancer . im not saying it will blow up tomorrow just that its there for good reason .

There are plenty of threads on here that talk about blowing engines using solid light weight pulleys. If your not AutoX or racing on Sebrings / Willow and your a guy that drives a little hard once in a wile you will be fine.

The ones that blow apart are doing dyno pulls at parties and racing there cars on tracks. You drive like that daily to work and back you need your engine blown.

Really? I can't find any where the pulley was the culprit