Nissan 370Z Forum - STILLEN lightweight crank pulley

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- - STILLEN lightweight crank pulley (http://www.the370z.com/engine-drivetrain/2497-stillen-lightweight-crank-pulley.html)

You two get a room :)

Quote:

Originally Posted by wstar (Post 60357)

Good point. Using the sharp multimeter probes made it easy to tell which parts were rubber and which were metal too, I think I understand the piece now. It wasn't built like I though it was at first. First, here's some pics from my cellphone:

Front view:
http://www.the370z.com/members/wstar...lley-front.jpg

Side view:
http://www.the370z.com/members/wstar...ulley-side.jpg

Rear view:
http://www.the370z.com/members/wstar...ulley-rear.jpg

The pulley is constructed from two separate pieces of metal which are not electrically connected, but it's not a ring on the back like you would think. The inner part of the pulley (the hub and spokes) is separated from the outer part of the pulley (the outer ring with the grooves for the belt). The circular groove you see in the front and rear views is the layer of (very stiff) rubber between the two parts, as highlighted in red here:

http://www.the370z.com/members/wstar...ley-rubber.jpg

I still don't know if that helps draw any independent conclusion. It's not like the design of V8 harmonic balancers I've seen in the past. Those are generally a solid complete pulley, with a ring (picture like a very large washer with a very large opening) mounted on the backside of the outer diameter, separate from the pulley by a layer of rubber. This could still easily be either a real torsional damper or just an NVH-reduction device to me, given how little I really know about the subject.

This is the exact same construction used in Ford V-8 applications. Its a injection molded rubber that is bonded between the inner hub and the outer inertia ring. I deal with the O.E. supplier for Ford's dampeners. That is indeed a harmonic balancer and should only be replaced with a pulley that also is a harmonic dampener, period.

Quote:

Originally Posted by 370ZDreamer (Post 60829)

There's a logic error here... just because it's constructed the same as a balancer on a Ford V-8, does not mean that it's necessary to prevent actual engine problems on a Nissan V-6 (as opposed to NVH).

Is there any way we can magically summon a nissan engine designer into this thread and settle this?

i dont know about a nissan engine designer, but RCZ should have this puppy on soon, so time will tell if the mythcial harmonic balancer (or lack thereof) will rape this motor or not.

Say it were necessary to have the dampener. How long before the engine suffers from the lack of one?

someone getting cold feet

Nope, Im still doing it.

Quote:

Originally Posted by ssqpolo (Post 60974)

i dont know about a nissan engine designer, but RCZ should have this puppy on soon, so time will tell if the mythcial harmonic balancer (or lack thereof) will rape this motor or not.

Mine's been on for about 3.5 days so far, the underdrive version (hence me having pics of the stock one off the car).

wheres your review wstar, how is it.. whats the butt dyno say? notice any difference in PS, or anything?

Quote:

Originally Posted by Brazilbro (Post 61391)

wheres your review wstar, how is it.. whats the butt dyno say? notice any difference in PS, or anything?

My info on the pulley install starts here in my journal: http://www.the370z.com/members-370z-...html#post59072

My apologies.. time has gotten away from me. I have some info that will clarify the OEM pulley and the illustrious rubber center section.. but if you'll give me until tomorrow so I can get with my techs to get everything 100%..

Confirmed my suspicions, and should yours.. I just want to make sure I have the wording right.. didn't mean to ignore a response..

Quote:

Originally Posted by 370ZDreamer (Post 60829)

This is a harmonic dampener of sorts, on that point you're exactly right. But it's not to balance the engine, it's to balance the pulley ITSELF.

http://www.stillen.com/misc/stockpulley1.jpg

The factory pulley is NOT balanced, and the dampening employed on the pulley is to protect the engine from the outside influences going inward.

http://www.stillen.com/misc/stockpulley2.jpg

The factory pulley is a rough casting, done this way for cost reasons. To cut the entire pulley out of 6061 billet aluminum and balanced is an expensive proposition. They chose to cast the pulley, and add a rubber insulator to act as a dampener. Some other things can assist in dampening, the rubber belts and tensioners in the serpentine belt can help with NVH, and suitable when using a balanced pulley.

You can see the differences in the quality of the part...

400370 - Underdrive Pulley

http://www.stillen.com/misc/400370_s...70z_pulley.jpg

400338 - Standard Lightweight Pulley

http://www.stillen.com/misc/400338_s...ulley_370Z.jpg

Good info, good to know, glad I have one.

Not to the level that they would run it without adding the extra security of the rubber ring.. yes

I really want to see some dyno results for the lightweight crank pulley. I'm almost certain I'll be getting one after I get my exhaust.