STILLEN lightweight crank pulley

SOLISIMO · 04-21-2009, 04:29 PM

You two get a room

370ZDreamer · 04-22-2009, 09:06 AM

Quote:

Originally Posted by wstar

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:

Side view:

Rear view:

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:

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.

wstar · 04-22-2009, 01:11 PM

Quote:

Originally Posted by 370ZDreamer

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.

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?

ssqpolo · 04-22-2009, 01:18 PM

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.

RCZ · 04-22-2009, 01:22 PM

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

ssqpolo · 04-22-2009, 01:23 PM

someone getting cold feet

RCZ · 04-22-2009, 01:27 PM

Nope, Im still doing it.

wstar · 04-22-2009, 03:36 PM

Quote:

Originally Posted by ssqpolo

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).

Brazilbro · 04-22-2009, 10:49 PM

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

wstar · 04-22-2009, 11:54 PM

Quote:

Originally Posted by Brazilbro

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: wstar's Journal

Josh@STILLEN · 04-23-2009, 12:02 AM

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..

Josh@STILLEN · 04-23-2009, 01:22 PM

Quote:

Originally Posted by 370ZDreamer

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.

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.

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

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

400338 - Standard Lightweight Pulley

RCZ · 04-23-2009, 05:18 PM

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

Josh@STILLEN · 04-23-2009, 06:11 PM

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

Skorch · 04-24-2009, 01:30 PM

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.

04-24-2009, 01:30 PM	#60 (permalink)
Skorch Enthusiast Member Join Date: Feb 2009 Location: Phoenix, AZ Posts: 469 Drives: 2012 370Z Rep Power: 540	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. __________________ '12 370Z + Sport \| Stillen Gen3 Intakes \| Stillen UD Pulley \| Motordyne M370 \| FI Exhaust \| FI HFCs \| 4.08 Gears \| Uprev tuned

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04-21-2009, 04:29 PM	#46 (permalink)
SOLISIMO Track Member Join Date: Apr 2009 Location: Florida Posts: 510 Drives: TOP SECRET G37S Rep Power: 17	You two get a room

04-22-2009, 01:18 PM	#49 (permalink)
ssqpolo Track Member Join Date: Jan 2009 Location: Florida Posts: 882 Drives: '12 Black Nismo Rep Power: 267	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.

04-22-2009, 01:22 PM	#50 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	Say it were necessary to have the dampener. How long before the engine suffers from the lack of one?

04-22-2009, 01:23 PM	#51 (permalink)
ssqpolo Track Member Join Date: Jan 2009 Location: Florida Posts: 882 Drives: '12 Black Nismo Rep Power: 267	someone getting cold feet

04-22-2009, 01:27 PM	#52 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	Nope, Im still doing it.

04-22-2009, 10:49 PM	#54 (permalink)
Brazilbro A True Z Fanatic Join Date: Mar 2009 Location: Indianapolis, IN Posts: 1,131 Drives: Juke/240Z Rep Power: 848	wheres your review wstar, how is it.. whats the butt dyno say? notice any difference in PS, or anything?

04-23-2009, 12:02 AM	#56 (permalink)
Josh@STILLEN The370Z.com Sponsor Join Date: Dec 2008 Location: Costa Mesa, CA Posts: 1,197 Drives: 2004 G35 Coupe 6MT Rep Power: 534	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..

04-23-2009, 05:18 PM	#58 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	Good info, good to know, glad I have one.

04-23-2009, 06:11 PM	#59 (permalink)
Josh@STILLEN The370Z.com Sponsor Join Date: Dec 2008 Location: Costa Mesa, CA Posts: 1,197 Drives: 2004 G35 Coupe 6MT Rep Power: 534	Not to the level that they would run it without adding the extra security of the rubber ring.. yes