Alright everyone. Let's try to settle this issue once and for all.
That is, if it can be settled...

Topic in question: UR Crank Pulley... Will it lead to crankshaft and/or bearing failure?

I actually have a UR Crank Pulley installed on my ride. For those of you that have it as well, you'll agree it's a great mod. Relatively cheap and nice gains. But now i'm hearing and reading more about the future problems that *MAY* eventually arise.

Here's What I'm Reading/Hearing (Facts and Theories):

1. Since the UR Crank Pulley *DOES NOT* come with a harmonic balancer, there is excessive/unbalanced "Torsional vibration" and it could lead to crankshaft damage/breakage in the long run. (Torsional Vibration occurs while crankshaft spins and rebounds back, resulting from the cylinders firing and rods spinning the crankshaft)

2. The lighter UR Crank Pulley will "lighten" the load on the crank pulley and would reduce the "Torsional Vibration" and thus, the lack of presence of the Harmonic balancer or Torsional Damper is not an issue.

3. Balance shafts, which are used by several manufacturers, are specifically designed to eliminate harmonic vibrations

Now, we all know no one has put more than 30k miles on a G with the UR Crank Pulley. The bearings and crankshaft wear would come about much later... like around 100k miles (in theory)

My questions:

1. Do our Gs have balanced shafts that do not require a separate harmonic balancer/torsional damper?

2. Would the lighter UR Crank Pulley reduce or magnify the severity of torsional vibrations?
Basically: Stock (Heavy) Crank Pulley + Slower Spinning Shaft vs. Lighter Crank Pulley + Faster Spinning Shaft

I know we've got some gurus up in here. Let's hear the final verdict!

 

I've went back and forth trying to decide if I want to get the UR pulley. Most people who have it say it's a great mod and have no problems but then there's always someone with a different opinion. Hopefully this thread will get a good response.

 

bump, Im still interested also.

 

Opinion just an opinion without any data or fact to support it. I just installed mine 3 weeks ago, and I certainly love it.

I'm a mechanical engineer and working for auto parts manufacturer. So, I did ask around about the pulley. All my friends said that it shouldn't affect the internal engine et al, because it's already balanced. Torsional problem occurs when you put the belts too tight or too loose. I'm not worry about it, and my dealer didn't warn me anything.

 

The guys on maxima.org have been using the pulley on their 3.5 liter VQ's for a couple years longer than us Z and G guys. Do a search over there. No issues and I'm sure some of them are over 100K miles and much more than that with the 3.0 liter VQ.

I've done 2 Blackstone oil analyses both with some very extreme seat time. One was extended canyon carving above 4K rpms for about an hour and 1 HPDE on the track. My lead levels (indication of bearing wear) came out to be 1/4 the average levels (2 ppm v. 6 ppm). I guess one could argue that the UR pulley may be better than the OEM pulley.

In response to the harmonic dampening: My understanding is that the stock pulley has a rubber ring glued and slightly recessed into it. Unlike other harmonic dampeners, it does not go through the pulley in any manner. Some have stated that the rubber band is present to tame belt noise, not dampen harmonic vibrations. I tend to agree.

If anything, the UR pulley is probably more balanced than stock. Being milled from an aluminum billet, it's tolerances are inherently tighter than the stock, cast pulley. Casting introduces many avenues of imbalance.
1. is the metal sufficiently homogeneous so that there aren't pockets of heavier or lighter metal in different parts of the pulley?
2. QC/QA: was there any ultra sound testing for pockets of air? Doubt it.
3. How long is that rubber band going to last without shrinking or dry rotting with the extreme temps, oil, dirt, etc., it has to endure?

 

theres no way i'm takin off my pulley, unless i found out some major damage to my engine which i dont think will really happen.

only thing with the pulley is that i drive it alot harder than when i didnt have the UR pulley. i guess thats the only damage that this product does to our cars. hehehe.

 

is it okay to use the pulley's with turbo

 

There has been so much debate on this subject for a long time (here), with no difinitive answer.

There are so many pros and cons, it's hard to get a feel for the mod.

For what it's worth, my dealer offered to help with my install, so I know he's cool with it. Others may feel differently.

At one time I was going ahead with the mod. but due to controversy, I shelved the idea.
I've now decided that after hearing all the pros on the sugject, and have not heard of any problems, that I would go ahead with it.

It's a great mod that I've done on many previous rides, and know it has benefits.......the only thing that's a guess is long term issues. (after 100k miles use).

My suggestion would be to make sure you have support from your local dealer, and even get their help with install b4 considering this mod.

G/Luck

 

If some dealers are helping with the install does that mean it doesn't void the warranty?

 

I had the dealer install all 3 of mine (crank, alt, and water pump). They work great and I've got about 24000 miles on them. Incorrect installation (over tightening leading to warp/tweak) is what leads to problems. The UR pulley is aluminum and extremely well balanced from the factory. Properly installed, it is better balanced and smoother than the OEM unit. Incorrectly installed and it becomes a bearing killer. Leave the install to a professional factory trained mechanic. This is one you dont want to screw up.

 

14k miles on mine and it's still one of the best mods to date - after the initial "squeeling" the first few days, I've had "0" problems with this... and as stated above, after inspecting both the stock pulley and the UR piece, the UR pulley is *much* better quality than the stock piece... so I've had no qualms about this since I received it...

besides the loudness of my exhaust, this is the one mod that makes my car feel the most difference between it and a stock G... revs like a beast!

 

There are indeed some pros and cons, but...I feel that the machined billet aluminum would be more balanced than the steel unit that comes stock. My old Harley can run for 100K miles of pretty hard use, and that motor rattles like a cement mixer. Yes, they might have huge bearings in the hog, but it seems that most guys wear down the piston rings long before the bottom end needs a rebuild.
The internal balancing of most new engines should not necessitate a balancer in the pulley. Just my 2 cents.

 

I now have over 8k miles on the crank pulley with no issues.

I took the car in for a 15k and they changed the oil.... I forgot to tell them not too, as i have been really busy lately. Anyway, I had a container in the car so they captured a sample for me. So the next analysis I will have done will only have about 1500k and 3 drag nights on the oil.


Stay tuned...

 

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If they help with the install, they couldn't deny warranty.
Go over this mod with the dealer and see what his attitude is. Some are cool with it and will help, others won't touch it and would prolly deny any warranty work.

 

Damn'it, you guys are going to talk me into installing one of these bad boys. I'll be the one with the engine problems, GUARANTEED! Can someone give me a link to a person who has the VQ30 with 100,000+ miles and the pulley? TIA