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Discussion Starter · #1 ·
Good afternoon,

If you have a UR Crank Pulley, PLEASE READ AND UNDERSTAND THE FOLLOWING!

I have been having some engine problems lately and I have conclusively traced them to my crank pulley/belt setup.

SYMPTOMS
1. Crank pulley appeared to wobble when the engine was running at idle
2. Engine "whined" ever so slightly at idle
3. Heard a fast-paced "whoosh-whoosh-whoosh" when the AC was on and at idle. This sound appeared to be coming from the bearings on one tensioner pulley.

OTHER MITIGATING FACTORS
I recently had an alternator replaced by the dealer and the belts were certainly on too tight. I do not believe this caused the crank pulley to fail. However, I do believe the belts being too tight could have caused symptoms 2 and 3 above.

EXAMINATION
Obviously, issue 1 (wobble of crank pulley at idle) was a very serious concern. So, I dismounted the belts. I then went to remove the crank pulley. It was immediately loose in the mounting socket. I could wobble it back and forth. Also, I could unscrew the center bolt with just my fingers.

Once removed, the issue was obvious. Both the stock and UR crank pulley have a bore in the middle to accept the end of the crank shaft. This bore also has a key-way that accepts a key on the crank shaft. When mounted, the pulley key-way must match up to the key on the crank shaft. This also keeps the pulley from just slipping. Obviously, the force exerted by the crank key on the pulley key-way is going to be pretty high.

On my UR pulley, the key-way started at about 1/8 inch wide. When I examined it after 1.5 years of use, the key-way had expanded to well over an inch in width.

So, when the UR pulley was mounted, I could easily rotate it back and forth in the socket without moving the crank! Also, the pulley no longer sat true in the socket. It was totally useless.

To make matters worse, the bore on the UR pulley had a light coat of oil on it. My oil seal at the front of the crank must have either leaked a little due to the vibration or it has been damaged. However, I don't think the damage is severe. I am not detecting any other signs of oil loss.

THE FIX
The UR pulley is now off and waiting on me to take photos. Since the warranty is only 1 year, I will trash the piece after I photograph it.

Thankfully, neither my crank nor the front oil seal appear to be damaged. I mounted the stock pulley and it is tight in the socket and runs very true. With the stock belts back on and the proper belt tension set, I no longer have any of the symptoms listed above.

RECOMMENDED SERVICE FOR ALL USERS OF ALUMINUM CRANK PULLEYS
Regardless of what type of aluminum crank pulley you use, I would recommend following the service recommendation below. The fact of the matter is that the key on the crank exerts a lot of force on the aluminum key-way on the pulley. In general, aluminum may be able to handle this force, but if you have a pulley with a defect, the aluminum could easily wear away like mine.

Perform the following with every oil change:
1. Observe the crank pulley and determine if it is rotating properly

Perform the following at least twice a year (regardless of results from 1 above)
1. With a clean paper towel, wipe some dirt of the center of the pulley
2. Examine the dirt and look for metal flakes. Regardless of presence of metal flakes, proceed to the next steps.
3. Dismount the belts
4. Dismount the aluminum crank pulley
5. Press some clay into the key-way on the aluminum pulley (I suggest using old, burned out detailing clay).
6. Match clay mold from 5 to the stock pulley. If the clay mold fits correctly into the stock pulley key-way, then you have no issue. If the clay mold of the aluminum key-way is too wide for the stock pulley key-way, then you have dangerous wear. The pulley should be replaced.
7. If you determine the key-way is sound, remount the aluminum pulley. If not, mount the stock pulley and take the appropriate action.
8. The above service should take less than one hour to perform. It takes me only 30 minutes.

In case you are curious, I will not be replacing my UR pulley with a new one. I am staying stock with this piece. Instead, I will use a new flywheel, clutch, and maybe a 3.9 final drive to recover from this SLIGHT decrease in performance.

P.S. - I will have pictures up sometime after this Sunday. Sorry, but I am in the middle of another project that cannot wait (installing a new patio).
 

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:doh: OY!

Thanks for the update. A popular mod, too....

I can understand the keyway widening because of a wobble & can understand a wobble because of the widened keyway, but....WTF would cause the keyway to go out in the 1st place?...bad casting is all I can think of.

MAybe a bit of Permatex black RTV on thet front oil seal...if it keeps dribblin...

:cheers: Ohwell, cars = car trouble. Hope yr baby gets well soon.
 

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Comprehensive diagnosis Peptid...glad your engine suffered no major damage.
 

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Discussion Starter · #5 ·
Couple of additional points:

My front oil seal is not dripping. Also, I don't think it could be repaired with RTV sealer. The front oil seal is more like the crush gasket on a pil drain plug. It is a single use thing that you don't want to damage.

I only noticed a little oil on the back of the pulley. During the time is sat with the pulley off, not a single drop dripped out. Also, there was no sign of oil loss on the under-engine cover.

As for what could have caused the key-way to widen in the first place, you got me. I know it was installed correctly and I never had an issue. I am thinking, due to lack of any other evidence, that it was just worn away over time.

Just wanted to make everyone aware. I may be the only one but I would hate to keep quiet and find out later that others are having issues too. The best bet is to check your components regularly and keep a healthy system.
 

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Discussion Starter · #8 ·
Thanks everyone.

Again, I am not suggesting this is a BAD mod. I am just suggesting that it is something that will probably need some monitoring.

Speaking of monitoring, I would like to toss in a world for regular check-ups. Whenever I do a oil change, I check all of my systems. I don't just look at the fluid levels. I check the brake pad and rotor thickness. I check the tread on my tires. I get under the car and check exhaust fitment and O2 seals. I clean the bottom of the engine. I get "intimate" with the car so that I know how it is performing. I think is is an important concept.
 

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Originally posted by peptidbond@Aug 4 2005, 08:55 AM
Thanks everyone.

Again, I am not suggesting this is a BAD mod. I am just suggesting that it is something that will probably need some monitoring.

Speaking of monitoring, I would like to toss in a world for regular check-ups. Whenever I do a oil change, I check all of my systems. I don't just look at the fluid levels. I check the brake pad and rotor thickness. I check the tread on my tires. I get under the car and check exhaust fitment and O2 seals. I clean the bottom of the engine. I get "intimate" with the car so that I know how it is performing. I think is is an important concept.
[snapback]141415[/snapback]​



:yourock: Smart.
 

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Normally, keyway widening or key ripping is caused by a loose crank shaft end bolt. The nose of the crank has a taper that should match the taper of the pulley. When torqued up tight, this taper is what holds the pulley in place and the keyway will actually be doing very little and is more there for alignment (the case if the front pulley was balanced with the crank anyway).

Chris
 

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Discussion Starter · #11 ·
Originally posted by HyperSprite@Aug 4 2005, 01:41 PM
Normally, keyway widening or key ripping is caused by a loose crank shaft end bolt. The nose of the crank has a taper that should match the taper of the pulley. When torqued up tight, this taper is what holds the pulley in place and the keyway will actually be doing very little and is more there for alignment (the case if the front pulley was balanced with the crank anyway).

Chris
[snapback]141624[/snapback]​

That certainly makes sense. My crank end is certainly tapered a little. So was the stock pulley. I cannot remember if the UR pulley is, but I will look tonight. The taper would certainly help to distribute the force better and way even eliminate any stress on the key way.

Like I said before, this may just be an anomally. My crank pulley bolt could have backed off (it was slathered in anti-seize) and that may have caused the stress on the keyway.

In any case, it is just something worth keeping an eye on. Goo point nonetheless though.
 

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Thanks for the really informative post. I installed the KJR pulley (not smaller, just 5+ lbs lighter) on my 350ZR and had some experiences that may add to those you expressed.
After removal of the stock pulley-a MAJOR pain in the neck-we installed the KJR, torquing the crank bolt to the recommended 37 psi. Less than 75 miles later, the pulley was wobbling and making strange sounds. Should'a known better when we saw the 37 psi on a crank bolt!!! but were worried about crushing the tapered edge with too much torque.
Turns out the instructions were wrong-tourque SHOULD HAVE BEEN 37 + 6 degrees, thus equalling +/- 95-110 lbs torque on the crank bolt. After torquing to proper spec, the pulley functioned very nicely-lighter, quicker acceleration and a pleasing sound. BTY, although the manufacturer says no, a little blue loctite added confidence.
Overall, I think it was a good mod, well worth the $150 price, but be careful about torque on the crank bolt and CHECK IT at each oil change.
 

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Definately good post and good news, I was looking to get the lighter pulleys and will still go with them but will now be checking them every oil change and pulling them for wear after 6 months to check. Awesome thread, as far as the 3.917 gears go, had them installed back in February and love every second of them, the car is so much quicker with the gear in its unreal, 0-60 is easily under 5 sec. Plan on doing the JWT flywheel or Fidanza flywheel as well, which one were you looking at?
 

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thanks for the heads up on the pulley. im gonna check mine tomorrow!
 

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That certainly makes sense. My crank end is certainly tapered a little. So was the stock pulley. I cannot remember if the UR pulley is, but I will look tonight. The taper would certainly help to distribute the force better and way even eliminate any stress on the key way.

Like I said before, this may just be an anomally. My crank pulley bolt could have backed off (it was slathered in anti-seize) and that may have caused the stress on the keyway.

In any case, it is just something worth keeping an eye on. Goo point nonetheless though.

this is what cause my motor replacement.

i had ur pullies and the crank pully wasnt installed properly and 15k later my motor let go. i trashed the main seal and lost oil.(funny thing was i still had 60psi of oil pressure) and blew the engine. my keyway was widened so much that the pully actually skipped over the keyway on the crank. 3 months later and big fights with nissan i got it replaced under warranty once the factory pully was back on it
 

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RECOMMENDED SERVICE FOR ALL USERS OF ALUMINUM CRANK PULLEYS
Regardless of what type of aluminum crank pulley you use, I would recommend following the service recommendation below. The fact of the matter is that the key on the crank exerts a lot of force on the aluminum key-way on the pulley. In general, aluminum may be able to handle this force, but if you have a pulley with a defect, the aluminum could easily wear away like mine.
There was no defect in your pulley, the only way wear along the keyway can happen is if the bolt was not tightened to the factory spec, which we provide in our instructions. If the belts were over tensioned and the bolt was not torqued exactly to spec or slightly above spec then it would accelerate the bolt loosening up since the shoulder of the bolt would no longer be contacting the entire pulley surface.

Perform the following with every oil change:
1. Observe the crank pulley and determine if it is rotating properly
Couldn't hurt to do this, also check the belts for wear and proper tension.

Perform the following at least twice a year (regardless of results from 1 above)
1. With a clean paper towel, wipe some dirt of the center of the pulley
2. Examine the dirt and look for metal flakes. Regardless of presence of metal flakes, proceed to the next steps.
3. Dismount the belts
4. Dismount the aluminum crank pulley
5. Press some clay into the key-way on the aluminum pulley (I suggest using old, burned out detailing clay).
6. Match clay mold from 5 to the stock pulley. If the clay mold fits correctly into the stock pulley key-way, then you have no issue. If the clay mold of the aluminum key-way is too wide for the stock pulley key-way, then you have dangerous wear. The pulley should be replaced.
7. If you determine the key-way is sound, remount the aluminum pulley. If not, mount the stock pulley and take the appropriate action.
8. The above service should take less than one hour to perform. It takes me only 30 minutes.
All completely unnecessary if the product is installed properly especially the bit about the clay since the factory tolerance for the keyway would allow for some to fit slightly tight and others to fit slightly loose. This is since once the bolt is tightened to spec the pulley wedges itslef against the key and will no longer move if the torque is correct.

In case you are curious, I will not be replacing my UR pulley with a new one. I am staying stock with this piece. Instead, I will use a new flywheel, clutch, and maybe a 3.9 final drive to recover from this SLIGHT decrease in performance.
Your leaving easy HP on the table, why miss out? The flywheel is definately a great idea but leaving out the pulley from your mod mix makes no sense.

Did you ever call us?
This is the first time I'm hearing this case, the other gentleman was local to us who had his pulley installed incorrectly.

Respectfully,
Shawn Baumgartner
President
Unorthodox Rcaing Inc.
www.unorthodoxracing.com
 

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Good afternoon,

If you have a UR Crank Pulley, PLEASE READ AND UNDERSTAND THE FOLLOWING!

I have been having some engine problems lately and I have conclusively traced them to my crank pulley/belt setup.

SYMPTOMS
1. Crank pulley appeared to wobble when the engine was running at idle
2. Engine "whined" ever so slightly at idle
3. Heard a fast-paced "whoosh-whoosh-whoosh" when the AC was on and at idle. This sound appeared to be coming from the bearings on one tensioner pulley.

OTHER MITIGATING FACTORS
I recently had an alternator replaced by the dealer and the belts were certainly on too tight. I do not believe this caused the crank pulley to fail. However, I do believe the belts being too tight could have caused symptoms 2 and 3 above.

EXAMINATION
Obviously, issue 1 (wobble of crank pulley at idle) was a very serious concern. So, I dismounted the belts. I then went to remove the crank pulley. It was immediately loose in the mounting socket. I could wobble it back and forth. Also, I could unscrew the center bolt with just my fingers.

Once removed, the issue was obvious. Both the stock and UR crank pulley have a bore in the middle to accept the end of the crank shaft. This bore also has a key-way that accepts a key on the crank shaft. When mounted, the pulley key-way must match up to the key on the crank shaft. This also keeps the pulley from just slipping. Obviously, the force exerted by the crank key on the pulley key-way is going to be pretty high.

On my UR pulley, the key-way started at about 1/8 inch wide. When I examined it after 1.5 years of use, the key-way had expanded to well over an inch in width.

So, when the UR pulley was mounted, I could easily rotate it back and forth in the socket without moving the crank! Also, the pulley no longer sat true in the socket. It was totally useless.

To make matters worse, the bore on the UR pulley had a light coat of oil on it. My oil seal at the front of the crank must have either leaked a little due to the vibration or it has been damaged. However, I don't think the damage is severe. I am not detecting any other signs of oil loss.

THE FIX
The UR pulley is now off and waiting on me to take photos. Since the warranty is only 1 year, I will trash the piece after I photograph it.

Thankfully, neither my crank nor the front oil seal appear to be damaged. I mounted the stock pulley and it is tight in the socket and runs very true. With the stock belts back on and the proper belt tension set, I no longer have any of the symptoms listed above.

RECOMMENDED SERVICE FOR ALL USERS OF ALUMINUM CRANK PULLEYS
Regardless of what type of aluminum crank pulley you use, I would recommend following the service recommendation below. The fact of the matter is that the key on the crank exerts a lot of force on the aluminum key-way on the pulley. In general, aluminum may be able to handle this force, but if you have a pulley with a defect, the aluminum could easily wear away like mine.

Perform the following with every oil change:
1. Observe the crank pulley and determine if it is rotating properly

Perform the following at least twice a year (regardless of results from 1 above)
1. With a clean paper towel, wipe some dirt of the center of the pulley
2. Examine the dirt and look for metal flakes. Regardless of presence of metal flakes, proceed to the next steps.
3. Dismount the belts
4. Dismount the aluminum crank pulley
5. Press some clay into the key-way on the aluminum pulley (I suggest using old, burned out detailing clay).
6. Match clay mold from 5 to the stock pulley. If the clay mold fits correctly into the stock pulley key-way, then you have no issue. If the clay mold of the aluminum key-way is too wide for the stock pulley key-way, then you have dangerous wear. The pulley should be replaced.
7. If you determine the key-way is sound, remount the aluminum pulley. If not, mount the stock pulley and take the appropriate action.
8. The above service should take less than one hour to perform. It takes me only 30 minutes.

In case you are curious, I will not be replacing my UR pulley with a new one. I am staying stock with this piece. Instead, I will use a new flywheel, clutch, and maybe a 3.9 final drive to recover from this SLIGHT decrease in performance.

P.S. - I will have pictures up sometime after this Sunday. Sorry, but I am in the middle of another project that cannot wait (installing a new patio).

did it make a chirping noise when running at low speed/low rpm or low speed w/higher gear? Also, did it make some sort of engine vibration at about 4000rpm?
 

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I would have to agree that it is from a lose bolt, causing the key to excert the force on the pulley and widening the slot.

I have had mine on for almost 3 years and 2 of those with boost and no issues at all.

Just make sure you tighten the bolt per the manual, 29-36 ft-lbs and then turn 60 degrees more.
 

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I would have to agree that it is from a lose bolt, causing the key to excert the force on the pulley and widening the slot.

I have had mine on for almost 3 years and 2 of those with boost and no issues at all.

Just make sure you tighten the bolt per the manual, 29-36 ft-lbs and then turn 60 degrees more.

it should be 24-28 or 31.4-38.2N.m, shouldn't it?
 
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