Crank pulley out of balance

Sport35Driver · 10-30-2017, 11:35 AM

So I revved the car the other day to redline and afterwards heard a weird noise. It was as if something was out of balance. I didn’t think anything of it as it’s been driving fairly normal since and no noise. I was fixing a fog light when I noticed oil collected in the center of the undertray. I removed the tray and found that the seal behind the pulley was wet with oil and oil was sprayed against the front cover and the sway bar and other components. I started the car to see if I could see it spraying from behind there. I noticed the pulley wobbling out of balance right away. Not terribly but enough to cause the pulley to cause a small leak with the seal. When I swapped the motor a couple years ago, I want to say I was able to torque the bolt on the pulley to spec but maybe not? It’s down almost to low on the stick in a couple days of it happening.

Any chance it’s the crank itself wobbling and not the pulley? I want to take it to the dealer at this point but also don’t want to get raped. Anyone have any ideas?

The dealer said they wear out sometimes and need to be replaced. He said there's rubber that could have deteriorated and cause it to come out of balance. This is the original crank pulley from my old motor so it's at 105k right now. They quoted me 2 hours of labor and potentially a new pulley which is $320 their cost.

BGTV8 · 10-30-2017, 06:25 PM

Pulley is either loose if it wobbles OR the rubber damper layer is fubar'd.

If the seal is gone, I'm pretty sure the pulley is loose in which case you risk further damage to the nose of the crank.

Needs attention asap.

Spooler · 10-30-2017, 06:55 PM

Yeap, sounds like the rubber insulator is warn out. I have seen it happen before. Oil leaking makes it happen even faster. Next time, if you mess with any crank pulley make sure you replace the front crank seal. They don't like to be disturbed when they get old and brittle.

Sport35Driver · 10-30-2017, 09:17 PM

Quote:

Originally Posted by BGTV8

Pulley is either loose if it wobbles OR the rubber damper layer is fubar'd.

If the seal is gone, I'm pretty sure the pulley is loose in which case you risk further damage to the nose of the crank.

Needs attention asap.

Well I didn’t drive it at all once I noticed it. You’re thinking damage already occurred? As in internal engine damage?

I have an appointment in the morning to have it looked at. Guess I should have it towed instead of driving it the 8 miles there.

BGTV8 · 10-31-2017, 03:55 AM

Tech ought to be removing the pulley and seal and then use his bore-scope tool (or Mark 1 eyeball if he can get a clean line of sight) to take a peek at the nose of the crank.

May also need to remove the front engine cover to get a good view .... I don't have the experience with VQ engine to know.

If the pulley was actually loose, it may have fretted on the nose of the crank which may have damaged it (the crank) .... if that is the case, and a new damper (it is a crankshaft damper rather than a pulley) won't pull-on cleanly, then the crank is fubar'd.

Take it step by step until you have a definitive diagnosis .... worry about a crank when you know that is a problem ... stressing ain't going to do anyone much good.

Sport35Driver · 11-01-2017, 06:59 AM

So it looks like the pulley is cracked and the key way is apparently jammed in the crank. I haven't had a chance to look at it myself so I will know more once I look at it. The tech said he would need 12 hours of labor to remove the front end to use a chisel and dig out the key way. He would install a new pulley and key way at that point. Anyone have a spare pulley and key way for a VQ35HR?

Rusty · 11-01-2017, 09:59 PM

That was a bad install when you swapped motors.

Sport35Driver · 11-02-2017, 12:00 PM

Quote:

Originally Posted by Rusty

That was a bad install when you swapped motors.

Maybe but I torqued it down to spec and it held for 2 years...so who knows. This has happened to other cars where the pulley was never removed as well. I talked to a Nissan tech who said he's done two of these repairs. I am pretty rough on the poor thing...

Rusty · 11-02-2017, 02:57 PM

Quote:

Originally Posted by Sport35Driver

Maybe but I torqued it down to spec and it held for 2 years...so who knows. This has happened to other cars where the pulley was never removed as well. I talked to a Nissan tech who said he's done two of these repairs. I am pretty rough on the poor thing...

I wish your pictures wasn't so big, so that I can get a better look. From what I see. It cracked at that key way. And looks like the damper has be moving back and forth on the crank. Because it looks like the key way has been enlarged.

In a past life. I worked on a few vehicles where the damper decided to take a walk. You're lucky that it didn't walk off the end of the crank into the radiator. The old chevy chevettes was famous for this.

10-30-2017, 11:35 AM	#1 (permalink)
Sport35Driver Base Member Join Date: Dec 2013 Location: Central FL Posts: 9 Drives: 6MT 08 G35S Sedan Rep Power: 11	Crank pulley out of balance So I revved the car the other day to redline and afterwards heard a weird noise. It was as if something was out of balance. I didn’t think anything of it as it’s been driving fairly normal since and no noise. I was fixing a fog light when I noticed oil collected in the center of the undertray. I removed the tray and found that the seal behind the pulley was wet with oil and oil was sprayed against the front cover and the sway bar and other components. I started the car to see if I could see it spraying from behind there. I noticed the pulley wobbling out of balance right away. Not terribly but enough to cause the pulley to cause a small leak with the seal. When I swapped the motor a couple years ago, I want to say I was able to torque the bolt on the pulley to spec but maybe not? It’s down almost to low on the stick in a couple days of it happening. Any chance it’s the crank itself wobbling and not the pulley? I want to take it to the dealer at this point but also don’t want to get raped. Anyone have any ideas? The dealer said they wear out sometimes and need to be replaced. He said there's rubber that could have deteriorated and cause it to come out of balance. This is the original crank pulley from my old motor so it's at 105k right now. They quoted me 2 hours of labor and potentially a new pulley which is $320 their cost.

11-01-2017, 09:59 PM	#7 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 68 Posts: 34,938 Drives: 2011 Nismo GM 6M Rep Power: 2684436	That was a bad install when you swapped motors. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

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10-30-2017, 06:25 PM	#2 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,503 Drives: 09 Nissan 370Z M6 Rep Power: 29907	Pulley is either loose if it wobbles OR the rubber damper layer is fubar'd. If the seal is gone, I'm pretty sure the pulley is loose in which case you risk further damage to the nose of the crank. Needs attention asap.

10-30-2017, 06:55 PM	#3 (permalink)
Spooler A True Z Fanatic Join Date: Jun 2014 Location: Ga Posts: 13,573 Drives: 2013 Nismo 370z Rep Power: 2684391	Yeap, sounds like the rubber insulator is warn out. I have seen it happen before. Oil leaking makes it happen even faster. Next time, if you mess with any crank pulley make sure you replace the front crank seal. They don't like to be disturbed when they get old and brittle.

10-31-2017, 03:55 AM	#5 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,503 Drives: 09 Nissan 370Z M6 Rep Power: 29907	Tech ought to be removing the pulley and seal and then use his bore-scope tool (or Mark 1 eyeball if he can get a clean line of sight) to take a peek at the nose of the crank. May also need to remove the front engine cover to get a good view .... I don't have the experience with VQ engine to know. If the pulley was actually loose, it may have fretted on the nose of the crank which may have damaged it (the crank) .... if that is the case, and a new damper (it is a crankshaft damper rather than a pulley) won't pull-on cleanly, then the crank is fubar'd. Take it step by step until you have a definitive diagnosis .... worry about a crank when you know that is a problem ... stressing ain't going to do anyone much good.

11-01-2017, 06:59 AM	#6 (permalink)
Sport35Driver Base Member Join Date: Dec 2013 Location: Central FL Posts: 9 Drives: 6MT 08 G35S Sedan Rep Power: 11	So it looks like the pulley is cracked and the key way is apparently jammed in the crank. I haven't had a chance to look at it myself so I will know more once I look at it. The tech said he would need 12 hours of labor to remove the front end to use a chisel and dig out the key way. He would install a new pulley and key way at that point. Anyone have a spare pulley and key way for a VQ35HR?