I have read alot of things on many different forums about people defending and bashings aluminum underdrive pulleys. I ran one a few cars ago with no issues, but, the one on my 350z has come to prove that they are infact bad! My engine began having knocking from the valvetrain. I ordered many parts and when I pulled the engine out and began pulling it all apart, I noticed this notch in my pulley.



I want to send out a warning to others to help save them from a very costly rebuild like me.

 

I'm not sure/how that notch would cause valvetrain issues. Isn't that the crank pulley? Even if the pulley completely fell off, wouldnt that only affect PS, Alt and WP?

 

So, are you trying to say that the notch wasn't there when you installed it? Perhaps that it appeared via "immaculate notch conception" or some other way?
How do you think the notch cooked your engine?

 

1) All pulleys are notched, that's what keeps them from slipping on the crank.

2) What brand of pulley is that?

3) Exactly what is the proof that the pulley caused the other problems with your engine? Why isn't the damage to the pulley a result of your engine's other problems?

BTW - you're only the second case I've seen in 8 years of someone claiming that a failure of a VQ engine was caused by an aluminium pulley.

 

Looks like the woodruff key broke, and caused that extra notch in pulley. If they key breaks it can easily screw the motor up since the key goes all the way over to the lower timing chain pulley off the crank.

A turbo G in the shop right now had that happen with his pulley. ATI damper is next.

 

http://www.350zmotoring.com/forums/3...th-damage.html

The ATI is the bomb though.

 

I remember reading that a "better" aluminum pulley would be one with a steel sleeve. what brand of pulley is the on in your pic?

 

Unorthodox Racing, the engine is not yet apart, I am currently in the very unfun process of drilling out a flywheel bolt... why did they choose to put a torx screw on a flywheel...

And I bought an ATI pulley from brett before I knew that this was the problem. Brett@IPP is SUPER helpful!

 

^ I know right?! I hate those torx bolts. Thanks for the kind words. Haven't seen too many damaged aluminum pullies, but if you really want to spin some rpm then ATI is the way to go.

 

I have the Unorthodox SS Pulleys installed on my car and I never had any issues. It sounds like user error to me.

 

i hear that using anything but a fuild damped unit like the ATI will put the engine out of balance internally and cause major issues in time.

Good enuff for me, wont be doing pulleys anytime.

 

That's the whole thing - how many thousands of VQ engines are using UR lightweight pulleys? How many hundreds of thousands of other engines are using UR pulleys? How does that compare to the number of reported failures? How many of those failures are really attributable to the pulley, some other mod or any mods at all?

 

totaly valid.. as with most internet myths or things the like.....

my 2 cents was aimed more at " What do you gain? and What can i possibly lose? Nah.. ill pass. "

just IMO.

sounds like OP is looking at a pulley that was not tightened right and had some play to make a notch open up like that.. and THAT would surely be a failure waiting to happen.

 

I don't see how not tightening it enough would cause that? Are you saying it's completely held on by a set screw? Or it was hanging half way off the whole time? If it were that loose why didn't it just fall off?

Our engines do have a ton more vibration than most due to the crank angle among other things...looks like woodruff key broke in half (why is only half the notch worn?)

 

THAT WOULD BE WHY I KEYWAYED THE CRANK AND GOT RID OF THAT DAMN WOODRUFF KEY, you think thats bad look at the timing chain sprocket only 1/8 the woodruff key hold it...