Apperantly a LightWeight Pulley is bad for your car?
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From: Las Vegas
This thread is getting interesting on this issue, I need to know more FACTS. If I knew for sure that an after market pully does not cause any damage to the main crank I will defenitely buy after market...
Originally Posted by lunartick13
This thread is getting interesting on this issue, I need to know more FACTS. If I knew for sure that an after market pully does not cause any damage to the main crank I will defenitely buy after market...
I still think a thread containing info about this and other stuff should be made for a sticky rather than one that you have to read like 15 posts down to get the info you want.
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From: az
Originally Posted by tonywenzel
hmmm... sounds like you need to practice what you preach.
D-
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From: Las Vegas
Originally Posted by Sharif@Forged
Interestingly enough, when we take apart stock motors with stock crank pulleys, we notice a little bit more wear on the front main bearing. This is actually somewhat normal, as there is more pressure on this bearing, due to the tension of the belts on the pulley. But overall, it was nothing to worry about.
Originally Posted by lunartick13
Thanks for sharing that little piece of info...Sharif. Do you know what the weight of the OEM pully is vs Alum. pully? I know titenium would be the ultimate but I guess that would cost a small fortune..
stock = 6 pounds 3 ounces
UR = 1 pound 5 ounces
titanium would be more or less the same as aluminum... Magnesium pulley would be better
Last edited by Nano; Sep 29, 2005 at 06:44 PM.
People talk like they are analysts who know where the causes of a particular wear or failure are. Only thorough analysis correlated by tests will show the effect of a particular variable such as pulley/flywheel in the engine. And engine manufacturer is most probably the only source who is capable of doing analyses and tests. So discounting or dismissing little things out of hand is not a smart thing to do.
There is a common misconception that if the part is CNC machined, its perfect. I hate to disagree that even after you CNC machine a pulley, there is a need to balance it because of non-homogeneity of the raw/billet materials. And this balancing should be done taking into account the imbalances in the crank that include the flywheel too, I would imagine thats how the stock pulley was designed/manufactured. And if you observe a rotating part that is balanced, there are holes drilled to remove mass just like wheels of a car are balanced by adding weights.
And one more mod that I see is lighter flywheel mod. The reason why a particular flywheel is a certain mass and mass distribution is balance the loading on a rotating mass by absorbing and releasing momentum. How many of these flywheel manufacturers actually analyse this. One of the fundamental reason why an engine has a flywheel is to even out the loading and the more cylinders you have, the more balanced is the engine without the flywheel, so that means it needs a lighter flywheel. So this flywheel mod just bothers me. I cannot turn a blind eye to these things being an engineer. I need to find an explaination as to how this is better and will affect other parts such as bearings etc.
Bearings, a common man cannot simply inspect the bearings and expect to know how the wear pattern is, how the lubrication/loads/temperature is affecting its wear. I work on momentum wheels that run at 100,000rpms for 15-20 years of mission life in space where you cannot replace them. And there are special bearing experts who have 30-40 years of experience who we rely on for them to work reliably.
There is a common misconception that if the part is CNC machined, its perfect. I hate to disagree that even after you CNC machine a pulley, there is a need to balance it because of non-homogeneity of the raw/billet materials. And this balancing should be done taking into account the imbalances in the crank that include the flywheel too, I would imagine thats how the stock pulley was designed/manufactured. And if you observe a rotating part that is balanced, there are holes drilled to remove mass just like wheels of a car are balanced by adding weights.
And one more mod that I see is lighter flywheel mod. The reason why a particular flywheel is a certain mass and mass distribution is balance the loading on a rotating mass by absorbing and releasing momentum. How many of these flywheel manufacturers actually analyse this. One of the fundamental reason why an engine has a flywheel is to even out the loading and the more cylinders you have, the more balanced is the engine without the flywheel, so that means it needs a lighter flywheel. So this flywheel mod just bothers me. I cannot turn a blind eye to these things being an engineer. I need to find an explaination as to how this is better and will affect other parts such as bearings etc.
Bearings, a common man cannot simply inspect the bearings and expect to know how the wear pattern is, how the lubrication/loads/temperature is affecting its wear. I work on momentum wheels that run at 100,000rpms for 15-20 years of mission life in space where you cannot replace them. And there are special bearing experts who have 30-40 years of experience who we rely on for them to work reliably.
Last edited by spacemn_spiff; Sep 30, 2005 at 08:13 AM.
Originally Posted by spcemn_spiff
I would imagine thats how the stock pulley was designed/manufactured
While I agree in general with your statement, the anecdotal evidence does not lie. I have not once, ever, in the 9 or so years I have been around UR pullies, seen a single Nissan V6 motor fail due to the installation of the pulley. Be it a VG series or VQ series. In fact I have not seen any other motors let go because of said pulley either, but thats not relevant to the motor at hand.
As I have said before, some engines can have pullies installed without rebalancing, some cannot..the Nissan V6 s one that is balanced internally, not externally, from the factory. As such, it does not matter what you hang on either end of it, so long as that part is, itself, balanced
Originally Posted by Z1 Performance
I am no engineer, but I cannot fathom how all that overengineering would ever be possible in a stamped piece of metal...which is exactly what the stock pulley is.
While I agree in general with your statement, the anecdotal evidence does not lie. I have not once, ever, in the 9 or so years I have been around UR pullies, seen a single Nissan V6 motor fail due to the installation of the pulley. Be it a VG series or VQ series. In fact I have not seen any other motors let go because of said pulley either, but thats not relevant to the motor at hand.
As I have said before, some engines can have pullies installed without rebalancing, some cannot..the Nissan V6 s one that is balanced internally, not externally, from the factory. As such, it does not matter what you hang on either end of it, so long as that part is, itself, balanced
While I agree in general with your statement, the anecdotal evidence does not lie. I have not once, ever, in the 9 or so years I have been around UR pullies, seen a single Nissan V6 motor fail due to the installation of the pulley. Be it a VG series or VQ series. In fact I have not seen any other motors let go because of said pulley either, but thats not relevant to the motor at hand.
As I have said before, some engines can have pullies installed without rebalancing, some cannot..the Nissan V6 s one that is balanced internally, not externally, from the factory. As such, it does not matter what you hang on either end of it, so long as that part is, itself, balanced
Nissan V6 is balanced internally? The external part that balances the crank loads is the flywheel. I dont know what your source is, may be you have more information than me. I know that crankshafts have balance weights for each con rod/piston assembly, I assume that is what you meant.
the engine is not balanced with the flywheel on the car - hence why you can put a lightweight flywheel on the car without ill effects as well (again so long as it too is balanced). Several American cars of old were balanced externally...these are cars that cannot have pullies merely bolted on, nor can you do lightweight flywheels as a bolt on bolt (typicall). The Nissan VQ is not such a motor however
Originally Posted by Z1 Performance
the engine is not balanced with the flywheel on the car - hence why you can put a lightweight flywheel on the car without ill effects as well (again so long as it too is balanced). Several American cars of old were balanced externally...these are cars that cannot have pullies merely bolted on, nor can you do lightweight flywheels as a bolt on bolt (typicall). The Nissan VQ is not such a motor however
If what you say is true, eliminate the flywheel altogether.
Originally Posted by spcemn_spiff
Then I would like to know why does VQ have the so called 'Heavy Flywheel'.
If what you say is true, eliminate the flywheel altogether.
If what you say is true, eliminate the flywheel altogether.
flywheel is what keeps the angular momentum going... they simply store kinetic energy. Without a flywheel a car would be pretty much undriveable. (potter wheel analogy)
Last edited by Nano; Sep 30, 2005 at 02:02 PM.