I recently installed an aftermarket Alloy crank Pulley, much has been said about them, however I for one will be removing it soon, I get a really bad vibration through the motor around 4-5 thou rpm. I discussions with a few mechanics today, they have recommended I put the original back on for longevity of the motor. If I was a pure horsepower phreak or into racing the Z etc. it would no doubt add a little in the performance area, however with the harmonic balacer on, I will feel the Z will last me longer and I won't grind my teeth and cringe every time I hear/feel it as I pass someone. (I may still grind my teeth but for a different reason...) there are plenty of other mods to make before needing to go down that trail. I think I got suckered in by the hype attached to this modification. For those who feel differently keep your eye on the for sale section !! See some of you in the morning at the G/House run ..
What pulley did you get? If you got a cheap pulley then you really get what you paid for. Personally wouldnt use anything other than the UR underdrive pulley or maybe the GFB pulley. Chewy has tested his UR pulley to 10,000 rpm and its perfectly ballanced. So if you had one of those, unless you were going over 10,000rpm it wouldnt of been giving you any vibration unless defective somehow.UR pulley, if a proper one had been used will not in anyway shape or form harm your engine or affect the longevity. Its like saying fitting tyres will ruin the engine and frankly anyone saying otherwise is talking from ignorance. This is one mod that is on thousands of cars with millions of miles of running and no problems whatsoever.If you experienced problems with this, I would check your pulley or start looking elsewhere for the cause. Also I wouldnt post it for sale on the forum here because now nobody will buy it if they think it is defective and unbalanced :N(
If you are worried about vibrations you can get lightened pulleys that absorb them. And they are only a tad heavier than the UR or GFB pulleys. A bit more pricey though.
Mine was aUR and when i had the engine > balanced during the rebuild the pulley was abit out of balance. not sure what rpm it was balanced to thou.
Zisluv, when did you make a career change:?) I see you are now a mechanical engineer !"UR pulley, if a proper one had been used will not in anyway shape or form harm your engine or affect the longevity."In the same way nobody can provide proof that fitting a UD pulley will have dire consequences, you my friend cannot unequivocally state that it will not !Any risks (however infinitesimal they may or may not be) involved with a UD pulley is a calculated gamble taken by individuals in the quest for additional rear wheel hp.Just for the record, I decided against a UD pulley on my zed. I figured it was only about 10-15hp and one pound of boost would provide that whenever I wanted it (and only when I wanted it). Each to their own ! Cheers Ian
I hope you never need medical> attention in WA Ian, you are in big trouble. >D<BTW, I agree 100% with your diagnosis.:YD
I think its also the way in which it gives that extra hpI can only speak for my NA experiences, but the UD pulley was by far the most noticeable mod I ever did. A full exhaust system would probably give you more power in an NA, but I dont think you would notice the difference as much as a lightened UD pulley. Its just the WAY in which it works that makes it so noticeable I guess.If you have to increase your boost to give you the 'UD pulley power gain' then could this not shorten the life of the engine or turbos as well? I guess its a trade off really
You're missing the point Peter..... Yes, an extra pound of boost could have an effect on the longevity of the motor/turbos, but you can switch on/off that extra psi to suit, whereas the UD pulley is permanently attached. Cheers mate Ian
Its called having a science degree... and its pritty straight forward really. We also do something similar in medicine, its called evidence based medicine. "In the same way nobody can provide proof that fitting a UD pulley will have dire consequences, you my friend cannot unequivocally state that it will not !" Yes actually I can and am saying that. If there is no proof that it hurts the engine, after being on thousands of 300s, with millions of kms of use, multiple engine pulls and I might add reviewed by a number of people WITH engineering degrees then there is no proof for a good reason. It doesnt exist! Very simple logic really. Its not as if this hasnt been looked at in detail before.Using your argument I go back to my previous point. Fitting tyres to your zed will damage your engine. Not using Mobil 1 will damage your engine. Not keeping the window washer bottle full will damage your engine. etc etc. Now prove to me that this ISNT the case. Same argument your trying to make with the pulley.
couldn't agree more, but has anyone actually had one in their Z long enough for their engine to obtain any type of damage? I am sure with your usual wear and tear of the engine, even if it is stock standard, no one can really tell if it is 'adding' to that wear and tear factor.I guess it's just like mobile phones, for years there was only 'statements' of it doing any harm and now 'statements' are evolving into evidence and proof... To cut it short, if it's not harming your engine anytime soon, it's a mod i wouldn't avoid.:YD :YD
Had mine for over 2 years and no damage thus far, this uncluding a couple of long LONG drives (15hrs+). Havent done track work and I havent done hundreds of thousands of K's with one, but to be honest I have no fear of having the UR Pulley installed.
The burden of proof.... "and its pritty straight forward really. We also do something similar in medicine, its called evidence based medicine."So if you cannot provide proof of something, it does NOT exist. I guess you don't get many speaking engagements at your local church !If a motor with a UD pulley is due for a rebuild after 150k how the hell can you say it would NOT have lasted 200k without a UD pulley fitted. You cannot.It took a whole 30 second search on ttnet to find a disgruntled UD pulley users post, an extract of which is listed below :-"Nissan went to great lengths to get this heavy car as fast as possible. They even put an aluminium hood on it! Don't you think they would have saved the weight and size in the crank pully if they could have. A 60 degree V6 engine created 2 harmonics (go back to physics class) at about 1800 and 4200 RPM. The lightened underdrive pulley is not a harmonic balancer letting your crank "wobble" instead of spinning at those frequencies. BAD!!! If you want to save the power on the accessories, then get the pulleys for the accessories only. I learned this through 3 engines with bottom end (bearing) trouble and a little advice from someone called Jim Wolf, maybe you've heard of him. He says "If you are at the top of your class and you need the extra couple of horses, then you are already on the level of rebuilding engines after every race anyway"I would like to see you convince him that there is no proof.Finally, using your analogy, "fitting tyres to your zed will damage your engine". UNDOUBTEDLY, because without tyres you cannot drive and therefore with or without a UD pulley you zed motor will never wear out. Very simple logic really.
Sorry I honestly think your being rediculous Your whole argument that UR pulleys are bad is just pure speculation, not based on an ounce of fact and just pure hypothesis that has not ever played out in real life. There has never ever been a documented failure due to a balanced pulley. There has never been ANY evidence of increased wear. The whole "harmonics" issue has been covered to death by people that have degrees in the matter (since your so keen on needing a degree) and its not an issue. There are plenty of other builders out there aside from JW who have fitted thousands of pulleys without a problem and I note the quote isnt even from JW himself. The whole argument that "if it could of been better then nissan would of built it that way" is also a load of crock. Why else do we fit aftermarket parts?If UR pulleys caused problems then it would be evident by now. There has certainly been enough testing and enough mileage. If you cant PROVE that it causes increased wear by now then you will never be able to. If at the stage of a 200,000km rebuild (and there are engines with this mileage and pulleys) and you cant prove any increased wear from a pulley then its obviously negligeable or nonexistant. Either way SAFE to use.
If you really are a "Man of Science", > please provide your evidence for your claims that, "after being on thousands of 300s, with millions of kms of use", no example of possible damage relating to UD pulleys exsists.As you well know, failure to provide such supporting evidence(in your chosen field of expertise) leads to being denounced and de-registered as a "charleton".Not having seen evidence of a specific nature, DOES NOT prove that such evidence is non-exsistant. If it did, then Science (and scientific research) is at an end.BTW, I haven't "seen" an atom, or electricity, or radiation, or a molecule of oxygen, does that mean that they don't exsist:?) :?) 8-}
Zisluv, try & read a post before gumflapping At no stage did I say that fitting a UD pulley was detrimental (FACT)You stated "UR pulley, if a proper one had been used will not in anyway shape or form harm your engine or affect the longevity" (at best : SPECULATION. At worst : utter BS)You continued with "If UR pulleys caused problems then it would be evident by now"Gee, hang on a minute while I email the guy on ttnet that needed 3 bottom end rebuilds and tell him he has been hallucinating .As for the Nissan engineers, I am sure that they designed and built a heavy & expensive two piece dampened pulley for exercise when they could have fitted a small alloy pulley for a fraction of the price.And finally, in relation to your "all conquering" science degree; I have two brothers who also have science degrees and whilst all of you probably excel at your chosen fields, you would not get my @rse in a rocketship that any of you had any part in designing :s
Why is it so hard to understand... "You stated "UR pulley, if a proper one had been used will not in anyway shape or form harm your engine or affect the longevity" (at best : SPECULATION. At worst : utter BS)"Speculation??? Out of thousands of engines with thousands of miles and no damage and you call this speculation? At worse utter BS? You truly lack any comprehension of what makes for good evidence. Youve found one person out of thousands that has rebuilt his bottom end 3 times and he blames this on the UR pulley? Again with what proof?Since your brothers are educated, why dont you ask them about it? Ask them which is more proven. A product that has been tested for over 10 years by thousands of engines without fault or your theory without any proof and mere speculation. You may not want to take a ride on a rocket ship Ive designed, but at least I know how to tell fact from pure fantasy unlike yourself. Id much rather place my faith in something PROVEN rather than completely unproven. Your failure to accept the fact of overwhelming evidence that these are safe just makes you look like a fool IMO.
Chili let me educate you then.... "Not having seen evidence of a specific nature, DOES NOT prove that such evidence is non-exsistant. If it did, then Science (and scientific research) is at an end."This is not quite what we are talking about. As always you seem to just miss the point but at least you try. We are not talking about something that has not been tested. We are talking about something that has been tested and has a weight of evidence behind it. Following such testing you can concur that if something is not present then it doesnt exist.Im running out of time now but when I get back from work I will explain to you a little about levels of evidence, their weight and significance in trials as well as sample sizes and statistical significance. We do it all the time and is common practise for drug trials etc.Essentially what we are doing with the UR pulley is a retrospective cohort study of all the engines that have this mod fitted. From all the evidence we have from these taken from the direct word of most of the major 300zx builders in the states and the fact there are thousands of these on 300zx all through the world with up to hundreds of thousands of kms per engine with no evidence of extra wear or catastrophic failure then we can say with significance they are a safe mod. The fact zx299 has found ONE person who thinks his caused a problem (and we cant even examine his evidence) is of absolutely NO statistical significance in a study this large.THAT is how you look at a question like this. You dont just state one persons experience in the face of overwhelming evidence to the contrary and call it fact. I thought you may of been a bit smarter than that Chili.
I'm with nathan on this one... The reason a big heavy pulley was used was because it was designed to run the accessories at 100% capacity, not 80% as an UD pulley would and secondly, the OEM pulley would be cheaper to manufacture.Remember, $1 saved on a part for 1 car = $20000 on a production run of 20000 vehicles.Cheers Rob
Yeh Lloyd what he said!! 8-} 8-} Sounds good anyway, seeing as I have a UD pulley, stop putting forward arguments to suggest it might be bad for my Zed p.s. stop picking on Nathan :-Z
