From the GFB website. They don't make UDP's for engines that aren't suited. I'm sure a company such as GFB have a pretty good understanding of automotive engineering etc. Otherwise, I would not have said such a thing. I don't say it unless I've found it written some where believable first. But if you can find an automotive engineer who knows their stuff then, get their opinion. Or unless you consider yourself highly knowledgeably on the topic. Then explain WHY. Debating goes no where useful without evidence to back it up.
That's what I'm hoping to find. Someone here with an ounce of experience in regards to harmonics. I'm sure if the theory doesn't make sense, I'll be corrected by an expert, with experience, who can present a detailed explanation.
No no no.... no lemon pledge.... Yes the OLD design polyurethane engine mounts that were basic copies of the stock mounts but with urethane replacing rubber obviously did have issues with failing rather quickly. The new design though is completely different, uses a much higher grade of polyurethane i'm told, and is fully captive ie, can't break free even if the eurethane completely disintegrates. Which i'm assured it wont anyway. There is at least one member that has been running/testing these new ones for around a year I think. Ben
There is urethane and urethane... Heat is a big factor, but the noltec compound (Noltec make the big OEM looking urethane mounts) is apparently easily damaged by water and oil. Not a good thing in an engine mount. I had Noltec radius rod bushings when I bought the car and they flogged out big time.
I have some more evidence to back up a few things. Just went out to the shed then and did a comparison of the Zed Crankshaft Pulley, to Harmonic Balancers found on other engines we have around. Both Harmonic Balancers found on the 2 V8 engines we have had a counter balance on the back of the wheel.. a fairly chunky piece of metal.. which has obviously been put in place to correct balance. The engine in my dad's hotrod is an inline 6, which also has a harmonic balancer, with various weights attached to correct any imbalances. And finally the harmonic balancer off a 4 cylinder engine we have had holes drilled out, offset to one side of the pulley.. Again to correct any imbalances. On the contrary.. the 300zx Crankshaft Pulley/Harmonic Balancer, has absolutely zero signs of counter balancing. No weights added.. no offset holes drilled to correct it's balance.. Everything is symmetrical. Which seems to point strongly to the fact that the 300zx does NOT have a Harmonic balancer at all. It only has a Crankshaft pulley. After more reading I have discovered the rubber ring only exists to reduce noise made from accessories.
Engines with external weights are usually not internally balanced so require a very lagre external balancer. These crankshafts use rather small counterweights to reduce over all crankshaft size and weight, doing so also gives an engine with less bulk. VG's do have a balancer and usually have a single balnce hole drilled around 120 degrees from the keyway. The question here is whether or not removingthe balancing will have any adverse effects on engine life. My proffesional opinion is no it will not effect the engine life at all. There are alot of stories about udp's causing failures on the vg but absolutley zero proof to back it up. The first failure I would expect to see from running a non dampened pulley would be #1 main bearing failure followed by turbo failure and then idler failure. Why did nissan put it there? Having a rather heavy balancer reduces vibration, very important to NVH tests carried out by all oem's, it also increases engine braking, the ability for the engine to hold rpm in the lower part of the range, helps the engine maintain speed enabling smoother shifts, reduces harmonics carried through the accessories and engine life is also be improved with less vibration. The vg is a very well balanced engine to start with, increasing the rotating mass at the factory helps give the little v6 the charactoristics of a much larger engine. It does serve a purpose on the vg and has it's place, but in the quest for power/response removing it presents no issue, same as removing/modifying everything else nissan put in there. It is there for a reason, but nissan's reason for having it may contradict your reason for getting rid of it.
Stupid question, how does the crank pulley have an effect on turbo life? I can understand the main bearings and the idler, but not the turbo
Elegantly expressed Dr Z. I have both UDP and lightened flywheel, and I expect I have sufferred some loss of torque in the interests of a fast spin up. But I don't have a tow bar on the car and I have a 4WD for pulling tree stumps so I don't think I am in too much bother. I do like the responsiveness (on the Zed, not the 4WD )
Engine harmonics, if severe enough will destroy every bearing and bush at the extremities of the engine. Sounds ab it out there, but as I understand it, the harmonics travel through the engine and are dispersed to all parts, anything rotating has the ability to amplify the vibration, once amplified in the turbos, it has nowhere else to go, so basically bouncing around kind of like an echo which then starts to reverberate until the pulse peters out. The Cummins STA-15 engine was very known for popping turbo's. Upon further inspection it was often found that there was a severe knocking noise at 1400-1600rpm unloaded and 1550rpm loaded(coincidently this is also where the power and torque curves converge). The cause of this was an internal inertia ring inside the dampener, they don't use vulcanized rubber dampeners like smaller engines due to the weight needed, somewhere around 18kg. This inertia ring would become jammed into one side of the dampener housing instead of floating in a bath of fluid, so now imagine an offset weight of some 18kg sitting is some random spot. The vibes where not usually felt through the cabin due to a rotating mass near 300kg. The finding of this cause were not something conducted in the field or by a particular workshop, Cummins employed what they call a "6 sigma" team of dozens of engineers being fed information by every branch worldwide experiencing failure of turbos, air compressors and fan hubs premature to expected life. The benefit of working for the worlds largest engine company was once all this info was sorted, the people on the front line were fed more information than we ever needed.
So in theory... because the UDP is not balanced for the crank.. and the stock pulley is.. then wouldn't it simply be a matter of balancing the new UDP to the crank? to have similar qualities to the stock one?... mmm i do see you point in regards to the harmonic vibrations etc. overall I would like my engine to last, but still perform better than normal. My original thought was... "less weight.. makes the engine's life easier"... though after discussion this seems to have become a second thought
Theorectically that will help a little, but the expense of doing it unless your engine is being rebuilt is not worth it. Use a good quality balanced pulley and you wont have an issue.
i see.. I'm considering keeping with the stock pulley for keeping my engine around longer. My only dilemma however is that as we type my UDP is probably in the process of being made, and then sent to me from cazracing. So it is a bit late in the process to say "nah I don't want it any more." So this is why I feel compelled to argue for it I suppose, instead of against it.
True, maybe could have posted up here before you ordered it. But when you get it, if you still don't want it, just sell it again in the for sale section.
Yeah. I'll put it on like you said before. See how it works with my engine when I do the timing belt change over and service. If there isn't anything happening that sounds lethal I'll probably just leave it. I have a spare engine. And if anything ever goes wrong, It's just a perfect excuse to rebuild it with forged internals and recondition it all, and learn from mistakes. All the learning process in the end.
by the way. Your 300zx is very nice. I like it aesthetically and performance wise i think it has a very good build. Probably very similar to what I'd be looking to achieve in the future. Currently it's my best reason to want to install my GFB UDP
UDP's are NOT 'made to order' by CazRacing(they are purchased from a supplier). This is just one more misconception you have concerning UDP's in general(and Harmonic Ballancers in particular).
... lol, a little pedantic, perhaps ....... ??? ... and could not resist ... What is a "ballancer" ...??? ...something to keep the scrotum in equilibrium, perhaps ..... ????
Never said they were made to order by Caz. I said Cazracing were sending it to me after it was ordered. After ringing Cazracing and being told that the supplier was still in the process of making it I'm pretty sure I was informed well enough to not make that misunderstanding. None the less, you would assume otherwise. Why would Cazracing manufacture a GFB UDP?.... I'm not that stupid. :rofl:
I wonder if it makes any difference how many K's are on my zed? This engine has only done about 77,000 km's. I imagine after that many K's there can't have been too much wear on bearings and such?
