NST Crank Pulley Reliability?

[WeeYari]

See if your tuners have anything to say about supposed damage potentially being caused by these light, undampened pulleys. I got a 10% underdrive on mine, and there have just been too many people raising concerns. Topic reared its ugly head recently over on MI as well. Ima starting to get a little nervous myself about leaving this pulley installed.

[Aothachos]

Originally Posted by WeeYari

See if your tuners have anything to say about supposed damage potentially being caused by these light, undampened pulleys. I got a 10% underdrive on mine, and there have just been too many people raising concerns. Topic reared its ugly head recently over on MI as well. Ima starting to get a little nervous myself about leaving this pulley installed.

before i did it myself i have brought it to shops and they give me a bs story saying if they tighten on the crank it will break in half or damage and this and that problem. I did it myself with just a torque wrench and i jacked it up with the jack that came with the car not even a big one or anything like that, pull the e-brake really hard, took off the wheel where the pulleys where, too the fender off, and then did it risky but to get more power on tightening it i had to put my legs under the car, and pull really hard, yea i could've had my legs crushed but i knew it was holding perfectly fine. And I tightened it on, its been about 8 months I believe so far, no problems with my 10% underdrive, been through hot blazing weather and cold freezing winters, and the big snow storm we had in new york here, no problems. I think it just needs a new belt because the belt sometimes squeaks, or just tighten it im not sure.

I have the 10% underdrive one as well and its worth doing. My lights don't dim or anything with my A/c or heat on hi, with the window back defogger on, etc etc, no dim. 8 Months I have had it installed and probably done about 30-35 thousand miles.

[cali yaris]

there have just been too many people raising concerns.

how many with actual concerns vs. theoretical concerns?

Besides the one guy (who did not prove cause and effect to me), I don't know of more real life evidence that an NST pulley causes any damage.

[tk-421]

Well, I've had not one but two separate crank pulleys in my car, as well as the rest of the set, for at least 50K miles with no problems whatsoever. There's also a dedicated YW thread that has been open for years with 0 complaints.

If that's not proof that these pulleys are a solid product, then I don't know what is.

[WeeYari]

Nowhere did I bash NST or this product. I have one which has been on for 6 months, and I had not expressed dissatisfaction with it. I'm sure you'll be as happy with it as the rest of us are.

All I made was a simple request to gather some information as there have been people whose opinions I, and many forum members respect, that have raised a caution flag with this mod.

RELAX!!

[cali yaris]

weeyari you didn't answer my question. I didn't say you bashed, I asked for the real information you have.

You stated information, you didn't ask for it, as in:

there have just been too many people raising concerns.

[WeeYari]

^^ outside of the YW entries we all know about, go to 4:03 pm (my timezone setting GMT -5) yesterday in your chatbox. This is the 2nd of two discussions in the past week. The first was much longer and indepth than yesterdays.

Maddog, I'm not here to pollute this thread. Seriously, enjoy your pulley.

Out.

[cali yaris]

"so many" becomes "go look it up for yourself" -- LOL. I didn't ask for theory or discussions, I asked for real life reports.

how many with actual concerns vs. theoretical concerns?

I will leave the subject with my opinion that I know of only one person who actually reported damage "caused" by the pulley (maybe!), and a couple of hundred (at least) who are enjoying their Yaris pulleys with no adverse effects.

Hey if anyone wants to know negative, real stories about this pulley it's me - I sell the darn things. There just aren't any to report.

[DerFlosser]

Does the stock crank pulley incorporate a vibratory dampener?

[ozmdd]

Originally Posted by DerFlosser

Does the stock crank pulley incorporate a vibratory dampener?

No. The stock pulley does not have a large rubber component like you mike find on an older american V engine.

BTW - I think I'm almost to the 10K mile mark on the NST U-drive pulley with absolutely no ill-effects. Water pump is fine, engine runs smoothly and normally, all is well. I daily drive and autoX/time trials this car 2-4 times a month.

[cali yaris]

No. The stock pulley does not have a large rubber component like you mike find on an older american V engine.

yes it does! I posted a pic of that on here, I'll try and find it.

[ozmdd]

Sorry, I thought it was agreed that it only has a very think rubber gasket between the inner and outer portions of the pulley, unlike the 1/2"+ thick rubber found in old harmonic balancers.
I know my oem pulley looks to have 3mm max of rubber.

[cali yaris]

oh you're right, it is thinner than that for sure. The one on my stock pulley looks about 1/8" or so.

[cali yaris]

Again there have not been anything that I have seen or read that a nst pulley has caused damage, but to say they cannot cause damage is just not an accurate statement.

Right --- there is no negative, real life data to report. And I don't think anyone has said they "cannot" cause damage.

[DerFlosser]

I will only go so far as to say this...I, personally, would not use a non-harmonic dampened pulley when the motor was designed to incorporate a "harmonic dampened one.

[cali yaris]

= flawed logic and stubborn refusal to connect theory with reality.

But it's ok, it's clear you would never, ever change your mind.

[ozmdd]

Camelll - I guess I'd like to know what your point is in pursuing your bashing of the NST product? Are you a dissatisfied customer? Do you think you are somehow helping others with your theories? There is a ton of empirical data that supports the safety and effectiveness of the NST pulleys. There is virtually NO data to suggest the contrary. One person claims a water pump problem, but they haven't documented a connection. Hundreds of Yarii have the pulley and have no problems. I personally have over 10K miles on the pulley - including racing - and no problems.

You keep referring to theories and Toyota's design - which is certainly good design and intended to make the car as long-lived and reliable as possible, with as little warranty need as possible - but you seem unable or unwilling to acknowledge the proven nature of the NST design.

Again - what is your point/agenda?

People who install an NST pulley are looking for a safe performance improvement, and that's what they get. Do you really think you have a valid argument against that fact?

[NonStopTuning]

On a relatively understressed near stock motor with bolt ons or low amounts of boost like what most of the people on this forum probably run, a solid pulley will not have any life threatening consiquences. The factory pulley with a 2mm (less than a 1/8th inch) damper is primarily there for wide band NVH (noise vibration harshness) supression from the engine and driveline. Removing the damper and replacing it with a solid pulley will lead to minor addtional NVH but will not harm the engine. In fact, most people claim their engines seem to run smoother with NST pulleys.

The engineering reasons are that most modern engines have a short, strong crank with, a relatively high natural frequency. The dangerous second harmonic that can cause damage occurs at an rpm that this sort of engine will never see, in the area above 10,000 rpm. Even the stock damper is not tuned for attinuation at this sort of rpm so the argument is somewhat of a moot point.

Now small engines that are pushing the limit with lots of revs, wimpy cranks, super long strokes, lots of boost and dwelling in the upper rpm ranges for long periods of time can benefit from a damper designed to deal with this sort of operation but our engine is not like this, and probably very few people with this motor on this forum push the envelope that hard. How many 1.5Liter, 400HP, 11,000RPM Yaris motors do we have on these forums?

As far as I can tell, our engine has a strong and stiff bottom end that is well built for our intended use. It has an internaly balanced crankshaft which is less like to break due to torsional vibration.

There are a lot of Nissan guys who use underdrive crank pulleys in road racing series like NASA or SCCA. Road racing is much more punishing on an engine than other motorsports. The engine is subjected to run times lasting 23 to 45 minutes with the engine always in the upper ranges of its rpm limit. One race weekend is the equivlent of hundreds of 1/4 mile passes.

NST sponsors the first ever wheel to wheel Scion tC NASA Road Race car. This car has been using underdrive pulleys from NST with great results since day one.

NST also sponsors two drift cars participating in the professional US drift series, Fromula Drift and D1GP USA. Both of these cars have been using NST pulleys with no issues of any kind for the past few seasons.

We could go on and on...

Is a solid crank pulley harmless to all engines? No it is not. Small, super high reving engines, when modified way past the simple bolt on stages may have problems. These engines reach critcal harmonics, past the 10,000 rpm range, an rpm often reached by certain race engines.

A mildly modded inline six will most likely be fine but one subjected to high rpm for long periods of time (90% of its life) with lots of boost will probably suffer. In this case , the stock balancer/damper is probably not adequate either.

Some of the older american V8 engines are externaly balanced and it is critical not to use a solid hub pulley not designed for these applications, or damage to the engine could result.

Our engines and most around here do not fall into the above catagories. Rest assured that your engines will not blow up and die or have a reduced life in street and even racing use with these parts.

I would bet that every "expert" that tells you otherwise has little personal, practical, real world experience with the subject.