FS: Unorthodox Racing (UR) Lightweight Crank Pulley for 5SFE Options

[slavie]

Up for grabs is a UR lightweight pulley.

I believe this to be an MR2 5SFE pulley with both belts being 4 groove. 4" in overall diameter, 14.6oz or 414g. It will fit either a 3S or a 5S crank, as they're the same on the front end.

I had it on my 5SFE Camry for a few years working fine. It is an underdrive pulley in a 5SFE Camry, and requires a different belt (418K4 - I'll throw in the belt if you're purchasing this for a Camry/Calica).
Celica/Rav4/Camry 5SFE pulleys from mid-90s are all same.

It's a bit banged up (see detailed pics), but perfectly functional.
Please do your research and understand what's for sale here before purchasing.

$80 shipped OBO.



This post has been edited by slavie: Jun 22, 2015 - 5:29 PM

[slavie]

nsxtypeR, I'm going to play the devils advocate and point out just a few shortfalls of the article you posted. Fair?
- The author makes no note of engine mileage or history. Yes, the last owner may only have had few modifications at the time of failure, but who knows what the engine had been through prior to that?
- There is also no mention of what pulley exactly was used. Brand name quality part, or low quality no-name special? This is not trivial.
- With a sample size of 1, there could be plenty of other factors contributing to the failure, manufacturing defect being not the last of them. Could it be out of balance from the factory? New engines fail, too, you know.

Because the failed engine had an aftermarket pulley does not mean the pulley caused the failure. Correlation is not causation - just because two factors are present does not mean one was caused by the other. Maybe this chart will help explain the concept:

More info on the concept here.

With that aside, let's go further and pull up some information from the UR site (here) to address this dampening science:

The purpose of a damper is to protect the crankshaft from cracking due to excessive torsional movement and harmonic frequencies. A damper has no effect on bearing wear, it is the engines balance and build tolerances that control bearing wear. Dampers are not necessary in most modern engines because of the many advances in engine design but more importantly the quality of the materials and machining tolerances. Factors such as shorter stroke lengths, short piston TDC dwell time, no piston pin off-sets, forged crankshafts and engines that are balanced to blue printing specs or better (Honda engines are 0 gram balanced). Another important factor is the actual tune of the engine, especially when modified. Poor tuning leads to detonation which is an engine killer and no damper can stop this damage.

Now that these important facts are out in the open you need to figure out if your engine does or doesn't need a damper. If your factory crank pulley is not interference fit onto the crankshaft you do not need a damper. A great example of this is the 4G63 engine (1990+ Eclipse, Evo, Laser & Taon) which has its crank pulley mounted to the engine with four small M8 bolts. The 420A SOHC/DOHC crank pulley (Chrysler Neon, etc.) is interference fit but not because it needs a damper but because there is no key or dowel pin to hold the pulley from spinning on the crankshaft. Still confused? If you unbolt your crank pulley and it slides off the crankshaft you do not need a damper. There are a few engines where the crank pulley is sometimes slightly tight (VG30DE & DETT) but these engine also do not need a damper.

...

Many earlier generation crank pulleys on domestic & import engines have no rubber at all. We have samples of many of these from Acura/Honda B & D Series engines, 2.4L Altima, 1.8L Eclipse, 2.3L Fords, 2.2L Chrysler's, and 1.8L VW's just to mention a few. Some people will now worry that because we remove the NVH damper they will start to hear more engine accessory noise. The type and amount of NVH is unique to every car. As an example NVH will increase with aftermarket intakes or exhausts. OEM intake and exhaust systems use baffles and resonators to quiet intake and exhaust noise. Aftermarket systems eliminate these baffles and resonators to increase HP but they also increase noise from the throttle opening and from the additional size of the freer flowing exhaust. To most people the increase of in NVH makes for a sportier driving experience not to mention more HP.

Interested readers can read the whole article for more info.

Everybody is entitle to their own opinion, and I believe they are also entitle to hear both sides of the argument as opposed to being scared into a decision.