Cause of blown motors?

[gramicci101]

Originally Posted by suaveflooder

It's always a brother of a friends who's sister metnioned it to him about her dad's car failing because of a lightweight pulley on a subaru.

And the sad thing is that her dad drove a Honda! How does that even happen?!

[suaveflooder]

Originally Posted by gramicci101

And the sad thing is that her dad drove a Honda! How does that even happen?!

[blackhawkdown]

Originally Posted by Monogram

There is currently a thread on this site where an owner lost an engine due to bearing failure. The only mod was a light crank pulley.

[pche]

My Perrin LWP had been on the car for around 10k miles now, no issues.

But I have to say that in a BRZ, at least mine, it really didn't do shit. Did not register on the butt dyno at all. I had it on my 07 WRX and felt the difference. Zilch, zip, nada on the BRZ. Hey at least it looks pretty and match my red Perrin intake.

[Poodles]

Originally Posted by charged86

this thread is insane. I just talked to ATI and they really wouldnt admit that the car was internally balance. But he did say that nascar, and top fuel dragster engine builders ALL USE ATI. I said agian, the rumor is that my engine is internally balance. He said would you trust your built motor to a stock cast machined part or a part engineered to keep everything in check. I did just build a motor and it was very expensive. So i am considering this part as another insurance policy to protect my engine.

On a second note I am considering a larger pulley to gain more boost instead of going to an even smaller supercharger pulley. My custom one will probably be built out of aluminum and I dont care if its lighter or not I am more concerned about having everything in balance. ATI offered to make me a larger balanced pulley but it would be 6-9months out which is not something i would consider.

I know this really didnt help either argument here but from a owner's stand point who is going on a fairly large build.

Balance =/= harmonics. The rotating assembly can be perfectly balanced, but the stresses from the cylinders firing can induce resonance in the crank.

Originally Posted by FirestormFRS

Oh you silly goose! You have no idea how much enough CNC machines to meet demand would cost. You have no idea how much tooling and maintaining said CNC machines cost. CNC is great and I love the ones I work with, but they are very expensive in comparison to casting iron. All steel/iron/aluminum parts would be CNC'd instead of cast if it were cheaper.

The stock part is machined...

Originally Posted by pche

My Perrin LWP had been on the car for around 10k miles now, no issues.

But I have to say that in a BRZ, at least mine, it really didn't do shit. Did not register on the butt dyno at all. I had it on my 07 WRX and felt the difference. Zilch, zip, nada on the BRZ. Hey at least it looks pretty and match my red Perrin intake.

Yep, the weight is too close to the axis of rotation and too low to really have much effect. The WRX has a larger damper because of it's higher output, so that's probably why you could fell the difference.


Save your money and go after upgrades that actually show on a dyno...

[FirestormFRS]

Originally Posted by Poodles

The stock part is machined...

There is a huge difference between running a cast part through a mill and lathe to knock the roughness off and CNC machining a billet aluminum piece.

[tennisfreak]

Originally Posted by Monogram

Found it: http://www.ft86club.com/forums/showthread.php?t=60047

The only thing that thread proves is that Toyota warranties an engine blown TWICE while having a lightweight aftermarket crank pulley installed both times.

Whether or not the crank caused the blown engine is uncertain but it is certain Toyota does not blame the pulley specifically and will still honor their warranty.

Auto makers are not in the habit of doing thousands of dollars (maybe tens of thousands in this case) in repair work on vehicles that obtained damage from owners putting on aftermarket parts.

[PMPB]

Originally Posted by FirestormFRS

There is a huge difference between running a cast part through a mill and lathe to knock the roughness off and CNC machining a billet aluminum piece.

There is also a huge different in machining steel vs. aluminium. Aluminium might as well be butter compared to the expense of tools, cut speed, and machining fluid required to make our stock crank pulleys.

I'm not sure how much a set of stock pistons cost, but an aftermarket set of FORGED pistons is around $600. Our OEM pistons are sandcast, and spend a lot more time in machining than a relatively simple pulley. I'm just pointing out that a sandcast part that requires extensive machine time, can still be made cheap. Just because the Perrin part is machined from billet, doesn't make it better than what Subaru could make using a cheaper method.

Also, before you start saying that billet is some mythical alloy production methods, it's just a cast aluminium rod (a billet) that is cut into round blanks. 6061 aluminium is the most common plain aluminium ever. T6 is also the standard tempering used. Often a part could be treated to T4 sent for machining, and then retempered to T6.

If Subaru wanted to make lightweight aluminium crank pulleys, they could produce them for about $12-15/ea, possibly cheaper. (I wanted to be conservative)
It would be an extruded part semi-hollow, which would subsequently be cut into blanks, bored on both sides, turned on the outside, and then reamed for concentricity. Pretty fast machining operations which would be automated.

(Myself and a few family workers have or still work in the manufacture of aluminium parts for several car makers, ATV, snowmobile, aircraft, manufacturing equipment, jet boats etc.)

I believe the stock crank pulley would require more manufacturing time. Each piece is likely sand-cast. Additionally, due to the design of the stock pulley, it requires balancing, the manufacturing time alone for that step is not insignificant. A one piece pulley would not have to be balanced after the turning is complete.

[tennisfreak]

Sorry if my post came off as an attack or rude but that is not how it was meant.

You posted that an owner had a blown motor with only a LWCP installed and then linked it with no further explanation.

I was just summing up what the outcome of the thread was for the people in this thread that did not want to read through the entire other thread.

This gives them more information than just "owner with LWCP and nothing else blows engine".

[Haeb]

If ya'll get this feisty over a crank pulley / harmonic balancer debate I cant wait to see what happens around here when some one starts a gay marriage / politics / football thread LOL.... blood will be spilled I'm sure.

[gramicci101]

As long as the crank pulley isn't trying to marry another crank pulley, we should be good.

[ZDan]

Originally Posted by suaveflooder

Once again, quote above was from perrin. I'm done buying their parts now that you told me their ideas are "absurd."

Don't be so credulous that you just take everything people say to you at face value when they are trying to SELL you something...

Here's what you said Perrin said, which is patently absurd:

The rubber ring between the two halves of the stock pulley is to make up for mfr. differences. Two cheap cast pieces pressed together with rubber allows for additional slop in both.

This is total and utter horseshit. The required tolerance for the pulley is the same whether you make it out of one part or two. If you make it out of two pieces with a rubber piece between them, you have to have *tighter* tolerances on the two metal parts to account for the tolerance stackup of the assembly.

It is most certainly NOT made as two steel parts with rubber in between them to save money, it certainly costs them more to make it that way.

The REASON is that a dual-mass damper (effectively two rotational masses with a spring between them) controls vibes better over a broader rpm range.

A one-piece with the same net shape and total mass would definitely be cheaper.

If Subaru chose to install a pulley like ours would add significant cost to the engine and is not cost effective for a production piece.

Of course Subaru would never waste money making it a pretty shiny anodized aluminum piece. They know what they want the two masses to be, if they made them out of aluminum they would have to be bigger, and they would cost more. That would be dumb...

Installation of our pulley will result in smooth, true, and long lasting belt wear and accessory lifespan is increased.

Highly doubtful, and I'm 100% certain whoever wrote this has no data to back up the claim.

Plus, throttle response, HP and torque are all increased dramatically for such an inexpensive painless part.

Not a chance you would be able to measure any difference on a rear wheel dyno or at a dragstrip. The effect of such a *tiny* reduction in effective overall mass would be well below repeatability of the measurements.

[SmsAlSuwaidi]

toni@fa20club is the cause

[Simply_the_best]

I have been running the BuddyClub Pulley set for roughly 6-7k miles with no issues to date. The car def. feels more responsive.