Cause of blown motors?

[stugray]

Originally Posted by suaveflooder

Our car does not come with a balancing component from the factory.

I disagree. Not only is the multiple part assembly clearly more than just a simple pulley, but mine has a hole drilled into it along the perimeter.

I can only assume that the hole was drilled to balance the rotating mass.

When pros build these engines, they have the rotating mass balanced.
This rotating mass includes the pulley and all rotating parts.

If you change one part, you invalidate the balancing.

Did the factory balance each of these engines as a complete rotating mass?
I have never had a definitive answer to that question...

[steve99]

Two thing that seem implausible

1. An OEM manufacturer would install a part that is not needed or install a part that is more complex and hence more expensive than it needs to be.

2. You have a rotating crankshaft that weighs many Kilograms with a flywheel bolted to it at one end with clutch and pressure plate and people are replacing the pully/balancer on it. You replace this to save probably less than 5% of the total rotating mass of the crankshaft flywheel clutch pressure plate assemblies, and this rotating mass is close to the axis of rotation. What difference does it make ??

Unless it smaller diameter and under-driving alternator/air cond/water-pump ect which will probably have other undesirable effects in stop start traffic, maybe fine on a track

[solidONE]

uh... plenty of folks have blown their FA20's with the stock pulley. so... no. While it may contribute, it's not the cause.

[BC-Boy]

I doubt the physical weight of the pully has any adverse effect to the balancing of the internals, mostly what i would come to think is the rubber damping unit helps absorb and dissipate vibrations going from center to each end <---C---> not to mention vibration from the accessory belt, as well as the oem steel flywheel, changing to a aluminum unit as we do know aluminum is not well known to absorb vibrations, if harmonic waves are trying to exit the crank and instead get sent back they collide with oncoming waves and could cause issues, i know for a fact the longer the crank the more harmonics it produces, in theory a strait 6 would be the worst and a flat 4 (short crank) would be the best at managing harmonic waves. i personally would not go with a aluminum pully excypte for a race car, instead lighten all the other pullys on the accessory belt, and swap the oem fly wheel for a chromoly unit thats thats 20-30% lighter than stock, maybe get a machine shop to bore holes into the oem crank pully, mill off a bit . going all aluminum not only loses too much weight but aluminum doesnt absorb or dissipate vibration. id like to see a smaller and more efficiant alternator, somthing with say .5lb rotating internal mass instead of 2lbs, and that uses 1 hp instead of 3 when in load, that would give a good difference. you could kill prob 3-4lbs with a smaller alt,lightened pullys on everything but the crank, and then kill another 3-4 with a chromoly flywheel and that would be a great combo that prob wouldnt affect the actual physics that the oem worked so hard to engineer, while at it id put a slightly smaller water pump pully, something 95-96% of its size barly enough to matter but while at your at it :P

[alan.chalkley]

The biggest cause of blown engines , here in down under aus is low oil and /or coolant levels.
Especially on summer days when the outside temperature exceeds 40 degrees celsius.

[suaveflooder]

Originally Posted by Gords_zenith

Just because a SOA customer relations guy said it doesn't have one doesn't mean he's right. He could be mistaken and be thinking of a different type of damper. But this is from ATI's website. I'm inclined to think that there is one based on what he said and how others have described the one that is on our car.

"For years, major manufacturers have used the elastomer-type damper design. These conventional, single-strip elastomer dampers have proven very effective on OEM applications operated at low RPM's. They were also surprisingly effective at high RPM's. Many engineering studies have shown that elastomer style dampers to be the far superior to the friction type and markedly better than the viscous type in controlling vibrations over a wide range.

Conventional single strip elastomer dampers are not re-buildable. The main problem with this type of damper is a loss of certain controls inherent in the manufacturing process. An inertia weight pressed with a rubber insulator to the crank hub allows the possibility of the ring to move in its relation to the keyway. It is also impossible to maintain the concentricity of the inertia ring during manufacturing. The ring must be machined after it's pressed to the hub, and then balanced after machining. When it works loose with age or from multiple cycles, the ring will move, and the damper will be out of balance."

http://www.atiracing.com/products/da...amper_tech.htm

It doesn't make any sense for an OEM to NOT have some form of vibration damper. Further more, I'm not trying to create hysteria. I was only questioning if there is a relation between the blown engines that people are posting about and LWPs. If you think your right than mathematically prove it. I will admit that I can't prove it mathematically, so I'm inclined to take the OEMs word for it.

The previous quote I showed was from perrin. God knows they have no idea what they are talking about on subaru's

This is a response from Subaru:

"Thank you for your patience as I checked with our Technical Services Department regarding your message below. They advised that the crank pulley is a pulley and nothing else. It is not used as a harmonic damper/balancer.

Thanks for the opportunity to be of assistance. If you need any future assistance, please feel free to contact us again."

Best wishes,

John J. Mergen
Customer Service Department
Subaru of America, Inc.

Originally Posted by ZDan

Of course. The dual-mass damper is there to keep the vibes better controlled over a broader rpm range.

I would feel better about a lighter dual-mass damper than a simple single-mass part.

The point about dual-mass damper with rubber being somehow cheaper to produce is absurd. You can't throw two parts with bigger tolerances together with a piece of rubber and magically get the necessary tolerances met! The two mass part will require tighter tolerances, and it's two metal parts with rubber. Definitely MORE expensive than a simple one-piece pulley. They do it for a reason, and it's not to save money...

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

Originally Posted by Poodles

Harmonic DAMPENER.


The engine is internally balanced. If someone asked if it needed a balancing pulley, of course the OEM is going to say no because you asked the wrong question.

From Wikipedia

A harmonic balancer (also called crank pulley damper, crankshaft damper, torsional damper, or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration and serves as a pulley for drive belts.

Feel free to shoot subaru the message and use the "correct" verbiage if you feel so inclined, but if you look above, they use the words "harmonic damper/balancer" so I'm pretty sure they got it. Although, they did call it a "damper" and not a "dampener" so I guess we could nitpick that one apart. Maybe we should write them again??

Originally Posted by stugray

I disagree. Not only is the multiple part assembly clearly more than just a simple pulley, but mine has a hole drilled into it along the perimeter.

I can only assume that the hole was drilled to balance the rotating mass.

When pros build these engines, they have the rotating mass balanced.
This rotating mass includes the pulley and all rotating parts.

If you change one part, you invalidate the balancing.

Did the factory balance each of these engines as a complete rotating mass?
I have never had a definitive answer to that question...

With all due respect, here's where you went wrong (you know what they say about "assume") and you are overthinking this.




I've been staying off most the forum a little more lately (been sticking mostly to the threads I've started), so I apologize for the late response to you guys. I've noticed that recently, this forum has very much become a buch of young boys d*ck measuring…like this thread. OP, there is SO much information out there on this subject that a simple google search should answer most, if not ALL of your questions. This has been debated A TON. End of the day, it ends up being a couple companies telling the manufacture that they have no idea what they put on their cars as subaru keeps replying the same way (no dampener or balancer on the car and that the pulley is just a pulley)….now that idea is pretty "absurd."

There are hundreds of thouands of cars running around with lightweight pulley's for a combined hundreds of thousands of miles with no issues. Do what you wish with your car.

Next thead "Do you know that lightweight flywheels are the cause of blown motors?"

[Gords_zenith]

Originally Posted by suaveflooder

Next thead "Do you know that lightweight flywheels are the cause of blown motors?"

I guess you don't understand what a question mark means....hence the one in my title. I was simply questioning if there was a connection to the blown motors on this forum and a LWP.

It's not a knock to Perrin and the like but was only a meant to get people thinking and debating, rather than falling for the next shiny thing on a website that claims to produce power, and blah blah blah.

I don't really care to debate semantics with you about wording, but it was only questioning that maybe they got it wrong.

[stugray]

Originally Posted by suaveflooder

With all due respect, here's where you went wrong (you know what they say about "assume") and you are overthinking this..

You just dismiss a fact because I used the word "assume" in my sentence.
I will rephrase that for you: My stock harmonic balancer has a hole drilled around the perimeter. Therefore, one can safely state that the factory performed some kind of balancing or there is no reason for that hole to be there.

And as for the "Subaru has stated blah blah, blah pulley......" THIS IS CLEARLY a "he said, she said" situation.
NOTE: If you search for "John J. Mergen" you will find dozens of quotes from him about this pulley issue, but almost all of them differ from the others in some way. I have never seen a post from the very person who received this email. It has reached birther status in the blogosphere...

I have read almost every thread about pulleys and every time it comes up: Someone's step-brother's cousin once saw an email from someone who might have been a technical person at Subaru that stated that the pulley is not a balancing pulley.

We have a number of facts (and common sense) that say otherwise.
1 - the Stock pulley on my subauru BRZ is a complex cast/machined/mulit-piece assembly. And NOT just a simple pulley.
2 - Apparently Subaru likes to waste money and engineering costs to make a complex fabricated heavier part and include it on our cars for apparently no reason whatsoever.
3 - Armchair automotive engineers know better how these engines work
4 - Experience building racing boxer engines counts for zero because of above "armchair automotive engineers" SOME of which dont know what end of a crescent wrench is adjustable....

[suaveflooder]

Originally Posted by Gords_zenith

I guess you don't understand what a question mark means....hence the one in my title. I was simply questioning if there was a connection to the blown motors on this forum and a LWP.

It's not a knock to Perrin and the like but was only a meant to get people thinking and debating, rather than falling for the next shiny thing on a website that claims to produce power, and blah blah blah.

I don't really care to debate semantics with you about wording, but it was only questioning that maybe they got it wrong.

I understand, and honestly, you have been beyond respectful, which says a lot about you. I agree on not arguing over semantics. There really are some great responses on different forums that goes over this. It's been a debate for a long time.

I actually held off for a long time on the pulley because I kept thinking, "well what if." The more I read, and the more opinions I got (even from engine builders) was that the pulley is fine. Although, some of the guys metioned not to put both a lightweight flywheel and pulley on together as it does create said vibration. Jury is still out for me on that one, but I'll keep reading as information continues to come out.

Originally Posted by stugray

You just dismiss a fact because I used the word "assume" in my sentence.
I will rephrase that for you: My stock harmonic balancer has a hole drilled around the perimeter. Therefore, one can safely state that the factory performed some kind of balancing or there is no reason for that hole to be there.

And as for the "Subaru has stated blah blah, blah pulley......" THIS IS CLEARLY a "he said, she said" situation.

I have read almost every thread about pulleys and every time it comes up: Someone's step-brother's cousin once saw an email from someone who might have been a technical person at Subaru that stated that the pulley is not a balancing pulley.

We have a number of facts (and common sense) that say otherwise.
1 - the Stock pulley on my subauru BRZ is a complex cast/machined/mulit-piece assembly. And NOT just a simple pulley.
2 - Apparently Subaru likes to waste money and engineering costs to make a complex fabricated heavier part and include it on our cars for apparently no reason whatsoever.
3 - Armchair automotive engineers know better how these engines work
4 - Experience building racing boxer engines counts for zero because of above "armchair automotive engineers" SOME of which dont know what end of a crescent wrench is adjustable....

lol, this is not a "he said, she said" idea, this is information from subaru. The "he said, she said" principle doesn't really come into effect in this case. Why not call the guy from above? I left his name on there.

Curious, is this the "complex" part you are referring to? Just took these from the pulley that came off of my car





Some more more "He said she said" for you. This one from FT86 speedfactory

Good information

An opinion often expressed is "if the manufacturer put it there, it must be there for a reason". However, if you look at it from the car manufacturer's point of view, casting pulleys from steel is very cheap and easy, because they can be produced in large numbers and there is no waste (as opposed to machining them from billet). But because the resulting pulley weighs significantly more than one made from aluminium alloy, it requires dampening.

Manufacturers will always build cars (even high performance cars) to suit the widest possible selection of driving scenarios and drivers, which means there are always compromises. The weight of the flywheel and pulley also affect how fast the revs drop between gear shifts, and a production car is designed to only allow the revs to drop fast enough for average shifts. If you hurry the shift the revs will be too high for the next gear, resulting in a sharp jerk as the momentum of the engine transmits through the drivetrain. Reducing the engines' inertia with a lightweight pulley kit allows faster and smoother shifting.

So maybe this heavy pulley is "dampened" for the same reason perrin said in the quote from post #11. Perhaps it's not as "complex" as you think

[stugray]

Originally Posted by suaveflooder

Curious, is this the "complex" part you are referring to? Just took these from the pulley that came off of my car





. Perhaps it's not as "complex" as you think

Yes that pulley is exactly like mine.
Note that the pulley is made from at least three pieces:
An inner cast & machined part, a rubber middle section, and a machined outer part.

If it really does not matter, WHY did the engineers put that part (that is clearly more expensive to manufacture than a solid aluminum machined pulley) on instead of a solid pulley.

And note how you have two holes machined into the edge of the pulley.
My engine came back from the balancer with holes exactly like that in the pulley and the perimeter of the flywheel.
Why do you suppose those are there on a factory pulley?

WHY??? - CUZ RACECAR?

[suaveflooder]

Originally Posted by stugray

Yes that pulley is exactly like mine.
Note that the pulley is made from at least three pieces:
An inner cast & machined part, a rubber middle section, and a machined outer part.

If it really does not matter, WHY did the engineers put that part (that is clearly more expensive to manufacture than a solid aluminum machined pulley) on instead of a solid pulley.

And note how you have two holes machined into the edge of the pulley.
My engine came back from the balancer with holes exactly like that in the pulley and the perimeter of the flywheel.
Why do you suppose those are there on a factory pulley?

WHY??? - CUZ RACECAR?

Lol, note, I explained why under the pic.... Well Ft86 speed factory did. Sounds like Perrin was correct.


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[stugray]

Originally Posted by suaveflooder

Lol, note, I explained why under the pic.... Well Ft86 speed factory did. Sounds like Perrin was correct.


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I saw your quote, and I call complete horseshit!

"An opinion often expressed is "if the manufacturer put it there, it must be there for a reason". However, if you look at it from the car manufacturer's point of view, casting pulleys from steel is very cheap and easy, because they can be produced in large numbers and there is no waste (as opposed to machining them from billet). But because the resulting pulley weighs significantly more than one made from aluminium alloy, it requires dampening."

Who can honestly say (with a straight face) that making three different pieces and attaching them together while supposedly machining them separately can in ANY WAY be cheaper than machining a pulley as one piece?

The pulleys sold as "superior" probably cost about ONE DOLLAR a piece to make at the machine shop churning them out by the thousands.

No-one that knows anything about manufacturing can hold each of the pulleys in question in their hands and say that the OEM pulley is cheaper to manufacture than a billet aluminum "disk".

[FirestormFRS]

Originally Posted by stugray

I disagree. Not only is the multiple part assembly clearly more than just a simple pulley, but mine has a hole drilled into it along the perimeter.

I can only assume that the hole was drilled to balance the rotating mass.

When pros build these engines, they have the rotating mass balanced.
This rotating mass includes the pulley and all rotating parts.

If you change one part, you invalidate the balancing.

Did the factory balance each of these engines as a complete rotating mass?
I have never had a definitive answer to that question...

No! The factory does not balance every engine that comes down the line. Mass production engines get whichever pulley is the next one in the box. The hole you see on the outside of the pulley is to balance the pulley itself. Kinda like balancing a tire.
The tolerances are extremely tight on the crank balance and the pulley, but that's about it as far as balance goes.

[suaveflooder]

Originally Posted by stugray

I saw your quote, and I call complete horseshit!

"An opinion often expressed is "if the manufacturer put it there, it must be there for a reason". However, if you look at it from the car manufacturer's point of view, casting pulleys from steel is very cheap and easy, because they can be produced in large numbers and there is no waste (as opposed to machining them from billet). But because the resulting pulley weighs significantly more than one made from aluminium alloy, it requires dampening."

Who can honestly say (with a straight face) that making three different pieces and attaching them together while supposedly machining them separately can in ANY WAY be cheaper than machining a pulley as one piece?

The pulleys sold as "superior" probably cost about ONE DOLLAR a piece to make at the machine shop churning them out by the thousands.

No-one that knows anything about manufacturing can hold each of the pulleys in question in their hands and say that the OEM pulley is cheaper to manufacture than a billet aluminum "disk".

Lol, okay then. Sounds like you and I are finished here. I give you information from the company who DESIGNED and BUILT the car, and two BIG companies that know a hell of a lot these cars than you and I both and you give me, "I assume." That's fine, man. Have a good night


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