How am I making an assumption?
Ford has used a number of different dampers on 4.6L engines over the years, across model lines and applications. There's the 5.8-lb F3AZ-6316-A. There's the 6.5-lb F6ZZ-6312-AB. Then there's the 8.95-lb XR3Z-6312-DA and the 9.90-lb 1W7Z-6312-AA unit. Don't forget the 8-rib 5.7-lb F75Z-6312-BA and the 7.20-lb XL3Z-6312-CA units...
One size does not necessarily fit all. Tell me: Why would Ford go to the expense and trouble of engineering so many different harmonic dampers if one would work for every situation?
The dampeners are in fact interchangeable!!!
Then why so many different part numbers and discrete masses?
Have you that same data to prove the contrary?
I'm not the one making the outlandish, salesman-esque claims of inferior OE parts based on
appearances. Generally speaking, the one making claims against proven, sound engineering practices is the one that has to back up his claims. Ford has the engineering resources and processes that no aftermarket company can touch. They develop the entire engine package as a massive engineering project and perform grueling verification and validation on dedicated dyno cells with often brutal tests: Ford's EcoBoost V6 was forced to endure 362-continuous hours of wide-open throttle testing in addition to 150-hours of thermal cycling where, every ten minutes, the engine operating condition was switched between "completely cold" to maximum power and maximum EGTs...
This is just standard boilerplate stuff in OE dyno cells. There's a good reason an OE could spend upwards of $1-billion on a new engine development program.
Again, it's up to you to prove that aftermarket pulley manufacturers can match this level of engineering, verification and validation, not for me to prove that Ford properly engineers things. That's just a given with nearly two-decades and millions of 4.6s and 5.4s in circulation without rampant crankshaft or oil pump failures using OE parts.
Do you have eyes? Eyes that see minor imperfections in the casting and production process that would otherwise affect longevity and effectiveness over an engines lifespan.
You said it yourself:
Minor casting imperfections. If they are minor they are inconsequential. Again, you're being fooled by shiny, polished bits spun on a lathe or CNC centre and are missing the bigger point: An OE damper can be perfectly fine as a torsional vibration damper even with a "minor" casting imperfection and an aftermarket pulley can be a ****ty damper even if it does like like Cindy Crawford.
Inferior operation as a result of slipped outer rings caused by repeated stress, rotted, or missing insulators.
And this is a rampant problem with the OE parts is it?
And with all due respect to you....follow your own advice? What have we got other than your own assumption that Ford has actually put that kind of thought into their dampener design and others have not.
Again, I don't have to because I'm not the one attempting to compare the engineering resources of, say, BBK or March or even Steeda with Ford Motor Company. There is plenty of empirical evidence to say that Ford's engineering is just fine and there's also empirical evidence to say that oil pump failures in particular began to surface -- and not just in the modular world -- around the time that underdrive pulleys became popular. Miata guys
talk about it. Hell, even SRT-4 guys
talk about it. A common thread here is that engines that have increased risk of damage also happen to be those that have oil pumps mounted over and driven directly by the crank snout.
If you’re a factory fan boy, that's fine....but if you're going to trounce the competition let’s see some real world proof that Ford is putting out a better product.
Again, oil pump failures only really began to show up and be discussed when UDPs became popular. And again, it's not just Ford engines that may be susceptible. If there was a problem with Ford engineering in this area we'd all know about it since just about every second vehicle in the US Federal government fleet and nearly every vehicle used by police forces and taxi fleets are also Crown Vics equipped with modular engines. Given the miles these things see if there was a problem with Ford's damper design it would have shown up by now. Only when people began bolting on UDPs did the notion of an oil pump gear shattering come to the fore.
Why is that?
Lawsuits, customer backlash, reputation and bankruptcy for starters....take your pick? Do you really think that because Ford is a large scale, multi-million company that they’re immune to put out an inferior product than a smaller scale aftermarket operation?
Not at all. But I do believe that Ford's engineering processes, verification and validation procedures and sheer resources outstrips that of common UDP makers that have two or three CNC machining centres and a guy in a cubicle driving SolidWorks.
I also believe that Ford's approach to engineering is more systemic, focusing not only on accessory speeds but also on critical torsional vibration damping. So far, I've only heard of one UDP maker -- Steeda -- that even
mentions this most critical parameter. Indeed, don't they say they're the only ones that can make this claim?
How much engineering is going into UDPs as a whole if only one maker can make this claim?
A smaller scale operation that’s less likely to take the risk...
And it could just as easily be argued that a small firm lacks the engineering resources to do it right. They're simply relying on the inherent "over-engineering" and safety margins Ford originally built into the design of the engine. But with such reliance comes the fact that those safety margins are reduced and with it, the incidence of failures goes up.
Don’t assume because the product has a big name behind it, that it’s going to carry a superior measure of quality with it as well.
I am still more inclined to believe that an OE manufacturer will get the heavy hardware correct than a small shop turning out pulleys on a lathe.
People buy aftermarket parts for their cars because they’re an improvement over the factory offering….not because they’re inferior!
Improvement in what regard? If they free up 4HP but reduce torsional vibration damping, is that an "improvement"? It depends on your definition of "improvement" I suppose.
To the lay-person only interested in dyno numbers but otherwise ignorant of the true complexity of the internal combustion engine I suppose they'd see that as an "improvement." However, had this individual made an informed decision, he might re-think the cost/benefit ratio associated with a given mod.
Skinnies on the front of a drag car can "improve" straight-line performance by reducing rotating mass. But are they an "improvement" in any other facet of the car's life if it's a daily driver?
Yes, I'm well aware of the purpose of the rubber ring. They're used to absorb and diminish harmonic resonances produced at various engine RPM and engine loads and reduce the amount reverberating through the engine that would otherwise cause excessive wear and in some cases like those of the fragile glass like powdered oil pump gears…catastrophic damage.
Very good. So why are you not more concerned about aftermarket pulleys affecting the effectiveness of this damping mechanism to get a couple more HP?
Many of the aftermarket pulleys also utilize rubber insulator rings in order to control resonance (although the good ones aren't simply "press fit" like the Ford dampers are.
It's not just about having "a" rubber "insulator" as you call it. In the damper topology that uses elastomers the durometer matters a great deal as does the mass and mass distribution of the inertia ring it supports. This is where engineering and testing comes into play. Most smaller UDP players simply don't have the resources to properly execute here.
Some of the higher end ones will instead utilize a gel like fluid to control and absorb frequencies and vibration and are far superior to anything put out by the factory. Please tell me you argue this point as well?
Glad you raised this point: Yes, there are decent viscous-dampers out there that actually meet or exceed OE performance. But how does the existence of such dampers that don't even bother to be "underdrive pulleys" (but rather superior
dampers) factor into the discussion of under-engineered UDP kits from small outfits with a lathe and a CNC machine?
Explain to me also why the garages and engine machine shops aren't full of blower cars (factory or otherwise) in need of engine replacements that are continuously stressing bottom end components and changing the characteristics of their dampeners (factory or otherwise) ability to control vibration and resonance with varying materials, weights and diameters of upper and lower pulley combinations, or even imperfections in the operation of the head units themselves?
While blower drives can and do stress the crank snout remember that the primary exciting forces on the crank are the power-strokes of the cylinders. As well, moderate, street-driven blower cars -- especially centris but also twinscrews etc -- do not place a ton of harmonics or loading into the crank snout...certainly not like those old-school 6-71 Roots blowers with the huge drive pulleys cantilevered out from the crank snout. I run my Kenne Bell at 9-psi with the factory damper and a 6-rib belt. This illustrates the efficiency of the blower and the fact that crank loads are evidently not a concern.
You are probably also aware that its very common for the rubber ring to deteriorate and wear over time...
Proof?
How exactly do they “stray too far from the dampening characteristics of the OE” unit?
I said
if they stray too far. And they can do so by putting the product requirements emphasis on bling and/or accessory slow-down percent instead of achieving those two requirements
and maintaining OE levels of damping. So far I've only seen one UDP maker even mention this -- Steeda -- but no one else.
Prove to me that the stock dampener does such a superior job.
The 4.6 and 5.4 is an extremely popular engine in use in millions of vehicles worldwide. The vast majority of these cars have OE dampers and have no problems with oil pumps or dampers "deteriorating" and separating.
Seems like Ford did okay.
Ford was really crossing their "t's" and dotting their "i's" when they designed those?
The manifold is indeed a disappointment in an otherwise extremely successful modular engine program. Of course this also highlights the cost Ford would incur if they failed to get the rotating assembly right...
And plug-ejections don't occur if torque wrenches are used when replacing plugs.
For the life of me, I can't understand why you would simply assume that because it wasn't made by Ford, that it must be garbage.
That's not what I'm saying. Pay attention.
The fact is that the bulk of UDP manufacturers do not put the requisite level of engineering into their products to maintain damping performance. It affects domestics and imports alike and is an
industry issue. In this regard, I'm willing to say that Ford's OE damper, designed by OE engineers in OE labs and OE dyno cells and built to OE specs is superior to the majority of UDP products out there because I believe that a few HP is not worth the cost of increased risk to the engine.
Yes, there may well be superior dampers out there (e.g. Fluidampr) but they are designed and marketed as
dampers, not underdrive pulleys. If I go to the Fluidampr website and check their Ford offerings, I don't even see the word "underdrive" there.
The bottom line though, is the damper is there to control harmonic vibrations at varying RPM and engine loads throughout its normal operation.
Yes, indeed it does, which makes your acceptance of under-engineered UDPs all the more puzzling.
I have already pointed out Fords use of the same the dampener on a variety of different engines, and varying dampener, sizes and weights on the same models of the same engines so please let’s not get into how precise and close tolerance Fords design and engineering process is again.
And I've given you Ford partnumbers for a range of dampers with varying masses and moments of inertia but all used on modular engines. The fine points of this stuff does matter to Ford, otherwise they'd have used a single damper across the entire line and for all applications to save money.
I have 5-years of practical, flawless service on an engine that has seen all RPM, under all loads and plenty of hard passes at the track.
A single anecdote. I have 8 years of service from my 02 and have never blown a spark plug. It doesn't mean the weakness isn't there, it's just that a failure hasn't occured. Still, my engine is at increased risk of a plug ejection compared to other engines. Similarly, depending on what pulley set you have your engine may be at increased risk of oil pump failure.
The very fact that I'm having zero issues after that length of time and under those conditions is proof enough that Fords engineering process probably isn't anywhere near as precise as you've led yourself to believe.
Look up the concepts of "statistical significance".
I’ve changed everything about my engine…from the weight of the dampener, to the weight of the rotating assembly, to the amount of stress being placed on the dampener itself. None of which has had a negative effect on this engine in the slightest.
So you've done measurements of the degree of torsional vibration your combo is seeing? No, of course you haven't. You're simply relying at this point on the fact that engines and components are over-engineered and esoteric stuff like torsional vibration never even entered your thoughts as you pieced the engine together.
It does not follow however, that the
risk of failure is equal to or lower than it would otherwise be had you paid attention to the finer points of "engine-eering."
I’ve accomplished this all while going against every aspect of your theory that the factory balance is so crucial.
It's with statements like that I wonder, again, if you actually know what we're talking about. Balance is not the same as torsional vibration and the beating that oil pump gears can take at resonance.
Your only other option is to admit that you just might be wrong in this instance….and you’ve got far too much invested in your opposing argument at this point in order to do that, don’t you?
Like you don't.
Curious: Your talking points make me think you sell these things for a living or work for a company that manufactures or sells them. In the interest of full disclosure, I'm a medical electronics designer with both electrical and mechanical engineering backgrounds.
If you would prefer to go through life with blinders on...
And some people prefer blingy, shiny objects, fall for glossy brochures and wordy sales pitches and are willing to trade a MPG or a HP or two for increased risk of engine damage, quite probably because they don't know they're doing so. Ignorance is bliss I guess, right?
I'm probably done with this GBer. Pretty much everything that needs to be said on the topic has been said and it can only turn into a nasty pissing match from herein. Readers can make their own decision from what we've both said.
Thanks for the tech, Brian. 
