Saturday, Nov 29, 2014 at 11:10
Interesting write-up about the DMF's. As a matter of interest, 20,000.00 ZAR = 2,124.46 AUD. The Rand is currently at 9.4 to the Aussie dollar.
The problem with DMF's, and particularly in their current form, is that they are purely and simply, a complex and unnecessarily expensive device - and they become highly trouble-prone as they age.
DMF's behind diesels are source of problems because of cost-cutting in the designs that does not account for the higher torque, and higher torsional impulses of a diesel engine - and particularly, 4 cyl diesels.
This is just one of the numerous reasons why diesel engines have not made major inroads into the light aircraft engine power market.
The torsional impulses are much greater than current petrol aircraft engines and there's a need for a rubber coupling to dampen the diesels torsional impulses to prevent propeller and propeller hub damage.
The simple fact that there's a sizeable market in selling simple, proven, heavy duty single plate clutches, and single heavy flywheels, as a replacement for DMF's, shows that DMF's are an expensive cure (to the owner) to a problem created by vehicle designers.
6 cylinder engines produce less crankshaft vibrations and torsional vibrations than 4 cylinder engines, simply because of the increased number of firing strokes at reduced angles between them.
The problem has been the manufacturers desire to eliminate 6 cyl engines from their lineups and their efforts to make 4 cyl engines produce more power and torque than the 6 cyl engines they replace.
The problem is exacerbated by designers (European designers in particular) who insist that a highly stressed, high power output, 2.0L, 4 cyl engine can do the same job as a 4.2L 6cyl engine.
Anyone who has ever read "The History of Holden" will know that GM designed the FX (or more correctly, the 48-215) as a 6 cylinder - even though it was only 2.2L - to reduce the need for a stronger and heavier driveline, which a 4 cyl engine would have needed.
DMF's in their current form, are an expensive idea that people will eventually refuse to start buying - particularly when the horror stories of DMF repair costs become widespread and general knowledge.
There's quite likely an opening for someone to manufacture a simple rubber torsional coupling to replace the DMF.
Rubber torsional couplings and vibration dampers have been around for 80 or 90 years, it's not like they're recent design hi-tech technology.
The problem is that a rubber torsional coupling might cost the manufacturer an extra $5 per vehicle and eliminate millions in current parts sales.
You could imagine how
well that goes down with the miserable, stone-faced, penny-counting bean counters who run these companies with an iron fist.
The clutch problems are largely related to the total elimination of asbestos from clutches (and brakes, too).
Despite its dreadful legacy, asbestos was a superb product for clutches and brakes. Unfortunately, asbestos kills - and it's still killing - and it had to be eliminated from all industrial use.
However, manufacturers were behind the 8-ball when it came to finding a suitable low-cost replacement (or replacements) for asbestos, because the banning of asbestos was forced on them, before they could find a suitable replacement.
No one company wants to spend a fortune on research and testing to find new products today.
It's not like there's a war on, like WW2 - where so many of even our current designs and materials still hail from.
So the companies scrambled to find asbestos replacements. They have tried hundreds of materials, then reduced that to dozens. The problem is today, they use customers as their
test bed.
No longer do they absorb research and testing costs and delays themselves, before putting a new product on the market - the customer can do it for them!
As a result, we now find that products that used to perform beautifully with long life and reliability, now fail much sooner and cost us more than they ever did before.
It's all to do with the new "consumer-friendly" products and materials that we are unwittingly testing for free, when we buy a new vehicle today.
The problem with wheel studs and nuts is possibly related to two likely factors.
One is the constant drive to higher tensile low alloy steels in the manufacture of vehicles.
This leads to weight saving and increased strength - but with a couple of downsides.
One downside is that high tensile low alloy steel, by its very nature, has an increasing tendency to corrode. If panels are made from HT tensile steel (now common), then they are made thinner, because of their inherent additional strength - but they are also more prone to corrosion.
With the wheel studs and nuts, higher tensile steels lead to increased chances of corrosion, particularly when water crossings are frequent - and higher tensile steels are more prone to "metal galling" - what many refer to as "threads picking up" - i.e., when the threads on a stud and nut effectively weld themselves together as you try to undo them.
The result from both corroded or galled threads is identical - totally destroyed threads. A sniff of nickel-based anti-seize is a necessity with these style of threads.
Surprisingly, Toyota manuals still insist that wheel studs and nuts be kept clean and dry, and not "oiled", for fear of wheelnuts coming undone.
However, nickel-based anti-seize has only minimal lube qualities, it contains a small amount of mineral oil to assist with application, but it can never be classed as a lubricant.
What the anti-seize does do, very effectively, through grease, water and exceptionally high temperatures, is prevent thread galling.
You can use nickel anti-seize on manifold studs and nuts, and they will still come undone easily even when
the nut has corroded away so badly, you need vice grips to grip
the nut.
The second factor that possibly applies to the wheel stud/nut problem - and this applies across a wide range of components - is the increasing amount of Chinese-sourced components.
Many Toyota, Ford, Mazda and Mitsubishi owners would probably be staggered at the volume of Chinese-sourced components in their current-model vehicles.
Most certainly, the Thailand-built vehicles (which includes almost all of the 4WD utes currently sold in Australia - except for the VW) use quite a sizeable percentage of Chinese origin components. VW probably still utilise a number of Chinese components, too.
The problem with Chinese components is their regular failure to meet QC controls.
It's known as Chinese "quality fade". It's recognised world-wide in manufacturing, and it's something that manufacturers tear their hair out over.
The "QF" problem is two-fold. The manufacturers are constantly striving for lower costs, to increase profitability and return to shareholders.
Customers come a very distant last in todays highly privatised world - shareholders, CEO's and banks are always first, and product reliability is no longer a "key word" or aim.
So the manufacturers bean counters give a supply contract to a Chinese manufacturer, and things start to roll smoothly.
Initial deliveries are good quality - then the bean counters start to apply the thumbscrews.
"We need to shave 3.6% off our suppliers margins, they're too high, and affecting our bottom line".
So the Chinese, already under price pressure, immediately find ways to lower prices again. "They want cheaper? We'll give them cheaper!".
However, the cost savings come in unscrupuluous activities such as reducing the steel specifications, the heat treatments, a reduction in the alloy content, shortcutting any QC procedures.
The Chinese rely on setting a good initial standard of product, then look at lowering that standard, the instant they know they aren't being scrupulously watched and tracked.
Thus we suddenly have stories of component failures in near new vehicles, that are traced to Chinese components suppliers that have failed to meet original specifications in the product supplied.
Add in frequent corruption within China and most of Asia (kickbacks and bribery that are simply regarded as "the price of doing business"), and you have the scene set for constant failures in QC, in reliability, and in product standards.
The CEO's and the bean counters constantly shoot themselves in the foot on these angles, but it means little to them.
The bottom line on the balance sheet is the only figure that matters - reliability, reputation, and customers, can always be purchased, to their way of thinking.
Cheers, Ron.
AnswerID:
542320
Follow Up By: swampfox - Saturday, Nov 29, 2014 at 18:35
Saturday, Nov 29, 2014 at 18:35
HI
Cheers for the wright up .
Another way by the Chinese is to design items to the lowest standard and only up grade what fails.This is most evident in the 3000- 4000 dollar small engine field . Designed in the usa and made in china . Upgraded parts, coils, inlet manifold 5 times, upgraded cylinder heads 3times, rubber parts and gaskets . These still are a problem . The Japanese str mtr was of a 10hp fitted to 30hp The larger Chinese str mtr fixed this .
If u can control the design and manufacture process 110 percent ,I have found USA design china made is ok .
This was for a 2 post clear floor hoist ,some very good design features .
Other Chinese design and made hoists I have looked at have very very poor design eg pre bent arms that donot allow for good under vehicle acess. The only good thing about these is that they r cheap $$ 3000
The Chinese hoist donot survive outside .
The USA designed hoist .The oldest outside in the weather is 12 yr old in town .
Mine is 4yr old . All have seen cyclones etc
The hoist company is a huge player in the USA
Yes the maker even has an Australian agent /workshop
Yes Chinese made does work when they have little to do with whole process. ha ha ha ha ha
Evidence of there rubbish product is why copy some thing when the copy is crap. They are no good at copied stuff .
swampfox
FollowupID:
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