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Yes, it is Continental for Mercedes. Same as old one.
OLD
NEW
Side Walking, yes that's a better description. Thank you.
If I recall correctly, I need to do 3 x 360 degrees spin on the main crankshaft pulley to get 1 full revolution of the belt.
Why is it everytime I pay close attention to something, I discovered some unpleasant facts ?
The multiple V shape of the belt groove itsel is the friction maker by design, isn't it ?
I know long belts like conveyor ( super flat , no grooves), which is custom glued/joint on work location, can have slight misalignment at the glued/joint if the cut + gluing placement is not perfect.
Yes, it is Continental for Mercedes. Same as old one.
......pics....
Side Walking, yes that's a better description. Thank you.
If I recall correctly, I need to do 3 x 360 degrees spin on the main crankshaft pulley to get 1 full revolution of the belt.
Why is it everytime I pay close attention to something, I discovered some unpleasant facts ?
The multiple V shape of the belt groove itsel is the friction maker by design, isn't it ?
I know long belts like conveyor ( super flat , no grooves), which is custom glued/joint on work location, can have slight misalignment at the glued/joint if the cut + gluing placement is not perfect.
Surya says: "Why is it everytime I pay close attention to something, I discovered some unpleasant facts?"
--> Because you are able to analyze objects to collect and understand data.
You ask yourself interesting questions in search of rational facts....
-- Typical questions such as:
- How does this work?
- What are the stressors
- What makes this fail?
I think you got the manufacturing defect figured out with the two ends junction improperly matched. That's pretty bad for a leading German brand!
This lateral load strains all bearings: compressor, alternator, water pump, plastic idlers... ouch 👎
Could this be the right time to step up to a perfect "Mitsuboshi belt": you get twice the mileage for 1/2 the price. They are Honda's OEM belt.
(Same thing with Bosch plugs vs. NGK/Denso spark plugs!)
Last edited by CaliBenzDriver; Sep 28, 2022 at 10:56 AM.
Before I declared that the belt is the bad dude, I done some other WHAT IF scenario verification.
01. Does the pulley itself has OUT and INNER face for its installation ? I can say YES.
I googled the bearing number NSK 6203DUM18A just to make sure, if this bearing has a requirement which side is to be installed as OUT or INNER face ?
Can't find any data and it seems, the bearing is not pushed into plastic pulley housing, but its seems it is pre-molded. Look at the outer race is so thin, I bet some of it is embedded inside the pullley when injection moulded.
Googllng NSK 6203DUM18A will get you pulley and not the bearing stand alone. European or Japanese cars use this NSK 6203DUM18A.
So perhaps NSK made these for car OEM including the pulley and everything bolt,washeryada yada....plug and play.
Did MB or NSK worker screw up during bearing placement on the bolt and wrong face installed ?
Well.................. it seems so
I don't know which is the correct version as far as PULLEY OUT facing face, pulley no 7 or pulley no 6 ?
My gut feeling is to choose the "R" for inner face. What do you think Cali ?
Even using straight edge, there is no way to measure the difference or misalignment between using L or R as OUT side face or INNER face, which is approx 0.35mm difference only.
0.25mm from pulley groove and 0.1mm from the bearing installed depth.
Bloody hell, need to remove aftercooler again. Sooner or later I will break some plastic fittings for sure and the rubber short & thick hoses on my aftercooler ( 2 units ) and for the throttle body ( 1 unit ) may
eventually get worn out from too much assembly and dis-asssembly . But at year 10th ( 2 more years ) , I will replace them anyway.
I have ordered 2 of 6PK2120, 2120mm. The MB one is 6PK212, or 2125mm which is 5mm longer . 5mm shorter by Bando or Optibelt won't matter, the tensioner can handle that.
One is by Bando Japan. One more is by Optibelt Germany.
Funny is that no brand carry 2125mm .... not even Mitsiboshi. All are 2120mm for 6PK.
I am still trying to find the Mitsuboshi one. Shorter ones available but MB length seems not common.
If indeed the pulley #6 assembled wrong for its inner face side by MB or NSK, how can 0.35mm misalignemnt look so obvious side-walking the belt ?
I think I agree with you that this Conti is probably the culprit.
First, I would make sure you are not falling under visual impression, where different colors on the belt makes impression of it moving sideways.
Bearings for generations are build with very high precision, so not likely you will find 1 with factory defect, what brings the issue of plastic run under the belt.
I can't say from the pictures, but are your ribs running on smooth pulley? That is not recommended, so I wonder if that is a case?
I am not familiar with this engine, but pulleys 6 and 7 looks identical and should be run either direction.
I did not say the bearing is defective, I said pulley 6 and 7 was not assembled the same for its inner facing side and hence there already 0.35mm misalignment between pulley 6 to 7.
=========== K1 wrote :
I can't say from the pictures, but are your ribs running on smooth pulley? That is not recommended, so I wonder if that is a case? The tensioner is designed to use the smooth side of the belt not the rib, and tensioner's pulley is also smooth. Use a big PC screen 27" to view video or photos, don't use smartphone or even tablet, our eyes are old
===========
The belt does have a slight side walking.
Also true as you said, different colors on the belt made impression that the belt is MUCH side walking, while actually only minor side walking. Still , it is doing side walking.
Again, even with slow-motion, I can see the belt changing color along the run, but I can't say if it is walking.
Rubber belts and tires do have pretty loose tolerances, so complaining about 1/4 mm play is splitting the hair.
I still don't like the design where ribs run over flat pulley, but if MB design it this way, it has to be acceptable.
Again here you got us focussed on interesting facts about the carefully crafted serpentine issues.
Since I got my car new, I can hear a cyclical "whoa-whoa-whoa" from my the belt train at low idle. This is a common sound of old neglected engines.
A normal belt sound should be smooooth or silent with no cyclical noise. I am sure you've heard this because you have an engineer's ear for noises to diagnose mechanical problems by sound.
Now we know why thanks to Conti amazing OEM serpentine as good as rebadged aftermarket.
This Conti serpentine issue examplifies my tag line about German carefully carving business opportunities with system designs. Great quality is bad for business as great bottom line is built on repeat business.
They design perfect systems then introduce variables to forecast profits.
The poor pulley alignment and the belt walking I think are two separate issues.
The idlers circumference is like 6 Inches or 15Cm. When it off alignment, its a static problem that does not vary.
Wobbling comes from misguided alignment with excessive freeplay . Here very little true freeplay. The funny belt walking sideways helps wear out bearings to create freeplay. It primarily strains the two idlers before impacting components (A/C, ALT, PmP).
Once the idler bearings are wobbling then ALT gets a wild ride.
Surya says: " it takes 3 harmonic balancer revolutions to see the belt defect".
- I believe the circumference of crank pulley is smaller than 1/3 belt length, more like 1/6 right?
- Perhaps there are more than one "sideway feature" per belt.
Let's put the belt defect to bed then deal with idler misalignment so we don't get everything mixed up.
I am not sure how to measure or visualize pulley static misalignment... we need a reference surface or perhaps an optical laser to project a line... there must be a time honored best-practice way to go about this old-fashioned chaos
Last edited by CaliBenzDriver; Sep 28, 2022 at 01:51 PM.
The very last part of each video session you can see the belt slide into engine side and comes out to radiator side again. Yes minor but so irritating for a belt with beautiful 6 ribs.
Information between 4 brands, Bando - Optibelt - Mitsuboshi - Conti, Conti does mention this , but on the CONTI V MULTIRIB ELAS ( elastic, I think ) : Suitable for reverse flexing
On my engine, it is the CONTI V MULTIRIB.
They got another one CONTI V MULTI RIB POWER
ADD INFO :
Last edited by S-Prihadi; Sep 28, 2022 at 02:14 PM.
Let's put the belt defect to bed then deal with idler misalignment so we don't get everything mixed up.
I am not sure how to measure or visualize pulley static misalignment... we need a reference surface or perhaps an optical laser to project a line... there must be a time honored best-practice way to go about this old-fashioned chaos
Appearantly the automotive serpentine application benefits from a little elasticity to absorb A/C compressor load cycling.
The Conti. "power" is for fixed and steady loads.
A tiny bit of length wise stretching helps the tensioner carve a "pigeon hole" around average position. This is why belt and tensioner live and die together.
A new belt is best not used on a tired 80kMi tensioner! Less with frequent A/C users: now we know how and why!
Last edited by CaliBenzDriver; Sep 28, 2022 at 02:22 PM.
I never had to replace AC compressor, even some of MB I sold were over 200k miles and living in CA, now in Vegas, the AC on my cars works at least 75% of the annual driving.
I never had to replace AC compressor, even some of MB I sold were over 200k miles and living in CA, now in Vegas, the AC on my cars works at least 75% of the annual driving.
200kMi is a good deal 👍
Can this longevity has something to do with not redlining your diesels like a twin turbo -Or simply use of basic clutch compressors like on my California W212.
Low stress > long life !
👏
Last edited by CaliBenzDriver; Sep 28, 2022 at 03:57 PM.
I drive MB for over 25 years and if remember only W123 and W124 had clutches on compressor.
W123 AC was so-so and after I converted it to r134 I did not expect much, but W124 at 1 point had evaporator sensor failure and was creating layer of ice at the bottom of windshield.
We had to shut AC off from time to time as ice was covering driver view. Before I fixed the sensor that is.
Than W210 with digital controls was real performer. I sold it to fellow forum member and he replaced compressor above 250k miles, mostly as a precaution as the system had miniature leak he was dealing with, but was still cooling.
Our W212 is often park in 110F when we go out. I always find a shade, but 110 is 110. Still AC performs so well that I never had to precool the car before entering. It takes about 10 seconds for the AC to start blowing cold.
Aftermarket is pretty strong those days.
I was just shopping for sway bar links for my W212, who I assume are rare parts to replace, yet amazon alone gave me about 5 aftermarket choices.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
