M156 Camshaft finish from factory rough
 

Video posted recently by Tasos Moschatos puts a brand new M156 camshaft under a microscope camera and shows the finish is poor from factory compared to other camshafts. Suggests this could be the reason lots of people have issues with Camshaft/Lifter wear?

Anyone have any thoughts? Anyone have any experience polishing these camshafts?

I was watching this yesterday and found it fascinating. I love his vids.

That video proves why all our cars make noise after a few thousand miles.

I'm thinking of running a 50 weight oil like he runs in some of his cars.

First:
There is a 5w50 available in the US, with the 229.3 compliance.
If you research the difference between the 229.3 and 229.5 the 229.5 is for longer intervals mainly.
So if you're willing to change the oil "often", you could be able to do 229.3.
It's the Mobil 1.

As far as the cams being rough, in Mechanical engineering, wear is planned.
Materials are selected, so that wear happens in the planned sequence.
Tassos points out that he thinks there's no hardening at all performed on these cams.
I'm willing to believe this, but normally, as he points out, the cam is hard and the tappet is soft.
This is engineered so that you can replace the tappet and incur a lower cost.
I'm not willing to concede that the AMG engineers did not have some different consideration when they reversed and made the tappet hard and the cam soft.
Maybe the consideration is not for cost.
Maybe the hardened cams become too brittle for this application.
Anyway, this type of stuff doesn't just get overlooked.
Tassos also points out that the tappets have a rough side machined area. He is surprised that the area is not smoother under microscope.
But the rougher area reduces the contact patch, because the tappet only touches on the microscopic ridges. So it actually helps.

What do you think of this oil

https://cimg6.ibsrv.net/gimg/www.mbw...d880a22669.jpg

It's a little lower in zinc and phosphorus than what might be considered ideal for the M156 but I would have no problem using it along with a bottle or two of MoS2.

A recent VOA from BITOG.
https://www.bobistheoilguy.com/forum...ort_5W50_Ester

Interesting points. So do you think polishing brand new cams before fitting them would be a bad idea? What I don't get is while worn cams/buckets seems to be a common problem on these cars, it's not every car that does have trouble with the tapping/worn cams/buckets, so is it the parts that differentiates them? Is it the maintenance (and oil used)? Or is it environmental?

The cam-tappet assembly has to allow for the tappet rotation as it goes up and down. If the rotation doesn't happen, or happens too slow, that will likely cause quick wear.
So what causes the rotation?
Te relative angle creates a tangential component to happen. But ultimately, I think that the cam lobe touches the flat, top part of the tappet and as it pushes down, it also spins it.
How does it spin it?
it drags the outer area of the circle.
How?
By friction

I would worry about modifying the designed friction between the cam and the tappet, by polishing the cam.

We can get into the finer details of friction, lubricated friction and such, I'm just not so sure. If both the surface of the cam and the tappet are close to perfectly flat, lubricated too, will the cam still drag the tappet into spinning it? Maybe not so much....


As far as why some cars do better than others with the ticking, I think it's not as random as it seems on the net. Nobody is 100% honest about what they do and don't do to their cars. So, yes, it has to do with the owners.
And check this out too:
At one point, a guy that I knew was in a high position at this company. The company leased him a top end BMW 3 series. The guy was basically well off.
So, as the lease was happening, the guy says that he's due for an oil change, but he won't do it. So I asked why, because BMW even includes the maintenance. He said because the parts are not included and it's only a lease. So he tried his damnest to not do an oil change for the whole duration of that lease.

Some of our cars, which are at second and third owner now, begun by being leases...

These problems would all be solved by a roller cam and tappet set. It looks to me like space is tight but I have to think this could be good solution if someone put their engineering skills to use. Might even open up some additional power with a more aggressive cam profile. Has this ever been looked in to at all?
AR

I didn't know this....thank you. I've been wanting a slightly heavier weight oil for more oil pressure to the cam gears and also rod bearings, but for some reason I kinda like having those Mercedes service stemps, so I get my oil done by them. On my next service I'll ask for 228.3 and then have a second change after 6 months.

Based on my experience with the Subaru, that has hydraulic cam adjusters as well, the higher top oil number, with its higher hot oil pressure, brings snappier actuation of the cam adjusters as well.
Based on the log I took with the Xentry, my adjusters, while in range, could stand to be faster in response.

Absolutely - I'm hoping it'll give me a couple of degree's more advance on the exhaust gears as mine are a little sloppy up top and I believe it's pressure related. I also find my intake gears struggle to hold a fixed value at times....makes me think either:

• My oil is thinned out/lost it's optimal thickness now from fuel dilation
• I have a teeny internal cam gear leak
• Physical wear inside the cam gears means more volume/pressure is needed to compensate

I suppose the only caveat to this is whether the oil pump is happy to push a heavier weight through the crank/journals (ie the most important part). I'm now spinning mine to 8k, so more protection to the bearings, along with accelerated oil changes are crucial.

How are you measuring that your engine feels sloppy up top and that your intake gears struggle to hold a fixed value at times?

I'm tuning/logging my car and I'm able to see the commanded vs actual cam angle figures.

Don't get me wrong, the engine feels great up top, but by sloppy, i was referring to nothing more than 2-3 degree's of commanded vs actual cam angle. It was ok a good couple of months ago. Perhaps my oil is just a bit diluted now due to a few rich patches while composing my tune file :nix:

Ahhh ok was going to say not sure how you'd feel that from just driving it!

What software/setup are you using to logging/tune your car?

Haha, funnily enough on my car right now, those 2-3 degrees are worth around 15hp, so on a very sensitive butt-dyno day, maybe i can :o:

I'm using HP Tuners VCM scanner to log and VCM editor to tune. I've had epic results now, but gosh the software isn't reeeeeally complete in my opinion and you have to jump through some serious hoops in order to make it work the way that the good Lord intended.

fc63, sorry for the thread hi-jack sir...one post...i promise :)

BLK, yes it's been a royal PITA and HP Tuners.....well...I don't want to speak badly of them because truth be told, if it wasn't for their product, my car would still be a slow POS running the POS EC V6 tune which doesn't do anything more than the stock tune on my car. But yes...it hasn't been straightforward and if you need help, there isn't really anywhere to turn to except to bang your head against the wall and curse. HP will be the first to tell you that they aren't there for tuning advice...they're there to make sure the product works as intended. After that, you're on your own. I always wanted to tune my car myself because 1) I couldn't afford a proper custom tune from Weistec and 2) I didn't have faith that Kleemann knew what he was on about half the time to warrant buying his tune. Besides, EC didn't want to know anymore either, so it's not like I could just enjoy a simple flash of the V7 onto my car and be done with it. That being said, the EC V7 tune does appear to be a very good tune for 80% of the people whom have it, so that would be a simpler solution for most.

There aren't any options to play with the runner actuators that I've seen...only to disable the codes for it. Really, they just need to be fully open when you go WOT. I've even tried a manifold without the runners, but funnily enough, it doesn't make any difference to airflow...which I found strange. How hard is it...? Depends really...how long is a piece of string? If you've tuned a car before, it's not 'hard' if you know what you're doing, but the pitfalls that you can face in terms of coming up against torque limiters isn't nice at all. It's not just the aspect of tuning on the road (having to go out late at night, thinking of police, noise, hazzards, lack of traction during the winter, finding a safe place to park and make changes on the fly, having a friend on hand to jump start your car because the battery went flat from uploading too many files and not driving enough, lol etc etc)...you then need to spend a couple of hours (well, that's how long I take on average) number crunching after an evening's worth of tuning, otherwise you'll be shooting in the dark and then inevitably ruin your tune and not know how.

Being without a dyno isn't too bad...i have something of my own dyno as shown below, hehe. I use the engine torque sensors to tell me roughly where I am in the true sense of power and not relying on a dyno with correction factors/wheel/tyres 18% transmission loss etc....the graph below shows a log of the EC V6 tune (which I called 'stock' but I kid you not - with the stock tune flashed to the car, it has the exact same airflow, timing and general feel) which dyno'd 460whp last Feb. According to the power figures, timing values, airflow etc that Scratch66 posted yesterday with 460whp, mine was running the same also on the dyno. The engine tells me the torque - I'm using the common torque to hp formula to generate hp. Now i'm not sure how accurate or 'to scale' the numbers are (because yes a 100+hp gain does seem a little far fetched according to the graph below), but what's interesting to note is the shape of the torque curve and how beautifully peaky the hp curve is. However...bear in mind that my car is cammed and thus the tune and results wont be the same for a non-cammed motor. However once I've nailed my cars tune down and dyno'd for glory figures back at the same dyno as last year, I'm going to start tuning C63s around London and then see what best compromise of a tune can be packaged up. Worth noting though that where Scratch66's airflow was around 360g/s at 6700, my car is now ingesting that much air at 5500 (with 3 degree's of cam slop right now too and I've seen it even higher at that rpm)...the on road feel vs 3 months ago is night and day. Driving to work or around town at barely any throttle is maybe my favourite part - daily drivability is just as epic as the top end. I'm expecting this graph to get a little stronger and then once I'm done, i'll dyno when I get time.

https://cimg6.ibsrv.net/gimg/www.mbw...f3e280cb03.jpg

I'll share more in due course, but I hope you've all found it interesting...I certainly have and I've been living it.

fc63 apologies once again my friend :)

Hey, you need to post a lot more details about this.
Just start a new thread, what's the big deal.

I tune my cars too and am aware of all the downsides you describe.
But why is HP inferior to what you're using, go a bit into detail. I'm looking to decide which to buy.
And it doesn't make sense. Once you start to use HP they would either marry your evil or lock your map. How did you go about re editing a map from HP with your current map editor/ tuner software?
I mean why the change, the definitions are better?
Do you get real time tuning with any of them?
And does anybody give you stock maps of misc M156? So you could see why is going on with the trims of the US air boxes ?

solid bump for this thread, excited to see Celicasaur has been doing.

This is old bud