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 Martin shows us how air valves work
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Ron B

Australia
11561 Posts

Posted - 01/02/2014 :  02:31:15  Show Profile  Visit Ron B's Homepage  Reply with Quote
http://youtu.be/jwY85kkkdgk

quote:
12-14-2004, 11:49 PM #8
Tom Hanson
MBCA Member

What the heck, try to stuff a MB 6.9 liter V8 in it. What a machine that would be..
__________________
Tom Hanson
Orange County Section

Art Love

Australia
6160 Posts

Posted - 01/02/2014 :  17:30:48  Show Profile  Reply with Quote
Martin learned a lot of what he knows from this Group, particularly from Chris Johnson. I am pleased that he has added his expertise.
Art
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werminghausen

USA
766 Posts

Posted - 01/06/2014 :  21:37:54  Show Profile  Visit werminghausen's Homepage  Reply with Quote
quote:
Originally posted by Art Love

Martin learned a lot of what he knows from this Group, particularly from Chris Johnson. I am pleased that he has added his expertise.
Art



That is correct. You guys kept me going...Ron, Art, Chris and many others... when I was close to giving up this W109. Especially delightful were the discussions with Chris about air suspension (who is always right). I also still know a lot of people in Germany working in Bosch Stuttgart (the mother ship)who helped me.
As I was studying and working with Maybach/Mercedes in the late 70s I was even a witness of the time (109 and 600)...not knowing that I'd pick up this route later in my life. I started as a kid when I was learning 'tool making' (a profession at that time)for 3 years at the Maybach factory in Friedrichshafen. I couldn't stand the factory...so I studied mechanics and then became an architect.
I was thinking lately to share and give back some of the insights to the community regarding air suspension. Not knowing where it is going but I am offering doing repairs in a 'limited edition' as this knowledge is missing and many are scared because of the expensive and mysterious air suspension...what a pity.
I am writing on an article about air suspension right now and planning doing a website about air suspension and repairs...but this takes time.
Thank, Martin

Edited by - werminghausen on 01/08/2014 20:50:49
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fullhappyfish

USA
713 Posts

Posted - 01/07/2014 :  10:16:22  Show Profile  Reply with Quote
Martin,

Your experience is very similar to mine when I had a couple of Mark VIII Lincolns a few years ago. People, especially most 'regular' mechanics are terrified of air suspensions.

What they can't seem to understand is that in its own way, air suspension is a huge upgrade and worth the extra maintenance. It is like the radiant heat in my house - nobody wants to work on it, but if it is understood and properly maintained can last the life of the structure.

What is somewhat irritating to me is the fact that due to so much owner loyalty and interest, you can't buy a W109 for a thousand bucks if it is on its knees. The last MarkVIII I had I paid 800 bucks for and it had under 100K miles.

Since I'm on a fixed income I don't suppose I'll be driving a 6.3 anytime soon.

John Hubertz
1977 450SEL (Max Headroom)
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FEMA

USA
1374 Posts

Posted - 01/24/2014 :  10:27:20  Show Profile  Visit FEMA's Homepage  Reply with Quote
I am enjoying the videos and didn't realize Martin, that you were rebuilding these valves. Can you please tell me (all of us really) if you are still doing this and how I should contact you about rebuilding valves that I have?

Francis E. Abate
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werminghausen

USA
766 Posts

Posted - 01/30/2014 :  18:36:22  Show Profile  Visit werminghausen's Homepage  Reply with Quote
quote:
Originally posted by FEMA

I am enjoying the videos and didn't realize Martin, that you were rebuilding these valves. Can you please tell me (all of us really) if you are still doing this and how I should contact you about rebuilding valves that I have?

Francis E. Abate




Hi Francis,
yes it is true. I am renovating level control valves and more. I have set up a 'lab'. I can do LCV, valve unit, antifreeze and pressure regulator.
Please send me an email: 600airsuspension@gmail.com
I'll set up a website for information. My time is limited right now but I like to help the community and share.
Best, Martin

Edited by - werminghausen on 01/30/2014 18:37:23
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werminghausen

USA
766 Posts

Posted - 02/12/2014 :  05:14:24  Show Profile  Visit werminghausen's Homepage  Reply with Quote
I am Martin of air suspension service.

My website is now up and running. Please have a look at

www.600Airsuspension.com

Kindest

Edited by - werminghausen on 02/12/2014 18:56:59
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werminghausen

USA
766 Posts

Posted - 03/04/2014 :  13:17:37  Show Profile  Visit werminghausen's Homepage  Reply with Quote
I did some research on valve timing within the LCVs during work on a set of LCVs: The opening and closing of the E and A valve relative to the neutral riding height. If someone is interested I am happy to discuss especially if we have knowledgeable people joining the discussion. Let me know.
Martin
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paul-NL

Netherlands
4204 Posts

Posted - 03/04/2014 :  13:36:44  Show Profile  Reply with Quote
At the arm in locked position in its middelposition you turn those inlet- and outletvalve just so far, that they just don't touch the "Steuerkolben". The narrower the distance the better it reacts on each difference.

When to close, it is possible, that they are continiously opend and not shutt off !!, which is not allowed.




Edited by - paul-NL on 03/04/2014 13:43:22
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werminghausen

USA
766 Posts

Posted - 03/04/2014 :  15:40:59  Show Profile  Visit werminghausen's Homepage  Reply with Quote
Excellent kick-off Paul!
The graphic is good... it is an older version of a LCV with the bullets secured with silicone and closed off with steel balls.
Bosch did some iterations until they settled with the counter 'screw'.
The other anomaly is the missing 'high' piston....
I’ll respond: Yes absolutely correct Paul
There shall not be any valve timing overlap nor shall there be a too big of a neutral zone or ‘Null Zone’ how I call it.
It comes down to the Bosch/MB spec and how to achieve it.
The problem lies for the hobbyist in the question: How do you know that a valve is open or when it is closed. You just cannot know if you can't see. You have an idea or you ‘hear’ something or your typical pressure gauge indicates a pressure drop or rise. But you normally can measure maybe 1/10 bar or 1 psi (1/15bar). Not enough.
I have a digital pressure gauge and I can see 1/1000 of a bar (1 mbar) and with this instrument I can see a hole different world of the valves. I can ‘see’ the valves open… oh they open way before you hear something.
'Way before' means: the opening of a valve from start to fully open translates probably in about 1mm +/- of axle movement. This is how much it takes until the valve seat moves and the o-ring disengages…and the process goes slightly. When you see minimal air flow (talking few mbar of pressure differentials) then you see clearer how things are working.
I have sketched up some diagrams lately showing graphs of the the valve timing and the opening and closing characters of the valves. If someone is interested I can post them here. There is a different graph for a valve opening vs a valve closing even if the starting and end points might match.
If I adjust the valve timing in a LCV I will use a dial gauge and measure the axle movement and I am using the 1/1000 bar gauge. Without these instruments I don’t know if you can produce the same results. I cannot and with the instruments if takes me a few hours to do it right. It is precision work.
The Null Zone should be at 2mm Axle movement which translates to a control piston movement of less than 0.1mm. Within the Null Zone no air is allowed to flow in or out of the work group (work group air is the air connected to the air spring volume).
If you do not have the correct bench testing instruments you should better not try to adjust these valves in my opinion because you cannot ‘see’ if you are right or wrong. You might end up with overlapping valve timing (and not even know) or a too large Null Zone if you listen to the valves or use a conventional gauge. Both adjustments might be out of spec and you cannot verify.
By the way who has the original MB specs for the Leveling Valve neutral zone adjustment of 2mm axle movement? I would be interested to know if MB is also defining the lower end of the tolerance if the 2mm are the higher end of the tolerance.
Martin

Edited by - werminghausen on 03/04/2014 21:50:27
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paul-NL

Netherlands
4204 Posts

Posted - 03/04/2014 :  16:31:56  Show Profile  Reply with Quote
I don't have any MB-specs for (adjusting) these valves ......



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Chris Johnson

USA
3751 Posts

Posted - 03/04/2014 :  18:57:48  Show Profile  Reply with Quote
An excellent topic.

The obvious question is: why is this important?

I bought my first air-suspensioned Mercedes in 1976. A 1962 300SE sedan. What a great car. And it had this delightful habit of dropping the front end perhaps two inches after coming to a stop. I love watching mechanical systems in operation.

It was necessary to drop the front end that two inches after each stop because the air suspension system would pump more air into the front under braking, when the front of the car would, naturally, drop a bit. Once the car had stopped, the front of the car no longer experienced the weight transfer and the excess air pressure would now be too high, and the front of the car would be too high. So, bleed off the excess pressure.

I can pretty much hear everybody thinking "my car doesn't do that!". These days, most don't. Recently, other than my own cars, I haven't seen a single one that still did this. There are a variety of reasons for it, not the least of which is that rebuilders generally don't try to get the setting of the internal valves that close to "perfect". Without getting into a debate about the correctness of their work, suffice it to say that the adjustment of the internal valves are intentionally a bit "loose", and they have their reasons for this.

Other contributing causes for this lack of display is inadequate system pressure due to a weak compressor and leaks that prevent the system from reaching it's maximum potential pressure.

The first time I got a set of rebuilt valves from Star Motors, the valves did not generate this sort of behavior. Neil agreed to tighten them up for me, which he did. After that, the front of the car behaved as expected. I understand that he has declined to do this in more recent times.

There are some relatively minor reasons for wanting this behavior, though they are valid, but the best part of a properly functioning system is watching it work!




Chris Johnson
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tom.hanson

USA
291 Posts

Posted - 03/04/2014 :  19:44:14  Show Profile  Visit tom.hanson's Homepage  Reply with Quote
Hey Chris!!!! Call me dammit!!

Tom Hanson
Supervisor, Parts Ops
MB Classic Center USA
949 598-4842 direct
thomas.hanson@mbusa.com
ex - 1970 6.3 #4045
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werminghausen

USA
766 Posts

Posted - 03/04/2014 :  22:11:27  Show Profile  Visit werminghausen's Homepage  Reply with Quote
quote:
Originally posted by Chris Johnson

An excellent topic.

The obvious question is: why is this important?

I bought my first air-suspensioned Mercedes in 1976. A 1962 300SE sedan. What a great car. And it had this delightful habit of dropping the front end perhaps two inches after coming to a stop. I love watching mechanical systems in operation.

It was necessary to drop the front end that two inches after each stop because the air suspension system would pump more air into the front under braking, when the front of the car would, naturally, drop a bit. Once the car had stopped, the front of the car no longer experienced the weight transfer and the excess air pressure would now be too high, and the front of the car would be too high. So, bleed off the excess pressure.

I can pretty much hear everybody thinking "my car doesn't do that!". These days, most don't. Recently, other than my own cars, I haven't seen a single one that still did this. There are a variety of reasons for it, not the least of which is that rebuilders generally don't try to get the setting of the internal valves that close to "perfect". Without getting into a debate about the correctness of their work, suffice it to say that the adjustment of the internal valves are intentionally a bit "loose", and they have their reasons for this.

Other contributing causes for this lack of display is inadequate system pressure due to a weak compressor and leaks that prevent the system from reaching it's maximum potential pressure.

The first time I got a set of rebuilt valves from Star Motors, the valves did not generate this sort of behavior. Neil agreed to tighten them up for me, which he did. After that, the front of the car behaved as expected. I understand that he has declined to do this in more recent times.

There are some relatively minor reasons for wanting this behavior, though they are valid, but the best part of a properly functioning system is watching it work!




Chris Johnson




Hey Chris, great you jump in here!

2" is a lot!
I don't know the early LCVs very well, a friend of mine in Germany is more familiar with these.
The later style valves at least like the ones in the 600 have throttled E and A valves in the front in order to reduce the airflow exactly for this reason: driving S-curves and braking. The reduced support pressure (10 bar for the 109/112, 14 for the 600) and the pressure holding valve that pushes the exhaust pressure down by 3 bars minimize the pressure differentials. And the throttle boring in the bullets reduce air flow...should make sure the system won't go up that high I believe in the later valves.
There is a great article of a Mercedes engineer from around 1965...in German unfortunately.

I am curious if you saw this behavior with correctly built and adjusted later style LCvs (after 1965)?

Chris, do you have access to the MB specs of the null zone?
I know that the closest you can go in reality is the 2mm axle movement...but I love digging in history and would like to know what Bosch and Mercedes were thinking...what tolerances were specified? I mean it is an amazing system that can be repaired to almost original specs and it works after almost 50 years!

Martin
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Chris Johnson

USA
3751 Posts

Posted - 03/04/2014 :  23:09:56  Show Profile  Reply with Quote
Sure, the late style valves should display that behavior as well. 600, W112, or W109, they all work the same way.

Throttles will slow down the air flow but not stop it, of course. And, even with the lower regulated pressure to the front axle, a properly working system will still over-pressure the front axle under normal braking conditions.

I don't believe the specs on these valves were ever published by Mercedes. Bosch is another story, and I think that is where you will have to research.

Of course, I would want any valves going on one of my cars to be set as tightly as possible, and this is precisely what I do when I'm setting one up. I suspect that most folks that do this work have not properly considered the o-ring that acts as the seal at the piston end of the internal valve(s) (especially the E valve). The cross-sectional diameter of the o-ring, along with its "hardness", has a major effect on how quickly (how little travel) the valves will open and close and, therefore, what the minimum achievable "dead play" can be.


Chris Johnson
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S class

South Africa
952 Posts

Posted - 03/05/2014 :  01:45:37  Show Profile  Reply with Quote
Interesting. I don't know much about the air suspension, but I am very familiar with 6,9 hydraulics, and a properly set up 6.9 also exhibits this behaviour.



116.036
116.036
116.024
116.028
116.028
107.044
202.026




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