OM606.910 valve on bottom of crossover.... - PeachParts Mercedes-Benz Forum

JimmyL · #1 01-31-2009, 03:14 PM

What is the valve on bottom of an OM606.910 crossover pipe and what does it do? I am in the process of tunneling down to my glow plugs [

] and when I finally got the crossover pipe removed there is a valve on bottom that appears to have a vac line to it.
The vac line is capped off and the valve is tie-wrapped open I guess with two black tie-wraps.

I'm taking pics the whole way and documenting the glow plug replacement on the non-turbo version of the OM606, but I found this along the way and needed to see what somebody did and why.
This car has tremendous hesitation after shifting gears and just falls flat, so anything I see out of the ordinary raises suspicions.
Back to my tunneling. Will check in from time to time.

Number_Cruncher · #2 01-31-2009, 03:58 PM

It's part of the resonance flap system.

You'll find another similar valve under the manifold itself - in fact, you'll be able to see the flap by where the ports are for the cross over pipe.

The resonance flaps are controlled by the same control unit which switches the EGR and the partial throttle which is just upstream of the EGR.

The resonance flaps are opened to tune the effective manifold length at different engine speeds. At low speeds, the flaps make the effective manifold length very long (think of the long organ pipes which produce the low notes), and, as the engine speeds up, the valves open, effectively shortening the length of the individual manifold pipes.

It's generally thought worthwhile to have the resonance flaps working properly, and investigating why the tie-wraps are there, and why the system was disabled.

JimmyL · #3 01-31-2009, 04:08 PM

Quote:

Originally Posted by Number_Cruncher

It's part of the resonance flap system.

You'll find another similar valve under the manifold itself - in fact, you'll be able to see the flap by where the ports are for the cross over pipe.

The resonance flaps are controlled by the same control unit which switches the EGR and the partial throttle which is just upstream of the EGR.

The resonance flaps are opened to tune the effective manifold length at different engine speeds. At low speeds, the flaps make the effective manifold length very long (think of the long organ pipes which produce the low notes), and, as the engine speeds up, the valves open, effectively shortening the length of the individual manifold pipes.

It's generally thought worthwhile to have the resonance flaps working properly, and investigating why the tie-wraps are there, and why the system was disabled.

Well, with my trusty Mityvac, the valve still hooked up holds a vac, the one not hooked up does not. It must have a torn diaphram, so it is tie-wrapped open. Maybe if it would close I would have better low speed acceleration? I wonder if that is causing the lag after shifts? Hmmmmm
Back outside.
Oh, and thanks!!

Number_Cruncher · #4 01-31-2009, 04:17 PM

Here's a link to a previous resoance flap thread, with some info about what engine speeds the flaps are switched at;

http://www.peachparts.com/shopforum/showthread.php?t=232729&highlight=flap

JimmyL · #5 01-31-2009, 04:50 PM

I will certainly study that Cruncher, and thanks!!!

So, of course my #3 glow plug is one of the ones that is bad. [and #5]
The alda looking thing is in the way such that no manner of extension or swivel will get to it. So I guess I will have to remove that thing.
Can anybody tell me what to what out for when I remove it, and are their normal threads under it? Seems like I remember there being something odd about how it comes off.
Or, any suggestions as to how to remove GP with that thing right in the way! Nothing I have will work.
Off to GP #5.....

TMAllison · #6 01-31-2009, 04:57 PM

Is it #47 Vacuum Box? http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=124131&M=606%2E910&GA=722%2E435&GM=717%2E433&CT=M&cat=19T&SID=07&SGR=045&SGN=01

Start soaking those GP's in penetrating oil now while head scratching the rest of what you are doing.

Jeremy5848 · #7 01-31-2009, 05:02 PM

A working resonance flap system is required to get the design performance out of the engine. There's no way to avoid a reduction of power and torque if the flaps are not operating. AFAIK, replacement is the only option. The PO of my '96 had to do that twice. On the one occasion where I have a complete service tag (from PO #1, 8-31-2004), part number 606 140 00 31 cost him $183.82. With labor, the PO paid almost $600 for that job.

At least the dealer threw in a free carwash.

(YMMV)

In addition to vacuum leaks, the flaps get crudded up with soot from the EGR system. Mechanics (especially at dealers) feel that it's more cost-effective to install a new mechanism rather than spending the time to clean the old one. For individuals doing their own work, the opposite is usually true, except that there is not replacement part for a leaking vacuum diaphragm.

Jeremy

JimmyL · #8 01-31-2009, 05:10 PM

Glow plug #5 is out!!! I just did the tighten, loosen, tighten, loosen method with occasional sprays of Aerokroil.
Gonna ream the hole and install the new one in there with antiseize.
I'm still stuck on #3, needing advice on what to do with the "Alda" that's in the way......
Back out to garage....

TylerH860 · #9 01-31-2009, 05:20 PM

Did Scotty get a hold of your Excelsior too?

http://www.youtube.com/watch?v=A_SGXx3pLzs

skip to 4:00 in

JimmyL · #10 01-31-2009, 05:33 PM

Quote:

Originally Posted by TylerH860

Did Scotty get a hold of your Excelsior too?

Tell me about it....

I guess you didn't get the text with pic I sent you?

Stupid phone [stupid phone operator

]

All finished with #5. Hole reamed and new glow plug, fresh with anti-seize installed. Still need to know what to do to get at #3 if somebody would be so kind......

Quote:

Originally Posted by TMAllison

Is it #47 Vacuum Box? http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=124131&M=606%2E910&GA=722%2E435&GM=717%2E433&CT=M&cat=19T&SID=07&SGR=045&SGN=01

No, it's right below #44...... Looks just like an Alda with cap and all......

TylerH860 · #11 01-31-2009, 05:45 PM

Quote:

Originally Posted by JimmyL

Tell me about it....

I guess you didn't get the text with pic I sent you?

Stupid phone .

nope.

JimmyL · #12 01-31-2009, 06:41 PM

Both glow plugs replaced.

Some assembly required...........

Number_Cruncher · #13 01-31-2009, 06:48 PM

>>I'm still stuck on #3

I can't offer any help there - I did my glow plugs while I had the head off - I had found at 125,000 miles that the inlet valve seats on No 6 had sunk into the head, and the valves were leaking compression and combustion gases back into the inlet manifold.

curlytom · #14 01-31-2009, 07:01 PM

I can't remember exactly how I got mine out. But I do know that the long Craftsman sockets will not fit in a couple of the glow plugs. I had to use the long socket from Husky which is not as long as Craftsman and it fits perfect in the tight space...

connerm · #15 01-31-2009, 07:50 PM

I did my glow plugs in May and used a big pipe wrench to remove that big round thing right in the way of #3. I never found out what it is, but I think its some sort of breather. By the way, I never got #1 or #3 out. Too tight. Fortunately I was able to easily remove and replace 2, 4, 5 and 6 (6 was bad).