Linkage Adjustment

[bpossel]

I have read and followed the earlier post(s) on how to properly adjust the linkage rods.  I still have one question.... :?:

What is the proper adjustment of the "middle rod", once the other rods are properly adjusted?  What is the distance (gap) between this rod and the exhaust manifold?  

Thanks!!!
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[rwmastel]

Not sure what you mean by "middle rod".  If you can't provide a pic, then can you describe what is on either end of this rod, how it is oriented, etc.?

Typically, the length of a rod is what's important, not how far it is from another part in the engine bay.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[bpossel]

Here is a picture of the "middle rod".

How is the length of this rod set?

Thanks!
Bob

Download Attachment: middle-rod.jpg
35.35 KB

bpossel
Memphis, TN.
1971 280SL
1997 E320

[rwmastel]

Bob,

Great pic!  I've never done this (adjust my linkages), but I believe the length is adjusted by spinning the end socket connectors.  They are threadded on and should screw on/off to get shorter/longer.  May require penatrating oil or PB Blaster (www.blasterchemical.com/store) type treatment.  This rod on my 1966 230SL currently measures exactly 6 inches (153mm).

Download Attachment: Copy of Pic 038.jpg
77.39 KB

I notice that your constant speed solenoid is "behind" this rod.  On my car, an automatic with no A/C, this rod is connected to a hinged bracket and the solenoid is on a fixed bracket.  This hinged bracket gets pushed forward (toward the radiator) by the arm that extends out of the solenoid when I put my car in gear.  This moves all the attached linkage which adds some fuel and air to the engine.  This is to maintain RPM when putting the automatic into gear and holding the brake.  An engine under load needs more air & fuel to maintain the RPM.

Download Attachment: Copy of Pic 042.jpg
80.12 KB

Looking at your picture again, I can see your solenoid is connected to the end bracket for the main cross linkage bar and it must be pushing on the same part that connects the linkage to the venturi unit.  This would product the same effect.

Looking at the details of your engine, we have several differences.  It's amazing what changed between a 127 and 130 engine:
- location the brake booster line connects to manifold
- style of idle air screw
- mounting of constant speed solenoid
- style of venturi unit
- what is the pipe that runs with the white vacuum hose?
- different oil filler cap
- you have some sensor connected to the top of your thermostat housing


Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[George Davis]

Bob,

I don't think there is any special procedure for the middle rod.  It should be disconnected while the end rods (to throttle and IP) are adjusted.  After they are reconnected, adjust the length of the middle rod so it fits exactly on the two balls.  Note that this is correct only for cars with automatic transmissions.  Manual shift cars have a progressive set-up that requires a different procedure.

George Davis
'69 280 SL Euro manual

[hands_aus]

Hey Bob,
That middle rod connects to a bracket (with another connecting point on it) that pivots. The other connection of the bracket drops vertically down between the inlet/outlet manifolds and connects back to the accelerator pedal somehow.
On my 250 RHD that vertical rod was touching one of the manifolds and using it as a stop and making it almost impossible to correctly adjust my linkages.

This situation was caused by the engine mounts needing to be replaced.
Once I had the engine mounts replaced the adjustment of the linkages went very easy.

The biggest critera of this process is to make sure there is no movement possible between the linkages.

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[bpossel]

Hi Rodd,

You have a question in your post about the pipe that runs with my white (now yellow) vacuum hose...  Not sure which pipe you mean?  What is running along side my vacuum hose is the main throttle linkage rod (as seen on pic, left of the vacuum).  To the right is the oil breather hose, with small vacuum hose...
Does this answer your question?  If not, happy to answer any others.
A couple more pics attached.

Bob

quote:Originally posted by rwmastel

Bob,

Great pic!  I've never done this (adjust my linkages), but I believe the length is adjusted by spinning the end socket connectors.  They are threadded on and should screw on/off to get shorter/longer.  May require penatrating oil or PB Blaster (www.blasterchemical.com/store) type treatment.  This rod on my 1966 230SL currently measures exactly 6 inches (153mm).

Download Attachment: Copy of Pic 038.jpg
77.39 KB

I notice that your constant speed solenoid is "behind" this rod.  On my car, an automatic with no A/C, this rod is connected to a hinged bracket and the solenoid is on a fixed bracket.  This hinged bracket gets pushed forward (toward the radiator) by the arm that extends out of the solenoid when I put my car in gear.  This moves all the attached linkage which adds some fuel and air to the engine.  This is to maintain RPM when putting the automatic into gear and holding the brake.  An engine under load needs more air & fuel to maintain the RPM.

Download Attachment: Copy of Pic 042.jpg
80.12 KB

Looking at your picture again, I can see your solenoid is connected to the end bracket for the main cross linkage bar and it must be pushing on the same part that connects the linkage to the venturi unit.  This would product the same effect.

Looking at the details of your engine, we have several differences.  It's amazing what changed between a 127 and 130 engine:
- location the brake booster line connects to manifold
- style of idle air screw
- mounting of constant speed solenoid
- style of venturi unit
- what is the pipe that runs with the white vacuum hose?
- different oil filler cap
- you have some sensor connected to the top of your thermostat housing


Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

Download Attachment: engine-2.jpg
60.17 KB

Download Attachment: engine-3.jpg
52.8 KB

bpossel
Memphis, TN.
1971 280SL
1997 E320

[Naj ✝︎]

Bob,
I think Rodd is talking about the pipe running along with the white (small dia.) vacuum pipe to the distributor vacuum retard unit??

Rodd,
Its one of the hot water circulating pipes to the throttle body. Its takes (I think) water to the top of the t/stat on the FI pump. The water inlet pipe to the throttle body comes from the engine thermostat housing.
Early 230s do not have this, while 250s have a coil running in front of the throttle body. 280s have it integral with the throttle body.

naj

65 230SL
68 280SL

[glennard]

quote:Originally posted by bpossel

I have read and followed the earlier post(s) on how to properly adjust the linkage rods.  I still have one question.... :?:

What is the proper adjustment of the "middle rod", once the other rods are properly adjusted?  What is the distance (gap) between this rod and the exhaust manifold?  

Thanks!!!
Bob

bpossel

Memphis, TN.
1971 280SL
1997 E320

Bob, Never saw 2 MB FI engines the same!  Each Herr Herman on the line must have had his own assembly criterion- diversity uber alles(sp).