Constant Speed Solenoid Location on 230

[itsmejustpurely]

Hi there,

I just bought a '67 230SL last week.  It runs great!

I've noticed that when the car heats up there are very minor fluctuations in the idle and oil pressure.  From this forum I think that it's a sticky Constant Speed Solenoid or that at least that's the first thing to check.

I can find many pictures of the css on what I believe is a 250, but cannot find the location on my car.  

I've found electrical running to the vacumm solenoid and choke idle control on the carburetor based on this manual:
http://www.docstoc.com/docs/79154808/Herztransplantation-beim

I also looked at the Chilton online library but minimal information was available there (or it's under a different component name)

I've repaired many vehicles in the past (basically by searching the net), but am still definitely a novice.  So, very simple instructions on where to find the CSS would be really really appreciated.

Thanks so much!
Grant

[66andBlue]

Welcome to the group!
In order to get help you'll need to tell us what model you have: 230SL, 250SL, or 280SL?
Automatic or manual shift?
Have you tried the search function, typing in "constant speed solenoid"? If you did you you must have gotten several hits including these:
http://www.sl113.org/forums/index.php?topic=15813.0
http://www.sl113.org/forums/index.php?topic=16098.0
In there are photos of the CSS on Pagodas with automatic transmission.

To diagnose your problem further you will find these instructions very helpful:
http://www.sl113.org/wiki/Restricted/Engine-starting-aid-tour
http://www.sl113.org/wiki/Restricted/Linkage-tour
But you must be a full paying member to access the info.  

[itsmejustpurely]

66andBlue,

230SL, Automatic.  The links you describe typically show a css on a newer model or 250+,  It doesn't not look the same as described in my original post.

Thanks again for your help!
Grant

[itsmejustpurely]

One more thing that might strike a clue.  It does NOT have linkage over the valve cover like the later models.

[66andBlue]

Hi Grant,
If it doesn't have a linkage over the valve cover then I suspect it is either not a W113, or if it is a W113 then a previous owner installed the wrong engine.  
Here is a photo of a really very early 1963 230SL and as you can see it has the transverse linkage and also a dashpot (since it is a manual shift) on the manifold were normally the CSS sits on an automatic. The second photo shows the CSS on my 230SL - built August 1966.

[itsmejustpurely]

Oh man... looks quite different.

See attached picture.  I can't imaging the engine being swapped on this car.  The manual shows routine maintance until '84, then starts again in '00, but I guess anything is possible.

I read that there are three types of carbs for this car.  This has the zenith twin carbs, which I do not see in the engines mainly on this site and in your picks...does that bring up any clues?

Thanks again for all of your help.  Really really appreciate it!

Grant

[66andBlue]

As the saying goes "A picture is worth ......."
What you have looks like a 230 Finntail and not a 230SL convertible or roadster.
Still a nice car .. but no cigar! 
The W113 (230SL/250SL/280SL) series never had carburetors, always Bosch injection pumps..

[ctaylor738]

And as fintail owner, I can tell you that slightly different idle speeds are totally normal.  I believe that your car has a vacuum dashpot to keep the rpm up in gear and while maneuvering at low rpm if you have power steering. 

[itsmejustpurely]

Haha.  well...  At least it's posted with pictures.  So if any other morons like me are confused they can see the difference here. 

It's more than just the idle.  As I've drove it this week, I've been able to understand it more.

On complete cold starts the idle is too high.  It's too high in park and too high in drive.  As the car warms up or when it's warmer in the afternoons the idle is more nominal.  However, while in drive and at a stop, there are little drops in the idle; not bad just enough to bug me.

I think I'll try going through the carb manual this weekend and see what I find there, but if you have any suggestions they would be much appreciated!

Thanks again guys,
Grant

[itsmejustpurely]

The next question is probably what is the idle speeds in each condition in rpms.  There was a aftermarket tach added to the car which is not working.  I'll get it working this weekend (or buy a new one) and then post the exact numbers.

Thanks again,
Grant

[66andBlue]

I have moved the topic to this board since we know now that it is not a 230SL.

[glenn]

The '230' pix shows some interesting 'modification' ideas.  Carbs get rid of those nasty FIPs.  Having the hood tilt the other way makes access easier.  etc, etc.  Wonder how much this cost?

[ja17]

Looks like you have a 230 W110 Chassis (finback)  not a 230SL.  Don't confuse it with a 230S W111 chassis (finback) or the W113 230SL (roadster/coupe). The constant speed function is a vacuum dashpot on the side of one zenith carb. There is a 12 page factory set-up procedure for these twin Zenith carbs, so they are quite complex. Let me know if you need me to email this information to you.

[twistedtree]

One other random thought.... does your idle speed fluctuation correspond to movement/pressure on the brakes.  If working the brakes causes idle fluctuation, then you have a leak somewhere in the vacuum boost circuit.