Linkage Tour

[boneheaddoctor]

Also...a question about the bushings at what point are the bushings considered "worn"  is it the point you can "feel" vertical play?  Or would you consider the point they are worn enough to be detrimental to best function when you can visually see movement in a vertical plane?

[wwheeler]

After I put all new bushings and sockets on my linkage, there is no play at all. Before, there was significant play with the bushing on the intake side but the opposite bushing wasn't bad. I have never seen a spec for the amount of play allowed. If there is a doubt, you might consider rebuilding it.

[Miloslav Maun]

My injection pump has no adjusting idle screw. There are just fixed metal stops on both ends. Is that normal? (230 SL, 1965, manual)
I guess the linkage should be adjusted so that the lever touches the low end while idling... Am I right?

First I should change the length of the linkage that is attached directly to the pump so that it has 233 mm. Eventually all the other likage rods should be adjusted too.

[jameshoward]

Muf,

I would say that what you describe is not normal. Although I have a later car I believe that my pump is one of the early ones. It has a screw. Can you post some photos of the end of the pump so we can see what you mean?

As for adjusting the linkage to 233mm, start with that rod and follow the instructions in the tour so that everything else is set correctly. You need to do this in one go. You also need to have checked the dwell, your plugs, timing, etc. It all adds up.

JH

[Miloslav Maun]

OK, this is the photo of the injection pump.

[thelews]

The idle adjustment, mixture screw, I believe can be seen in this picture.  You push it in and turn through the clicks.  Clockwise rich, counterclockwise lean (if I recall correctly).

There are two other mixture screws for other rpm bands hidden behind a removable plate.

[jameshoward]

Muf,

You can see the screw clearly in Lews photo, and I think one can see the end of it in your photo. Clcokwise to enrich, as is written. The screw is spring loaded - you have to gently push it forward to engage the head inside. Rotate it a little whilst pushing it forward and you will feel it. NOTE: you must only make this adjustment WITH THE ENGINE TURNED OFF. Before doing anything, I suggest that you do a few searches on the site and read up a little on how it works. You should also understand how the air idle screw on the inlet manifold works, as there's a balance to be struck between the two.

Let us know if you find the screw.

JH

[Miloslav Maun]

Sorry, I have not expressed myself clearly. Of course my pump has that screw on the back which changes the mixture. I know that it can be turned only with the engine off.

What I meant is probably not called idle adjustment screw. It should be a screw located on the low end stop of the lever with the ball connection to the rod. I have read in one of my clever books (I think the black 1966 tuning manual), that the stop is adjustable but should never be tampered with. This is so vital that the clearance is stamped on top of the injection pump for future reference.

Looking at the two pictures of the pumps I can see they are different especially in the lever area. The other has different shape and just the low stop. (And also no adjustment screw).


I had a very high fuel consuption. Something like 18 l/100km (13 MPG). My engine was completely apart and redone so I thought that the lingage could use a reset. Actually what I first thought was that the start valves do not work alright and that the motor runs rich because it still receives the mixture for the start. Having gone through some tests described in both Haynes manual and in that black booklet, I have found the starting relays and solenoids seem to be working fine. So I took the car to the emission test. The guys there looked at the car like it was a UFO. Although this was an authorised BOSCH shop, they have never seen this type of mechanical injection. They were kind and willing to help though. With the help of those books and your excellent "Linkage tour" we managed to adjust the CO emissions close to 4,5% (Haynes says they should be 3,5-4,5 but we never managed to get under 4,5). We tried to lengthen the pump rod to 233 mm (it was 229) but then the injection pump lever wasn't leaning against the stop. I did not actually realize that we can change the length of all the other rods so we adjusted the pump rod to 223, which was the length when it touches the low stop. I plan to go to the garage and change this back to 233 and adjust all the other rods so that the pump lever touches the stop.  I understand this is important as there needs to be a proportion between opening of the butterfly and the pump because they open at different rates.

[Miloslav Maun]

Well, I have adjusted the length of the rods. No observable change so far. (But due to the weather I did not leave the garage.)

What does slight pinging in the air filer area mean? Seems to have disappeared after couple of accelerator presses.

[ja17]

Hello Muf,

The slight "pinging" you describe in the air filter area is most likely a lean condition under acceleration.  I describe it as a coughing through the intake. Not especially a problem but you will probably notice a loss of power under acceleration from the lean condition.  If you know the process for doing the "split linkage" CO test you can diagnose the situation further. If not let us know and we can try to describe the process. 

[glenn]

What I meant is probably not called idle adjustment screw. It should be a screw located on the low end stop of the lever with the ball connection to the rod. I have read in one of my clever books (I think the black 1966 tuning manual), that the stop is adjustable but should never be tampered with. This is so vital that the clearance is stamped on top of the injection pump for future reference.

Looking at the two pictures of the pumps I can see they are different especially in the lever area. The other has different shape and just the low stop. (And also no adjustment screw).

What do you think is the 'probability' that the lever has been 'adjusted' by some PO?  50, 75, 100 % ?

[jeffc280sl]

Been working on my linkage and have replaced the ball and pivot joints as well as the brass bushings on the cross shaft. Joe's information was extremely helpful.  I think it is important to remember the 233 mm length and bore hole settings for the venturi linkage are good starting points.  The most important thing to remember is the need to have the FIP and intake valve resting firmly on there stops.  It takes some work but it is worth the effort.  I started by fixing the pivot joint one end of the linkage and then adjusting the opposite end to get the correct length.  As I fine tuned the lengths keeping in mind to get the FIP and venturi resting on there stops I needed to loosen both ends of the linkage arm.  In other words a full turn adjustment on one end was too much.  With both ends not locked in place you can spin the shaft to get the exact length.  Remember you have left and right thread fittings on the end of the shaft.  This is why they are there.  I then removed the linkage arm noting the location of the shaft in relation to the end and locked the ends in place on the bench using a vice.

Once you have the linkage ends tight you can readily see where any loose joints are.  I was able to compensate with linkage adjustments for a loose joint where the cross shaft meets the support bracket on the intake manifold.  Despite having a new barrel bushing the bushing itself it loose in the bracket.  I'm speaking of #40 and #41 in the attached picture.  I'm going to try and take up the considerable slack in this joint.  Anyone have suggestions how to do this?

[bpossel]

Hi Jeff,

When I replaced the bushings (#41), I too was surprised at how much play there still was (is) in the cross shaft....
Replacing these bushings also didnt really tighten things up for mine either...
bob

[Naj ✝︎]

Hi, Jeff,

You may also want to consider changing these pivot bushes

naj

[jeffc280sl]

Thanks Naj and Bob,

The only way for the bracket to wear like that is if the bushing binds on the cross shaft and spins inside the bracket.  If we can push the cross shaft towards the passenger side the play in this joint is minimized.  This can be accomplished if the put a spring around the cross shaft section going over the head and put some sort of stop on the shaft.  That way ther will always be a little tenstion on the cross shaft forcing it towards the intake which removes the play in that joint. I'll experiment with some other ways to tighten this joint also.

[jeffc280sl]

Bob,

Here is a real quick fix to tighten up the bushing over the intake manifold.  Works great play is eliminated.   Now I just need to find a better/neater implementation.

[bpossel]

Hi Jeff,

Thanks.  Creative solution.
Bob

[jeffc280sl]

Glad you like it.  It's not very tidy and one day I'll come up with something better.  I found the spring in my shop and had extra hose clamps.  Best part is it works and the linkage can be adjusted with extreme precision.  With the 123 and linkage repairs my car is better than ever.  I thought the FIP and air valve were returning to their stops.  Once I changed the bushings, balls and sockets and took a very close look I could see that it was not so.  I almost used a feeler gauge to make sure they were closed.

[xcashewx]

i am in the middle of overhualing my linkages,
i found that the FI rod, the venturi rod and,the middle rod have significant "slop" to the point where they wiggle around in all directions.
 i bought 6 new LHT and RHT ball sockets, but i was wondering if the ball heads should be replaced as well, i noticed only 2 ball heads can be removed easily and the others are riveted onto to venturi lever,FI lever and block pivot etc.

[jeffc280sl]

I replaced the balls on the pivot block.  It is easy to remove and drill out the rivited ball joint.  The washers and nuts did not cause clearance problems with the brackets or other linkage.  I did not change the FIP nor venturi linkage becasue I did not want to remove them to drill out the ball.

The linkage is very tight now and the car idles better than ever.

[xcashewx]

does anyone have a source for the ball head nuts? or do they need to be ordered from SLS?

[awolff280sl]

Jeff, I also identified some left-right slop of my linkage and your fix is pure genius. I didn't go as far as using a spring, just a clamp abutting the bearing tower to keep the rod pushed to the right. In conjuction with adjusting the throttle damper, decelleration and idle rpm are now consistent. In addition, idle rpms when my compressor activated solenoid kicks on are consistent as well. Thanks!

[waqas]

Funny, the hose-clamp trick was the exact 'fix' the previous owner used at that very position on my crossover linkage. When I replaced all the bushings last year, there was still a lot of play, so I swapped out the bracket (I had a spare in my spare car ). No play now. I've always wondered why the bracket wore out... isn't the brass bushing supposed to wear out first??

[jeffc280sl]

Andy, Glad the idea worked for you and that your linkage is tight and working well. 

Waqas, Its possible the brass bushing became stuck on to the cross shaft and the outside of the bushing was rotating in the bracket assembly.  I would have thought the brass bushing would have worn down first.  Or it could just be a very minor design flaw.

[ja17]

Hello Waqas and xcashewx, 

It would be nice to list the current part numbers for those bushings and other bits. I will  paste them in the linkage tour afterward. Thanks,