Linkage Tour

[ja17]

7-17-07 re-loaded Matt Merrill's information
6-30-07 added information by "merrill"  (Matt Merrill)
11-19-06 intake venturi linkage information added
11-17-06 accelerator pedal linkage info added
11-16-06 information corrected, thanks Matt!
4-4-06 updated (parts numbers added)

There has been a lot of information posted on the subject of linkage adjustment. Thought it might be nice to have it all in one document with photos and diagrams. I have added factory information and what I know on the subject. Feel free to add, or correct as needed.

Sorry if some of these plates have become fuzzy after compression.
 
The intake venturi is one of the most  important aspects of the engine linkage adjustment, engine tuning and automatic transmission shifting. When not adjusted properly problems with improper idle speed, hard automatic transmission shifting, up or down and erratic engine behaviour may result. Proper linkage adjustment will be nearly impossible if the venturi is not correctly set.

The intake venturi stop screw.......

The most common and first item to check is the small slotted stop screw with lock nut on the intake venturi.  This is factory set and is frequently mistakenly used as an idle adjustment screw. This stop screw must be set so that the intake linkage arm and venturi valve in the intake closes all the way! When not set correctly too much idle air will be admitted to the engine causing lean idle mixture and/or too high engine idle rpm. An uninformed person may compensate for the situation by tampering with injection and linkage adjustments thus getting the engine even further from being in correct tune.

Download Attachment: venturi illus.JPG
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W113s with automatic transmissions also have a electrical switch attached to the venturi.  This switch lowers and raises modulator pressure by activating the three position solenoid on the transmission. Harsh downshifts (especially the last downshift before a stop) may result when not adjusted correctly. Correcting an improper set venturi can make an amazing difference in shifting, engine idle and engine performance.

Download Attachment: venturi illus2.JPG
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Disconnect the linkage rod going from the cross over rod to the venturi. If you have a USA version with the vacuum dash pot, you will need to move it out of the way so it does not interfere with the adjustment. The small slotted venturi set screw must be backed off enough to allow the venturi valve to close all the way and then adjusted in just enough to keep the venturi valve from binding in the intake.

USA 280SLs had an "Vacuum throttle control" on the intake venturi linkage. A special linkage with a "slip joint" was also used between the venturi and the cross-over rod on the engine. Adjust the slip joint linkage so it is fully compressed with the engine running and warm at idle in neutral. Adjust the vacuum control/linkage to
zero clearance. Now with the transmission in gear, the throttle lever will open 1.0 mm to 1.5 mm.
If you have a factory shop manual with the USA versions look on page 07-14/7.  It gives the procedure to adjust the unit.
Adjustments of the other linkage and tune-up items can follow afterwards if the idle is too high or too low or the mixture is incorrect.

Download Attachment: linkage 1.JPG
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Download Attachment: linkage 11.JPG
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Download Attachment: 12.3.JPG
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Download Attachment: linkage 13.JPG
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Naj points out that linkage parts should be checked for wear and has supplied parts numbers. Thanks Naj.

127 072 0185 spherical brass bushing (2 required)
000 991 8922 rod end ball socket RHT (as required)
000 991 9022 rod end ball socket LHT (as required)

During regular maintenance engine linkages should be lubricated with a light oil. Often times the block pivot is missed and may begin to bind or seize after periods of inactivity or storage. Try using some penetrant first then oil after it becomes free. This photo is a sedan pivot. The location is the same (under the intake manifold) and the unit is very similar. Also not the factory coolant drain plug location in the picture.

Download Attachment: block linkage lever.JPG
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Here is some information on the firewall accelerator pedal linkage and adjustment. The linkage between the block pivot and the intake manifold lever should be checked first before tampering with the firewall adjustment.

Download Attachment: pedal linkage .2.JPG
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When the accelerator pedal is at the floor the venturi valve should be wide open. If not you are loosing a lot of power. This is fairly common problem.  With automatics the pedal must also contact the "kick down switch". Adjust at the firewall after checking the other linkages.


Information and diagram contributed by "merrill" Matt Merrill;

"I have put the part numbers for another linkage bushing, ball stud , washer and nut.
all are available at the price in the photo. the bushings are only in germany"..........

Matt Merrill's information;
Download Attachment: Merrill.jpg
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Joe Alexander
Blacklick, Ohio

[Cees Klumper]

This is super Joe - having the linkages set up correctly is critical to the proper functioning of the engine so this information is very valuable.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[Kenneth Gear]

Thank you!  This is a great set of instructions, it's nice to have all the steps in one place.  

I bet this post turns out to be the "most read" one the site over time.

Ken G
1971 280 SL
Silver/red

[Naj ✝︎]

A good time to check the two spherical brass bushes on the control rod mounting posts before starting any adjustments.

naj

65 230SL
68 280SL

[Ben]

This is great.........thanks Joe, I've read it before, done it before but never seen it documented like this before !

Regards,
Ben in Ireland.
'64 230SL 4sp.

[ja17]

Hello naj,

Yes thanks, check for worn bushings and linkage rod ends. If you have the current part numbers I will splice them into the tour.


Joe Alexander
Blacklick, Ohio

[ja17]

Thanks naj!

I spliced the information into the original post.

Joe Alexander
Blacklick, Ohio

[merrill]

Joe,
I thought I saw a post that discussed linkage adjustment that went something like this.

"set the venturi linkage to 233 mm in length from the centers of the ball socket, then make sure that when the inj pump is wide open the intake venturi is wide open."

1. is the venturi linkage referring to the ijn pump to cross link or the cross link to the intake venturi?  the linkage for the inj pump to cross linkage on my car was exactly 233 mm center to center.
I just want to make sure this is ok.

(the link from the cross linkage to the intake was about 12 inches long. while the inj pump to cross linkage was about 9 1/2 inches long.)

2.  when the inj pump was wide open, the intake venturi was not wide open, so I lengthened the linkage from the cross linkage to the intake venturi.  I also made sure that the butterfly valve in the intake fully closed / opened after adjustment.


It will be interesting to see if this changes the performance of the car.

matt

Matt
66 230 sl - "white"
78 300 D - Blue
98 C230

[al_lieffring]

Joe

You might want to include a reminder to check and lubricate the bell-crank on the cooling jacket cover.

66 230sl
113-042-10-014715
904/396 blue, Ivory Tex
condition: not-as-rusty-as-before-bucket

[ja17]

Hello Matt,

I am glad you caught this!  Now I need to go back and correct this, yes the 233mm dimension is for the linkage rod going from the injection pump to the cross over rod!

Be careful, Yes make sure that the venturi is closed and the injection pump lever is on its stop.  Also make sure the venturi stop screw is only adjusted just enough to keep the butterfly valve from binding.

Make sure that the engine is getting full throttle when the accelerator is on the floor. There is a accelerator pedal height adjustment at the fire wall near the brake booster. By loosening the 13mm bolt head and removing the spring, you will be able to adjust the accelerator pedal height. Afterward make sure the accelerator pedal gives you full throttle when floored. Also make sure that the accelerator pedal just hits the kick down switch (on automatics) when the pedal is depressed at  full throttle.  Changing the length of the linkage rod going to the block pivot will also change pedal travel and throttle.
Thanks,


Joe Alexander
Blacklick, Ohio

[merrill]

Joe,
yep, now I see it, the first attachment in the original post above note 4.  
Since, I had not heard back from you this afternoon I swapped the linkages and there is no way this would have worked.

I have ordered new linkages and the brass bushings from cheryl at K&K so I can get it working like new again.

I will also check to make sure my gas pedal portion of the linkage is correct.

yippeee, It is nice to see the hard work pay off.
matt

Matt
66 230 sl - "white"
78 300 D - Blue
98 C230

[ja17]

Hellow Al,

Good point on lubricating the block pivot.  I will have a photo I will splice into the "tour".

Thanks,



Joe Alexander
Blacklick, Ohio

[saygold]

Excellent explanation and pictures.  Thanks for posting them.

Is there a specific length for the "linkage to manifold lever" (shown in the "Block linkage Lever.JPG" photo), or is it adjusted "as needed"?

Thanks,

Ken
'66 230SL (Euro, 4-speed)

[ja17]

Hello Ken,

I have never seen a specific length listed for the rod between the pivot and the manifold, but if it is too short your accelerator pedal may be too high. If it is too long you may not be getting full throttle.  One easy test is to hold the accelerator pedal all the way to the floor (engine off). Next have someone check to see if the venturi is open all the way.

Joe Alexander
Blacklick, Ohio

[Peter van Es]

Joe,

if you can mail me the pictures in as large a format as available, I can make this into a document which I can create a "member-only" downloadable PDF of. This pdf then should print great on someone's printer, and will have full picture quality.

Let me know if you think this would be a good idea, and you can mail me the original images to admin@sl113.org
Peter



Check out http://bali.esweb.nl for photographs of classic car events and my 1970 280 SL

[jeffc280sl]

Joe,

Thank you very much for the write up and pictures!

Jeff C.
1970 280SL 4-speed

[waqas]

So I have some basic questions:

Are the linkage adjustemnts (dimensions from ball-center to ball-center) specific to the chassis or the engine?

What if you have a sedan engine in your pagoda? (which dimensions do you use?)

Are the dimensions listed in the BBB ?  Which section? my CDROM is a bit tedious to navigate... looks like the MBZ climate control system group also worked on the CDROM...  

Thanks for such a helpful and informative thread!

WAQAS in Austin, Texas

[ja17]

Hello Waqas,
The linkage rod between the injection pump and cross over rod should be the same on the 250 and 280 series in both the SL and sedans. I am fairly certain  that the 230SL is also the same. There may be some differences in the other linkages depending on the model. As far as I know the installed lengths of the other rods is not called out in the BBB, just the one from the pump to the cross over rod 233mm.

Installing the 233 mm rod and setting up the venturi to be completely closed will dictate the length of the rod going from the venturi to the cross over rod. Also use the alignment bore in the linkage support if your car has it. The linkage rod going to the block pivot should be set so the venturi is all the way open when the accelerator is at the floor while still allowing the venturi to completely closed when the pedal is up.

Joe Alexander
Blacklick, Ohio

[sjiatrou]

Thanks for the great information!  I have a quick question about the Progressive Regulating Linkage (top diagram in your linkage 13.JPG pic):

Is there supposed to be some play in the linkage when I press the accelerator?  I have the linkage rod adjusted so the roller rests as indicated, however, I have to depress the pedal about a 1/2" or so before the linkage engages (i.e., the linkage engages the roller); is this the correct configuration?  I hope that isn't too vague or misleading?

Thanks,
Steve

Steve Iatrou
Seaside, CA
1964 230sl roadster
White (050)/Black (116)

[RCS Coupe]

Installing the 233 mm rod and setting up the venturi to be completely closed will dictate the length of the rod going from the venturi to the cross over rod. Also use the alignment bore in the linkage support if your car has it. The linkage rod going to the block pivot should be set so the venturi is all the way open when the accelerator is at the floor while still allowing the venturi to completely closed when the pedal is up.

Joe Alexander

Sorry, but I need to beat this out one more time. I am installing all new (or replated) link rods, balls, sockets, and pivots from the pedal to the venturi and FI pump. Mine is an M129 (250SL) engine, non-US spec, manual transmission, R11 FI pump.
With a pile of shiny metal bits in front of me, some rods right threaded, others left-threaded, I have to start somewhere to get it all back together and working.

For the link rod between the FI pump and the crossover shaft: is the length dictated by the cross shaft being on the alignment bore in the shaft support and the FI pump lever on the stop, or does the link need to be 233 mm long?

With my FI pump lever on the stop and the cross shaft aligned through the support hole, the link rod measures 230 mm center-to-center (socket balls). Lengthing the rod to 233 mm will open the FI pump off the stop with the throttle valve shut. Any thoughts on this?

Ray
(268)Green 250 Coupe

[merrill]

I have put the part numbers for another linkage bushing, ball stud , washer and nut.  
all are available at the price in the photo.  the bushings are only in germany


Download Attachment: parts for linkage.JPG
37.97 KB

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[Ben]

quote:With my FI pump lever on the stop and the cross shaft aligned through the support hole, the link rod measures 230 mm center-to-center (socket balls). Lengthing the rod to 233 mm will open the FI pump off the stop with the throttle valve shut. Any thoughts on this?

Ray
(268)Green 250 Coupe

..........good question !!

Regards,
Ben in Ireland.
'64 230SL 4sp.

[ja17]

Thanks for the good added imformation merril,

I will cut and paste it into the original "Linkage Tour" (with a credit to you) so it does not get lost!


Joe Alexander
Blacklick, Ohio

[ja17]

Hello RSC,

Sounds like some of the other linkage rod lengths have been changed. Set the injection pump rod to 233mm, disconnect the other rods, including the rod going to the block pivot. Adjust and install the linkage from the cross over rod to intake venturi (venturi must be closed) now install the block pivot rod so it does not disturb the linkage at rest.  Next make sure that the venturi is fully open when the accelerator is on the floor. When the accelerator pedal is at rest the venturi should be completely closed and on the linkage lever on the stop at the injection pump.



Joe Alexander
Blacklick, Ohio

[ja17]

Hello Steve,

By the looks of the diagram it appears that the progressive linkage is meant to move a bit before things start to happen, however the "roller openings" do wear and yours may be bit excessive. In this case you may wish to replace the linkage plate or adjust it a bit off the rest to compensate. Make sure you get "full throttle" (venturi fully open) with the accelerator pedal on the floor.

Joe Alexander
Blacklick, Ohio

[merrill]

so, checked my linkages per the tour,  adjusted the inj pump to cross linkage to 233mm.  from there adjusted everything else.

the only problem is on my 230 sl auto, when I put the car in gear the idle selenoid increases the rpms to over  1,000 rpm

the adjuster is all the way in.  should I put everything back ?

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[J. Huber]

Hi Matt. So close but yet so far! I don't know if this will help but I just measured a few things for comparison:

With the 233MM fuel side, my intake side is @289MM (center ball to ball) and the small center rod is 138MM. (again approx. to my best measuring). My CSS shows 3 full threads showing. My stop screw has 5 full threads showing. Good luck.

PS I tend to have a slightly higher idle than the book -- but my CSS keeps things very close to park numbers. Less than 1000 to be sure.

James
63 230SL

[merrill]

james,
went out and checked the linkages, thought I had the gas pedal mis adjusted.  wrong

finally I lengthened the short linkage till there was a gep between the selenoid and the linkage.

once there was a gap, I started the car and then I was able to adjust the selenoid.

now I wonder if maybe I need to check the pedal set up.

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[wgl]

Joe,
I was unable to load the last download "Merrills info" can you refresh that?
Thanks for this info.
Bill Lindquist
Portland, OR

[Benz Dr.]

The arm on the air control doesn't need to be fully opened to be adjusted properly. On most cars it will come close to the full stop screw but still not touch. This is OK.  What you want is for injection pump and the air controller to open at the same time from the idle postion. The arm on the injection should hit the full stop in this case.
Due to the way the linkage is set up the air control linkage moves faster in the mid open position than does the injection pump. When the arm on the pump is opened at about 40 degress the air control arm is maybe 50 degrees but they both end up at the same 80 + degrees when fully opened.
In order for the linkage to be able to move freely to the max opened position there should be about 1 mm of gap at the full stop screw so that it doesn't touch.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[ja17]

Hello Bill,

Now re-loaded, the "label" on the photo was to long.  Try it now.



Joe Alexander
Blacklick, Ohio

[J. Huber]

quote:Originally posted by Benz Dr.

... In order for the linkage to be able to move freely to the max opened position there should be about 1 mm of gap at the full stop screw so that it doesn't touch.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

This is a subtle but important statement the Doc makes. Often times this stop screw gets involved in the linkage and somehow becomes part of the idle adjusting process. This makes sense since if it is pushing/holding the linkage -- any turn of the screw would change the idle... Problem is, besides throwing the linkage off its true course, this has an effect on the transmission (usually leading to harder, clunkier shifting.) As Dan says, they should be separate from each other.

James
63 230SL

[merrill]

joe,
I figured something out, if one stars at the inj pump and starts to "adjust back" to the pedal then the pedal will need to be adjusted.

i tried to adjust per the instructions but the linkage from the block to the cross member was out of what and then of course the pedal needed to be adjusted.  

thoughts on how to update the post so the tour is clearar for the novice?

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[Peter van Es]

Note that this content will move to the Tech Manual as soon as Joe has provided me with high res photographs. That is the place where we would need to make the definitive article.

Merril, Joe, this Linkage is probably where it will end up.

Have a look at what's there... better yet, start modifying it there!

Peter



1970 280SL. Also known as 'admin@sl113.org' and organiser of the Technical Manual.

[jwalk]

Hello JA, I hope I am not out of order by jumping in here but the topic of discussion is similiar to my problems. For my 65 230SL I believe the following are true. (1) vacuum retard distributer & throttle (2) ignition timing 4 BTDC (3 linkage correct with 10 MM hole as a start point and down rod to FIP bring 230 MM long C to C. The throttle is then closed and when the throttle is full open the FIP is also full open.Sounds good so far except the will not start or run .
 
 I use the plugged hole on the rear of the intake manifold as a source for a vacuum gauge and I found that with the vacuum gauge removed and the port open the car starts immediately and with no throttle  or pump opening the RPM jumps to 2200 with an advance 28 degrees. I isolated the intake manifold from the brake vacuum booster but what would you recommend that I do next to get mu idle back? I have learned so much from your directions throughout the forums and would appreciate any help you may offer.

Sincerely jwalk

[jwalk]

quote:Originally posted by jwalk

Hello JA, I hope I am not out of order by jumping in here but the topic of discussion is similiar to my problems. For my 65 230SL I believe the following are true. (1) vacuum retard distributer & throttle (2) ignition timing 4 BTDC (3 linkage correct with 10 MM hole as a start point and down rod to FIP bring 230 MM long C to C. The throttle is then closed and when the throttle is full open the FIP is also full open.Sounds good so far except the will not start or run .
 
 I use the plugged hole on the rear of the intake manifold as a source for a vacuum gauge and I found that with the vacuum gauge removed and the port open the car starts immediately and with no throttle  or pump opening the RPM jumps to 2200 with an advance 28 degrees. I isolated the intake manifold from the brake vacuum booster but what would you recommend that I do next to get mu idle back? I have learned so much from your directions throughout the forums and would appreciate any help you may offer.

Sincerely jwalk

As the associated topics have not yet progressed to the WIFI manual and as I have not yet learned any description of the 9/16 in. hex head adjuster which stops the spool one of two levels which differ by 5 mm. attached are two pictures. What is the purpose of this adjustment?

jwalk

Download Attachment: DSC00358.jpg
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Download Attachment: DSC00359.jpg
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[ja17]

Hello jwalk,

The adjustment on the early WRD injection pumps (230SL) is for testing only. It serves no other purpose. It should be left in the upward postition so the air valve piston can have full travel.

If your car will not start unless you have a open vacuume leak, your injection pump air filter may be plugged and not allow needed air into the engine for cold starts. Check this first. Please describe your problems again for us so we can be of more help.

Keep in touch,

Joe Alexander
Blacklick, Ohio

[glennard]

Re: Linkage adjustment.  As in Casablanca- of all the cars and of all the mechanics----.   It is sacrosanct on this Forum to alter the rod connection on the FI pump control shaft.  Unfortunately, all those garage good wretchs around the world don't abide by this.  Bet a good percentage of Pagodas, 113s, etc have had this tampered with-all in good intention.  Solution??

[66andBlue]

quote:Originally posted by jwalk

...  I use the plugged hole on the rear of the intake manifold as a source for a vacuum gauge ...

Hi Jwalk,
I have been searching for that port hole for a long time and cannot find it on my 230SL.  Where is it?
Could you post a picture, please?

Alfred
1966 blue 230SL automatic

[Naj ✝︎]

quote:Originally posted by 66andBlue

quote:Originally posted by jwalk

...  I use the plugged hole on the rear of the intake manifold as a source for a vacuum gauge ...

Hi Jwalk,
I have been searching for that port hole for a long time and cannot find it on my 230SL.  Where is it?
Could you post a picture, please?

Alfred
1966 blue 230SL automatic

Its busy feeding vacuum to the autobox

naj

68 280SL

[jwalk]

Hello Alfred,
 Pardon the delay in responding but have been away. The attached image shows a quick connect attached to an opening which is normally blocked by a cap bolt on my car which has the ZF 5-20 transmission.I believe naj is correct in that your car, being an automatic, uses this port for the transmission.

jwalk

[jwalk]

Hello Joe,

Thanks for the reply. Let me qualify my situation. I have been trying to solve an idle speed that is not > 500 rpm. When it wont run it is difficult to adjust. I am sure the linkage is correct per the book and the WIFI manual. Ignition timing and dwell are very close. this car, engine 012501 has one square relay, one round time switch, one injection pump solenoid and the cold start valve which all appear to be working and in order. I have not included the thermo time switch in the afore mentioned parts because I believe it is faulty. The W terminal is grounded in the switch and I am in the belief that it should be normally open. I have a switch on order. You mentioned the air filter on the FIP, It is new and the port sucks when cold and does not when hot. The fuel control rod to be moved to its extremes and returns to the full load position. My conclusion is that the engine is getting over abundance of fuel because, on one occasion I did start with the 10 MM  hole in the manifold open to atmosphere and the engine starter immediately and ran smoothly at 2300 rpm with throttle and FIP in the idle position.

Thanks for all help
jwalk

[66andBlue]

quote:Originally posted by jwalk

 ... I believe naj is correct in that your car, being an automatic, uses this port for the transmission.

Thanks Jwalk.
And I thought naj [.. feeding vacuum ..] referred to a new dieting fad   .
So Naj, where is the best place to tie in a vacuum gauge (with a T-connector), distributor line or brake booster line?

Alfred
1966 blue 230SL automatic

[Naj ✝︎]

quote:Originally posted by 66andBlue

quote:Originally posted by jwalk

 ... I believe naj is correct in that your car, being an automatic, uses this port for the transmission.

Thanks Jwalk.
And I thought naj [.. feeding vacuum ..] referred to a new dieting fad   .
So Naj, where is the best place to tie in a vacuum gauge (with a T-connector), distributor line or brake booster line?

Alfred
1966 blue 230SL automatic

The distributor line, using the rubber pipe that goes into the throttle body.

naj

68 280SL

[jwalk]

quote:Originally posted by RCS Coupe

Installing the 233 mm rod and setting up the venturi to be completely closed will dictate the length of the rod going from the venturi to the cross over rod. Also use the alignment bore in the linkage support if your car has it. The linkage rod going to the block pivot should be set so the venturi is all the way open when the accelerator is at the floor while still allowing the venturi to completely closed when the pedal is up.

Joe Alexander

Sorry, but I need to beat this out one more time. I am installing all new (or replated) link rods, balls, sockets, and pivots from the pedal to the venturi and FI pump. Mine is an M129 (250SL) engine, non-US spec, manual transmission, R11 FI pump.
With a pile of shiny metal bits in front of me, some rods right threaded, others left-threaded, I have to start somewhere to get it all back together and working.

For the link rod between the FI pump and the crossover shaft: is the length dictated by the cross shaft being on the alignment bore in the shaft support and the FI pump lever on the stop, or does the link need to be 233 mm long?

With my FI pump lever on the stop and the cross shaft aligned through the support hole, the link rod measures 230 mm center-to-center (socket balls). Lengthing the rod to 233 mm will open the FI pump off the stop with the throttle valve shut. Any thoughts on this?

Ray
(268)Green 250 Coupe

Ray You are not the only one confused about the proper linkage setup. I am also fighting to obtain the optimum setup. My 65 230 SL, like yours is set with, as a starting point, the cross shaft located by the hole in the intake manifold. this does result in the down shaft to the FIP being 230 mm. All should be well as the throttle shaft length is fixed by the closed throttle and the cross shaft locked in the setup mode. My reference source is BBB August 59/loose leaf edition with job No 00-16 Model 230 SL added. These instructions give no dimensions for link lengths but give detail detail numbers for the relationship between the throttle valve and the FIP in degrees throughout the 82 degrees of travel. What has me concerned is if the 233 mm number is good and use of the lineup hole in the intake manifold is also good, then on my car the FIP is not on the idle stop but open due to 3 mm of movement of the FIP arm. I know that my FIP arm has not been altered. If the 233 mm number surfaces from a later model, are we assuming that it applies to the 230 SL also? My BBB does say to use the line-up hole in the intake manifold.

jwalk

[jwalk]

quote:Originally posted by ja17

Hello jwalk,

The adjustment on the early WRD injection pumps (230SL) is for testing only. It serves no other purpose. It should be left in the upward postition so the air valve piston can have full travel.

If your car will not start unless you have a open vacuume leak, your injection pump air filter may be plugged and not allow needed air into the engine for cold starts. Check this first. Please describe your problems again for us so we can be of more help.

Keep in touch,

Joe Alexander
Blacklick, Ohio

Hello Joe!

Thank you for the input on th e WRD test feature and the air filter. I believe that I previously had Miss adjusted the FIP so rich, in an attempt increase the idle, that it would not run. Only when I inadvertently left my vacuum port open did it start, but while idling > 2000 rpm. I have since corrected the fuel and air to achieve a 800 rpm idle. All is not yet right as it bucks severely under moderate acceleration. Am I rich or lean? Another concern is, although the WRD does move the spool valve from supplemental air to to no air, what effect does this device have on fuel supply. My BBB, which may be referring to to the 220seb gives a dimension of 6 mm for the extension of the working pin on the WRD thermostat. Is this correct for the 230 SL? Mine is much less.

Thanks again , jwalk

[wwheeler]

I am on the cusp of completely rebuilding my linkage set up on my '68 M130. I have memorized this tour and have looked over everything I can find on this topic but still have one question.

When everything is adjusted according to spec, will the injection pump lever be completely open when the pedal is on the floor and the venturi hits it's stop? Or does the 233mm rod adjustment take care of that?

[ja17]

Hello Wallace,

As long as the factory-set stop on the injection pump has not been tampered with, then the adjustment of the linkage rod to 233 mm  should restore the correct geometry to the linkages. Consider that the lever on the injection pump is on its factory-set stop, the lever on the venturi is adjusted so as "just not to bind" and the injection pump rod is adjusted to the prescribed 233mm. The linkage rod from the venturi to the cross-over rod must conform to what is left. (It must be in the collapsed position if is is the later US style "slip linkage"). Any vacuume dashpot must be temporarily moved so as not to influence the set-up. Finnally the linkage rod from the engine block must allow the linkage and venturi to open all the way when the pedal is to the metal! There is an adjustment on the accelerator pedal height at the firewall (engine compartment) if needed.

[paults1]

I was having trouble getting an good 233mm reading with a tape measure for the distance between the IP pump & the cross over rod.  I found a web site that you can print a "printable paper ruler" that is very accurate. Simply lay the rod on the paper ruler & adjust the sockets to the 233mm length. The site is www.vendian.org.

Regards, Paul '63 230SL

[wwheeler]

I finally got the entire linkage rebuilt and adjusted on my M130. Wow! What a difference the bushings and sockets can make. The venturi housing was also rebuilt and finally adjusted correctly. I am lucky to have the bracket with the alignment pin hole. Eventhough I did double check the 233mm dimension, the alignment hole made it a lot easier. Everything is now adjusted to spec.

Thanks Joe for all of your work on the linkage tour. I am not sure I would have had the confidence to tackle the job with out it!

[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,

[Naj ✝︎]

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

Ask your local MB dealer to order you  127 990 01 51


naj

[UJJ]

I need to say it again, thanks for this excellent information. You are the best!
Urban

[Saman 280SL]

Great article. A must read to help avoid the frustration and confusion with tuning these engines. Very helpful for me to adjust the rod from the injection pump to the throttle linkage

[ja17]

This thread just reached over 100,000 views. That's nearly two views for every pogada ever produced.

[Saman 280SL]

It definitely helped me.  Great post

[calicoup]

Good morning, I recently had my late 250sl tuned and now after a cold start with engine idling at 8-900 rpm, rpms will drop and/or stall when accelerator pressed quickly. No problem if gently pushed or when warm or in gear.
Any thoughts? Thank you.

[ja17]

Good chance they may have gotten your linkages out of adjustment.

[johnk]

This thread just reached over 100,000 views. That's nearly two views for every pogada ever produced.

That's pretty amazing Joe, but very indicative of the time, effort and knowledge you put into it. I know I will be going through every step of it the second time this next week as I put my linkage back together. I have it printed and ready to take with me tomorrow. What a priceless resource to Pagoda owners worldwide.

We can never say thank you enough!
John

[stickandrudderman]

We just had a car in (actually one we bought) that was only getting half throttle. Examination revealed that someone incompetent had been at the throttle linkages......
What we found might well catch others out:
The bellcrank on the block pivot had been installed the wrong way around; there is a "long throw" and a "short throw" to this bellcrank and the long throw is the one that connects to the vertical throttle control rod. Getting this wrong is very easy to do and will result in only half throttle.

[1000nutsnbolts]

I can't thank you all enough. I am a true DIY'fer and I appreciate how much work and selfless effort this "Tour" took.

Thanks Again,

Tom McManus

[yves]

While i was fitting my "new" injectors, i had a look on the cross rod "master linkage element!" and tested it .....i found a vetical play of 1 mm and a lateral one of 2 mm ..... on the right end  and no play at the left end .
Of course you'll say to replace the bush but i am scared about modifying all the rods positions by un fitting and refitting the cross member.
I thought to mark each angle position at the different rods points fixation . Is there a specific method to do that ? and eliminate some mistakes?

[Nicolas Aristodemou]

While i was fitting my "new" injectors, i had a look on the cross rod "master linkage element!" and tested it .....i found a vetical play of 1 mm and a lateral one of 2 mm ..... on the right end  and no play at the left end .
Of course you'll say to replace the bush but i am scared about modifying all the rods positions by un fitting and refitting the cross member.
I thought to mark each angle position at the different rods points fixation . Is there a specific method to do that ? and eliminate some mistakes?

I think you will have to replace the bush, put everything back together and do all adjustments outlined in the linkage tour in the specified sequence. That should give you the correct operation of your car’s FI system. Your car might be running well as it is now but it will run even better after the new bush/linkage reset as per linkage tour.

[yves]

Job done after cleaning the cross shaft and replacing the bushes. The only problem is the lenght of the rod which goe to the Inj pump adjusted at 233 mm ( as the tech manual say) needs to turn the pump bracket about 20 ° clockwise . Now when i start the engine the idle is a little erratic ( not so much but not steady ) 
I have also replaced some "ends" of the rods which have some play .

[Pawel66]

Do you have the orifice in the cross shaft support for the rod length adjustment? The book advises to use it if you have it and but if you do not have it is the given mm length.

[ja17]

Never change the angle of the linkage lever on the injection pump. It is factory set when the IP is calibrated during manufacture. If your linkages do not fall into adjustment as they should, chances are that the some linkage rods are not correct or some other non original alterations to the levers or linkages have been previously made.

[yves]

Pawel , i don't see any adjustment orifice on the bracket of the shaft . To minimize the rotation of the rod at the pump i have shortened the rod to 230 mm , but it is still too long ! I am now scared to take as a start point  :
233mm for the pump rod with not any rotation of the pump angle where the rod attach, and then adjust the other rods with the shaft in a new position.
Another problem: the pump lever is not vertical and the rod end is not neatly fitted at the pump junction. It works but not in a ideal angle ....( i have not any reference to compare with
I think i'll go in the Joe way:
233mm on the pump rod with no rotation of the lever as a start position , and then adjust the  3 other rods to the new position of the shaft

[mrfatboy]

Yves,

I think it would be wise to start your own thread on your issue. People will be more than happy to help you  there.  This way this thread will not get out of control and cluttered 👍

[yves]

Yes Y're right
 

[cfm65@me.com]

Thanks Joe,
Much appreciated.
Compliments of the season.
Regards
Chris
Cape Town