cold mixture adjustment for 2 plunger 220SE

[wwheeler]

Does anybody know how to adjust the cold mixture for 220SE (2) plunger pump? I am familiar with the warm mixture adjustment.

Thank you,

Wallace

[Benz Dr.]

I did one last fall and it wasn't easy. Before you start you need to check all of your injectors. Breaking pressure should be within 7 PSI for the working group of three injectors. Try to match them so they all break at about the same pressure. You can have one group higher than the other as long as the three injectors in each group are a matched set. If even one injector is weak you won't ever get a decent idle mixture and the engine will always sputter and miss.
After you get your injectors sorted out you should make sure that your distributor blocks are all flowing evenly. I always tested them with the lines and injectors attached so I could see what the final output was. Again, any problems at this point will need to be sorted out. Good used injectors are getting very hard to find - and no, I don't have any. 

The slide valve is similar to our 113 cars but it may have a small screw on the top of it which can be adjusted. The one I did last fall didn't have a screw so we very carefully ground a small amount off the central pin until the air valve was completely shut off. I think we may have removed the air jet to give it a bit leaner idle mixture. Took the better part of a day before we had it right.

All I can say is that this is a very difficult engine to tune.  The car we did never really ran right until we did all of this stuff and then it was like a totally different car. No more stalling, great idle hot or cold, and it started every time. 

[wwheeler]

Thanks Dan.

I have checked the injectors and blocks with my injector tester from India. I am familiar with the six plunger pump and was hoping the adjustment was as easy. I guess not. I have the service manual on the pump and it talks about the air slide valve as you mention. The engine has been rebuilt and is currently on a test stand to work out the bugs before install. Warm idle is great, just a bit too much fuel during cold running. I do need to see at what temperature the air valve shuts off though.

Thanks for the help and sounds like fun!
Happy New Year, Wallace

[PeterPortugal]

Hi Wallace,
Can you provide any details of your "Indian" test equipment? I will need to do this job.
Regards
Peter

[wwheeler]

http://www.fiptestbenches.com/injector-nozzle-testers.html

I have the NTG 400. Yes, it is a diesel scale gauge, but it is easy to see the 200PSI or so mark where the injectors are supposed to open up. The cracking pressure is just one reason to check them. The spray pattern at the cracking pressure and leakage below are the other reasons. You can really tell a difference in the spray pattern with some injectors after a cleaning.

I went ahead and bought two more gauges. One that is a max 1000 psi for the injectors and one to 60 PSI that check the cold start valve. I believe the original threads are BSP (British Standard pipe) and so to use tapered pipe gauges, it requires an adapter. I hope that helps.

[PeterPortugal]

Hi Wallace,

Thanks for posting the link and the info.

I was under the impression that when you said "Indian" it would be a cheap version from the "sub continent" of the same name !!

Regards

Peter

[wwheeler]

I do believe this company is from India. I guess that is what you are asking?

[PeterPortugal]

My God you are right !!

I opened the webpage and thought it was "Indian Machine Tools" in the same way it would be "Indian Motorcycles" i.e. a US company who just happened to choose that name.

I had a feeling I would be paying handsomely for carriage from the USA....but no....readily available on Amazon UK.

Thanks again for your help Wallace.

[perry113]

What issues are you experiencing?
Did you make sure that your cold start valve system is working? Did you pull it out to see if its spraying fuel?
I've seen this system work but actually have a clogged system so fuel is not making its way out.

[PeterPortugal]

Hi Wallace,
Whilst you were setting this engine up did you discover the correct length to set the linkage rod which is connected to the fuel injection pump?

The technical manual gives it for the Pagoda (233mm or similar) but this is a six plunger pump.

Regards

Peter

[mrfatboy]

Peter ,

It's a slow Sunday afternoon so I thought I would chime in.  Full disclosure,  I know nothing about the 220se engine but I thought I would offer a suggestion.

On my 280sl, there is a hole in the bracket (mounted on manifold) for the cross over bar to the FIP.  See pic. I use this hole to set all the rod lengths.  Does the 220se have such a hole in the bracket?
 
Disconnect all rods.  Make sure the throttle body stop screw and IP stop screw are on their respective stops. I then align the ball of the connecting rod to the center of the hole on the bracket.  From there connect all rods while making sure the original ball socket is always aligned/centered in hole.

At this point the connecting rod length to the FIP is what it is. 

Again, I have no idea if you can do this type of technique on the 220se.

[wwheeler]

The 220SE has at least two different versions that I know of. 1) the 220SE W128 Ponton engine (the exact engine number escapes me now) and 2) the W111 220SE Fintail versions.

I have a 220SE W128 Ponton and a 280SE W111. I know the injection system for a W111 220SE uses basically the same pump as the W128 220SE Ponton, but the linkage is more similar to the later six plunger W111 and NOT the W128. I cannot help you for a W111 220SE. I also wouldn't assume your 220SE W111 linkages are the same as the later six plunger pump linkages. I would look in the starting 1959 Blue Book and I would bet there is a host of information there.

Does that help?

[Benz Dr.]

There's a small bearing block sitting behind the IP that's mounted on the cylinder block. This block holds the arms that control the IP linkage. One of the arms has a small hole drilled through it that lines up with another hole in the bracket. Once you have those two holes lined up all other linkages are adjusted to that basic position. As far as I can remember, only the 128 ponton cars use this arraignment and with only about 5,000 units produced it's getting hard to find spare parts today.

[PeterPortugal]

Gents,  thanks for your responses but it seems my car falls between the cracks.

It's too early for the arrangement shown by mrfatboy (W111 250SE and 280SE)
It's too late for the arrangement described by Dan (W128)

I may have to get onto google translate and try the German forums !!

[Benz Dr.]

What year is your car? 220SE ( 128 ) was built until 1960 and then the 220SEb took over from there. Early 111 coupes and fin cars had straight intake manifold pipes while later ones have an intake similar to a 230SL.  You may need get creative.

[wwheeler]

There's a small bearing block sitting behind the IP that's mounted on the cylinder block. This block holds the arms that control the IP linkage. One of the arms has a small hole drilled through it that lines up with another hole in the bracket. Once you have those two holes lined up all other linkages are adjusted to that basic position. As far as I can remember, only the 128 ponton cars use this arraignment and with only about 5,000 units produced it's getting hard to find spare parts today.

Yes. That is exactly the way that works on the W128. The early 128 cars had yet another gizmo mounted on the throttle body that would allow calibration at different throttle openings. The later cars like mine (1960), had only the alignment hole on the bearing block and that hole only set the idle position. The later 128 cars were suppose to use protractors and such on the IP and throttle body to dial it in. Of course, nobody but the dealers had these tools and the DIY just did what they could. As far as I can see, there are no specs for linkage parts on the W128 cars like there is for the six plunger pump cars.

[wwheeler]

Peter,

Attached is a pic of the 220SE W111 motor. Yes, it is different than the six plunger W111 cars. I would look on the intake manifold where the linkage mounts. Look for any alignment holes that may line up with the socket on the linkage. On the six plungers, you stick a pin in the hole as shown by mrfatboy that aligns to the ball on the linkage arm. If so, that should be similar to the 250 and 280SE. Pretty sure the linkage rod will not be the same as the six plunger pumps though.

Do you have a starting '59 BBB?

[mrfatboy]

Since I don't have a proper size alignment pin I use a mirror.  Align the ball connector so it's perfectly centered in bracket hole. 👍

[PeterPortugal]

Gents,

Thanks for the continued support and advice.

Dan hit the nail on the head for my car. It is a March 1963 car with  the early (straight) intake manifold. As far as I am aware it has neither of the facilities which you describe (no ball on the linkage for sure, the holes on the FIP...maybe but I am not at home to check this)

I do have a service manual and it refers me to the protractor tool which you describe Wallace.

Regards

Peter

[PeterPortugal]

What I can tell you is the linkage rod for the FIP was set within a few mm of the length recommended for Pagodas in the technical manual.

[wwheeler]

FYI, here is a picture of my W128 220SE with the two plunger pump. Similar pump, totally different set up.

[PeterPortugal]

Wallace,

Another perfect 10 !! Bravo !

It gives me something to aim for !

Regards

Peter

[wwheeler]

I would think the linkage set up is straight forward as long as no one has messed with the IP stops. At idle just make sure the IP is on its stop as is the throttle body. You can adjust the TB as you know by closing until you get a slight bind on the butterfly. Then just make sure they both open fully at the same time. I believe the throttle body is at 99.9% of its max travel when the IP is on its full open stop. There is a mm or two gap to the stop on that piece at wide open throttle.

What happens in the middle is magic and can only be determined by the unbelievably complicated protractor devices. Assuming levers and the rods are not bent, you should be in good shape.

Thank you for your compliment and is a labor of love. I drove it for the first time in 4 years the other day after the mechanical rebuild and have a few bugs to work out. Working on that car is like stepping back into another time.

[PeterPortugal]

Hi Wallace,

I am just waiting for a 0-300psi pressure gauge and then I am going to get the NTG 400 out and test my early style injectors (the ones with the 90 degree bend).

You mentioned cleaning yours. How did you go about it? Kent Bergsma has a video for cleaning the later style ones. Is it a similar job for the early?

Regards

Peter

[Benz Dr.]

I would think the linkage set up is straight forward as long as no one has messed with the IP stops. At idle just make sure the IP is on its stop as is the throttle body. You can adjust the TB as you know by closing until you get a slight bind on the butterfly. Then just make sure they both open fully at the same time. I believe the throttle body is at 99.9% of its max travel when the IP is on its full open stop. There is a mm or two gap to the stop on that piece at wide open throttle.

What happens in the middle is magic and can only be determined by the unbelievably complicated protractor devices. Assuming levers and the rods are not bent, you should be in good shape.

Thank you for your compliment and is a labor of love. I drove it for the first time in 4 years the other day after the mechanical rebuild and have a few bugs to work out. Working on that car is like stepping back into another time.

The correlation between the IP and throttle body isn't linear and it's actually progressive. If your IP is at 30 degrees open, the throttle valve is going to be more like 40 degrees open. As the IP and throttle valve both come to full stop, wide open, they again match in degrees of movement. MB figured out that you need a rich mixture at idle and also at WOT. During mid range driving, which would cover almost all of your trip, they increased mileage and performance by leaning out the mixture to 14.6: 1 , or at least very close; all done through throttle valve opening angle. Those clever Germans.