Diff in Distributors?

[TheEngineer]

What is the difference in distributors 0231 116 051 and 0231 185 008?
What I found so far: 008 has an aluminum body, 051 body is steel painted black.
The points in 008 face the opposite direction.
008 used on 230SL and 220SEb.
008 is replacement for 051.
I do have the graph for centrifugal advance and vacuum retard for 051 (it's in the work shop manual) but do not have the graph for 008. Does anyone have it? And is the info I have correct? Is there any benefit installing one or the other? I found a notation that 051 was installed to meet US emissions.

[Tyler S]

They can be interchanged however the throttle body also needs to be compatable. The 051 distributer uses manifold vacuum from just behind the throttle plate. Need to check if the 008 does as well or if it uses ported vacuum. The emissions portion of the 051 being that retarding the timing at idle and decel helped with US tailpipe emissions laws.

[Benz Dr.]

The 051 unit uses vacuum retard but the ignition should still be about 8 degrees BTDC if you have everything working right. Vacuum retard gives a stronger signal on deceleration but it has little to do with emission controls. The 062 uses ignition retard and it does affect emission controls. Easy to get all of this stuff confused.

[TheEngineer]

Hello Dan!
A very very happy New Year to you! You are the one who would know everything about distributors. I have a 051 installed and a 008 laying around. The 008 has also vacuum retard - I can see that much, but I can not tell how much retard in terms of degrees of crankshaft and of vacuum applied. Also, the advance curve of the centrifugal weights may be different. In my workshop manual - the one from the factory (in German) it shows the graphs for retard and advance for the 051 distributor and I had hoped that someone has an older book that shows the graphs for the 230SL because the 008 distributor was used. You may just be the man to have it. I know you are very busy and there is no hurry. I can always hang the 008 in there and measure advance & retard and see how the car performs. The engine is a little different now because I installed a 09 camshaft. It is a small base circle, high lift cam and gives me 7.5 mm valve lift together with longer valve open timing. It very much improves engine performance - I seem to get much more torque. We have hills here and I have much experience with how fast the car goes on selected hills. With the new cam it goes much faster but it does not idle as smooth as with the 08 cam. I am just experimenting! And I was wrong about having no leaks after I installed the engine - I found a few after running a while.
Happy New Year! Live long and prosper!

[Naj ✝︎]

I don't think the '008' is meant for a Pagoda. It was a supersession for the 0 231 116 049 both of which have a different advance curve to the '051'. Also, the points facing 'the other way' would suggest its a vacuum advance distributor.

It would be interesting to learn if you have a vacuum advance or vacuum retard throttle body.
The differences are discussed in the wiki and elsewhere on the forum.

naj

[TheEngineer]

Hello NAJ!
It is a vacuum retard - no doubt about it. And it is more recent than 051. It has vented points and the geometry of the points are "an opposite" of the points in the 051. The 051 (and most others) attain full centrifugal advance of 20 degrees at about 2200 rpm and full retard of 10 degrees at about 300 mm Hg. There are test benches for distributors and I may look for an availability locally. I suspect it would not make any difference which distributor I'd install.

[66andBlue]

....
008 used on 230SL and 220SEb.
008 is replacement for 051.
I do have the graph for centrifugal advance and vacuum retard for 051 (it's in the work shop manual) but do not have the graph for 008. Does anyone have it? And is the info I have correct? Is there any benefit installing one or the other? I found a notation that 051 was installed to meet US emissions.

Hello Peter,
as always the devil is in the details. Here some details:
1. The 1963 230SL had a distributor with the very old Bosch number VJUR 6 BR 49 TMK = 0231116040
2. For the 1964 230SL the "letter numbering" changed to the JFUR 6 series = 0231116046
3. Here are the strobe values and curves for the VJUR distributors from the 1959 workshop manual (actually the one you sold to me many years ago  )
See: image "strobe values" and "VJUR_striibutors"
4. Searching the Bosch Classic Archive brings up information that was current as of 9/1975 in a PDF (0231116):
5. That PDF shows the number for the distributor that you have at hand 0 231185 008 and what it replaced (that is: 0 231 116 049) and also shows that a 0 213 116 051 was replaced by  0 231185 009. Apparently the "008" is NOT a direct replacement for the "051".
Let me know if you want large sized images.
Hope this helps a bit but it is now up to you and Naj to find out which one is "retard" or "advance", I pass on that issue.

Happy tinkering!

[Benz Dr.]

The 051 is the most commonly used distributor on a 113. 230, 250 and early 280SL all used this unit. The mechanical portion is about 20 degrees and the vacuum portion about 10 degrees. I adjust the vacuum pull rod to obtain the full 30 degrees of movement regardless of where each portion starts at during my testing. So, if I have 19 degrees mechanical and 9 degrees vacuum, I adjust the pull rod about one full turn and then I test it on my machine until I see 2 more degrees - it is possible for me to get it that close. The later 062 is preset and the vacuum portion can not be adjusted. It should be noted that on the 051 unit, the vacuum will always advance first and will be full by about 1,500 RPM. Mechanical usually starts about 1,200 RPM and will normally finish at about 2,800 RPM. The notation that you should have 30 degrees at 3,000 RPM is only for distributor movement and you must also add about 8 degrees of idle speed timing which is present before your distributor begins to advance.

The mechanical portion can be adjusted to slow down or speed up by moving the arms that hold the springs. This requires a complete disassembly of you distributor so I would not do that unless you know how to do it. You can also bend the arms in or out slightly without taking anything apart which will fine tune down to about 100 RPM differences as to when advance starts. However, you really need a tester to do this because you will never see that small amount at your degree markings on the end of your crank. Also, the crank spins at twice distributor speed so small amounts are hard to see. My tester runs at distributor speed so I can see advance movement down to 25 RPM or less.

Different advance curves are mostly a result of different flyweights and their response to centrifugal force. The most difficult unit to set up is the early VA unit used on a 230SL. This advance curve is almost straight up. Too much tension on the springs and it opens tool late and too little makes it open too quickly. It can take a lot of trial and error to get it right. This is just one of the reasons why an early 230SL will make more power per liter than the 250 or 280 SL.

[Naj ✝︎]

Hello, Peter,

Sorry to disappoint but as Alfred has shown, the '008' is a replacement for the '049' which was a vacuum advance distributor.

Not interchangeable with your '051'

naj

[TheEngineer]

Hello Naj:
My sincere apologies! I really screwed up! The distributor is 0-231-185-009! My big mistake. My eyesight is not so good any more and at age 85 maybe you can accept that as an excuse. So I put the 051 back in. I set it to 30 deg. before TDC at 4000 rpm and when I connect the vacuum line it the strobe indicates just about TDC at 700 rpm idle. I don't think I'm going to adjust the threaded rod on the vacuum retard module to obtain 8 degrees after TDC because - and correct me there - it is only an emission requirement and the vacuum goes away as soon as the throttle plate opens, which it does when the constant speed solenoid extends to adjust for the drag of the A/T when I put it in gear. I found one spark plug connector to have 70 kilo 0hm resistance, all the others are about 1 k ohm, as they should be. When I changed to different connectors the slight humping at idle went away. I am using solid copper wires and have not been able to dis-assemble the metal spark plug connector p/n 0-356-30-10-22. Is there a trick to it?
All you guys: Thank you so very much for your help!   

[Jonny B]

The wire for the spark plug connector should just screw out of the connector. There is a wood type screw at the bottom that the wire is threaded onto. Should be able to just twist to get it out.

http://www.sl113.org/forums/index.php?topic=10772.msg74962#msg74962 has some good illustrations.

[Benz Dr.]

Hello Naj:
My sincere apologies! I really screwed up! The distributor is 0-231-185-009! My big mistake. My eyesight is not so good any more and at age 85 maybe you can accept that as an excuse. So I put the 051 back in. I set it to 30 deg. before TDC at 4000 rpm and when I connect the vacuum line it the strobe indicates just about TDC at 700 rpm idle. I don't think I'm going to adjust the threaded rod on the vacuum retard module to obtain 8 degrees after TDC because - and correct me there - it is only an emission requirement and the vacuum goes away as soon as the throttle plate opens, which it does when the constant speed solenoid extends to adjust for the drag of the A/T when I put it in gear. I found one spark plug connector to have 70 kilo 0hm resistance, all the others are about 1 k ohm, as they should be. When I changed to different connectors the slight humping at idle went away. I am using solid copper wires and have not been able to dis-assemble the metal spark plug connector p/n 0-356-30-10-22. Is there a trick to it?
All you guys: Thank you so very much for your help!

30 degrees is how much your distributor advances. Add another 8 degrees at idle for a total of 38 degrees @ 3,000 RPM. You are loosing a lot of power if you're only at TDC at idle.

[TheEngineer]

Dr. Benz wrote:30 degrees is how much your distributor advances. Add another 8 degrees at idle for a total of 38 degrees @ 3,000 RPM. You are loosing a lot of power if you're only at TDC at idle.
I measured: Centrifugal advance at 3000 rpm is 20 degrees. Vacuum retard at 300mm Hg is 10 degrees. Distributor is 051. Vacuum is only present at idle because as soon as throttle plate opens it goes away. Centrifugal advance remains constant from about 2500 to 4500 rpm (not tested at higher rpm)
The shielded spark plug connector did unscrew from the wire, just not as easily as the bakelite ones. The wire really sticks to the rubber boot. I plan on using Dow#7 when I get another one. Thank You!

[Benz Dr.]

Dr. Benz wrote:30 degrees is how much your distributor advances. Add another 8 degrees at idle for a total of 38 degrees @ 3,000 RPM. You are loosing a lot of power if you're only at TDC at idle.
I measured: Centrifugal advance at 3000 rpm is 20 degrees. Vacuum retard at 300mm Hg is 10 degrees. Distributor is 051. Vacuum is only present at idle because as soon as throttle plate opens it goes away. Centrifugal advance remains constant from about 2500 to 4500 rpm (not tested at higher rpm)
The shielded spark plug connector did unscrew from the wire, just not as easily as the bakelite ones. The wire really sticks to the rubber boot. I plan on using Dow#7 when I get another one. Thank You!

20 degrees of mechanical advance is right on for a 051. Add 10 degrees of vacuum retard and you have a total  of 30 degrees of timing movement on your crank shaft. Vacuum is present at idle on a 051 distributor and quickly lowers to zero as you open the throttle. At idle, the vacuum cell is pulled to the zero position and as you open your throttle the diminishing vacuum signal is overcome by the spring behind the vacuum cell. This makes the vacuum cell spring forward against rotation a total of 10 degrees. When you close your throttle ( idle position ) vacuum is again applied to the vacuum cell which then pulls the advance plate inside your distributor in the direction of rotation to the zero position which is also know as vacuum retard.

One of the advantages of this system is a strong vacuum signal normally available at idle. Our engines should easily produce 18 -22 inches of vacuum at idle and it only takes about 6 - 8 inches to fully move a vacuum cell to the zero position, or in this example, no indicated advance. Since vacuum movement happens first as you throttle up, you will get an instant timing advance followed by mechanical advance ( from the fly weights ) that starts around 1,200 - 1,500 RPM. Even at higher engine speeds, releasing the throttle to the idle position will give you an instant 10 degree ignition timing retard which may help in reducing back fire in your exhaust.

I don't know if back fire reduction is factual or not ( just a guess ) so maybe others can comment on that.




 

[TheEngineer]

The backfire, which was so prevalent with the other engine, has apparently completely disappeared, but I have only 77 miles on the new engine with the high lift cam. We shall see after a while. I re-used the old injection pump and it has a fuel shut-off solenoid that is actuated by a switch on the throttle linkage: When the throttle is not depressed the switch closes and there is an electronic circuit that measures engine RPM, the book says - and I am quoting from memory - when the engine rpm falls below 1,100 it energizes the solenoid again. Meaning, when I coast downhill, fuel is completely shut off. So far the car appears to run fine with a lot of power. The test will come when the mountain pass roads are snow free and I can chase the car uphill without going much over the 70mph speed limit. We have a 3 lane road going up to Snoqualmie pass at 3000ft. So far, I have been driving without the hood and I got funny looks. I tell people: "got the car for half price because it has no hood" Yesterday I put the hood back on. Is that a good sign?

[Rolf-Dieter ✝︎]

All I know is "you are not at a dead end" your car is ready to take you anywhere I know for they love to be driven, the more you drive them (I'm sure you know this very well) the better and smoother they drive.

Love the pic with the Dead End Sign

Dieter

BTW. If you meet the people again that you told you got her for half price, will you tell them then you had to pay the rest? ~grin~