Basic Timing Question

[n/a]

A couple of weeks ago, I was able to set the timing exactly as the BBB stated - 8 degs. BTDC. However, I when back to check it the other day after adjusting the fuel/idle air the car was at 27 deg BTDC, then when I unplug the vacuum connection on the manifold and reconnect the vacuum line to the distributor the timing moves to 8 degs BTDC. Am I missing a step or something in the timing process? The BBB states that for 051-distributor timing should be 8 degs BTDC without vacuum. I can only get that with vacuum connected - when I disconnect the vacuum and plug the manifold vacuum line and rotate the distributor to 8 deg. BTDC, then reconnect the vacuum line to distributor the system retards so much that the car stalls. What am I missing - I know it's got to be something simple as it was set the other day!

I'm never touching the idle fuel/air again, this time I mean it!!!!!

Thanks


Scott
1966, Signal Red, 230SL

[Cees Klumper]

Are you sure your distributor is correct for your engine? I was able to adjust my timing in accordance with the specs without any problem, disconnecting the vacuum line right at the distributor (no plugging the manifold/line). A seemingly-knowledgeable Mercedes mechanic told me last year he fine-tunes the timing simply by listening to the running of the engine ...

white 1969 280 SL

[Ben]

On my '64 230SL the owners manual says it cannot be set statically and should read 26deg. before TDC at 3000RPM. It doesn't mention what the setting is at idle. I used a strobe lamp, got someone to sit in the car and hold it at 3000 while I set it.

Thing is the pulley doesn't apear to have an exact mark it shows what I believe to be 20,30 & 40 degrees. I guessed at 26 !

Hope I'm right but the car is driving very well and there is no pre ignition which there was before. I had to readjust the idle settings and recheck the timing a few times to ensure the idle was sweet.

Now it idles at 800 DEAD and pulls like a train !  

First time in 2 years its running this good !

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

[Naj ✝︎]

Scott,
Check your distributor. My guess is its an '046' in which case the '051' settings do not apply.
naj

naj
'Kloines Scheisserle'
65 230SL
68 280SL

[Albert-230SL]

Hi Scott,

Depending on the engine number of your 230 SL, it's supposed to work with vacuum advance or with vacuum retard, and the vacuum port of the throttle body/manifold has to match with the distributor:

--- 230 SL UP TO ENGINE 10786 (manual 10/20), and 2990 (auto. 12/22):
VACUUM ADVANCE (Vac. port on top of the throttle body - as in the attached photo)
- Distributors (Bosch references): VJUR 6 BR 49, 0231 116 046, 0231 116 050.
Note: Bosch 0231 116 046/050 is now replaced by 0231 185 007, 0227 100 911


--- 230 SL FROM ENGINE 10787 (10/20) and 2991 (12/22):
VACUUM RETARD (Vac. port on the lowest part of the throttle body)
- Distributors (Bosch Ref.): 0231 116 047, 0231 116 051.
Note: Bosch 0231 116 051 was replaced by 0231 185 009

Hope it helps you to check if you have the correct distributor+throttle body for your car.

Best regards,

Download Attachment: Vacuum advance port.jpg
15.45 KB

Albert de la Torre Chavalera
Barcelona (Catalunya/Spain)
Feb.'64 230 SL Euro 113042-10-002432

[n/a]

Albert/all:

It appears that I have the correct distributor/engine/throttle body combo.  The distributor is an 051, the engine number is 13,945 and the Vac. port is at the lowest part of the throttle body.  

A Bosch tech told me recently that the timing should be set at 2 deg BTDC w/o vacuum; not at 8 as stated in the BBB.  I can't check it right at the moment as my lady is at the shop having a new soft top put on.  Plus, I don't think that could be right as she always stalls when I reconnect the vacuum at anything less than 15 deg BTDC.  At this point I'm lost, not sure what to do.

Scott
1966, Signal Red, 230SL

[George Davis]

Scott,

from the MB Tabellenbuch, edition 1969:

230 SL, 250 SL and 280 SL, through 1969,
with distributors 0 231 116 051; 0 231 301 002; 0 231 301 004; or 001 158 02 01

Installation spec: 8 degrees BTDC at cranking speed, with spark plugs removed and vacuum disconnected.

2 +/- 1 degrees ATDC at idle speed, vacuum connected;
12-19 degrees BTDC at 1500 rpm, vacuum disconnected;
30 degrees BTDC at 3000 rpm, vacuum disconnected.

For those with an 046 distributor, those have different specs, not in the Tabellenbuch.

George Davis
'69 280 SL Euro manual

[Naj ✝︎]

Scott,
I've been thinking! (Yes again!!)
The advance weights inside you distributor may be 'sticking'.
If this happens all the time, maybe you should consider a rebuild.

naj

naj
'Kloines Scheisserle'
65 230SL
68 280SL