[AkkerKid]

I was looking for any possible reason my engine was idling high and shaking quite violently at idle. (I found out I had an open vacuum port on the intake manifold where the tube to the smog valve was disconnected.) One place I looked was to see if there were any burnt marks inside the distributor. Under the distributor rotor and dust cap, I noticed there are small weights. I think they're for advancing the rotor at higher RPMs. Above one of them is a spring that would hold the rotor in the lower RPM position, but it looks like there should be two springs doing that. Without that second spring, my rotor could be advancing too soon. (And the dizzy could be slightly off balance) Can anyone confirm whether there are supposed to be two and if those springs come in different tensions? Image here.

 

[liviu165]

Only one spring.

 

[Lagonia]

My 560 87 SEL distributor also only has once spring and the car is doing ok (imperceptible/intermittent idle miss that I am currently attributing it to the fuel distributor since everything else relevant is either replaced or fixed). *HOWEVER*, I was in the junk yard the other day scavenging parts from a 89 560 SEL and decided to scavenge the distributor. That distributor does have two springs making me wonder..... I'll go in the shop at the end of the day and take a pic and post...

I have posted a relevant thread sometime back but no bites other than one spring is normal:
http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/2820866-w126-560-sel-how-many-springs.html

 

[John350]

Different springs, different advance curves. Make sure the distributor you are looking at is the one that belongs on the engine. There could easily be different configurations for the same engine in different years.

 

[liviu165]

On Gen 2 the advance curve is in the EZL. The spring does not dictate the advance curve, it just advances the rotor enough to insure the voltage transfer between the rotor and the corresponding pole in the cap so no electrical arc occurs inside the cap as the advance is determined by the EZL.

According the EPC, the 560s and the 420s use the same distributor assembly. Mine has one spring too.

 

[Lagonia]

Distributor Pic

This came out of a salvage car with VIN: WDBCA39E0KA497315 manufactured August, 1989

 

[liviu165]

Here is the content of mine ('89 420SEL).

 

[GreenT]

My 1990 has two.

From Ebay, P/N 003 158 3401

Mercedes W107 W126 Distributor & Cap Unit 0237505003 500SEL 560SL 560SEL 86-91 | eBay