Thank you for your forbearance of my seemingly endless questions.
In my efforts to achieve perfect idle, perfect starting and perfect running, I recently stripped down my distributor. I have an early 250 SL from 1967, so have the JFUR(6) type 051 with vacuum retard.
I stripped it all down and cleaned and checked everything, which was all good due to only 60,000 miles from new.
Once cleaned and lubricated, I re-assembled it, but on running the car, I found that I had somehow lost about 6 degrees of advance /retard.
When I set the timing to 38 BTDC at 3,000 rpm as per Dr Benz advice, I found that I had around 14 BTDC at idle, rather than my previous 8 degrees. This is not a huge issue in itself as the car rarely sits at idle in neutral or park, but the excess advance produces a rough idle in gear when under the influence of the constant speed solenoid.
The vacuum retard seems to be working OK and sucking by mouth on the vacuum tub does move the plate, so I am wondering if I have inadvertently assembled the distributor’s internals incorrectly.
The one area I was not entirely clear on was how the centrifuging weights and advance plate fit together. Referring to my image, how should the weights and the little counter rotational springs be placed, prior to the advanced plate being lowered into place? I assumed the springs would go on the outer side of the pins, and the weights help inboard while the plate was lowered. I found this very tricky so suspect this is where I may have gone wrong. I did work out that the advance plate has different length pins, so can only be installed one way, so wondered what the R and L signified.
I am missing something really obvious here?
