Thanks Stickandrudderman, Not sure how I got into this one. I'm new here but bought my first Benz, a 190sl, in 1970. Unfortunately it was from Germany and the body was mostly bondo and I could not get over the drop pedals and 90 HP 4 banger. But the overhead cam, tuned intake, tuned exhaust, and beautiful dash cause a viral brain infection. I was part time working my way through school as a foreign car mechanic at the local college: Stanford. A wide variety of european and japanese cars to play with. in 72 I snatched my 250SL for $4200. Bought a full set of manuals and tore it all apart and rebuiltnearly everything. I've learned a lot from mistakes, but living in Coopertino CA, I easily located a few real experts who were grateful to share correct wrenching tips to a neophyte who appreciated the expertise and engineering excellence that went into 1960's Benz's. I've owned nothing but Benzs since and I do all my own work and work on a few friends cars. Its a passion / hobby with no end, there is always some new challenge, sometimes self-inflicted.
Here is just one example: My wify borrowed the sl one day and fried the motor, Exactly what happened has never been fully disclosed. Her 280sel was hit from behind, smashed into the car in front while stopped at a light, totaled the sel. Hense, the need to borrow the sl. So I eagerly swap the 250 with her totaled 70 280sel motor.
Why? The 250, while much better than a 230 motor, just never accelerated as much as I need. The 280 was better, but had a mis-adjusted FIP, running too rich according to work orders from the prior owner and many things, even valves where tried, but nothing directed at the FIP. I've played with the FIP adjustments for about 20 years now. off an on for years with tail sniffers all with no repeatability. I stumbled onto an air/fuel /O2 sensor/meter that does repeat and really dug into fine tuning the FIP. It is, just today, pretty close to perfect and accelerates a bit quicker that I hoped. It feels more like low 200HP. Impressive! It still has the 250 pressure plate and disk and on these 110 degree days at 75 mph if I floor it the clutch will slip, next project: will a 280 pressure plate bolt to a 250 flywheel? and take the torque of this reborn 280 beast.