Timing M130 Engine

[alchemist]

I have 1967 230 SL with M130 engine. The original engine was replaced by the previous owner along with the distributor (aluminum) and R20Y FIP. The original 230 ignition system was replaced with Crane transistorized electronic ignition. I timed the engine at 8 degrees BTDC at 800 RPM without vacuum. The engine idles well at this timing without the vacuum. However, when I hook up the vacuum, the engine misfire and it does not drive well. I had a similar experience with 1972 250C for which crane electronic ignition was installed over 10 years ago. This car is also equipped with M130 engine. The car runs and drive well with no vacuum, and it misfire if the vacuum is hooked to the distributer. Apparently, the vacuum is advancing the timing to cause the engine misfire. I wonder if any has similar experience and if any has an explanation or a fix for this problem.

[ctaylor738]

I am wondering if your engine has the 230 throttle body.  If so, you should look at footnote 4 from the 1966 Technical Data Book (attached).  If so, at 8 BTDC, you are too far advanced.

Also, if you have the triangular timing pointer and the dual scale on the balancer, be sure you are reading off the inside scale.

Good luck,

CT

[alchemist]

Thank you Chuck, I do not have the 230 throttle body, I have the 280 one. the manual is very helpful, that may solve 2 of my Mercedes timing.