Question about '82 380SL coil... - PeachParts Mercedes-Benz Forum

Richard Wooldridge · #1 12-04-2008, 11:27 AM

I'm looking for reassurance here - last week my '82 380SL quit running while I was going down the freeway at about 60 mph, just like the switch was turned off... I immediately took the next exit and made it most of the way up the off ramp, where I waited until my brother and his friend came and towed me home with his car dolly. I took the ignition control unit apart and found a bad output transistor, which I changed out, using a horizontal output transistor, type 2SD1175, which is rated at 1500 volts, 5 amps, and has a clamping diode internal to the case. Well, when I tried it the car wouldn't start, and upon further examination I discovered that the coil was shorted. I replaced the coil with one I had on hand, from a 1977 Nissan 280Z. The new coil looks just like the old coil except for the mounting bracket. The car once again runs beautifully, but my concern is whether the 280Z coil is really a match for the 380 coil. The parts listings all show that the 380SL coil only fits years 82 - 85 380SLs, and a couple other mercedes models, and nothing else.
Tomorrow I'm going to put about 400 miles on the car, and want to make sure I have an appropriate coil installed. The 280Z also had an ignition control unit somewhat similar to the 380SL, but other than that I don't know the specs. Can anyone offer meaningful advice here? (I could order the correct coil but it won't arrive for at least a week.)

Richard Wooldridge · #2 12-04-2008, 03:02 PM

I may have answered my own question - a look at the substitute coils listed for the 380SL shows that the coil's primary resistances are listed as being from 0.6 to 0.9 ohms, and the 280Z coil's primary resistance is also in that range. So I think they should be swappable. I have another ignition control unit on hand, a hueco "functionally equivalent" unit, so I think I should be ok for my 400 mile trip tomorrow.