Author Topic: 450se tachometer into 280s  (Read 1052 times)


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450se tachometer into 280s
« on: 17 February 2010, 03:11 PM »
I am aware that this question must have been answered a few thousand times, but i still don't get it:

Can i buy in ebay a whole instrument cluster from a w116 450se to use in my w116 280s?
Will the 8 cyl tacho work in my 6 cyl 110?


TJ 450

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Re: 450se tachometer into 280s
« Reply #1 on: 17 February 2010, 04:49 PM »
I think the issue is that the tach runs off the coil input. Of course, a 6 cyl engine fires six time per revolution and so on. As MT stated in another post, the tach would need to be set up to account for this difference.

I have no idea how you would go about doing that, though, as I haven't looked at the circuits of these tachs in detail.

1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500


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Re: 450se tachometer into 280s
« Reply #2 on: 17 February 2010, 08:37 PM »
TJ's right.  No idea how one can be converted but basically an 8cylinder tach counts every 8th pulse and a 6 cylinder tach, every 6th pulse.

Further to that, the gearing behind the speedo/odo will be different too I presume.  I've compared a 280 and 350 speedo/odo and that was the case.  So look for a 280 tacho and or a complete 280 instrument cluster.
1973 350SE, my first & fave