Good Day all; I have a question about the ignition timing on my 1981 380SL. Would some one please tell me what is the maximun ignition advance this engine can safely tolerate? Stock setting is 5 degrees BTC, but I would like to go as much as 10 degrees BTC. I run nothing but premium 92 octane and perhaps some Jectron once in a while. I also have a MSD ignition installed with intake and exhaust upgrades. Thanks for all your replys. -JK380SL (formally Jim380)

Timing...
 

I really am greatful for this resource and I know people are busy but would someone please answer my earlier post about ignition timing on the 1981 380SL? Is 10 dg. BTC O.K.? -Jim

I am of the opinion that as long as you are not
 

experiencing any "pinging" then you are probably ok. Keep it set where you do not experience you could eventually melt the pistons.

Hang loose and get an answer from one of the techs too though.

Jim
'85 300D
'95 E320
'97 CRV

Thanks, I'm experimenting with it now. I can't hear what's going on under the hood due to such good insulation. Will pinging be very audible? -Jim

Reading from the 1981 TDM (a great book at 25$ plus shipping)...

The european versions of the 116 motor show distributors 0 237 404 003 & 0 237 405 014 being set to 30 degrees at 3000 RPM WITHOUT vacuum (disconnect and plug BOTH lines). This presumably gives you TDC +/- 3 at idle or 15-19 at 1,500 RPM (both w/o vacuum).

Compare that with the US version with distributor 0 237 405 021, which is set to 5 BTDC at idle WITH vacuum, and should reach 10-14 at 1,500 RPM w/o vacuum.

So, you probably can get that extra 5 degrees. You may need to explore how the US distributer is different from the Euro. Not to mention the Cams and other control items on the engine.

I know the european motors have code 60/61 cams where as the US motors have code 62/63 or 68/69 cams. That implies different valve timing.

-CTH

Thanks cth350. What is the "TDM"? -JK

The technical data manual. It's put out every year and has all the specs you'd ever want to see for every benz in production that year across the planet. It covers recent years as well, some more than others.

The parts shop should be able to sell it to you. If not, try mercedes directly at 1-800-for-merc.

-CTH

you would hear the pinging
 

without a doubt.
Jim
'85 300D
'95 E320
'97 CRV

You can't miss a baby rattle that big, unless of course, you like to really blast your stereo.

-CTH