Camshaft Timing Specs 1970 280SL

[dkalfadoc@aol.com]

I am looking for the intake and exhaust valve opening and closing points for 1970 280SL/8 with an 01 camshaft.  The Haynes manual has them listed as I.O. 16 deg. BTDC, I.C. 46 deg. ABDC, w/ 242 deg. duration, E.O. 53 deg. BBDC, E.C. 15 deg. ATDC, w/ 248 deg. duration.  The valve lash is measured between the cam and the rocker at .003" intake and .007" exhaust.  After just rebuilding the engine, the crank pulley lines up with 0 deg. mark and the camshaft thrust washer mark also lines up while both lobes are pointing up.  The measured timing is as follows; I.O. 40 deg. BTDC, I.C. 65 deg. ABDC, w/ 285 deg. duration, E.O. 63 deg. BBDC, E.C. 19 deg. ATDC, w/ 262 deg. duration.  An offset key was used, set to retard the timing.  Can any tell me if the Haynes numbers are correct, if they aren't, what are the correct numbers?  Having set it up with the correct lash, why is there 40 deg. gain in duration on the intake and 24 deg. advance on the opening, while the exhausts closing was retarded yet gained 14 deg. duration.  Any insight would be helpful.

thanks,
Dave

[wbain]

Hi Dave

I have a 1970 Chilton's (Glenn's) hardback manual from 1970. On page 62 is a table of Valve Timing Figures. The table includes the 190Dc thru the 300SEL 6.3. There is no seperate 280SL/8 listing but the 280SE/8 will be a close fit. Camshaft code 01, stamped on the end, is not listed in the table.

Code 0835 is listed foe 280S/8, 280SE/8 and 280SEC/8 and shows:
Intake Valve opens BTDC 11 degrees. and closes 47 deg ATDC.
Exhaust Valve opens BTDC 48 deg and closes 16 deg ATDC.

Code 0935 is listed foe 280SE/8 and 300SEL/8 and shows:
Intake Valve opens BTDC 12 degrees. and closes 56 deg ATDC.
Exhaust Valve opens BTDC 53 deg and closes 21 deg ATDC.

The timing events may have been reset to shift the power band up or down the rpm range. I know one way shifts power down to have more lower end torque. I can look up the offset direction in my engine rebuilding textbook. I can't remember which way does what.

The Technical data book has the correct info and I suggest you get one from Mercedes.