w126 280se: noisy valves and high fuel consumption.....help!
 

Noticed a high oil consumption with corresponding smokey exhaust. Since the car has only 150,000km on the clock, the assumption was that of leaking valve seals, which were changed.

It no longer consumes oil, but the valves were noisy despite a readjustment after running in. Furthermore, since the valve seal change, fuel consumption has worsened from 6km/L down to 5km/L....a 16.7% change city cycle.

The valve clearance were decreased to below factory spec (factory spec 15/25, down to 15/20, and finally 10/20 {Inlet/Outlet}) as measured in the cold state. This helped the noise somewhat, but has not changed the fuel consumption.

The question is whether to:

1. Change the rocker arms, and restore the clearance to original spec (relatively simple and cheap fix), or

2. Do a top-end overhaul and convert to running unleaded at the same time by changing the valve seats and valves in addition (more work and more cost, but hopefully a more permanent and definite fix)?

Would appreciate any input. Thanks!


Kenny

1983 W126 280se
1983 W123 200