Idle is smoother after some work (long)... (archive)

1. Adjusted valves (to a "tight" 13 thou - engine cold)
2. Checked spray bar bolts (had about 3 ft lbs on them, not loose, but not tight either. They are original w/ the car. Newer bolts have a "o" on top, mine don't)
3. Changed spark plugs. Used the Bosch WR9LS. Opened the gap from 0.7mm to 0.77mm since many claim this helps smooth the idle.
4. Changed valve cover gasket
5. Changed rubber hose that runs from valve cover to throttle body (~3/4" diameter hose w/ small vacuum hose coming off the bottom.
6. New air filter.

The result of this was a much smoother idle. Not perfect, but about an 80% improvement. I don't know which of the above was the biggest factor. The old plugs had >0.8mm gap, but were in very good shape. Slightly tan/gray, no oil, though.

I now hear the valves ticking slightly. Before this, I don't remember hearing the tick, but didn't pay a whole lot of attention to it. Some of the valves were <0.12 before I adjusted them (cold engine).

Anyway, wanted to share my experience. This was my first time doing this type of work and this board (and Bentleys) sure help a lot. Thanks to all of you that post such good information.

Doug
'87 535is
(what's next? SS brake lines? New big rotors? Turbo?)

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