Valve Stem Seals Sucessfully Replaced
I just finished replacing the valve stem seals on my '88 260e and it went flawlessly thanks to the help from this board.
I used the compressed air method described by Dennis about a month ago using 100 psi air and holding the crankshaft from turning with a wrench on the crankshaft bolt. Looking thru the spark plug hole with a flashlight, I turned the engine to a little past TDC- until I could see the piston just starting to go down, and then put a big 27mm socket on the crank bolt and braced it against the garage floor. I figured with the piston up high, I wouldn't lose the valve if my air compressor quit or something. When I let the air into the cylinder the engine tried to turn and I could see the wrench tighten up.
After removing the spring from each valve, I shut off the air and checked the play in the valve guides. There was a little play in each one but not too bad yet. The valves moved down only about 1/4" before hitting the pistons. No chance of losing the valves with this repair method but this is definitely an interference engine.
The only problem I had was with the No.6 cylinder. I could not see into the cylinder and had to use a long thin screwdriver as a "feeler" to check for TDC. I also had to loosen the trans. dipstick because it was in the way of the valve compressor tool.
After compressing the springs, I had to rap the valve spring tool with a hammer to free the keepers.
Had to be very careful handling the small keepers and rocker shims because I think they could fall down into the oil drain holes in the head. I used foam ear plugs to temporarily plug the drain holes but it's very important not to forget about the plugs and leave them there.
I also sealed the upper timing cover and replaced the serpentine belt.
Thanks everyone for the excellent help and advice, and Fastlane for getting all the parts to me so quickly.