Valve-guide Seal Replacement Question

[wrwetzel]

Greetings,

The New Jersey Division of Motor Vehicles claims that my 1986 325ES (mileage about 210,000) is smoking. I can see a small amount smoke that disappears a few feet from the exhaust pipe suggesting only water vapor but I need to deal with it. My plugs are pure white but do show some white deposits built up on one side of the insulator suggesting I might be taking in oil through the valves as opposed to the rings. I though I would start by replacing the valve-guide seals.

Bentley says that the head must be removed to replace the seals. I have done it on other cars with the head on by bringing the piston up to the top on the cyllinder to prevent the valve from dropping.

Does anyone here have any guidance on replacing the seals, especially can it be done without removing the head and without removing the intake manifold? I have various valve spring compression tools and an air-compressor I could use to pressurize the cyllinder to keep the valves closed.

Thanks,
Bill Wetzel

[njtech]

It can be done in the car, but you will have a problem with the rockers being that they are shaft mounted. Instaed of air I would try a cloth rope to fill the cylinder and hold the valves. With 210k on the clock, I would pull the head do the guides, seals, gaskets, t-belt as well if you are going to keep it.

[e30fanm3]

yea you have to take the head off and tear it apart

[doug davis]

You can replace valve seals on an M20 with the head on and engine in car, but it is VERY difficult and not worth the effort. I tried it a couple of months ago and was too bullheaded to give up in the middle of the job and take the head off.

At the very least, it will take about twice as long and you will most likely have to buy new rocker shafts (I ruined mine beating them out).