Nissan Repair: 86 hardbody z24 problems, excessive blowby, cam followers

Question
First off, when I try to start the truck the key stays in the start position, it doesn't spring back into the run postition.  Next, sometimes it starts and other times it just clicks.  Tried with fresh battery with same result, but it will roll start.  I think that might be the nuetral safety switch.  And the big problem is, when the engine is running it has a tick in the top end and when driving blows lots of white smoke.  There is oil around the throttlebody in the filter.  The coil has a crack in it.  The truck is full of oil, and it is not milky.  Haven't read the plugs yet.  Any suggestions on narrowing it down?  Thanks in advance.

Answer
First, the ignition switch has to be replaced since the return spring is broken.  Second, I would think the switch is allowing the battery to run down and that is where the clicking and intermittent starting is coming from.  The tick on the top end is probably the valves need the cam followers adjusted.  Look at the hood and there should be sticker with the hot lash settings for the valves.  .014 / .015 inch is usually in range.  The oil is probably the rings being blown and the excessive blowby is getting into the filter and coming out the exhaust.  You need to do a compression test to see if the rings are gone.