Nissan Repair: truck dies, nissan pickup, optical pickup

Question
hello I have a 1984 nissan pickup 2.4 motor.  It's got about 249,000 on it and is a good running truck but recently it's started to stall out.
What happens is I rarely drive it, maybe a couple of times a month to the dump or when I need to.  
Everything goes normal when I first start out, runs good no problems but after I have gone say about 30 minutes of driving something I think heats up and then causes my truck to die then I have to let it set for about an  hour before it will start back up.
After it dies it turns over etc.. but act like it's not getting any spark to start the motor.
Can you give me some advice on what you think might be the problem?
thanks
dave

Answer
Dave,

Check the distributor for oil getting past the seal into the optical pickup.  That is what it sounds like to me.  Take the cap off and the rotor off and the center post the rotor sits on and then the cover on the base of the distributor.  Just make sure you remember how it goes back together.  You will notice oil on a disc under the cover if it is bad.  If so just get a rebuilt one and you are good to go.