I needed to change the oil in the bus before the next trip, so I did some research on who used what oil and why. What I discovered is that the government has made the motor oil producers to eliminate the Zinc and Phosphorus used to assist in extending the life of the motor. This was done to extend the life of the catalytic converter. Newer motors are now built so these materials are no longer necessary in the oil, but what is a person with a 30 to 40 year old motor to do? What I learned is that there are a couple of choices. One is to purchase ZZDP additive, or buy Brad Penn Oil. This is the old Kendal 1 oil according to the man at Knapp Energy in Kalamazoo, where I purchased the oil. Brad Penn was the consensus choice too. I used 20W-50 in the bus because I noticed that when the engine was hot the oil light came on at idle. The thicker oil took care of that issue.
Changing the Oil