I have 97 4Runner that has what seems to be a great engine with only 117k on it, but the trouble is the frame is all rotted out and there are numerous electrical issues. OK, so I am looking at another 98 4Runner in pretty good shape but that one has a motor with 170k on it. I would like to know what is the best way to save, store, or otherwise preserve the motor with 117k until the higher mileage engine craps out and I need to do a swap. What should I do to keep the spare motor in good shape until I need it? We are talking about the 5VZ motor.
-Thanks for your advice & suggestions.

 

Is it running?
If so, put some fuel stabilizer in the tank and run it for awhile.
That will prevent any fuel left in the fuel system from gumming things up.
Pull the plugs and spray fogging oil in each cylinder and rotate the engine by hand.
Plug up any openings to prevent critters getting in.
Change the oil and filter as well.