When I was deciding what to do with mine I researched extensively, all of the MR2-S model years default to the same part number. it's posted here somewhere, maybe in my "light mods" thread.One, often mentioned, remedy for excessive oil burning is to acquire a new short block from Toyota. According to this Wikipedia article, the Spyder engine is equipped with light-weight cast connecting rods, while other incarnations (mundane Toyota models) use forged powdered-metal connecting rods.
One might assume that the cast rods are prefferable to the powdered-metal forgings because one expects the Spyder engine to be subjected to more vigorous use.
I asked the local Toyota dealership's parts man to look up the part number for a 1zz short block. He found only one number. There was no distinction between the Spyder and mundane applications. In all fairness, he may have only looked for Spyder short blocks.
My question is:
If I order a short block from Toyota, what assurance do I have that it has cast rods (and the extra tapped holes needed for the Spyder).
This might have been one page..I saw somewhere a visual and descriptive comparison between the pistons, rings, and connecting rods of the 1zz and something; I just don't remember if it was early 1zz vs late 1zz or 1zz vs 2zz, but it was substantial.
In relation to that link and the 1zz-FE and 1zz-FED engine differences, the bottom ends are the most similar part. Perhaps the pistons , rings and rods are different, but the larger difference is the head, head design, and valves.This might have been one page..