While a soft cast iron side seal cannot machine away a cast surface that has been nitride hardened. It is possible for the seal to drag bits of combustion carbon and debris from a faulty air filter, or an air filter with to high an absolute micron rating, that can machine away the nitrided surface.



There is a very slim possibility that the nitriding was poorly done, or was not done at all. This rapid wear was why Mazda started nitriding in the first place. Early engines were not nitrided.



The wear rate can be reduced by using a synthetic top oil (two cycle) as a premix, or through an altered OMP that delivers two cycle oil. At a rate of 3/4" to 1 ounce of top oil per gallon of fuel.



Generally poorly oiled seals get a "T" shape to them where the seal edge just spreads out from overheating, rather than damaging the iron. If you run premix only and used the engine hard after forgetting to add oil to a tank of fuel, it can ruin the seals. The apex seals will be fine but not the side seals.



Since the zero clearance side seals do not survive the break in period, and this engine started with .002" clearance, I suspect that seal clearance is not a factor in the iron wear.



Two years of racing between rebuilds has been adequate longevity for me. I like the idea of forgetting all of the grief required to remove and reinstall an engine. More time to rebuild the transmissions.



Lynn E. Hanover

as far as i know theres just that one length

Thanks j9fd3s . Good try,

Barry