These pistons are a product of ours and our customers real world testing and result driven design changes. The 2.5L engine that's commonly swapped, and commonly boosted with our own EFR Turbo Systems is a bore/stroke recipe for disaster. If you've been in the presence of a built 2.5L NC Miata you might know what we're talking about. The previous market options had skirt design flaws that while weren't entirely harmful, would leave your car sounding like a diesel truck during the warm-up cycle and often continuously there after.
These are the only 2.5L pistons that features uninterrupted ring lands. Previous designs have had the requirement to run the wrist pins through the oil scrapper ring lands causing a gap in coverage. This was remedied by using an "oil rail support" which is fine, but another potential failure point that is no longer an issue with these new slugs.
Another note worthy update is the wrist pin choice. These now use an extreme duty "tool steel" over-sized 21mm wrist pin. Won't over-sized pins cause an incompatibility with the connecting rods? Nope! We are also stocking Molnar 2.5L 21mm little end rods. All the benefits of a well thought out custom piston, none of the wait time!
- Ford Duratec 2.5L (NC Engine Swap)
- Phosphate Dry Lube Coating
- Low thermal expansion 4032 alloy with a 3 step forging process
- Extreme Duty 21mm Tool Steel Wrist Pins
- NPR XX Chromoly Piston Rings INCLUDED
- Gap-less oil scraper ring lands (no need for additional rail support)
- Sold as a COMPLETE SET OF 4 PISTONS, WRIST PINS, RINGS, CLIPS