Fast forward 5 years and the engine is undergoing upgrades, hoping to achieve upwards of 770 bhp this time. So, what's changed? I will chronicle this version of the build through this blog from post-machining through to final assembly and dyno testing.
- New Ross pistons. 4.130 bore, 14:1 compression, 2.250" steel pins. These pistons are a bit more robust than the featherweight CP pieces from build 1. These weigh in at 433g, up 60g from the CPs, while the retainers and pins make up for some of that. Bobweight is 1624g.
- Total Seal AP (Advanced Profiling) steel rings. These are conventional, not gapless. Top and 2nd rings are .043", while the oil ring is a custom std tension 3mm piece. Note the std tension 3mm is still less than the OEM, and the usual high tension 3/16" rings. The 2nd ring is again of the napier design to help with oil control. These rings are a step up from the CP rings last time, and combined with the bore finish should improve ring seal. Keith at Total Seal gave us the exact bore finish to aim for, and the machine shop has a profilometer to ensure we get the peaks and valleys at the right height.
- Although the Carrillo 6" tapered beam H-section rods are the same, the bolts have been upgraded to the highest spec material. These are $1000/set bolts, but it is the highest stressed joint in the entire engine, especially at 5000 feet per minute mean piston speed.
- Rod bearings are new Clevite V-series. Mains are the same coated OEM bearings as last time.
I'll keep this blog going as the parts come back and get prepared for assembly, including the various build procedures.
Till next time,
Todd
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