I recently helped replace the stock camshaft and rocker assembly in the CR-Z with junkyard parts from a GE8 Fit that had 19,000 miles on it. Unlike the CR-Z, the GE8 Fit fully opens both intake valves regardless of RPM. The GE8 camshaft also uses higher lift and duration intake cam lobes and has a separate cam lobe on it that is only used during VTEC.
The differences between the two camshafts can be seen here.
The CR-Z was purchased used with about 17,300 miles on it and has about 52,300 miles on the odometer now. The car also spends three to four weekends a year at track days and has accumulated over 1,300 miles of use on the racetrack. Low-end torque has definitely improved with the new parts. We'll really know how much of an improvement it's made at the next track day.
The engine has mostly used Castrol Edge since it was purchased. It's been running 0W-20 in the winter and 10W-30 in the summer.
Here it is with the new cam and rocker assembly installed. All the casting marks were removed from the rockers and the valve adjustment screw lock nuts were replaced with titanium ones to reduce strain on the assembly.
How did you get the power vtec to work on the crz? I had a Fit sport 5M with my previous commuter. Would be a semi-hoot on a 300lb diet, but its no Fiat 128. IIRC It does fully open both valves, but has an aggressive powerlobe (using VTEC) in the intake that seems to come in around 4500 or so rpm depending on load. As an engineer I poopoo the L shaped Intake rockers that will add a significant rotating moment to the rockershaft bearing. Almost elegant due to compactness but BAD engineering.
Car was an O.K. buy for 13Kmax NEW but not for 18K. Let down by mushy Garbage-bin strut front suspension with the wimpiest components. Def not a handler like the old 80's and 90's Civic with a proper SLA front suspension.
I will say Again, S.Honda-san is roiling in his grave over the fat boring pigs his subcompact cars have become.
Such price "safety".
here's a HONDA TSB (PDF) on lost motion springs: I guess not.. Wont allow.
HONDA Service Bulletin 11-010 Feb 19 2011
Safety Recall: Lost Motion Springs BACKGROUND The lost motion springs in the engine's variable valve timing and lift electronic control (VTEC) may break. In rare cases, the broken pieces of the lost motion spring may jam the rocker arm and cause the engine to stall and prevent it from being restarted. An engine that stalls while driving increases the risk of a crash. VEHICLES AFFECTED 2009 Fit FromVIN JHMGE8...9S000027 thru JHMGE8...9S075923 FromVIN JHMGE8...9C000005 thru JHMGE8...9C007783 2010 Fit FromVIN JHMGE8...AC000001 thru JHMGE8...AC013589