Originally Posted by macca_779
Only reason I say they aren't as reliable is because of the statistics. The failure rate of C4B's is astounding. I know quite a lot of guys with them and easily over half have had spring or cam issues, if not both. Don't let that turn you off them. Its a brilliant excuss to spend a mere 1k and put some decent gear in there.
I agree - the C4B engine - CnC'd heads, etc is a good thing, but it was let down by a mismatching of the valvesprings used to control the the more aggressive cam. The camshaft itself was a fairly good grind, as far as specs go, but the mismatched valvetrain led to failures.
As a result, there would be excessive lifter float off the cam lobe (caused by valvesprings that were not rated high enough) and when the lifters crashed back down onto the lobes, damage would occur - microscopic damage mind you, so it would take a while for anything to break. Some camshafts (one that I saw and measured myself) have had 1/8" (3mm) gouges taken out of the lobes.
So, if I was to purchase a C4B-engined car, I'd be changing camshaft / lifters / valvesprings at the get go - unless that has already been done.
HSV Senator 300 - the Classy C4B..
2001 HSV Senator 300
C4B - ETP215s 62cc, Comp 215/223 .601/.609 @111+3, Manley 8.050" 5/16" P/R, Morel Link-bar lifters, Powerbond 25% UDP, 36lb injectors, SLP pump, Rollmaster chain, OTRCAI, T-56 - RipShift, 3.91:1 rear, DiFilippo 1.75" 4-1s, twin 3" st/st cat-back, 3" metal substrate hi-flow cats. AP-Racing 6/4-pots. EFIlive COS3 SD tune. 308rwkW(413rwhp)