Anybody have any problems with broken cam caps on any of the DOHC engines? B18a/b or D16a1 or ZC? Just trying to trace down a problem. I built two virtually identical engines for a couple circle track racers using D16A1 heads. Engine 1 works great, set track record and won points championship. Engine 2 used an unported head and won track championship at a different track. I then ported the head and had Crower regrind the stock cams and I am using slightly longer than stock valves. Engine 2 dynoed with more HP than Engine 1, two weeks later 4 intake and 4 exhaust cam cap split down the middle and also broke the snout off the intake cam. No galling on any of the caps, the cam journals are within .001 of a stock cam, no unusal wear patterns, no bent valves. I looked at another head here and found what look like hairline cracks on a few of those caps. The only thing that really comes to mind is the more agressive cam created some kind of hamonics when using the stock valvesprings. The grind is similar to the Crower Stage 1 for B18A/B which specifies stock springs. Called them and they don't have anything to say about it, not even an actual spring pressure recommendation for the cams they ground for me. As it is I have 42#/110# intake and 32#/95# exhaust. Even if it was not enough spring pressure I would think the valves would float giving some hint of trouble. Revved crisp and clear to 7200 rev limiter. What do you think?