Recently replaced head on D16A6 in a 91 Civic Si. Can't get timing right. Did some research on this site and it appears it probably has a D15XX cam in it and I'm not sure of the head. Casting number is PM3-11. Reading another thread on this topic, it was stated that the stock A6 cam in the D16A6 motor is retarded reference the keyway by 4.75 degrees compared to the D15 cams. Can I see the cam markings by simply removing the valve cover? I'd like to know exactly what's in it. What about the PM3-11 head? This saga started when I initially cranked it up after the head change - dist is full retard against the stop and it's still ~4-5 degrees advanced according to my timing light. The same timing light and cam sprocket as well as distro are being used. Can't get it past emissions testing, fails NOx in the low speed part. Also, have a adjustable timing sprocket for it - need 4mm key for it - ordered today. I'm thinking put the adjustable sprocket on it and dial it in to get passed on emissions as sticker expired last month. Then find an A6 cam for it. BTW - I changed injectors, temp sensors, thermostat, water pump, belts, hoses, head bolts, & total exhaust system when doing head work.