I just put a new cam into my 73 comet 302(stock motor i think) its a mild cam 433 lift and it runs sorta its real hard to start it it backfires and doesnt wanna go but once it does it runs ok but still no good but no more backfires. now whenever i put it into gear the motor really struggles and almost feels like one of the spark plugs wires is off but its not i replaced the wires and still the same thing it idles kinda rough to. im thinking its my valve ajustment. I should have positive stop rockers in my car and just just torque them to about 20 foot pounds right, but no whenever i do that i have no compression but if i do them like THE EVIL BRAND *chevy* feel for takeup in the pushrod and tighten them an extra half turn to 3/4 turn it runs and has good compression . It is possible that these arent the stock heads or maybe the stock rockers because i can tell some one had the them off before i bought the car. Every one i have talked to say i should have the positive stop rockers but i think i have adjustable rockers. I dunno? HELP ME PLEASE
if you replaced the cam then recheck your timing and distributor placement, then recheck your plug wires and make sure its wired right,check you advance on your distributor and make sure everything is working.
Look at a rocker stud and see if it has a shoulder for the rocker arm pivot ball to ride on. If it does then they are positive stop. Personally, if it runs good at 0 lash + 3/4 turn, I'd leave it there. Actually I would only add an extra 3/8 turn past 0 lash.
Its new HO firing order but that shouldnt matter one my older 302 that was the old 154 firing order right? i will try adjusting my valves again and by a shoulder on the stud do u mean a lip that ball sits on and cant go any further down ? If so i dont have that type my ball pivit can move from the top of the stud right to the bottom.
Then you have adjustable rockers. Do them just like a Chebby. Take out the slack and I personally go 1/2 turn more.
Are the nuts free to spin on the studs or are they hard to turn? If they are free to spin you will need a way of locking it in place after you adjust to 1/2 turn past zero lash(poly-locks or crimped style locking nuts).
Are you sure the cam was installed correctly, the gears were correctly lined up? If you have ever had a timing chain slip a tooth or two, you know it can start to act like this.
they better be tight to turn...if they are adjustable....if they spin easily...they will back off real quick and then you will have to take the valve covers off all the time.... you can buy new nuts and washers for 20 bucks i think....i would do it...and pay close attention to the tightness of the nut as you screw it down....if it doesnt give you a little resistance then the locking mechanism isnt functioning properly...i had to squich a couple of the nuts to get them to lock a little better good luck
