good evening to all, I recently install a new cam( bullet) in my 455. Got it running and top in is clattering! I took off both valve covers and started engine to verify I was getting oil up top. It was good. I want to mention, I had the heads cleaned up and had machine shop install new springs and bigger valves . My question is, is it a breakin time for the new springs? Or is it something that's not right with the springs themselves? Its not a good sound to hear your valvevtrain over your cam and exhaust system. Im hoping someone could give me feedback on what I should be troubleshooting! Thanks in advance. Calling out for help!!!! Larry
The Cam was likely made for more lift which means when they grind the lobes they reduce the base circle of the lobe. This makes the lifter sit lower in its bore and creates the need for longer than stock push Rods ! This is the only way to get the adjustment back and also have good valvetrain geometry so you don't kill the valve stems and guides in 20,000 miles or less.
Hello all , Thanks for the replies. Stevem my machine shop mention the same thing , may need longer pushrods. Larry , I'm using ta 5/16 pushrods and lifters from 212 cam. The only thing I change was the springs because ta stage 1 only went up to 500 lift and this cam goes up 524. The strange things is , i took the passenger side rockers off which reads left side on all rockers and replace them with some new rockers that had LR LR On each set of rockers and hand tighten( not torque spec) , started the engine Until it warmed up and it seems the clattering had gotten quiet. I don't want to wear anything count din 20 k miles so do you suggest getting longer push rods or adjustable? Thanks for the advice. Larry
Warning on the rockers The "L" and "R" stamping on the rocker refers to the pushrod cup/seat offset, NOT the side of the engine they are to be installed on. If all the rockers on the passengers side read "L" they were installed wrong. All "right" and "left" reference is when your standing BEHIND THE CAR LOOKING TO THE FRONT, therefore, the passengers side is the RIGHT side, drivers side is the LEFT side. The proper offset of the pushrod cup will put the pushrod in the center of the pushrod hole in the head, so theres no rubbing of the pushrod in the hole, or side loading of the rocker. If you look at the pic, you'll notice the pushrod cup is offset to center the pushrod in the hole in the head.
Anytime you change cams, you need to measure for correct pushrod length, I'm surprised the machine shop didn't do that unless you assembled the rocker arms. If all the valve tip heights are equal, you can use one adjustable pushrod, at each corner of the engine, adjust it, then measure it, and order the correct length pushrods. It might be better to use an entire set of adjustables though. As far as the rocker arms go, the L and R arms must be assembled correctly on the shafts. If you look down at the rocker assembly (pushrod side up), like in Mark's picture, you will see the shaft has 4 holes for the hold down bolts to the head. The L rockers go to the left of the hole, the R rockers go to the right of the hole.
Good evening , Thanks Mark and Larry for the response> I am going to order some TA adjustable push rods to make sure everything is at the right height. GrandSportSedan, Yes I had the TA and new lifters installed and maybe had 300 or less than 500 miles on came and lifters> I " thought" the lifters would still be in good shape. Are you recommending new lifters as well? Larry , the machine shop only serviced the heads and I brought them home and installed.
Lifters and Cam wear together during break in. reusing lifters on a different Cam is definitely asking for trouble
. Thanks , I've learned a valuable lesson. Where do I go from here? Can the cam be salvage with new lifters? Should I pull the cam and check the damage? How can I know cam is bad or has failed ? Please advise ! Larry
