1971 impala, 350 2 bbl...replaced the timing chain and all, but every week so far there is one rocker arm that is always breaking, and it's a different one every time...what is the issue cause this is the 3rd time this had happened and i am tired of taking it back to the shop for them to try to gank me (charge me shop fees) and how to correct it so that this doesnt happen again
2007-06-24 03:07:15 · 5 answers · asked by eightballe 2 in Cars & Transportation ➔ Maintenance & Repairs
you may be adjusting your rocker arms too tight. with the valve covers off & the engine idleing (yes it will be a little messy) back off (turn the nut counterclockwise) each rocker arm until it clatters or makes a clicking sound -turn it back in until the clicking stops then tighten 1 fourth of a turn. do this on all 16 rocker arms. Im assuming you have hydralic lifters. this is the recomended procedure in the shop manual for 71 chev. if you have solid lifters then you will have to use a feeler guage & set them at what the cam manufacturer recomends
2007-06-24 06:14:54 · answer #1 · answered by Who Dat ? 7 · 0⤊ 0⤋
Eightball, I had the same problem on a 327 hydraulic lifter motor and a 427 425 hp. solid lifter motor. Be extremely careful in choosing quality stamped steel rocker arms. Choose genuine Chevrolet or Seal Power parts. I had trouble splitting the arms around the trunnion ball beneath the rocker arm stud. I was lucky to have access to a metallurgical lab at work and we did a hardness test and an SCM test to find the different types of metal that were used to manufacture the broken arms. Sure enough there was no chrome or nickel in the crappy arms. The hardness was substantially softer than the genuine GM arms. If you changed valve springs you may need to toss in a set of Crane, Comp Cams, Chevrolet Crower, Sharpe or other roller rocker arms with a stud girdle.
2007-06-24 03:24:47 · answer #2 · answered by Country Boy 7 · 1⤊ 0⤋
Rocker arms and rods are worn. Metal is thin and finally giving away. Replace them all ,rods and arms . Performance will increase to. In human words it`s like a knee joint after time it wears away and nothing is left
2007-06-24 04:03:30 · answer #3 · answered by miiiikeee 5 · 0⤊ 0⤋
Is this happening only on one bank? It sounds like they got a cam out of time when they replaced the chain and the valves are trying to open at the wrong time. Yes, it is possible to have a camshaft out of time and the engine will still run.
2007-06-24 03:25:58 · answer #4 · answered by Hondu 7 · 0⤊ 2⤋
what all did you change? rocker arms dont break- the pushrods will bend before your rocker arms will break... unless theyre aluminum rockers, if they are ditch the cheap crappy ones and get some comp cams stainless steel ones, or some good crane cams aluminum ones
2007-06-24 03:24:52 · answer #5 · answered by darrin b 4 · 0⤊ 0⤋