Small Block & Big Block Chevy Specific - 350 major problem, need help!
camaro84
07-17-2007, 02:09 PM
my 350 engine recently started knocking, so i took off the valve cover because that is where the sound is coming from and the 4th cylinder exhaust valve,spring,rocker,pushrod is not moving when the motor is running. what are the possible problems?
mzoomora
07-17-2007, 02:23 PM
A flat cam or a broken lifter.
Jon5212
07-17-2007, 02:56 PM
Wow... Cam lobe is broken? I would think even with a collapsed lifter it would still move a little bit? Maybe I'm wrong...
jmm98LS1
07-17-2007, 03:37 PM
Probably wiped cam lobe and chewed up the lifter. I lost the #5 exhaust lobe (comp xtreme energy) on my old 355 after just 12k miles. The lifter was missing nearly .25" and the lobe barely had a ramp left. It still moved the valve a tiny bit though.
camaro84
07-17-2007, 03:51 PM
ok, if i just replace the cam and/or lifters, would i have to have the heads machined or would it be alright?
jmm98LS1
07-18-2007, 10:05 AM
Never re-use flat tappet lifters on a new cam, always get new ones. You don't need to do anything to the heads.