On my last post about noisy lifters, I really never got my question on proper engine sound answered. Someone did say it should sound like a couple of sewing machines. I'm not sure I know what they would sound like. So if anyone else could maybe discribe this to a younger guy who is trying to keep these old sixes going, and trying to learn as much as I can. I would really appreciate it.
Should I have lifter noise with solids. Engine seems to run fine, but you can hear very easily a "tapping" sound. It is consistant and smooth. All the V8 guys think I need to do an adjustment or I have an exhaust leak. I do not think I have a leak. I did just adjust the valves warm and engine sounds exactly the same. I am just wondering if it sounds like it should? And I should just ignore the V8 guys.
Describing a sound is hard to do. You need to experiment. Your 216's and truck 235's had mechanical (solid) lifters. First set them by the book, .006 Int and .013 Ex if I recall right. Listen to this. Now set them on .012 and .026 and listen to them when they're too loose. It won't hurt them, just noisy. If too tight the engine will run rough and shake and eventually cause damage, not good. These old engines have rockers with wear in the bushings, wear on the rocker shaft, and usually "eyebrow" grooves worn in the rocker from the top of the valve stem all of which means a little noise even when the valves are adjusted to specs. No harm and if it runs good just enjoy it. I have a 37 Buick with the same rocker set up and I guess GM didn't want Buick buyers to hear the tapping so they coated the inside of the rocker cover with about a 1/4" of asphalt like stuff and then put a 1/2" thick strip of felt the length of the rocker assembly. Makes it dead silent.
Valve lash specs for a ;57 235, 1/2 through 1 1/2 ton, .006" intake, .018" exhaust, both set hot. It is also suggested that you check the toruque on the head bolts (90-95 ft/lbs) rocker shaft support bolts (25-35 ft/lbs) and the manifold clamp bolts (15-20 center, and 25-30 for the others). And yeah, ignor the V8 guys. Obviously, they've never been around an old solid lifter Chevy V8 from the '50s/60s, like the old Feullies with the Duntov 30/30 cam or the L72/L88/ZL1 big blocks.
Thanks guys! I am not much of a mechanic, but do enjoy the old stuff and am trying to learn. My dad is an old mechanic, but of course I didn't care growing up. Dad is a pretty deaf now so he really is no good when it comes to engine sound.
When at full operating temperature the tappets shouldn't make a lot of noise but they can clatter a bit as the engine warms up.
Save a life, adopt a senior shelter pet. The three main causes of blindness: Cataracts, Politics, Religion. Name your dog Naked so you can walk Naked in the park.
Properly adjusted, a solid lifter 6-cylinder engine should emit a rhythmic clicking/metallic tapping sound. There should be no individually louder clicking - it should be a harmonic sound. The sewing machine analogy is a good one... it's simply a smooth mechanical rhythm.
