My 2002Siverado transmission went bed so I’ve been driving my panel daily. Kinda forced me to do updates I was putting off or ignoring. I put lap belts in and got all the lights, horn, and windshield wipers working. I tuned it up, adjusting the valves first then setting the timing. She’s running nice barely hear it, she has a speed limit of 50mph. More than that it starts to scream nasty things at me. Ok now my dilemma, after driving about 7 miles the valves start making noise, it has hydraulic lifters as it is a later engine. So when I say I adjusted the valves I did it according to the numbers in the manual. Intake .006-.008 exhaust .013-.015. I believe these numbers are for solid lifters? I haven’t found numbers for hydraulic lifters but have been told set up with zero lash plus a quarter turn? Which is it?
If hydraulic lifters it definitely should not be "Intake .006-.008 exhaust .013-.015. " The zero lash + 1/4 turn may be close or even correct, but I'd figure out what the specs are for you particular engine. Forum member (and my buddy) Bill Brubaker had this same problem. We both assumed that the 55.2 Chevy 235 truck engine that was in his '50 GMC was equipped with solid lifters. After attempting to adjust the valves many times and noticing that some of the pushrods were not spinning like they should, we pulled a lifter so we could examine the cam for improper wear. Imagine our surprise when we saw the lifter was hydraulic instead of solid. Bill looked up the specs for later hydraulic equipped 235s. We set them accordingly and he now has a quiet, happy motor.
Thanks for the reply Bill. I’m certain the engine has hydraulic lifters. And went to this manual for specs 1948-51 Chevy Truck Shop Manual I guess that’s the wrong one for my engine. I guess I’ll go the zero lash method. Bill
Get the engine serial number from the machined surface on the block to the rear of the distributer. Can figure engine info from that.
I'd expect the engine serial number to be longer than that. Here 1955 Chevrolet Specifications is an example of 1955 numbers, including engine serial numbers.
If I remember correctly, the way we figured out where to set the preload on Bill Brubaker's hydraulics was to measure the total amount of possible movement of the plunger in the lifter, divide that by 2 to get in the middle of the adjustment range, count the thread pitch of the adjusting screw and see how many turns from first contact (zero lash) it would take to get to the middle of the range.
