Parked the car late last Fall. It ran fine. The car sat for 6 months and was not started until late this Spring. When it started, it made a hell of clatter. This happened once before when I bought it. It had sat for several months and then quieted down rather quickly once it ran. I figured the lifters bled down. This time, it never really quieted down. I added some Marvel Mystery Oil, about 8 oz., thinking there may be some varnish on the lifters preventing them from building up. I drove it gently for 10 miles Doing the long screwdriver test, cylinders 4, 5, 6, & 8 were suspect. Cylinder 4 did start to quiet down. I'd like to think miracles can come from a can, but I am not so sure. I pulled the rocker arm cover off the right side first. A couple of the rocker arms have some play in them. Not much, but seems indicative of collapsed lifters. I am wondering if just snugging down to zero lash per the FSM and then flushing and replacing the oil would solve my problems or will I lose to much lift and really hurt performance? Or, am I just in it for the long haul and should replace the entire set of lifters?

It has Amsoil in it that has about 700 miles on it in the past 2 years. I'd like to be able to flush it and go back to Mobil One.

Any thoughts or previous experience would be appreciated. Thanks!

 

700 miles in two years?
Boy, you need to go out and drive that car!
10 miles, gentle driving.... Take her out for a good romp on the highway.
Get 'er hot and sweaty for an hour or two.
Then consider changing oils or whatever.....

 

Yeah, I know! Last 2 years were sort of tough. My father passed and I spent a lot of that summer taking care of things for my Mom, and then last year, the weather was consistently crappy on the weekends. We also had a hiatus with our local autocross venue but hope to be back for the end of summer and fall.

 

Do you autocross at the Airport in Cumberland Md??... with riflecoach,you need to pour the rest of the bottle of "Marvels oil" into the motor and run it hard.....If this happened from sitting you may be able to break the lifters loose by just running it hard...You may just have some dirt clogging the feed holes....I had to replace the lifters in my 383 about 6 weeks ago because I had 1 lifter that was collapsing and getting worse , but mine happened from running the car, not from sitting...I don't live to far from you , If you want me to check it out when I'm up your way , let me know....WW

 

I do autocross at CBE. I am looking forward to next month. I'm glad things were able to work out with the airport authority. What do you run? Chances are we may know each other. I ran a '80 Datsun 280ZX for a number of years before I got my Vette.

After mulling my things over, I was thinking that I would snug up the loose rocker arms per the FSM, button it up and run it and then flush the oil. Will I do any harm by that? I'm thinking I would get no more than 1/4-1/2 of a turn at most.

 

So as an update to help make this thread relevant in the future, I thought I would post my progress. I put over 300 miles on the car. The car continues to have the same ticking sound. At the recommendation of a friend, I took the car to a Chevy mechanic and he was inclined to think that the spider plate that holds the lifters in place may be cracked and the banging was the result of the spider plate. Well, after a lot of work, I got the intake pulled. The initial inspection shows the spider plate in one piece. Now, at the right rear and the left front, there appears to be some movement in the arms. They are also the furthest from the 3 bolts that hold the spider plate in place.

Any other thoughts? Thanks.

 

I have never seen a spider hold down plate ever crack or malfunction, all it does is hold the dogbones in place,it never even moves, your mechanic just gave you a WAG..... But while you have the motor torn down , why not just replace the lifters while your in there...Around $119.00 and your problem is solved...Also the FSM says 1 full turn after 0 lash in my 89 book, why would you only want to go a quarter to 1 half turn? Less preload would make the lifters louder not quieter.......WW.
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Actually did adjust the right side per the FSM and it was quieter initially, but was right back after sitting for a week.

So, I pulled each of the lifters and did a visual inspection. There is a bit of wear on each of the sides of each of the lifters. I miced the lifters from the cylinder that was loudest and there was 2/1000 wear. I am not sure of the tolerances, but it's companion was at 0. So based on the evidence, I intend to replace the lifters as well as things like the heater & radiator hoses while I have things apart. Hopefully, I have it back together for the Pumpkin Carve Autocross.