Is Lifter Bad ?

[8door]

Got back to my 68 after a few months on another project.It is a 350
with a heavy ticking in valve train as best I could determine. I tried adjusting
valves while running. The one that sounds like the noisest , backed off , no change but as I turned down the nut ( less than 1/2 turn) the engine began to idle rough.
Am I correct that this indicates a collaped lifter?
I hope so because I don't want to rebuild engine at this time if it is bottom end .
Anything else I need to look at if it a lifter? Like cam lobe?
Chris

[8door]

Collaped ?????? I mean collapsed.
opps
Chris

[jhow66]

Sounds like a lobe worn down. Check it's travel against another.

[8door]

Good idea, I did notice the exposed threads at the rocker were the same as others,
how else would I check travel?

[8door]

Any other thoughts? Am I on the right track?

[Livrat]

You can check the travel by watching the other rocker arms next to the one in question and see if they are all opening about the same as each other.. I normally would not suspect a worn cam lobe on a small block (its more ff a big block woe) but it does happen.. the most common lifter noise I have found in the small blocks is the rocker ball is seriously worn into the rocker arm itself creating a ticking... just remove the nut and ball and look into the rocker arm and see if you can see groves... if so that may be your noise... you could just replace one assembly but chances are if one is bad the rest are not far behind...

[Stroker]

Originally Posted by 8door

The one that sounds like the noisest , backed off , no change but as I turned down the nut ( less than 1/2 turn) the engine began to idle rough.
Chris

The engine running rough is an indication that the lifter is bottomed out and the valve is being held off the seat. It should take a lot more than a half turn from zero lash. Have you tried adjusting the lifters with the engine off. Sometimes it's difficult to set by ear if a lot of the valvetrain is making noise.

BTW is this a new cam or does it have some miles on it?

[8door]

Livrat and Stroker. The po told me engine was rebuilt 5 years ago but could not verify miles or exactly what was done in rebuild, you know how that is. All I know is that it is a later block that a 68 according to numbers it is a mid 70s engine with camel hump heads and a Qad jet carb. Runs strong but of course has the noisey valve which just showed up.
I did not try a static adjustment yet. When the idle changed I did not attempt anything further just backed off till engine settled down and shut it off.

[kaycee]

I had 1 that sounded just like a lifter but it turned out to be a wrist pin.I adjusted the valve' 2or 3 times before I relized I was not gonna get rid of the noise.I ran the motor for 6 more yrs never missed a beat or used any oil hope yours is a lifter.GOOD LUCK

[Super Duck]

sounds like a lifter to me. call summit and get one of their cams with lifters shipped for about $90. they are good parts made by crane. should take care of the problem. also you can try some marval mistery oil, that usualy frees up stuck lifters. sorry for my poor spelling but hey I am a red neck

[72 CustomCamper]

[QUOTE= I normally would not suspect a worn cam lobe on a small block (its more ff a big block woe) but it does happen.. [/QUOTE]


I had it happen in a 74 blazer I had. 10 of the lobes were worn and 6 were wiped...


Chuck

[8door]

Thanks for all the info.
I like the wrist pin story that way I can build an engine have it ready and drive this one till bits the dust.
I'm going to pull the top and look at the lifters after a few miles with a little mistery oil.
Like they say about chichen soup "can't hurt"
Chris

[hobby67stepside]

I had a problem that sounds just like yours earlier this summer in a 383 stroker I have. I tightened down the lifter a couple times and when out on a drive it developed a real bad knocking. Lifter and cam had a disagreement. Both were destroyed. New cam and set of lifters solved the problem. Oh, I didn't have more than 5000 miles on cam and lifters.

[8door]

Hobby67stepside
Sounds like you cranked down on a lifter that didn't have any more travel and beat the lobe of cam and the lifter.
I wonder if mabey I should change cam and all lifters? like someone recommended.( Super Duck?)
Has anyone just replaced one lifter. New lifter on a old cam hummmmm.
Not a good idea for new cam and old lifters, they would never seat in correctly.

[hobby67stepside]

8door, I'm pretty sure things were shot before I tightened down on the rocker. I was just hoping and that doesn't usually work in mechanical things. I only gave it a fraction of a turn.

[kaycee]

If you wiped a lobe off the cam then it should make a pop sound through the carb when u try to accelerate.