Rocker arm noise?
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Pro
Joined: Aug 2002
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From: Warner Robins GA
Rocker arm noise?
This is for a friend of mine.. the motor is a late 70's Corvette standard 350.
It's developed a dead miss in the last few days. The plugs, wires, and cap are less than two months old.
About the same time, we're starting to hear some clattering that I'm pretty sure is from a rocker arm. It's not just a faint clatter like bad gasoline either, it's pretty loud and annoying.
I'm almost certain the two are related. It'll always do it under a load but rarely does it at idle. That makes it difficult to figure out where it's coming from but I'm pretty sure this evening I can find it by pulling plug wires until I find the dead cylinder.
The first thing I thought was a dropped valve, but everything appeared to be okay when I removed the valve covers. I'm no expert but the pushrods and everything seemed to be functioning properly.
One thing I wasn't sure about was when I ran the car with the valve covers off, one rocker arm on each side shot oil about 3 feet whereas the others only barely trickled. Is this normal?
So to recap.. dead miss, clattering sound I'm almost sure are from rocker arms. No other unusual sounds.
It's hooked up to a TH350 so it doesn't really see high rpm's. Any ideas?
It's developed a dead miss in the last few days. The plugs, wires, and cap are less than two months old.
About the same time, we're starting to hear some clattering that I'm pretty sure is from a rocker arm. It's not just a faint clatter like bad gasoline either, it's pretty loud and annoying.
I'm almost certain the two are related. It'll always do it under a load but rarely does it at idle. That makes it difficult to figure out where it's coming from but I'm pretty sure this evening I can find it by pulling plug wires until I find the dead cylinder.
The first thing I thought was a dropped valve, but everything appeared to be okay when I removed the valve covers. I'm no expert but the pushrods and everything seemed to be functioning properly.
One thing I wasn't sure about was when I ran the car with the valve covers off, one rocker arm on each side shot oil about 3 feet whereas the others only barely trickled. Is this normal?
So to recap.. dead miss, clattering sound I'm almost sure are from rocker arms. No other unusual sounds.
It's hooked up to a TH350 so it doesn't really see high rpm's. Any ideas?
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Rocker arm noise? (Tourney3p0)
One thing I wasn't sure about was when I ran the car with the valve covers off, one rocker arm on each side shot oil about 3 feet whereas the others only barely trickled. Is this normal?
Burning Brakes
Joined: Jun 2000
Posts: 892
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From: GA
Re: Rocker arm noise? (Fevre)
I had the clatter and sputter above 3500- 4000 RPM. My lifter munched and the cam worn flat.
My engine "sounds" while driving.... Errrrrrr.... shift ERRRRRRRR shift VAREEEEERRRR pop pop spit spit crackle crackle... shift.... crap...
I tightened the rocker too much and caused my OWN carnage! The lifter became concave and the cam lobe looked more like a mini bearing journal!!!
:cry
My engine "sounds" while driving.... Errrrrrr.... shift ERRRRRRRR shift VAREEEEERRRR pop pop spit spit crackle crackle... shift.... crap...
I tightened the rocker too much and caused my OWN carnage! The lifter became concave and the cam lobe looked more like a mini bearing journal!!!
:cry
Thread Starter
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Joined: Aug 2002
Posts: 715
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From: Warner Robins GA
Re: Rocker arm noise? (Mr.Gearhead)
I had the clatter and sputter above 3500- 4000 RPM. My lifter munched and the cam worn flat.
I think I'm going to run some seafoam through it this afternoon when we change the oil on the off chance that there's some carbon on the valves or something.
I'm probably going to be taking the rocker arm off this evening to check the pushrods (or will this be evident without doing so?). When I go to put the rocker arm back on and need to adjust the valves, do I simply turn the pushrod by hand until it's too tight to turn, then back off a bit? Or is there a better way of doing this with the motor running?
