Engine issue tap, tap, tap tap, tap, tap

[Boog]

Worth mentioning here is the mechanical fuel pump can peck too and sound just like a lifter. In my many years I have had two pumps do this. The spring inside gets weak on some allowing the slack at the pushrod causing the peck. Since the fuel pump is located directly under #2 cylinder it is easily missed as the cause. AC pumps usually last longer than others.

[Oldironside]

I had the same issue and like Boog already wrote, it was a worn out fuel pump. After replacement the problem was solved. I did put in an edelbrock pump since my carb is also edelbrock.

[Steeveedee]

Originally Posted by Boog

Worth mentioning here is the mechanical fuel pump can peck too and sound just like a lifter. In my many years I have had two pumps do this. The spring inside gets weak on some allowing the slack at the pushrod causing the peck. Since the fuel pump is located directly under #2 cylinder it is easily missed as the cause. AC pumps usually last longer than others.

I've had brand new fuel pumps knock too, very annoying, when you're a mechanic and have to replace a part twice. The old one (original) leaked.

To the OP- use a stethoscope or a wood dowel and try to find the closest location of the noise.

[brown7373]

I pulled the right rocker cover and see no evidence of any metal shavings. I turned the engine to #1 position and the #2 intake rocker is loose and there is way too much play in the push rod. I need to make sure the rocker stud didn't pull out, but my next step will be to pull the intake to get to the lifters.

[demian5]

Originally Posted by brown7373

I pulled the right rocker cover and see no evidence of any metal shavings. I turned the engine to #1 position and the #2 intake rocker is loose and there is way too much play in the push rod. I need to make sure the rocker stud didn't pull out, but my next step will be to pull the intake to get to the lifters.

Slow your roll!

Before doing all of that work, see how much it takes to pull the push rod out of the lifter. If its more than 1/8" then it is a collapsed lifter. You can't really see in there, but you can try. Maybe a borescope.

You can visually see if the stud is pulled out. It's gonna be higher and there will be a witness mark at the bottom where it meets the head.

Originally Posted by demian5

Pull valve cover and ID the culprit.

I dodged a bullet by adding about half a pint of marvel mystery oil to the engine and poured right down onto the lifter.
I then started the engine every few days and let it get almost to operating temp.
Then one day it free'd itself, I adjusted the rocker and we live happily ever after.

[brown7373]

The rocker studs are all exactly the same height, so no stud pulled out. With the engine in the #1 firing position, #2 intake rod has about 1/8 to 1/4 up and down play. Rocker arms and tips look fine.