Tapping on cold start?

[dhumboldt12]

Nee lifters with rebuild?

Pretty certain, yes.

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[Supercharged111]

If so it's unlikely that they are gummed up. With stock valve springs it seems unlikely that you'd bend a pushrod, but I've had rocker nuts back off before. Strange though that it only does it cold.

 

[dhumboldt12]

That's the interesting part. I'm pretty sure the springs and everything is stock, the cam in it is only a little bit bigger than stock

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[Supercharged111]

Easiest way to narrow it down is pull the valve covers and wiggle the rockers with 1 and then 6 at TDC.

 

[redfishsc]

Fully agreed with Suoercharged111. I don't know if you have a Vortec or a TBI, but I know the vortec valves are easy to adjust. You only have two motor settings, TDC for cylinder 1, and TDC for cylinder 6.

A quick Google search will tell you which valves to adjust at TDC 1, which for TDC 6. Basically you tighten the nut just enough to remove the wiggle on the push rod, and then tighten the nut one full 360-degree turn beyond that.

After listening to your video, it almost sounds like exhaust leakage to me. Make sure your exhaust bolts are tightened to spec and the gaskets aren't leaking

 

[dhumboldt12]

Fully agreed with Suoercharged111. I don't know if you have a Vortec or a TBI, but I know the vortec valves are easy to adjust. You only have two motor settings, TDC for cylinder 1, and TDC for cylinder 6.

A quick Google search will tell you which valves to adjust at TDC 1, which for TDC 6. Basically you tighten the nut just enough to remove the wiggle on the push rod, and then tighten the nut one full 360-degree turn beyond that.

After listening to your video, it almost sounds like exhaust leakage to me. Make sure your exhaust bolts are tightened to spec and the gaskets aren't leaking

Whatś kinda funny, is that the y-pipe on the truck was newer at some point, and i noticed one of the exhaust studs looked kinda wonky. I wonder how that would cause an issue only when cold though.

 

[df2x4]

Whatś kinda funny, is that the y-pipe on the truck was newer at some point, and i noticed one of the exhaust studs looked kinda wonky. I wonder how that would cause an issue only when cold though.

Expansion. When everything gets a little heat in it the leak seals up more. Very possible.

 

[El Tigre]

Mine taps when cold also. Likely piston slap. Mine has always done this,and noise goes away within 1/2 mile...

 

[dhumboldt12]

Another thing I noticed, is when warm at idle, it has a deeper slow knock. Goes away right as soon as you rev up.

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