Tapping from Head (not my lifters)

[LarryJoe]

So I recently put new ss valves in and replaced my head gasket. Well upon starting there's a rapid loud tapping from the head. It's not my lifters I checked them. My timing marks line up at the cam gears. I pulled each plug wire and the noise stays. Also I noticed my idle vacuum is extremely low. Around 12 at idle. When I listen while its running the sound takes me to the intake manifold although I know it's not in there obviously. Anyone have any ideas for me to check?

 

[BogusSVO]

Line up the crank marks and see if the cam marks still line up.

Also check the intake manifold support bracket.

 

[LarryJoe]

I got rid of that support bracket awhile ago. Could the crank be off just enough to make the valves kiss the pistons making the tapping noise?

 

[BogusSVO]

If the valves kissed the pistons I would expect other issues,valve leakage, low compression

Even at idle speeds, any valve to piston contact will tweek a valve.

 

[LarryJoe]

I double checked my timing. It's dead on. What else could it be? I'm at a loss now.

So I pulled my head to find that all my intake valves made contact with the pistons but my exhaust ones had not. What could cause this? These are EPN ss valves off eBay.

 

[BogusSVO]

Well apparently the timing was off to allow valve to piston contact. It is more common to bend the intake valves than the exhaust.

EPN valves are Engnbldr valves, a good valve to use.

 

[LarryJoe]

A little update. I figured out why my intake valves all hit even with the motor in time. Turns out I had the plate with the timing mark for the crank flipped the wrong way so even though it looked like my timing was dead on, it was off multiple teeth.

 

[BogusSVO]

When you remove the bent valves, check for cracked guides, replace as needed.

Keep in mind, when guides are replaced, the seats need to be cut.

 

[LarryJoe]

I checked all the valves. None of them were bent at all. Guides looked to be good too.

 

[BogusSVO]

How did you check them?

Fluid test?

Or pull them out and chuck them up in a valve grinder?

 

[LarryJoe]

I tested them with brake cleaner. That's how I figured out my stock ones were slightly bent. Just gotta make sure the lobes are up and spray inside with brake cleaner. In my experience if they aren't totally sealed it'll run right out.

 

[92AWDHX40]

I learned some can look ok but are actually bent enough to cause problems, without a proper way of testing.

 

[LarryJoe]

Right but when my timing took out my stock valves you couldn't tell at all. Light wouldn't even crack through. Hit them with brake cleaner and it leaked right through.

 

[BogusSVO]

Personally, I would pull them and run to a machine shop and have them ground.

I have seen valve seal from light contact, the spring pressure pulls them staight.

But when they get ground, you will hear them "scromp, scromp, scromp" When a valve is ground, is should sound like bacon sizzling.

 

[LarryJoe]

I ground them in myself when installed. Why would I need to regrind them if they are showing no signs of being bent?