Loud tapping from valvetrain

[marcmsj]

To make a long story short, started up car one day and there was a loud tapping coming from the head that would increase frequency with engine rev but wouldn't get louder.

Compression and leakdown tests came back good, also had good oil pressure. No apparent loss of power, just sounded like a diesel. Nothing seemed odd in the valve train so figured collapsed lifters.

Changed lifters and problem was solved... for about 48 hours. Then same noise came back. We suspected collapsed lifters but why would it be doing it again with a new set of lifters?

Any ideas on what to test? Again, we have good oil pressure and flow to the head.

 

[spyderdrifter]

What about possible imperfections on the rockers? Such as something being gouged enough to make a noticeable gap. Just a thought.

 

[LiquidX]

Double check the lifters, it only takes a few mins to do it and you don't need a new gasket set either.

Consider taking a pick to the underside of the rocker to see if any material has built up.

 

[marcmsj]

Rockers look good. Any good way to test lifters? I just doubt that both sets would go bad back to back like this for no apparent reason.

 

[marcmsj]

Update:

Had the car towed back to the shop since I didn't want to drive it. Noise was gone when it got there. Idled fine for 15 minutes and still no noise after a drive.

Started it up this morning and the noise is back. Starting to think one of the lifters is not getting enough oil pressure intermittently but not sure why.

 

[talon2gbuyer]

Sounds like normal lifter tick to me. If your really that anal about solving the problem, try the 3g revised lifters.

These engines are notorious for lifter tick, doesn't really harm the engine, but can be rather annoying.

 

[marcmsj]

I do have 3g lifters installed and this is way beyond lifter tick. It's definitely a mechanical problem. We're probably working on a fix this week, will update when I have some news.

 

[honda_burner]

Started it up this morning and the noise is back. Starting to think one of the lifters is not getting enough oil pressure intermittently but not sure why.

I was going to suggest something along these lines.

 

[marcmsj]

Notice the rocker arm on the left, looks like the oil passage was machined incorrectly. That one was different than all the other ones and it was either clogged or not getting enough oil.

Updated them all to EVO 8 lifters and problem solved.

 

[keltalon]

Notice the rocker arm on the left, looks like the oil passage was machined incorrectly. That one was different than all the other ones and it was either clogged or not getting enough oil.

Updated them all to EVO 8 lifters and problem solved.

How much did the evo rockers set you back?

 

[marcmsj]

How much did the evo rockers set you back?

The shop I had it at (UCS Performance) had a few extra sets around and sold them to me at a good price. Let me know if you're looking for some and I'll ask if they have more.