I have a tapping sound that seems to originate from the valve train. Used a big screwdriver handle to my ear and it was coming from somewhere in the middle portion of the valve cover. I adjusted my valves three times and the tapping persisted.

There is a thread on hybridz about a valve train tapping and several people found that the portion of their rocker that contacted the lash pad was contacting the side of the lash pad and not the middle. I thought I was in the same situation so I removed all my rocker arms. 

This is what I found:

Rocker #8 has a groove that is huge. Also the lash pad for #8 has lopsided wear. 

I posted a thread a few days ago about finding all my passenger side camshaft bearing bolts totally loose. I guess this is the result of unsecured cam shaft bearings. 

I carefully inspected my cam lobes and they look and feel perfect. I am going to order a replacement rocker and lash pad on Monday. Will I have issues since I am not replacing my cam?

I also carefully inspected all the rocker arms and they are perfect except for #6 and #10. They have almost indistinguishable lines that are hard to capture on camera. They are perfectly smooth to the touch and their lash pads have perfect wear.

Howard 

1974 260z

Edited November 26, 20177 yr by 882993md

Yikes, what does the cam look like?

It looks good. It appears the rocker took most of the wear. 

Howard

 

 

Edited November 26, 20177 yr by 882993md

A plausible story might be that the PO installed a set of rebuilt rocker arms, didn't inspect them closely, and missed #8.   Or got in a bind and decided to use it anyway.  And didn't properly tighten the bolts.  I can't see how you get a groove like that on #8 except during regrinding of the pad surface.  If the cam lobe had worn out there might be a groove closer to the end, but not where that one is.

If the others are all good you'd probably be okay just replacing the bad parts.

Thanks Zed. Am I ok with reusing the lash pads? They look fine and have consistent wear across their surfaces for all 12.

Howard

I'm not an expert n the area, just regurgitating knowledge I've consumed, and adding some basics to it.  The cam lobe is the area that almost always has wear problems, not the lash pads.  

Wait a while and you'll probably get some more experienced views.  Doesn't seem like you have a major problem though, just minor details to correct.

Would anybody recommend  using a thread locker on the cam towers?  Serviceable Loctite or the stronger one? 

Thanks

I always put a dab of Medium Strength Loctite ( 242 Blue ) on any small bolts like that. Don't use the High strength or Stud Lock. You may never get the bolt out in one piece again. 

Hi guys:

I want to provide an update on the replacement rockers. I installed four new rockers and adjusted the valves cold then I let the car idle for a hot valve adjustment. Great news the tapping is gone and it's just regular valve train noise now!

Howard

Edited December 2, 20177 yr by 882993md

That's great news. Where did you source the "new" rockers from?

Edited December 3, 20177 yr by rcb280z

17 hours ago, rcb280z said:

That's great news. Where did you source the "new" rockers from?

I got them from the Z store. ($37.95 each-ouch!)

Howard