Valves tap after checking compression???

[RyanL]

I just checked out my compression today (which checked out okay 150-160 in all cylinders) and replaced the plugs while I was at it even though they weren't too old. Anyway, after I put it all the plugs in and fired it up I had a nasty valve tap (I just adjusted all of them again like not even 2 weeks ago!). Obviously I know how to fix it, but what they hell would make the adjuster screws loosen up after testing compression? All of the adjuster screws seemed fairly tight to me when I messed with them last. Do I need to use thread lock on them or something? Maybe a lifter just decided to take a crap altogether (I did have a handful that were rather spongy when I adjusted them). I don't know if it matters much, but I did remove all of the spark plugs when I did the compression test mostly so it would turn over easier. Would no compression while turning it over mess with the valves in some way which I never heard of? This truck is really getting on my nerves.

 

[jhammel85]

Are you sure it's not spark knock or something related to the plugs you just put in? Does this happen only at idle?

 

[RyanL]

Are you sure it's not spark knock or something related to the plugs you just put in? Does this happen only at idle?

Yeah, it's definitely a valve tap. I tried starting it up this morning and it was gone so it must just be a bad lifter. I'll be following the thread about 2.8 lifters in a 2.9 to see what happens with that. The motor seems to be in good condition otherwise; heads are almost spanking new (put them in myself and few years back), the oil pan didn't have much of any build up in the bottom when I changed the oil pan gasket, it has plenty of oil flow up to the heads (I had it running with the valve covers off a couple of weeks ago, no oil consumption and the compression seems to be fine, and not to mention there's lots of other little new parts floating around the engine bay. It just sucks that I have to remove the heads to extract those lifters. Oh well.