History: I've only had my truck about a month now. Tried adjusting the valve lash to get rid of the loud clacking, and it sounded good for about 10 minutes, then came back.

I ordered new studs from engnbldr (thanks, the PO box worked!) and installed them yesterday. I adjusted to .007 and .011 cold, with moderate-heavy drag. The truck sounds great now, ~40 miles later. But, check out the condition of the old adjuster studs:



The worst one, far left, is from the #4 intake. There is no original surface left. The middle one (#4 exhaust) is how the rest of the studs looked, with the hourglass wear pattern. The far right one is from the #3 intake, and is not quite as bad as the other one, but is still pretty bad.

Is this common? Are these just really crappy studs? The truck has 180k on it, but supposedly 30k on the rebuilt engine. I don't know if it was really rebuilt or not.

The mating surfaces on the valves looked perfectly fine, and the truck runs much smoother and quieter now, although when it's cold it stumbles at low rpm's where it didn't before. Any suggestions on whether or not the correctly (probably) adjusted valves could cause the low rpm stumble?

Andy

Dang, them look all kindsa messed up! Running with too much lash can hammer them like that though...I suppose. I have a couple of rocker assemblies, misc rockers and of course studs.....not mentioning the assemblies on my 4x4 (250K+) and 4Runner (205K+) and none have looked that severe. Common on these engines...yup. Just the nature of the beast, some just are more ummm, advanced than others. LOL

~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

>>>*We see that a lot, probably the most overlooked wear point on these engines.
Once they start to go, they go fast. I would be a little worried about the valve tips from the damage I see there....*EB

Would any damage to the valve tips be obvious? From what I could see, they looked perfectly smooth and clean, so I was hoping maybe these were cheap adjusters and were much softer metal than the valves.
Regardless, I plan on inspecting everything in a week or two to make sure there is no accelerated wear of the new adjusters due to some damage to the valve tips that may not have been easy to see.

neither darin nor EB, who both know wayyyyyy more than me about this subject, mentioned this, so maybe it doesn't really matter, but...

i think you should adjust the valves to 7/11 cold with *very slight* drag on the feeler guage (the FSM says 8/12 hot with *very slight* drag)...

my guess is that, with moderately heavy drag at 7/11, you are actually running 6/10 or maybe even 5/9. i would think this might cause idling problems.

darin or EB (or anyone), what do you guys think?

this brings up an interesting issue i always have when adjusting my valves...what constitutes "very slight drag"?

if i ajust the valve lash to where i think it has "very slight drag" with the correctly sized feeler gauge, i find that the next bigger size feeler guage will also fit without too much problem (though with noticeable drag) and that, if i force it, i can get a feeler guage 2 sizes bigger to fit and slide around with lots of drag.

does that sound about right? or am i taking the *very slight* part too far?

Slight drag, heavy drag....dressing in drag are all confusing to me. <img src="/forums/images/graemlins/wink.gif" alt="" />

Seriously though, trying to determine the amount of drag is like asking a group of people what is better a 3.0L V6 truck or a 22R-E! Its opinion in my mind. Considering the lack of direct easy access to the intake side, the thin profile of the feeler gauges (flexing etc) Id say its not an exact science getting the valves set to a specific number. I generally check mine/adjust to spec's then follow up with a rattle them check. Basicly rock the rocker so that it contacts the valve tip and cam, if one doesnt sound right I check/reset it again without the feeler gauges until I get them all singing the same.

That make any sense??

Growing up my brother would "barely" hit me when the folks busted him....my thoughts on the subject were he "pounded the hell out of me". See the similarity?? <img src="/forums/images/graemlins/zombie.gif" alt="" />

~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

<img src="/forums/images/graemlins/lol.gif" alt="" />Darin,you kill me!lol <img src="/forums/images/graemlins/lol.gif" alt="" /> I didn't see this mentioned either so I'll jump in!The valve adjustment depends on what type cam you are running.If stock,run stock spec's.Each cam comes with a card telling you what the lash should be.When I first got my truck,I knew it had a crane cam but I didn't know any better so I set it to stock spec's.I found the card in the glovebox 1 day but by then it was to late.My adjuster screws were mushroomed and my rockers were off their rockers.Bought a complete rocker arm assembly from EB and adjusted to cranes spec's and haven't had a problem since.Good luck to you! <img src="/forums/images/graemlins/cheers.gif" alt="" />

Well, I do have a non-stock cam, but I have no idea what it is. The previous owner just told me that the engine was rebuilt by a shop 30k ago and he didn't know specific details of the rebuild. At this point, if I make sure to listen closely to the engine when driving, and if I check everything in a couple of weeks to make sure there is no rapid wear taking place, is that about all I can do (other than buying a new cam for which I do know the specs)?

Andy, give THIS a read; might help. Could the PO point you in the direction of the shop that did the rebuild? Just a thought.

I definitely want to make use of that article in the future. The main thing I need to do is get my hands on a good dial indicator and adjustable cam gear, but that is a ways down the road. Even if I did that though, I still wouldn't know what the recommended valve lash values are for my cam.

I think you're right though, probably my best bet is to contact the previous owner and see if I can get more info from him. He said he didn't know much about the engine before, but he at least ought to know the shop that did the work.

Also, a friend suggested that if the head has been machined, or has odd head gaskets or something, that this could possibly cause the adjusters to wear like they did. This doesn't quite make sense to me- anybody know if this could be the case?

Thanks again.