Quote:
Originally Posted by Jake1074
Good points. Both rockers were extremely loose on #6 - As if they were intentionally backed off. The clatter and visual was obvious once the valve cover was off.
#6 was also the cylinder with the old spark plug that had no gap.(see pic above) All the other plugs were gapped at .035 and were burning clean.
Let’s say the cam is bad on #6. Would both lobes go? Seems there is more to this mystery - perhaps the seller’s short term fix to get rid of the truck?
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I'd ignore anything the seller told you, unfortunately. Both lobes would not necessarily go bad together. No idea how the plug tip got bent, seller probably only had 7 good ones to put in it. As far as intentionally backed off - if the cam lobe gets wiped, the respective rocker will only appear backed off, even though it's in the same place (and probably similar to the others). Do you happen to recall before you tightened down the rocker arms whether roughly the same amount of rocker stud thread was visible (compared to the known good cylinders)? What about now? Also - another thing to consider is that sometimes rocker studs can pull out of the head partially. Might be a good idea to, as best you can, sight across the tops of all the rocker studs and see if the #6 cyl ones are notably higher than the rest. This can give the appearance of a wiped cam lobe - but the giveaway is one (or two) rocker studs noticeably sticking up higher than the others. Doesn't have to be much though to essentially keep the valve from opening or only allowing it to open partially. Re-tightening, as you did, may solve the issue temporarily (or for good if the stud doesn't slip any further). But, once loose, they normally won't just suddenly be happy in their new location. Just one more thing to check. If you have screw-in studs, then disregard, only possible with press-in studs, which is how they came from the factory. If this turns out to be the case, the cam is likely still good - but screw in studs are the only reliable solution at this point, and that requires machining of the stud boss and purchase of a set of screw in studs.