So, i finally got the time to get my passengerside valvecover off to see what is causing the ticking noise in my engine. I noticed that the rockerarm closest to the front of the vehicle is superloose when compared to the others (a gap of ~1 mm). I had my friend to look at the car, and he thought that the "pusher?" or "lifter?" that pushes the pushrod that felt worn and that it should probably be replaced. What do you guys think? Its a -97 blazer with a 4.3 vortec. thanks!

 

At the point you are at, I would turn the engine over by hand and measure the full travel of the rocker. Check a few of the rockers thru full travel. If you find that the loose one doesn't have the same travel, then possibly you have a worn camshaft.

The rocker nut is not loose is it?
By the way, it's easier to turn the engine by hand with the spark plugs removed.
Keep us posted and we'll figure it out.

 

If it's loose while the engine is off, I'm betting that you have a worn cam lobe. It's possible that you have a collapsed lifter or even that the rocker nut loosened up, but there have been more than a few worn cam lobes in our engines... You'll definitely need to run through the checks as Chevy Lover has described. Before you do, make sure that the rocker arm is tightened down.

 

thanks! i'll update you when i've checked the travel distance when i turn the engine!

 

I just got in from measuring the travel distance of the rockerarms:
counting from the one closest to the front, the difference between lowest and highest position:
I : 10 mm <--- the loose rocker arm
II : 8.8 mm
I (measured again) : 9.8 mm
II (measured again) : 8.5 mm
III : 9.6 mm
IV : 8.8 mm
V : 8.3 mm
VI : 9.9 mm

the loose rockerarm has a gap of about 2 or 3 mm from the "lifter"? (not the pushrod, the other thing)

Me and my friend came to the conclusion that the camshaft should be okay, but he said that the "pusher"? , the thing between the pushrod and the camlobe, might be stuck. What would you guys think about applying pressured air into the pushrod while its in place? Might this damage something or could it possibly make things work? I should add that before this i changed the oil 3 times, and had some cleaning stuff in it in between, even nafta and ATF. The lifter would occasionally stop ticking but then it would start again.

Thanks!

 

How did you do this measurement? To check the cam lobes, I would tighten down each rocker, then with a dial indicator, check the travel of the push rod end of the rocker, zero'ing the indicator at it's lowest point and recording the highest point.

Once you have verified that the cam lobes are ok, then it is most likely that you have a stuck or collapsed lifter. I for one wouldn't try unsticking it if you can afford a new set of lifters (although they aren't cheap).

 

i'd say try tightening the rocker nut and see if there is an improvement before deciding on a stuck lifter. rocker nuts backing off a little are far more common IMHO.