unknown noise

[Tank]

Did cam swap, headers, springs, valve job... everything was running and sounding fine. Then i changed the oil back from the 10w 40 to my 5w 30 syn power. And later that afternoon i unhooked exhaust at cat back to see what straight headers sounded like. Next day i cranked it, idled for a minute, then put it in drive then a loud knocking noise and rattle and grinding sound took place.

Couldn't find the noise and went away. Now after it idles for a second it makes the same sound but softer. Cant hear it from top side with hood up. Laying under neath it sounds as if it coming from the right rear of the motor, actually almost in the bell housing???? i've touch all heat shields, etc... no luck.

Any ideas?

[ThumpinZ]

You have to love the unknown sounds... I hate it when I get one of these issues. Everything tight? WD-40 and duct tape??

[6.0vortecchevy]

Did you mess with the oil pick up tube?

[Tank]

hahaha

and no i didn't. i did check it tho... it was tight

[Duct_tape123]

Headers hitting frame. Pacesetters are known for this. Unbolting the exhaust caused it to loosen up because you didn't have the u-bolt clamps tight enough. Let the truck get to operating temp and then take a pry bar of some kind and move the passenger primaries away from the frame.

[chevyboy.520]

My pacesetters did same thing, one of my O2 sensors was loose and it sounded exactly like a loose heat shield, I'd check them and maybe that could be it, just my .02

[Tank]

i'll check on it, but they aren't touching nothing... it sounds like it's in the bell housing still. I'll check the O2's

I got another bigger prob.

Coming home today all of a sudden on the driver side one cylinders valvetrain started yelling. It is loud chatter/clack. We stopped finally and truck was idling funny and acted if had loss of power slightly, but cruised fine. It went away after we took back off. I didn't know if i was gonna make it home or not it was that loud.

It then went away right before we got home. Lifter stuck while running? never heard of it. Carbon got wedged between valve and seat keeping it from closing?

ideas?

[molitor]

pour a whole bottle of marvel mystery oil in it and run it till your next oil change. That might free up a piece of sludge trapped in a lifter. I just swapped cams and lifters and reworked my heads. When I put everything back together it was fine for about 30 miles and then started clacking again like i had another bad lifter. I ended up installing a .025'' short pushrod on the No. 1 exhaust valve because the head shop forgot to shorten the valve stems when he grand the valves, and he just happened to take too much material off of that one. Not sure if all of this helps, but if you pull the valve cover and the rockers arms you should be able to put a straight edge across the valve tips and find out if one is short or long.

[Tank]

Yea that sounds like an idea. I had valve job and the bowls cleaned up. And its been over 1000 miles on it since the swap... i'll give it a try. It was still sounding good today, so maybe it's good.