64 C10 Engine Ticking Sound Help

[850_C10]

I've been trying to figure out this ticking noise on my 64 C10 for a long time now and haven't made any progress. The engine is a 1978 250 Inline six and I have put a new cam in it, new lifters, new pushrods, and even new rockers and the ticking still won't go away. I have also taken the head off and cleaned the valves and one valve does not slide through the guides as easily as the others. Could that be the problem? I am at a loss, any help is appreciated.

Video of ticking
https://www.youtube.com/shorts/hxsebdoDo-Y

[geezer#99]

Does it do it with the valve cover off?

[jayoldschool]

On my 230, the ticking was one of the rocker nuts that kept loosening. It had lost its lock/oval shape. One trip to the shop for a free nut, install, lash... no tick. Worth having a look/feel of your nuts ;-)

[weq92f]

.

I'm thinking a look and feel of your nuts is something that will likely make you feel better about where the ticking is coming from. Uhmm well, I had something very similar a long time ago in a sbc that turned out to be a wrist pin had come loose.

More recently I've had bad lifters do that when they would not pump up and so the extra space in there caused a tick just like yours.

I'd pull the valve cover, run it to make sure that's not it, then examine the rockers and pushrods, confirm geometry is good and no interference(at zero lash and throughout the movement). If all that is good, I'd suspect lifters, this assuming no cam lobe issues and anything else running off the cam like fuel pump is working as expected and not causing the tick.

Disclaimer, I've never worked on an I6.

Hth,

-Kevin

[54blackhornet]

Bad lifter or multiple ones. China has not figured out how to properly heat treat metal.

[RustyPile]

I listened to the video for several minutes.. That's quite the hammer noise. loose lifters make more subdued tick-tick-tick.. If that's a lifter, it is waaay loose and hammering.. My guess is a rocker arm is hitting that purty valve cover. Could also be a bent pushrod hitting the side cover..

Here's how I locate stubborn lifters.. Remove the valve cover and start the engine.. With a gloved hand, press against the pushrod end of each rocker arm.. The one making the noise will "tick" in rhythm to the rocker's push against your finger...

God forbid it's something more serious, like a cracked piston...

[cag]

cut the oil filter open, look for shiney stuff, if so cam is prob toast