HELP - Do I have a Rod Knock or Bad Lifter?

[NO SLO PK]

Guys this is killing me...

I did a pass in my 5.0 at Fontana last March. When I got onto the return road I noticed a ticking sound from the engine.

Over time, the ticking has become louder, more like tapping. Now the tapping is sounding more like clacking.

The noise used to disappear when the engine warmed up. Now I can hear it all the time.

I pulled both valve covers and everything checked out okay...no broken push rods or rockers...everything in spec. (DARN!)

It's definitely not exhaust. I've had those problems before.

I was thinking it was a bad lifter, but it's getting so d*mn loud so I wonder if it's worse.

How can I find out without pulling the motor?

When you checked out the pushrods...did you happen to inspect the tips of the them? I had a similar ticking noise that turned into a knocking noise. I finally ripped it all apart and it ended up being a pushrod wasn't getting adequate lubrication due to a piece of gasket to RTV silicone. It was jammed into the hollow, center part of the pushrod where the oil travels up to lube where the rocker pivots on the top of the push rod. So the pushrod & rocker were not getting any lubrication really, at all. I replaced the scratched up pushrod, readjusted the valves...and everything has been a-ok.

[tireburner163]

Pull the plug wires one by one. If it's rod knock usually it will get quiter when you pull the plug to the cylinder that's knocking.


-Josh, aka the tireburner

[andy669]

Originally posted by tireburner163
Pull the plug wires one by one. If it's rod knock usually it will get quiter when you pull the plug to the cylinder that's knocking.


-Josh, aka the tireburner

I'm impressed Josh, thats an old timers trick.

Something else you might try is to hook up a timing light. If the noise seems to follow the light flashes, then its valve train related. If the noise seems to be twice the speed of the light, the its something related to the rotation of the crank.

Andy

[NO SLO PK]

#7 and #8 pistons are hitting the heads.

Probably from collapsed piston skirts.

I'm bummed out since this motor had only 15k miles on it. Now I'm trying to figure out if I want to do a stroker or just rebuild the engine I have. Once again, it boils down to a question of money.