rod knock?

[im2bad4ya]

Great, just as i fixed my SSAFC issue, now it seems I have a rod knock. At least it sounds like it. It's very faint at 2.5K and you really hear it between 3-4K. It only happens on acceleration, when I decelerate it goes away. No CEL's so I'm just hoping that harmonic vibration is making something slap under the engine, because doesn't rod knock happen all the time, no matter what rpm range and whether you accelerate or decelerate?

 

[tweety2300]

No rod knock can come and go. Have someone rev the engine while you listen to see if its coming from the head or bottom end. Rod knock and lifter tick have the same tone and can happen under same circumstances but rod knock is louder. When I spun one I thought the lifter tick had just gotten louder

 

[Jaleik]

If your exhaust manifold is cracked it can also amplify the valve train noise quite a bit. Put a long screwdriver on the head and put your ear to it to see if its coming for a particular cylinder, you will hear it much louder that way.

 

[powderider87]

Exact symptoms i had when my rod bearings were going. I caught it early and replaced the bearings and all was good until i spiked 20psi one night.

 

[jeffmsp]

i crushed a fs rod bearing once, there was literally a sliver of bearing left on the crank and the motor still ran lol

checking your exhaust manifold as mentioned above should be your first step

heres a dumb question. when is the last time you changed your oil? Any chance you just having a ticking valvetrain? if your exhaust isnt leaking you could always try some heavy oil and see if the sound goes away.