Piston Slap?
 

I've got an '88 Trans Am, 305 TBI. The heads belong to the engine and there have been no mods to the block, cam, crank, or heads.

At idle my car has a fast, rythmic clicking sound on the passenger side head. The click continues, though faster, as the engine revs. Could this be valve / piston slap? It only happens on the passenger side head, and it is NOT an exhaust leak (as I checked for this as the car ran). I'm going to get video / audio tomorrow after work.

If it is piston slap, how do you fix it? What causes it? It's definately a clicking sound, which made me think of the valve train instead of the pistons themselves.

Thanks!

I have never heard piston slap sound like a "tick", only like a diesel "chug". It sounds like you may have a bad lifter or something like that.

could be a bad lifter, worn rocker, bent pushrod, or light piston slap...ive heard LS1 piston slap sound slightly like a click, though usually it doesnt sound that way

edit: pull off the valve cover on that side and start wiggling things, turn it over by hand as you do so....see if anything is loose

Yea, could be a loose rocker as well. My guess would definitely be something in the valvetrain before piston slap though.

- Justin

Piston slap will go away as it warms up. My 93 LT1 had a little bit and my 00 SS has it when first started up in the cold. It's annoying, but goes away within a minute or 2. If you still hear that ticking noise, it could be ignition(spark jumping) or valvetrain related. Hopefully it's not a bearing.

After doing some reading online it sounds more like a lifter problem. What would visually indicate that? A loose rocker? This is a flat tappet, not a roller. I also read up on "lashing" but haven't a clue how to set it. Would this cause something to be loose enough that it would cause a continuous clicking sound?

After re-reading this, it may be time to call someone in to look at it. Starting to get in over my head here. :P

Dave:

Have a look.

http://www.cranecams.com/?show=techarticle&id=2

Thanks Bill! I think I followed most of it, however it reinforces my thoughts about getting help. :)

Chevy cams have a rep to be on the soft side , you might have a cam lobe that has worn off and because of that will sound like a loose tappet , normally they stay quiet with out something going on , if you can take the valve cover off and run the motor the bad lobe, on its rocker arm will not move up and down as much as the others ((( caution ))) oil will spray all over doing this so be advised , you can try to adjust it but the noise wont go away --- if its just loose it will go away but thats almost never -- just what i have seen doing this -- jz