hbgben

I have researched piston slap on the net as well as on this entire forum. I am interested in buying a 99 Z28 that has 100k on the clock. I managed to get to the dealership when the car was cold and started it up. I knew that these motors have piston slap, but after driving the car for 20 minutes, the slap is still there. It is very prominent at idle. Shouldn't the slap quiet down after the engine has reached operating temp?

I am being offered a good deal on it and don't really want to walk away from it, but I don't want to buy it if the piston slap is always there when in fact it should go away when warm.

Any insight is appreciated.

Z28LS1camaroguy

iTrader: (3)

are you sure its piston slap??? i use to have a tick sound that i thought was piston slap but it ended up being that EVAP canister thing ticking, and it didnt go away after heating up either. What side is it mainly coming from or is it from both sides???

hbgben

Sounds like it comes from the passenger side

xXSilencerXx

iTrader: (4)

What does piston slap sound like?

markp03

iTrader: (4)

what are they telling you it is? where is it coming from and what does it sound like.... I would get it checked out first...unless you are getting a sweet deal and plan on building the motor sometime....

Smokin00WS6

iTrader: (4)

could be an exhaust manifold. Check your headers out, put your ear down there! lol easier said then done. But check that out

Thule

pistons dont slap for 20min, you dealing with something else

hbgben

I took the car to my mechanic and he looked the car over, underneath also. The car was 1 qt. low so he put in a qt of Valvoline 5w30 just because of my interest in the car. The car drives straight and pulls hard, as they should. The car doesn't shake and you can't hear the noise driving through town. When we got back to the shop, the noise was still there and my mechanic told me about piston slap.

If I were to purchase this car, how much would a rebuild of the bottom end cost roughly with new pistons and a clean up of all of the cyclinder walls?

Would it be a good idea to have a compression check done on the car before purchase to find out any current issues?

darom

iTrader: (2)

yes, this will be a good idea to do before you decide to purchase it. Ask your mechanic doing it to check the spark plug condition as well.

hbgben

I'm going to have the compression check done.

Any thought as to why it still slaps after it warms up?

8a8mfh

iTrader: (3)

Well...at least the seller didn't put something in the oil to make it go away.
This post makes me feel good. I bought my car at 22,500 miles. Didn't notice any noises.
First oil change with mobil 1 5w30 it was making some lifter noise, so less than 20 miles I change to mobil 1 10w30, same noise. Took it to the dealer and had the lifters replaced under warranty, it was quiet for a few days. They said they checked to oil pump o-ring.

Now at 39,000 miles it still makes the same noise, I've raced it, run it hard, etc. At one point I took all the rockers and pushrods out, everything looked normal.
I've had people that don't know anything about cars ask me what that noise is, like my mom.
My opinion is the lifters aren't getting enough oil. If I rev it to maybe 2000 rpm it goes away, bring it to idle and it slowly comes back. Temperature doesn't change the noise. Heres a sound clip of it. I've posted this clip several times.

greysteel_M6

iTrader: (5)

/\ I want to say that sounds like rocker arm lash, but if you've inspected everything. The trick I use to isolate sounds is to take a wooden rod, about 1/8" in diameter, small enough to stick in your ear, then place it on different parts of the motor and listen. It muffles everything while amplifying a particular area.

NDFORSPD

exactly(using the wood as a "stethascope").....my buddy who works as a GM tech walks around the shop like he is a doc sometimes with a home made one(you can also use any sort of tubing), he uses it all the time he says, got to the bottom of which pulley was grinding pretty quick too.....maybe give it a shot