is there a test to determine pistonslap?

[warren]

im really bummed out today, im 99% sure i have pistonslap. im takeing it too the dealership on monday, i have a couple of concerns. 1, my car is slightly modded, cold air intake,x-pipe w/cats,catback and its lowered. and after readind an earlier post about voiding warrenties im wonering if they will give me hell for it. 2, i called into the customer service in mischigan and they got back to me and said its a normal sound with these cars because of the forged pistons. i think its BULL S@#$!! anyways they told me to bring it in and have it looked at. if they try to tell me its a normal sound is there some kind of test they can do to determine if its is pistonslap? is a stethiscope good enough? that might be a dumb question. anyways i hope im wrong, if the car sits for a day or longer on a cold start it sounds like a diesel and then when she warms up it goese away. i paid cash for this car because i fell imediateley in love with her when i first laid eyes on her in themustangs and fast fords mag. my original plan was too build a badass fox bodied street machine:shrug: if it is piston slap i hope they will take care of me without the hassle with the mods.
ooooooooohh brother;-)

 

[Hunter]

I would just take the filter and exhaust off. It's not hard to do. That way your warranty won't be in jeopardy.

 

[warren]

my dumbass put everything in the garbage

 

[Hunter]

Originally posted by warren
my dumbass put everything in the garbage

Too bad. Good luck with the warranty. I hope you have a cool service manager.

 

[94SVT Coupe]

Piston slap sounds like a knocking/tapping sound that increases in volume and speed with engine RPM's. It's worse the colder it is, and goes away usually within a few miles depending on how cold it is. Mobil 1 can help reduce the noise.

FWIW, my Cobra @ 1000 miles (2nd oil change now) has ZERO slap or tick noises. My F150 is a slapper in the cold, so I know what it sounds like. I even listen for ticking or tapping noises in the garage when it's started up. Nothing.

 

[SID297]

Find someone with a newer Chevy truck if you want to hear some real piston slapping, especially the 6.0.

 

[94SVT Coupe]

Yea, I hear the Chevy's slap bad even the 5.3's. The Ford 5.4 is a slap happy motor too.

 

[JB]

I've posted this link before but its a good synopsis of the issue so here it is again:

:read: http://www.canadiandriver.com/articles/jk/020320.htm

 

[rskdsk]

94svtcoupe is right on with his description. Piston slap sounds like a desiel on start-up if the car is cold. It goes away after the car warms up. The reasoning behind it is that piston slap is caused by a clearence difference the piston and the cylinder wall, and once they heat up the metal expands and the tick goes away. It usually happens within the first 2000 miles of a car, or after a engine has been worn or beaten on (75000+ miles). My first 03 cobra had the engine replaced due to piston slap, and the dealer filled me in on the above details. The main reason piston slap is bad on a new car is because it causes the piston/cyclinder walls to ware prematurley. I do not know if all of this is fact, but this is the way the dealer explained it to me. The way they tested my car was to let it sit for 2 days during a couple of cold nights, when they did start it ... you would have thought they just started a mercedes deisel. They reved the engine to about 1500 rpms, and it got worse. With 2 minutes the sound was completely gone. I never notice any performance problems with the car.
Good luck.
One last point, I did notice that every now and then when I started my car, I would see a puff of blue smoke ... I guess the oil was getting through the bad clearance and burning.

 

[SID297]

From what I've heard all the newer Chevy vortec v-8s are slappers. I guess it's just luck of the draw.

 

[Dana]

Piston slap is not normal. It is an indication of ill-fitting pistons in the cylinders.

If it was normal, they would all do it, and they don't all do it.

Initially, it shouldn't hurt performance, but eventually it will cause premature wear and ring failure.
I would keep fighting until something is done to correct the problem.
As far as a test for it goes, a skilled mechanic can tell the sound from a block away. Technically, the block would have to be torn down and the suspect cylinders and pistons measured to check for excessive or out of spec clearances.
Dana

 

[warren]

update! brought the cobra to the dealership on monday and left it overnight. met with the service manager the next morning. i started her up and heard the tap for about 10 secounds and it was gone! he reved the engine up a little and asked me what oilfilter i use. ford motocraft, and what oil i use(5-30) mobil 1. anyways he gave me a few options 1- he said my warrentie is good for a long time and that i could just keep driveing it until it gets worst then bring it back in. but that doesnt make sense to me, why make it worst before fixing it??
or they will have to keep the car for a minimum of 2 weeks and tear into the motor an find the problem. he also said that the tapping sound could be a lifter and , when i cold start it theres no oil in the heads and that can cause the tap. but the tapping just started last month and i already have 8,200 miles on her. doese that make any sense. anyways he kept the cobra and will be starting her back up tommorow to try to isolate the sound. good news is he didnt say anything about the mods, but i noticed him checking the pulley and throttlebody! but he was checking out tha aftermarket air intake and the position of the mass air meter. but he seemed cool about everything!!woooow!!

 

[Dana]

Take this for what it's worth, but whether the dealer is cool with the warranty isn't going to matter if you have a pulley or chip and end up needing a motor. The Ford reps get involved at that point and there goes your warranty claim if you have either.
From what I have read here and other boards, the dealers are not repairing the motors, but instead replacing them. This is apparently Ford's policy with this motor. The farthest into the motor I have heard that the dealers have gone it the valve train.
I don't know if you do actually have a chip or pulley, but if you are going to pursue the noise issue at this time, pull them off for the time being.

Dana

 

[warren]

thanks Dana!, i have neither chip or pulley.

 

[rskdsk]

I have heard the same thing and in fact Ford told the dealership to replace my engine. They did not want the dealer tearing it apart because they wanted to do that at SVT. It was a good thing because while pulling the engine out they found that I had a head gasket leak as well.