Question on my 03 Cobra: Piston Slap! ...day after I purchased my Cobra in Oct. 05, started cold and thought I had a knock in the engine, being an old 5.0 guy...after a little research & calling SVT, they told me this is normal!?

My car only does this when it's cold for about 5-10 sec. and then goes away once warm. The Cobra does run strong based on my ET's....just seems odd to me!

Anyone else have any info. on this??

Thanks....Tim

 

Piston slap would be caused by 2 things. The forged material being cold and knocking around the cylinder wall or the lack of oil reaching the top of the engine making it "sound" like piston slap. I don't see either of these things happening on purpose from the factory. I'm not saying that it's going to blow up or anything but it doesn't seem right at all.

 

my understanding that this is common with the modular engines (97-04)....

 

I never had "piston slap" and i've had a 04' GT, 03' Cobra and a 03' Mach 1... not to mention my stepbrothers 04' GT and his dads 04' 440A Roush, and none of us have ever experianced that..

Injector noise, yes... are you sure it's not something like that? Or a/c noise? I use to have an issue from my compressor that was making noise on first start up... ended up being a compressor that was in the midst of breaking down, lol..

 

trust me, it's not the a/c or injectors; friend on mine had a '99 Saleen that had it so bad, he had to sale!

 

No clue then... Like I said, I've never had piston slap on any of my New Edge Mustangs... including my 03' Cobra...

Does it ONLY happen when the motor is cold? Could it be the head tick? Just not sold that it's piston slap if SVT is saying that it's normal.. lol

 

I'll try to post a clip the next time I start the Cobra....if it was a head tick, wouldn't it be there all the time? ......yes this happen ONLY when the engine is cold!

I called SVT, they described it as "piston slap", because of the tight tolerances on the 03Cobra, they described this as "normal"......I just wanted to see if others experienced this.

 

Do a leak down test bud. While you're at it, maybe a compression if you want. I always tell people to start there when it comes to internal issues. Might be nothin, might be something. Also remember that your reading can be different from a warmed motor and a cold motor so try it both way. Start cold though, cause that could save a bunch of time.

 

i'm looking at selling my gt for a cobra in the next few months. what do u need to look at( listen to) to avoid gettin a car thats going to have alot of piston slap?

 

First thing I'd do is make sure the engine is "Ice" cold; I travel twice before I purchased the car from the dealer, and every time I got there, the Cobra was running....I noticed the next day I started it.....it was a 3 hour trip back to the dealer, so I called SVT....

Don't get me wrong, this Cobra (and most) run real strong! ....I will try to post a clip & hopefully you can hear it!..........