Noticed my P31 C63 seems to have a little bit of piston slap until it reaches engine temp when it’s slightly cooler out or on colder mornings. Only reason I feel this is because my race engine in one of my previous WRXs had piston slap but was much louder than this car is.

I remember my engine builder saying for forged pistons this can happen with the expansion and contraction of the piston based on temperature. figured with the P31 forged pistons this might be common. Although I’ve tried to find threads on here to see and haven’t come up with much. Just ticking noise threads which my engine has zero ticking noises. So I’m reaching out to you all

any C63 owners with the P31 package notice any “knock like” noise upon partial load when the engine hasn’t fully warmed up that you would agree is piston slap? There are zero of these cars local to me so I can’t ask around locally at all.

 

end of this thread a few people talking about it recently https://mbworld.org/forums/c63-amg-w...lifters-4.html

 

Right, i read through that thread and messaged an individual or two but no one that i saw actually mentioned piston slap accept for one that had compared it to his LS motor. Funny, I’ve have 3 Vette’s with various LS motors and only one of them had piston slap but it went away fairly quickly.

someone did post a video though of exactly what i had heard and i messaged that individual as well. Just don’t want this to get blurred together with the adjuster threads. Not too worried about it, just wanted to see if others had heard the same on their cars. That would help me decide next steps although as of now I don’t plan to do anything because this behavior could be viewed as normal engine behavior or a performance engine with forged internals.

 

I agree with luvboost in that I believe its piston slap.
When my engine had the dreaded ticking you didn't notice it.
But now that there is no more ticking or rattle on start up I can here the lite knocking between 1200-2000 rpm as you accelerate slowly.
Above 2K the exhaust is too loud to hear it any longer.
With my old LS engine I just learned to ignore it until it went away with warm engine.

 

Thanks Cwagon - so replacing your timing belt tensioner didn't help this at all?

 

Mine definitely has a slight knock at low load when cold, but it goes away completely when warm. TBH, I just assumed it was lifters, camshaft adjusters or any of the other 101 things that make noise on this engine, LOL. But this kinda makes sense since the noise is only present after a cold start.

 

Engines make noise. There’s nothing you can do about this one if it even exists. Move on.

 

right, Just want to make sure the threads are out there to educate and provide information for those who need to know what the difference is in these noises being heard. I'm not worried about the car making noises. It's basically a race built engine. I just want to make sure the noises it's making are commonplace and expected (sounds like they are). I've had many race cars in my time and heard many noises that don't bother me.

Also, if the non P31 cars don't have forged pistons then they probably don't exhibit this behavior. I haven't read into the non P31 C63's though so I could be wrong.

I'm just glad these forums are as active as they are. Several others have died in the recent years.

 

thanks again for pointing me in this direction as well!

 

..

 

Mine makes the same noise but intermittent, cold or hot. I hear more from inside the cabin, when I open the hood it's not so obvious.

 

Here is a video I took this morning of it, a bit clearer than my last one - https://www.dropbox.com/s/3wz0ook4ml..._7015.MOV?dl=0

 

is yours a p31 c63?

 

Mine is P30, in Brazil we do not have P31. I believe to be the same thing.

 

Sorry to dig this up, does it sound like this?

 

The noise I here in that video sounds more like rocks/stones being flicked up underneath the undercarriage... is that the noise you're referring to? But no, i can't hear the same noise in your video as mine.

 

sorry for the awful video. I just checked out your link and yes it’s the exact same sound in both videos. Follows the rpm when car is cold, most noticeable around 1500-2000 rpm?

 

definitely according to the video if they are true to sound...very different. the OP's video sounds like engine knock/detonation, engine mount, or something ancillary, and heavy knocking around.

yours sounds like a heatshield/splash guard is loose and rattling.

 

Yes and loudest under light load (ie guessing 10% throttle where as 5% you can't hear it as much)

 

detonation? Try changing gas. Shell 93 seems to be a good 93 octane product. All aren't equal.