Notices
Drivetrain Gearbox, Diffs & Driveshafts etc

whats piston slap? what happens?

Thread Tools
 
Search this Thread
 
Old 19 October 2004, 05:58 PM
  #1  
Jamo
Cooking on Calor
Thread Starter
iTrader: (23)
 
Jamo's Avatar
 
Join Date: Oct 2001
Location: in a house full of girls!
Posts: 23,346
Received 7 Likes on 2 Posts
Default whats piston slap? what happens?

as above really.

jamo
Old 19 October 2004, 07:27 PM
  #2  
atkins0n
Scooby Newbie
 
atkins0n's Avatar
 
Join Date: Aug 2004
Posts: 23
Likes: 0
Received 0 Likes on 0 Posts
Thumbs up well...

Basically its where the fuel and air mixture is ignited before the piston is at TDC (top dead centre) (at its highest peak on the crank revolution)... and therefore in basic terms it now explodes rattling the hell out of the piston rings and piston...causing PISTON SLAP..

Regards

joe
Old 19 October 2004, 07:31 PM
  #3  
mitch p1
Scooby Regular
 
mitch p1's Avatar
 
Join Date: Sep 2004
Posts: 48
Likes: 0
Received 0 Likes on 0 Posts
Default

i think thats called pinking??????
not to sure


well if its the same as a motor bike then its when the rings wear down and the piston tilts in the bore not by much about 0.02mm. it normaly sound terrible. not so common on cars i think!
Old 19 October 2004, 07:32 PM
  #4  
atkins0n
Scooby Newbie
 
atkins0n's Avatar
 
Join Date: Aug 2004
Posts: 23
Likes: 0
Received 0 Likes on 0 Posts
Red face WOOOOOPSSSS

Originally Posted by mitch p1
well if its the same as a motor bike then its when the rings wear down and the piston tilts in the bore not by much about 0.02mm. it normaly sound terrible. not so common on cars i think!
Sorry guys I am an idiot,,,I was thinking of Pinking!!!

joe.
Old 20 October 2004, 01:00 AM
  #5  
StickyMicky
Scooby Regular
 
StickyMicky's Avatar
 
Join Date: Feb 2003
Location: Zed Ess Won Hay Tee
Posts: 21,611
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by atkins0n
Basically its where the fuel and air mixture is ignited before the piston is at TDC (top dead centre) (at its highest peak on the crank revolution)... and therefore in basic terms it now explodes rattling the hell out of the piston rings and piston...causing PISTON SLAP..

Regards

joe
gimp
Old 20 October 2004, 01:02 AM
  #6  
StickyMicky
Scooby Regular
 
StickyMicky's Avatar
 
Join Date: Feb 2003
Location: Zed Ess Won Hay Tee
Posts: 21,611
Likes: 0
Received 0 Likes on 0 Posts
Default

the bore is slightly out of shape, which means the piston can slap about a bit while its cold, when its warm it expands and genraly clears up

mine slaps when cold, and so do a lot of other cars

its not half as serious as sum make out, as long as it clears when its hot
Old 20 October 2004, 01:13 AM
  #7  
Welloilbeefhooked
Scooby Regular
iTrader: (3)
 
Welloilbeefhooked's Avatar
 
Join Date: Sep 2003
Location: Sheffield
Posts: 3,577
Received 0 Likes on 0 Posts
Default

Originally Posted by StickyMicky
the bore is slightly out of shape, which means the piston can slap about a bit while its cold, when its warm it expands and genraly clears up

mine slaps when cold, and so do a lot of other cars

its not half as serious as sum make out, as long as it clears when its hot
Out of shape or worn bores can cause it. MY98 cars had one of the cylinders with too large a clearance that caused piston slap. I think its mainly the cylinder nearest the turbo?
Old 20 October 2004, 02:07 AM
  #8  
ALi-B
Moderator
Support Scoobynet!
iTrader: (1)
 
ALi-B's Avatar
 
Join Date: Apr 2002
Location: The hell where youth and laughter go
Posts: 38,034
Received 301 Likes on 240 Posts
Default

I've got some pistons hanging around taken out of my old slappy Rover somewhere. I've typed the full wind of this somewhere, some chappy has even posted it on a website somewhere....

In short, piston is too small/bore too big/out of shape, piston skirt makes contact with the bore at TDC and BDC, causes wear to piston skirt and bore. In the long run (and I mean VERY long run) it will cause oil consumption and a little loss of compression. Normally only something to really worry about when it's doing it whilst hot.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Matt_182
Wheels, Tyres & Brakes
19
07 October 2015 01:05 PM
bluebullet29
General Technical
9
05 October 2015 02:17 PM
Ganz1983
Subaru
5
02 October 2015 09:22 AM
bluebullet29
General Technical
2
27 September 2015 07:52 PM
wrx2015
General Technical
2
12 September 2015 08:07 AM



Quick Reply: whats piston slap? what happens?



All times are GMT +1. The time now is 02:15 PM.