WHAT CAUSES PISTON SLAP?
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Banned
Joined: Apr 2000
Posts: 299
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From: athens, TN
WHAT CAUSES PISTON SLAP?
I am not sure I understand how piston to bore clearances can cause piston slap.
What causes this problem?
Is this a generic problem to all lightning engines?
How detrimental is piston slap to engine life?
Thanks!
What causes this problem?
Is this a generic problem to all lightning engines?
How detrimental is piston slap to engine life?
Thanks!
Senior Member
Joined: Feb 2000
Posts: 1,544
Likes: 0
From: Kalamazoo, MI, USA
The rare occurance of piston slap involves rocking of the piston in the bore -- causing an audible noise from the rocking of the piston skirt against the piston wall.
It usually accompanies OLD engines where the pistons have worn the cyllinder to an oval shape.
Symptoms of collapsed valve adjusters are very often blamed on piston slap.
The checklist for rod knock (the bearing end) is:
Noise for first half-second to two-seconds upon start up.
The checklist for valve-adjuster is all of:
a) noise upon start up
b) follows engine speed *regardless* of whether in or out of gear
c) noise continues at idle in gear
d) noise continues from idle thru and over 2,000 rpm in gear
The checklist for piston slap is:
a) noise upon start up
b) noise *does not* occur at idle but
c) noise *does* occur in neutral between 1000 and 2000 rpm but
d) noise *goes away* if in gear at idle
*and*
e) noise goes away upon mild brake-torque at 1000 rpm
I have not seen a case of piston slap with the Triton engines documented on this board (all have been 'reports' -- with no piston and bore measurements in support offered).
No 'slappy' engine has had the piston slap corrected by replacing the pistons.
Sightings of Elvis and Big-Foot are more credible than slappy-piston engines.
I am betting a nickle that when the dust settles, the 'slappy piston' engines will be valve-train noise and not piston slap noise.
I have a personal hunch that the 'fix' will be 10w30 oil (would someone with a noisy engine please try it???) -- and further the bet is that it will be collapsed valve adjusters.
Flame me now -- but just remember 30-Jun-2K cuz later -- I'll be a 'told-you-so'.
But then again, just who the hell is Y2K 7700 4x4, anyway?
It usually accompanies OLD engines where the pistons have worn the cyllinder to an oval shape.
Symptoms of collapsed valve adjusters are very often blamed on piston slap.
The checklist for rod knock (the bearing end) is:
Noise for first half-second to two-seconds upon start up.
The checklist for valve-adjuster is all of:
a) noise upon start up
b) follows engine speed *regardless* of whether in or out of gear
c) noise continues at idle in gear
d) noise continues from idle thru and over 2,000 rpm in gear
The checklist for piston slap is:
a) noise upon start up
b) noise *does not* occur at idle but
c) noise *does* occur in neutral between 1000 and 2000 rpm but
d) noise *goes away* if in gear at idle
*and*
e) noise goes away upon mild brake-torque at 1000 rpm
I have not seen a case of piston slap with the Triton engines documented on this board (all have been 'reports' -- with no piston and bore measurements in support offered).
No 'slappy' engine has had the piston slap corrected by replacing the pistons.
Sightings of Elvis and Big-Foot are more credible than slappy-piston engines.
I am betting a nickle that when the dust settles, the 'slappy piston' engines will be valve-train noise and not piston slap noise.
I have a personal hunch that the 'fix' will be 10w30 oil (would someone with a noisy engine please try it???) -- and further the bet is that it will be collapsed valve adjusters.
Flame me now -- but just remember 30-Jun-2K cuz later -- I'll be a 'told-you-so'.
But then again, just who the hell is Y2K 7700 4x4, anyway?
Senior Member
Joined: Feb 2000
Posts: 1,544
Likes: 0
From: Kalamazoo, MI, USA
Nobody.
But I'm not going to worry about my engine until some facts surface.
Until then, I just turn up the CD player and enjoy Shania, Whitney, and Britney.
213 days with no slap, cracks, or trips to the dealer.
Go Ford!
------------------
Y2K™
Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"
But I'm not going to worry about my engine until some facts surface.
Until then, I just turn up the CD player and enjoy Shania, Whitney, and Britney.
213 days with no slap, cracks, or trips to the dealer.
Go Ford!
------------------
Y2K™
Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"
Member
Joined: May 2000
Posts: 72
Likes: 0
From: (Sabar Springs) , CA, San Diego
Y2K 7700 4X4 - A few thing about my noise from my engine. The Noise is the loudest from the bottom of the car from the oil pan. The Sound is like a Diesel truck and it make this when the engine is cold. For my engine it takes more then a few minutes to settle down like the others trucks are seeing.
If I had a Value-adjuster with no lash or too much lash then the noise would be Louder from around the value covers?
All Lightnings have automatics transmissions so the engine has a little load turning the input side of the tourqe converter at start-up.
If a fix action is running heavy oil, then this is a cover up of a my engine problem. Ford(SVT) says to use 5-30W then it better work at 5-30W!
Dave
If I had a Value-adjuster with no lash or too much lash then the noise would be Louder from around the value covers?
All Lightnings have automatics transmissions so the engine has a little load turning the input side of the tourqe converter at start-up.
If a fix action is running heavy oil, then this is a cover up of a my engine problem. Ford(SVT) says to use 5-30W then it better work at 5-30W!
Dave