Found fix for #7 piston problem

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08-21-2009, 01:53 PM
farmtruc

Found fix for #7 piston problem

You guys won't believe how simple it is!

Simply replace number seven piston with a forged one.

Maybe a group buy?

If ur worried about the rotating assembly being off balance simply replace #2 as well.
08-21-2009, 02:00 PM
Jamest

WOW?

Quote:

Originally Posted by farmtruc

You guys won't believe how simple it is!

Simply replace number seven piston with a forged one.

Maybe a group buy?

If ur worried about the rotating assembly being off balance simply replace #2 as well.
08-21-2009, 02:01 PM
DamnYankee

Gotta yank the engine to do this, correct?
08-21-2009, 02:01 PM
ducky

How much are we talking for a group buy and how many people need to be in it?
08-21-2009, 02:32 PM
Slimsilverado

Yea and how much labor to do the tear down and replacement..
08-21-2009, 02:36 PM
GasGuzzler

Do it in the truck. Pull head and pan. I think 8 people would be a good start for a group buy. Since the forged piston or most likely heavier, just grind off some of the rod.
08-21-2009, 03:10 PM
CHEVROLADE

more info on piston#7?? what happens to be the problem?
08-21-2009, 03:16 PM
Chevy-Art

Quote:

Originally Posted by STUNNA

more info on piston#7?? what happens to be the problem?

Same here.
08-21-2009, 03:23 PM
PurpleMinivan

:laugh:
08-21-2009, 03:34 PM
Slimsilverado

there seems to be a lean issue on Piston number 7, i think its caused by the intake manifold. Allen might also be pulling our leg on this one not sure....
08-21-2009, 03:38 PM
408.Luke

ok what if we already have a forged motor can we a a SUPER forged piston for number7? or maybe a SUPER DUPER forged piston? i wana be able to melt 1-6 and 8 before 7 even get the idea of changing formation
08-21-2009, 05:03 PM
CHEVROLADE

wont changing the intake solve the problem,be easier i m o?
08-21-2009, 05:14 PM
Sleaper

Quote:

Originally Posted by STUNNA

wont changing the intake solve the problem,be easier i m o?

That's not necessarily the cause of the problem. It COULD be a contributing factor but people have had #7 fail with aftermarket intakes too.
08-21-2009, 05:17 PM
Maui4x4

Is this a joke from a Ford forum? :confused:
08-21-2009, 05:29 PM
rutroe

Quote:

Originally Posted by Maui4x4

Is this a joke from a Ford forum? :confused:

The fix may be but the problem is not. Both Jay (ramair2002) and I both had #7 pistons go south. If I'm correct, the 5.3 is the only one with an advertised issue. Or does anyone know of someone with a 4.8 or 6.0 with the same issue?

A forged #7 piston only covers up the problem. If you could find why #7 is detonating, that would be the way to go. Of course, a forged piston may be strong enough to handle the existing problem...
08-21-2009, 06:21 PM
zeake

Does the LSX block have this issue.
08-21-2009, 06:26 PM
ff_jeff

:lol:
Ill be first in line for a forged transmission.
08-21-2009, 07:51 PM
CHEVROLADE

cant the tuner just work his majic on his laptop to #7 injector to throw more/less fuel?iam very confused here.is this only when running n20 or f/i???
08-21-2009, 09:43 PM
GasGuzzler

Are there really regular visitors to this site that have never heard of the ole number seven issue?

Anyone wants to call me out for making too many posts needs to realize I read all new posts (there's an ap for that LOL) and comment when it helps someone, makes me laugh, or OTHER. This is one reason I know about #7 and other stuff.

Let's not be surprised by ANY elephant in the room.
08-21-2009, 09:56 PM
PurpleMinivan

As long as they are not TSP shrinking pistons:argg:

Edit: oh yeah that was the tune, nevermind... Wait! Who's going to be tuning for these pistons?:D
08-21-2009, 10:17 PM
CHEVROLADE

Quote:

Originally Posted by GasGuzzler

Are there really regular visitors to this site that have never heard of the ole number seven issue?

Anyone wants to call me out for making too many posts needs to realize I read all new posts (there's an ap for that LOL) and comment when it helps someone, makes me laugh, or OTHER. This is one reason I know about #7 and other stuff.

Let's not be surprised by ANY elephant in the room.

ok smart guy explain :argg:
08-21-2009, 10:39 PM
DBRODS

I'm sorry, but if my motor is getting torn down, its getting all 9 pistons replaced with forged, not just #7.....:tacos:
08-21-2009, 11:02 PM
cjriojas

Quote:

Originally Posted by STUNNA

ok smart guy explain :argg:

Dont worry about it. Just keep posting UFC vids and you will never have this problem :spit:

JFWY
08-21-2009, 11:18 PM
bud8fan

the problem with #7 piston is a cooling issue with the way the water ports are made around it...thats how it was explained to me.
08-21-2009, 11:31 PM
molitor

i haven't had any problem with no. 7, but my no. 6 piston is noisy noisy. replaced rockers and pushrods, no change, been gritting my teeth hoping it will last until the 5.7L is finished, i'm a very regular visitor (high fiber diet). . . .and i have never heard of this problem
08-22-2009, 02:59 AM
Maui4x4

I knew about the #7 piston problem from reading in this forum and others... just was pointing out the fix seemed like a joke.:(

Btw I think one of the site members has one of those custom balanced "9 piston" blocks.

Quote:

Originally Posted by DBRODS

I'm sorry, but if my motor is getting torn down, its getting all 9 pistons replaced with forged, not just #7.....:tacos:
08-22-2009, 03:04 AM
ff_jeff

Quote:

Originally Posted by Maui4x4

I knew about the #7 piston problem from reading in this forum and others... just was pointing out the fix seemed like a joke.:(

Btw I think one of the site members has one of those custom balanced "9 piston" blocks.

Naw the 9th piston gets bolted on to the block. Its independent. He only uses it for going in reverse. That way he doesnt blow hot exhaust fumes out the intake manifold.
Looks like this http://www.ls1truck.com/upload/files...x_cylinder.jpg
08-22-2009, 03:49 AM
sprayedenali

^^^ i thought that was only an issue when using a turbo?? :confused:
08-22-2009, 11:40 AM
Sleaper

Quote:

Originally Posted by mitch cobb racing

^^^ i thought that was only an issue when using a turbo?? :confused:

This has happened in many different applications, FI, N20 & N/A, with different intakes, stock, LS6, Vic's... and fuel systems, return or returnless. The arguments are as follows:

1) #7 is the farthest back and due to block design doesn't have adequate coolant circulation since there are block offs unlike earlier years that had cross overs.
2) Returnless fuel systems can have trash build up in the fuel rails/injectors since there is not an inline filter and no way to return the trash to the tank.
3) The stock intake design doesn't allow for even air distribution, especially in heavily modified applications, which cause #7 to run lean and not show on a wideband.

These are the main arguments or theories. The problem is failure has occured when some of these are not present. For example, someone is running an aftermarket intake or upgraded fuel system and they still lose #7.
Nothing has been absolutely, 100% proven to be the causing factor that I have read. IMO, I think that it's probably a combination of some of the above issues and not just one in particular. In addition, the factory clearances are set up tighter than what you would normally run in a highly modified set up which just adds another possibilty of reason for failure.

If you have never heard of this being an issue, now you have! :bow:
08-22-2009, 12:01 PM
LARRY01Z28

I think allen is just joking.
08-22-2009, 12:26 PM
zeake

Quote:

Originally Posted by ff_jeff

Naw the 9th piston gets bolted on to the block. Its independent. He only uses it for going in reverse. That way he doesnt blow hot exhaust fumes out the intake manifold.
Looks like this http://www.ls1truck.com/upload/files...x_cylinder.jpg

That was good. :LOL:
08-22-2009, 12:26 PM
CHEVROLADE

Quote:

Originally Posted by LARRY01Z28

I think allen is just joking.

hes got to be,whos going to put one forged piston :LOL:
08-22-2009, 12:34 PM
Sleaper

Quote:

Originally Posted by LARRY01Z28

I think allen is just joking.

I know he's joking but I do believe that there are people not aware that this is a common issue. That was the reason for the explaination. I guess I forgot to put the REAL reason that #7 fails.......IT's THE TUNE!!:LOL:
08-22-2009, 12:45 PM
pl4yboy

I heard Allen's tunes break trannys. No one buy from him!

jk.
08-22-2009, 01:12 PM
Chevy-Art

Quote:

Originally Posted by ramair2002

This has happened in many different applications, FI, N20 & N/A, with different intakes, stock, LS6, Vic's... and fuel systems, return or returnless. The arguments are as follows:

1) #7 is the farthest back and due to block design doesn't have adequate coolant circulation since there are block offs unlike earlier years that had cross overs.
2) Returnless fuel systems can have trash build up in the fuel rails/injectors since there is not an inline filter and no way to return the trash to the tank.
3) The stock intake design doesn't allow for even air distribution, especially in heavily modified applications, which cause #7 to run lean and not show on a wideband.

These are the main arguments or theories. The problem is failure has occured when some of these are not present. For example, someone is running an aftermarket intake or upgraded fuel system and they still lose #7.
Nothing has been absolutely, 100% proven to be the causing factor that I have read. IMO, I think that it's probably a combination of some of the above issues and not just one in particular. In addition, the factory clearances are set up tighter than what you would normally run in a highly modified set up which just adds another possibilty of reason for failure.

If you have never heard of this being an issue, now you have! :bow:

I heard of it just never knew what it was.
08-22-2009, 01:49 PM
Sleaper

Quote:

Originally Posted by Chevy-Art

I heard of it just never knew what it was.

I know!! That's the million dollar question!!!! The real reason for typing up that long post was for some of he newer people on the site who may not know the common problems and weak points when you start modifying. I wasn't directing it towards any one person.
08-22-2009, 02:17 PM
Chevy-Art

I didn't take it that way. I am glad to finally know what it is. Thanks Art...
08-22-2009, 03:26 PM
gmctruckmotorsports

I didn't know about the #7 piston failure til it happened to me :pow: but I do know my 02 sensors were bad, one side was dead and the other was really weak.
08-22-2009, 03:32 PM
CHEVROLADE

so in other words the design of the ls blocks are crap,cause 7 piston will always fail?well that sux if it cant be fixed
08-22-2009, 03:38 PM
ff_jeff

Quote:

Originally Posted by STUNNA

so in other words the design of the ls blocks are crap,cause 7 piston will always fail?well that sux if it cant be fixed

wrx's have a similar problem with the #3 piston. These problems may not be completely cured, Having forged internals will eliminate most of the problem.
I know the thought behind the Subaru piston failure was linked to the heat from the turbo. Maybe there is a similar situation with the LS motors. I know that the belief is less air flow. But maybe its extra heat, or a weakness to.

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