2004 GTO LS1 - Cracked Piston #5 and #7
03-02-2013, 07:54 PM
#1
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2004 GTO LS1 - Cracked Piston #5 and #7 Hi guys,
Long time lurker, first time poster. This site is and amazing resource... although you already know that I am sure.
I have an '01 Honda s2000 with an LS1/T56 from an '04 GTO. I purchased the motor/trans from a donor car with 67k miles last summer. The motor seemed to run flawlessly until late January during my first track day with her. HPDE event, NOT drag racing.
The car limped itself off the track with a fairly heavy knock that I diagnosed (using my internet PhD
) as a bent pushrod. After removing the valve covers and examining the pushrods, they appeared perfect. Assuming next a lifter was to blame, the heads came off. All 16 lifters looked perfectly normal, with no apparent damage to them or the camshaft. Damn.
Then I noticed this...
Cylinder #7
Cylinder #5
Combustion Chamber #5
Combustion Chamber #5 (Spark Plug)
After searching around here and other sites, it appears I am not the only one to run up against this issue in the exact same location(s) no less.
I find it odd that combustion chamber #5 shows obvious markings from foreign material including a damaged spark plug, but #7 appeared perfectly fine.
The GOOD news is the cylinder walls look great. No obvious scarring or cracking. Yet anyway.
Time for a rebuild! Which leads me to my questions.
I don't plan on keeping this car much longer, but do want to make sure the rebuild is solid for the next owner. I wouldn't mind bringing a little more power to the equation, but reliability is more import to me.
What would you do in my shoes?
-Hone the cylinders and drop in some new OEM pistons?
-Go with an aftermarket pistons like Mahle?
-Is it OK to keep the OEM rods?
-Would you bore it to a 6.0L?
Thanks in advance for your advice!
Long time lurker, first time poster. This site is and amazing resource... although you already know that I am sure.
I have an '01 Honda s2000 with an LS1/T56 from an '04 GTO. I purchased the motor/trans from a donor car with 67k miles last summer. The motor seemed to run flawlessly until late January during my first track day with her. HPDE event, NOT drag racing.
The car limped itself off the track with a fairly heavy knock that I diagnosed (using my internet PhD
) as a bent pushrod. After removing the valve covers and examining the pushrods, they appeared perfect. Assuming next a lifter was to blame, the heads came off. All 16 lifters looked perfectly normal, with no apparent damage to them or the camshaft. Damn.Then I noticed this...
Cylinder #7
Cylinder #5
Combustion Chamber #5
Combustion Chamber #5 (Spark Plug)
After searching around here and other sites, it appears I am not the only one to run up against this issue in the exact same location(s) no less.
I find it odd that combustion chamber #5 shows obvious markings from foreign material including a damaged spark plug, but #7 appeared perfectly fine.
The GOOD news is the cylinder walls look great. No obvious scarring or cracking. Yet anyway.
Time for a rebuild! Which leads me to my questions.
I don't plan on keeping this car much longer, but do want to make sure the rebuild is solid for the next owner. I wouldn't mind bringing a little more power to the equation, but reliability is more import to me.
What would you do in my shoes?
-Hone the cylinders and drop in some new OEM pistons?
-Go with an aftermarket pistons like Mahle?
-Is it OK to keep the OEM rods?
-Would you bore it to a 6.0L?
Thanks in advance for your advice!
03-02-2013, 08:16 PM
#2
You shouldn't bore it. The LS1's can only take a little bit oversize on the bores, with 3.902" - 3.905" being most common.
If it were me, I would use this as an excuse to use a forged piston. Mahle makes a great piston, as well as Wiseco. Bang for the buck, Probe makes some decent pistons as well that will work with the stock connecting rods.
If it were me, I would use this as an excuse to use a forged piston. Mahle makes a great piston, as well as Wiseco. Bang for the buck, Probe makes some decent pistons as well that will work with the stock connecting rods.
03-02-2013, 09:25 PM
#3
I would run a set of Wisecos, that's just personal preference but Diamond, Mahle, Probe and many others make forged pistons that all would work.
Last edited by 2000PewterT/A; 03-03-2013 at 12:33 AM.
