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Lost piston #7 AGAIN

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Old Jun 13, 2011 | 11:46 AM
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Default Lost piston #7 AGAIN

Lots of drag racing - stock short block. Number seven is chipped in upper right corner showing the ring. Here is the question.

I have 370 rwhp. Don't need any more.

I have ARP bolts in the rods and a small cam with harlen rockers

Will Forged pistons ALONE eliminate the damage (assuming it is a lean condition) or do I need forged rods too?

By the way. What happens in a lean condition WITH forged pistons? Is there still a risk of other damage?
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Old Jun 13, 2011 | 11:57 AM
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Originally Posted by futuretech
Lots of drag racing - stock short block. Number seven is chipped in upper right corner showing the ring. Here is the question.

I have 370 rwhp. Don't need any more.

I have ARP bolts in the rods and a small cam with harlen rockers

Will Forged pistons ALONE eliminate the damage (assuming it is a lean condition) or do I need forged rods too?

By the way. What happens in a lean condition WITH forged pistons? Is there still a risk of other damage?
Just curious. What intake manifold are you running, and how are the rear coolant bleeds hooked up?
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Old Jun 13, 2011 | 11:57 AM
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Nope need better oiling.

#7 goes as it gets starved for oil

and you want run er RICH
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Old Jun 13, 2011 | 12:03 PM
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Originally Posted by lucky131969
Just curious. What intake manifold are you running, and how are the rear coolant bleeds hooked up?
LS6 intake. Closed back port.
First engine with same problem was LS1 with back crossover
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Old Jun 13, 2011 | 12:04 PM
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Originally Posted by AU N EGL
Nope need better oiling.

#7 goes as it gets starved for oil

and you want run er RICH
Has high output old pump - always over 40
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Old Jun 13, 2011 | 12:19 PM
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Originally Posted by futuretech
LS6 intake. Closed back port.
First engine with same problem was LS1 with back crossover
Thanks. Both engines tuned by the same shop?
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Old Jun 13, 2011 | 12:21 PM
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Originally Posted by lucky131969
Thanks. Both engines tuned by the same shop?
Yes
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Old Jun 13, 2011 | 12:28 PM
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Originally Posted by futuretech
Yes
Ok. First to address your question. Yes, forged pistons will hold up much better to abnormal conditions, compared to hyper-eutectic pistons. Forged rods will provide more stability, ARP bolts to prevent stretch, etc.

......the tuner is one possible common denominator.
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Old Jun 13, 2011 | 12:32 PM
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AU N EGL

How do you improve oiling to just ONE cylinder? If theres a way,, Im game!
I added a Melling high volume oil pump to my engine and I have good pressure at idle and at high RPMs. What else can prevent the #7 issue??
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Old Jun 13, 2011 | 12:36 PM
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How does one lose a piston on an N/A motor only pushing 370 rwhp? Maybe your tune is the culprit.
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Old Jun 13, 2011 | 12:49 PM
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I suspect a lean tuning problem causing detonation.This is NOT an oiling problem.Forged pistons and a different tuner should cure your problem.
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Old Jun 13, 2011 | 12:51 PM
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I say too much timing advance.
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Old Jun 13, 2011 | 12:54 PM
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Originally Posted by rebelheart
I suspect a lean tuning problem causing detonation.This is NOT an oiling problem.Forged pistons and a different tuner should cure your problem.
Hard lesson but I think you are correct. Can I used forged pistons and my stock rods?
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Old Jun 13, 2011 | 12:56 PM
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Yes you can,LS1 rods are quite good but use good new rod bolts.
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Old Jun 13, 2011 | 01:17 PM
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Originally Posted by rebelheart
Yes you can,LS1 rods are quite good but use good new rod bolts.
I have ARP bolts from the previous build. I assume they are ok to reuse.
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Old Jun 13, 2011 | 01:23 PM
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Were the same injectors used in both motors in the same location? If so #7 may not be working 100% for whatever reason. Air leak on that cylinder makes since also. I'm wondering though how forged rods add stability to a rotating assembly. I agree with reliability. Oh well JMO.
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Old Jun 13, 2011 | 01:53 PM
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Injector is the first thing I would look at. It is not an oiling issue. LS1's and LS6's have had this issue for years in C5 Vettes. Lean condition is present..
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To Lost piston #7 AGAIN

Old Jun 13, 2011 | 02:17 PM
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Originally Posted by Xtreme Z06
Injector is the first thing I would look at. It is not an oiling issue. LS1's and LS6's have had this issue for years in C5 Vettes. Lean condition is present..
Same injector, same spot both engines. How can I get injectors tested? BTW LS1 injector used on LS6 engine.
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Old Jun 13, 2011 | 02:22 PM
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Originally Posted by futuretech
Same injector, same spot both engines. How can I get injectors tested? BTW LS1 injector used on LS6 engine.
Depends on the year. If I remember correctly, the 2000 injectors were smaller (26 lbs)....than the LS6 28 lbs.
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Old Jun 13, 2011 | 02:49 PM
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Fuel injector connection can flow test your injectors. I would try that out.
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