Factory LE5 Connecting Rods - PLEASE READ - Pontiac Solstice Forum
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post #1 of 18 (permalink) Old 11-26-2010, 10:02 AM Thread Starter
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Factory LE5 Connecting Rods - PLEASE READ

Hi everyone. It has come to my attention that the 2008 connecting rods used in this engine may be of a weaker construction (powder forged steel as opposed to forged). So my question to boosted 2.4 LE5 ecotec kappasf, as well as vendors is how many of you are 2008 and later? What power levels are you running on your 2008+ solstice/sky and for how long. For example, i know Hahn's "soulfood" solstice is an 06 and held up well to over 350whp, but are there any 2008's at that level?

The rumor is, as a cost cutting measure, GM must have sneaked some cheaper rods into the later production years. A reputable vendor had one break at only 303whp (a 2008) and sent the rods for analysis to find they are similar to the L61 2.2 rods rather than forged like early LE5 rods.

Thanks for your time in sharing your experiences,
Ryan

2008 BRAZEN GXP - 5M Loaded Tuned to 22 PSI with HPT, AEM water/methanol injection kit - 4gph, Hahn Racecraft Intercooler. Solo street race exhaust, Catless, LE5 Throttle body, ZFR 6758, custom CAI 307whp on dyno dynamics - stock turbo (21 psi) 463whp/454wtq EFR 6758 26-27 psi,100 octane - tuned by me


2006 SLY 2.4 Comfort and Power - TRADED 28-Aug-2008

Last edited by oldskool; 11-27-2010 at 05:36 AM.
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post #2 of 18 (permalink) Old 11-28-2010, 07:11 AM Thread Starter
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Ok, see the pictures in the link below:


Build pics

My 2007 bottom end has rods that look just like factory LSJ rods...my buddies 2008 bottom end has rods that look different - much more like stock L61 rods.

i'm NOT saying every 2008 has these weaker rods, but an appreciable number of them likely do.

FWIW, i have emails out to all the major vendors who deal with the LE5 regarding building 2008 model years, and have not heard back from anyone yet.

2008 BRAZEN GXP - 5M Loaded Tuned to 22 PSI with HPT, AEM water/methanol injection kit - 4gph, Hahn Racecraft Intercooler. Solo street race exhaust, Catless, LE5 Throttle body, ZFR 6758, custom CAI 307whp on dyno dynamics - stock turbo (21 psi) 463whp/454wtq EFR 6758 26-27 psi,100 octane - tuned by me


2006 SLY 2.4 Comfort and Power - TRADED 28-Aug-2008
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post #3 of 18 (permalink) Old 11-28-2010, 09:29 AM
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I really hope that GM didn't play the same kind of games on LNF in 2008.
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post #4 of 18 (permalink) Old 12-01-2010, 03:06 PM Thread Starter
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Here are the different part numbers for the rods:

2006-2007: 12596088 A 2.4-B/P (LE5), (1ST DES) ROD, CONN (FORGED STEEL W/ROUNDED EDGES ON CAP AND MFG TRIM MARK AROUND OUTER PERIMETER) (FOR 2ND DES SEE 12611360)

2008+ 12598216 A 2.4-B/P (LE5), (2ND DES) ROD, CONN (POWDER METAL W/SMOOTH SURFACE CAP AND SINGLE RIDGE ACROSS CAP, W/O MFG TRIM MARK AROUND OUTER PERIMETER) (FOR 1ST DES SEE 12596088)

Any one running over 300hp on the later rods is playing with fire! (note this is only for the LE5)

2008 BRAZEN GXP - 5M Loaded Tuned to 22 PSI with HPT, AEM water/methanol injection kit - 4gph, Hahn Racecraft Intercooler. Solo street race exhaust, Catless, LE5 Throttle body, ZFR 6758, custom CAI 307whp on dyno dynamics - stock turbo (21 psi) 463whp/454wtq EFR 6758 26-27 psi,100 octane - tuned by me


2006 SLY 2.4 Comfort and Power - TRADED 28-Aug-2008
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post #5 of 18 (permalink) Old 12-01-2010, 05:15 PM
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Ok, I have a really stupid question:

How much of a difference in cost did this represent for GM to go to the cheaper caps? I find it difficult to imagine that the cost savings would have been significant enough to justify making this change, especially on such a critical engine part.
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post #6 of 18 (permalink) Old 12-01-2010, 05:24 PM
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Ok, I have a really stupid question:

How much of a difference in cost did this represent for GM to go to the cheaper caps? I find it difficult to imagine that the cost savings would have been significant enough to justify making this change, especially on such a critical engine part.
It's not just the caps, it's the entire rod and cap assembly. I'm glad I have a 2006.



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post #7 of 18 (permalink) Old 12-02-2010, 07:41 AM
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Oh, that would definitely make a cost difference, especially when you times by 10,000 engines.

Well at least I understand why GM did this. Can't say that I approve, but I understand.
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post #8 of 18 (permalink) Old 12-02-2010, 03:13 PM
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Just one more reason for Eagle to make an inexpensive replacement.
OR if you are doing an OEM rebuild try to use -'07 rods over '08+

-Adam Chant
2007 Supercharged Saturn SKY (Rotrex C30-94)
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post #9 of 18 (permalink) Old 12-21-2010, 08:20 PM
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This also seems to be the problem with swapping a 2.4 into a fiero and boosting it. a guy on my forum did it and from what I understand switched out the rods.
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post #10 of 18 (permalink) Old 01-14-2011, 08:56 AM
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Very frustrating. I've been edging towards a Stage IV Hahn turbo for my '08, but this really grinds things to a halt, pun intended.

For those passing through this thread who'd like a good overview of common types of connecting rods (including powder) and to see a comparison, here's a good YouTube video:

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post #11 of 18 (permalink) Old 01-14-2011, 09:38 AM
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Very frustrating. I've been edging towards a Stage IV Hahn turbo for my '08, but this really grinds things to a halt, pun intended.

For those passing through this thread who'd like a good overview of common types of connecting rods (including powder) and to see a comparison, here's a good YouTube video:

YouTube - Automotive Connecting Rods 101
ToxicGumbo that video is best explanation of the differences in connecting rods that Iíve ever seen. I was a manufacturing engineer for Pontiacís connecting rods from 1979 to 1986. The rods we made then were very similar to the first Buick rods shown in the video.

Back then I was pushing for rods that were similar to the powered metal fractured rods. I was looking to fracture the cast rods. (Back then powered metal rods were talked about, but needed a lot of research.) Fracturing of the rods actually give you the most accurate rods you can get and lower the cost of machining by about 60%.

When it comes to cost on any part used, the cost of a failed part weights heavy in the calculations. Iím sure that when the decision was made to use powered metal rods, the first thing that was tested was failures and that powered metal could fail no more than what the current production rods that were being used.

For me on the street I wouldnít have a problem with powered metal rods with designs that made it through testing.

Jim
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post #12 of 18 (permalink) Old 01-14-2011, 11:03 AM
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I'm a little confused... I assume that Sintered=Powder-forged? If so, that video seems to imply that they are actually better than the regular forged rods, or am I wrong?

Owner of "Campbelle", a Brazen 2008 GXP ... with mods piling up...
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post #13 of 18 (permalink) Old 01-14-2011, 11:31 AM
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I'm a little confused... I assume that Sintered=Powder-forged? If so, that video seems to imply that they are actually better than the regular forged rods, or am I wrong?
He did say in the video that the powered/sintered rods were good for about 7,000 rpm which surprised me. He did make it sound a little like the powered metal rods were better than forged. But he was only talking about rpm before they let loose.

The thing with a powered metal rod is that when they go they break and youíll have a real mess on your hands. The forged and billeted rods will usually give you some warning and you may lose a crank, but the rest of the engine will probably survive.

Jim
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post #14 of 18 (permalink) Old 01-14-2011, 04:59 PM
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Detonation is the killer of any non-forged rods. And detonation usually happens near peak torque, not at peak horsepower. Or at a different part of the rpm band.

I was running about 10 psi in a 2.8/3.1 V6 with higher than stock compression and no knock sensor without problems. It's all in the tune and this is where I'd spend most of your time if your boosting a stock motor. Avoid detonation and you'll avoid the shock waves that break stuff like ring lands, pistons....

07 Sky Hahn Boosted- 44 mpg - 40 mpg with air conditioning on.
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post #15 of 18 (permalink) Old 01-16-2011, 08:23 PM
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I was a manufacturing engineer for Pontiacís connecting rods from 1979 to 1986.
Jim, good to have your expertise floating around here.

oldskool, thanks for getting the word out about this change. I'm disappointed more 2008 owners aren't frustrated.

Even with a good tune, slapping on a turbo makes me really nervous. What would you guys do with a stock '08 LE5? If I crack my engine open to replace the connecting rods, seems like an entire overhaul's worthwhile. Anyone from Werks feeling generous enough to assemble a set of forged pistons and rods for order? Any other weak points outside of the 2.4L engine block itself (ie. cracking between cylinders) that should be addressed once the head and pan are off? Valves?


-Jeff
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