I tried to look before posting what is the real difference between a l92 and l9h 6.2 engine reason I ask is my 2009 denali shattered a piston and there is a $600 difference in the long block motors the l92 being cheaper and the only thing I can find is flex fuel being the difference between the cam and crank part numbers but the specs seem the same besides that but if flex fuel is the only difference that is a intake and fuel pump not the engine so please someone clarify this for me because I plan on buying a longblock and if I don't have to pay that extra 600 because there is no actual internal engine difference that money can go to my exhaust headers or programming and rear o2 delete (I am in Florida no emissions) and thank you in advance for the help ppl
L92 or l9h
- Thread starter Sc0rp
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iamdub
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FlexFuel capability is really the only difference. Swap an L92 injector setup onto an L9H it'll be an L92. Swap an L9H injector setup onto an L92 and it'll be an L9H. In the earlier years, the L92 had AFM components but AFM wasn't activated. This is irrelevant to your '09, though. With just long blocks, I don't see the reason for the price difference unless they're including the intake manifold with the long block. Even then, it's just higher-volume injectors on the L9H.
14RamHemiSport
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If you dont mind me asking, what caused the destruction? My 09 denali runs great but you now have her worried. I dont recall reading a lot about engine issues with these 6.2L trucks.
Don't know if he'll be back so I'll chime in. The most common cause is a dropped valve - usually a broken valve spring. It's the reason I'm doing a cam swap with a dual valve spring upgrade in my '12 and will also do it in my '07 if I like the results.
14RamHemiSport
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appreciate the info....but what is the cause? these 09s do not have active afm so the whole cam/lifter issue associate with afm shouldnt apply.....correct? is it just bad luck causing the broken valve spring?
Pretty much. A few guys here have experienced a broken valve spring in their 6.2s. The only root cause I can think of is poor metallurgy or QC. Poor metallurgy will lead to early fatigue failure, and a significant nick during manufacture can cause a stress riser point that leads to failure.
14RamHemiSport
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Maybe poor maintenance too? Pushing limits on an oil change interval is always asking for trouble. It's just not worth the risk. Either bite the bullet and change it early or do a few oil analyses to validate your longer intervals. Not all oils are created equal. Anyway....that's another subject altogether.
wjburken
Supporting Member
I can attest that even with regular 3K-5K OCI using high quality synthetic oil I lost a valve spring on my non-AFM 2007 Denali at 140K. Fortunately it did not contact the piston.
Unfortunately, at 150K a lifter roller grenaded and took out the motor.
