DANGER ZONE: 650-700 RWHP
Now six years into its production run, the verdict is still out to how much horsepower and torque the LML Duramax can handle. While we haven’t heard or seen a lot of rod or piston failures on stock bottom-end engines yet, it doesn’t mean they’ll handle more power than what the LBZ or LMMS will. In fact, the pistons are very similar to the LBZ and LMM engines, which means the 650hp range may just put you on the carnage radar.
One edge the LML piston might have over the LBZ and LMM versions is that its design eliminates wrist pin bushings. While GM claims it did this to achieve a lighter weight rotating assembly (along with a lighter crank and lighter connecting rods), it added strength back into this area of the piston. We’ve seen several 700rwhp LMLS sporting the stock bottom end, a few of which were running compound turbo arrangements. The key to these trucks living at this point has been torque limitation at low rpm via spot-on EFILIVE tuning. UDBG
In case you’re wondering, the verdict is still out on how much horsepower and torque a stock bottom end will handle on the ’11 and newer LML mills. With rods similar to what you’ll find in the LBZ and LMM’S and slightly stronger pistons, it looks promising, we caution anyone building an engine past the 700rwhp mark.
Although the LML Duramax shares a similar piston to what you’d find in the LBZ and LMM engines, GM did away with the wrist pin bushings that were thought to be the key weak point (according to those in the aftermarket). This might explain why more LML powered trucks are surviving the 650 to 700-rwhp range on stock internals.