LSJ / LE5 Hybrid

Iwanttogofast

Well-Known Member
I’ve searched threads (here and elsewhere) first, but cannot see where this question has been posted before. I’ve always been a small block chevy guy, and I know them well. My knowledge about the Ecotec is much more limited, but I’m learning as I go. I’ve heard some say that “most Ecotec parts are interchangeable”, while hearing very problematic issues (if not horror stories) from others.

If I go the LSJ route from a Cobalt SS… Can I use an LE5 block (with upgraded forged rods and pistons) AND reuse the LSJ crank (for reluctor wheel and flywheel pattern)? Using everything else from the LSJ (supercharger, heads, accessory drive, etc.)? Essentially, I’m asking if the problematic GenI LSJ block is interchangeable with the much better GENII LE5 block - WHILE USING THE LSJ crankshaft. I’d like the strength and bore size of the LE5, with everything else from the LSJ.

If this IS possible, are the deck heights the same? And can the forged LSJ rods be reused with the LSJ crankshaft (upgrading to forged pistons anyway – if there is an option) in the LE5 block?

Please only respond if you know for sure. Lots of money being spent soon. THANKS!!
 

Rauq

Goblin Guru
Unfortunately I cannot respond with a firm, comprehensive answer, but I will tell you that I am confident in my understanding that an LSJ crank position sensor/reluctor setup will not drop into an LE5 block... but ZZP does make a spacer for that specific application.

If you're willing to accept my speculation, yes, I do believe that besides that specific issue, you can replace an LSJ block, rods, and pistons, with an LE5 block, rods, and pistons. I'm not sure if that's one of the builds where balancing is recommended or required, but I trust you can sort that out.

The only other potential area for attention that I'm aware of is with the oil squirters. ZZP says "LSJ Note: Forged pistons will not work with the stock rectangular LSJ oil squirters. They must be replaced with the LNF/LDK tube type Gen 2 oil squirters. And, they need to be bent about .060" to the side to clear the JE pistons." I assume an LE5 block doesn't have LSJ oil squirters, but again, I'll leave that to the folks with the hands on the parts.
 
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