New V8 LSA engine will use cylinder honing process used in GM racing programs to increase horsepower and longevity.
OSHAWA‑GM will use a precision-machining process known as deck plate honing on cylinder blocks in its Chevrolet’s Camaro ZL1 to help maximize engine life, reduce friction between engine parts and increase horsepower.
The 2012 Camaro ZL1, to be manufactured in Oshawa, will boast a 550HP 6.2L supercharged V8 LSA engine, which will be made at a GM facility in Wixom, Mich. GM’s LS engines are the only V8 engines found in its rear-wheel drive cars and trucks. The LSA engine debuted in 2009 in the Cadillac CTS-V
Deck plate honing is also used in GM’s NASCAR and Corvette racing programs.
The technique involves a machining process in which aluminum plates clamped to the engine block, which simulate cylinder heads, before the final boring and honing of the cylinders. The clamp load of 10 bolts per head creates normal, minute distortions in the block and thus makes the bore slightly out-of-perfect shape.
While the cylinder heads are attached to the engine block, a boring machine bores and hones each cylinder. Later, when they cylinders are assembled to the block under identical torque loads, the cylinder bores are near-perfect for the engine’s lifetime. The ZL 1’s pistons will fire about 6,200 times a minute.
The deck plate bore-and-hone process uses billet aluminum plates with steel bolt sleeves for compression limitation. The plate’s bolt attachment points have the same height and clamp loads as the actual cylinder heads.
The LSA cylinder block is made of 319T7 aluminum with cast-in-place cast iron cylinder bore liners. The final honing process brings the 103.25 mm (4.06 inches) bores to within eight microns tolerance. The deck plates remain installed for the final honing of the crankshaft bores.
Because the ZL is so powerful, the deck plating process ensures cylinder sealing and prevents scuffing of the piston against the bore wall. The process is usually used in applications where pressure on the cylinder head is greater than average. In the Camaro LSA engine, this means improved bore life and ring sealing, keys to optimizing power.
GM plans to begin distribution of the Camaro ZL1 in early 2012, according to the company’s website.