Any merit to zero-decking the block?
04-26-2005, 04:39 PM
#1
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Any merit to zero-decking the block? I'm curious about this one...
On a recent engine rebuild for a '72 Nova that I'm restoring for a customer, we took the engine to a machine shop that absolutely swore by zero-decking the block. I'm curious as to what the general consensus is on zero-decking for performance gains are, or if this guy was simply talking out his *** in order to get more money out of the people having the engine built. I appreciate any input you guys have.
On a recent engine rebuild for a '72 Nova that I'm restoring for a customer, we took the engine to a machine shop that absolutely swore by zero-decking the block. I'm curious as to what the general consensus is on zero-decking for performance gains are, or if this guy was simply talking out his *** in order to get more money out of the people having the engine built. I appreciate any input you guys have.
04-26-2005, 07:13 PM
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Decking can do several things. First by decking you know that the block is level, a used block has a tendency to sink several thousands in the area between the cylinders between exhaust valves. This can cause a blown head gasket here. Also by decking you can bring the piston top up to the block level helping the quench area, which in turn may be worth 5-8 hp and can help reduce detionation. Decking the block will reduce the volumn by 5cc's or so helping raise compression, taking some of the load off of milling the heads
04-26-2005, 07:46 PM
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If you use flat-top or d-dish pistons and heads that have a flat surface next to the combustion chamber and run a tight clearance (.035-.040") between the piston and head you will cause a lot more turbulence when the piston comes up and compresses the fuel/air mixture. Physics aside, it will cause the mixture to become much more even and atomize the fuel even more, increasing efficiency and lowering the engine's octane requirement.
As a matter of fact, sometimes adding a thicker head gasket to reduce compression will cause the need for HIGHER octane, due to the loss of the squish/quench.
As a matter of fact, sometimes adding a thicker head gasket to reduce compression will cause the need for HIGHER octane, due to the loss of the squish/quench.
