In a 7m motor with forged pistons. Is there a significant difference between a bored block with oversized pistons and a stock bore block with a slight hone (or none at all) and stock bore pistons? Would there be significant differences in performance, reliability, or durability?
Bored vs not bored
- Thread starter supra jesus
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Like Supracentral already posted. Whenever you're considering machining, you only want to do it to correct any flaws that might exist. The performance gains you would get from overboring is little to none and not worth losing rebuild potential unless you are specifically building the engine for a race purpose and expect to throw it out if things go sideways. The latter gets VERY costly VERY quickly. My buddy tried that with his CRX race car this year, and it didn't go so well. He ended up spending SIGNIFCANTLY more money that year because of the one engine he built to ride right on the line of legal limit in his "improved production" class.
Depends how much power you're making, in terms of effecting reliability and durability.
My line of thinking is that since the 7M is a 'wet noodle', as IJ so affectionately put it, at high horsepower high RPM, removing any material at all that helps with longinatudinal strength allows the engine to flex along its' main axis. This is bad, real bad, for longevity.
I mean, we're probably only talking a few percent, but it all adds up when you're pushing the envelope. At the end of the day, a stock block has the most meat possible on it, which is good for strength... and strength is good for power.
The rebuild sacrifice is the main reason, because let's face it, if money were no object, wouldn't you be driving a Ferrari and sipping martinis on your yacht while some schmuck did all this grease work for you?
Not having to buy a new block and machine it saves big $$$ in the event a piston melts or a chunk of valve rapes a piston.
My line of thinking is that since the 7M is a 'wet noodle', as IJ so affectionately put it, at high horsepower high RPM, removing any material at all that helps with longinatudinal strength allows the engine to flex along its' main axis. This is bad, real bad, for longevity.
I mean, we're probably only talking a few percent, but it all adds up when you're pushing the envelope. At the end of the day, a stock block has the most meat possible on it, which is good for strength... and strength is good for power.
The rebuild sacrifice is the main reason, because let's face it, if money were no object, wouldn't you be driving a Ferrari and sipping martinis on your yacht while some schmuck did all this grease work for you?
Not having to buy a new block and machine it saves big $$$ in the event a piston melts or a chunk of valve rapes a piston.