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      04-06-2011, 10:35 PM   #51
mike-y
just another bmw douche bag
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Drives: 1.9L of fury
Join Date: Nov 2008
Location: Los Angeles, CA

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well, you don't necessarily need larger valves. just getting a good valve job will increase flow and yield power. most of the heads we worked on did not get new valves, we would re-profile the stock valves and install them with a new 3 angle or 5 angle valve job. Oversized valves were available, but we mostly only used those in race engines, or cars going forced induction from NA.

if you are putting in new pistons, you might as well get it honed.. I've seen newer cars go without a hone, and just install new rings, but if everything is out of th car, it would be best to hit it with a light hone.

Also, pay attention to the weights of the aftermarket rods and pistons.. you want to stay as light as possible, especially for NA. Also get the entire rotating assembly balanced too (crank, flywheel, clutch plate, rods+pistons matched) while the motor is apart.

though if you are on a budget, you can still get good gains with just the top end, without touching the block.. of course, a lot will depend on the tune.