Can I install je pistons into a stock bore sized b16? I know I have to roughen up the cylinder walls with a bore out tool that gets hooked upto a drill.

 

it depends if you bought over bore pistons or not. the pistons should drop right in. if they dont then u know. if you are trying to buy pistons then make sure you know what your stock bore is on the b16 and order appropiaty.

 

I ask this question cause I've heard somewhere that the cylinders have to be bored out just slightly bigger than stock to allow the forged pistons to expand. I want to know if this is true?

 

i believe you are referring to a honing tool.
yes you should give it a quick hone to get some nice crosshatches on the cylinder wall. that will help the oil ring to not let any oil by.

 

Buy a helms manual

 

helms is great. or download it from this forum..
stock b16=81mm, when you order your pistons ask for stock bore. and also make sure your motor was never rebuilt before, because the previous owner could have bored it over.
then go to sears, napa, autozone etc. or online tool store and order a ball type honing tool that will fit your bore=get one slightly bigger than 81mm. use a drill with the honing tool and use honing oil which is mostly kerosene, or automatic tranny fluid, during honing you must always pour a lot of oil in there to prevent damage and create a perfect cross hatch pattern in each cylinder.. after that clean the cylinders very good.. you can do this with the block still in the car and crank still installed. just cover the crank by stuffing rags in the cylinders so you wont get any of the shavings or dirty oil in the oil holes, or damage it with the honing tool... then you are good to go with installing you pistons and rod combo.. also make sure you order the correct size rod bearings.

 

do I have to bore out the stock cylinders to compensate on when the forged pistons expand when hot?

 

no you do not have to I just hone it out so the rings have a nice crosshatch to wear into and you are good to go. just make sure you don't buy oversized pistons. then you will have to bore it out. building forged setups is just like a oem setup. just mic everything out. but to answer your question straight up do you have to bore it NO. 81mm all the way baby.

 

its very easy when its a stock bore. and also ring gap, and rod bearing size is very important also