Well im building my d16z6 bottem end and am ordering CP pistons. The block is stock sleaved. So i was wondering, do i get the 75mm std pistons or the 75.5mm .020 pistons???

I guess it really matters if im getting the block bored and honed or just honed right?? If i bore it and hone it, will i get a better ring seal or does it not matter??

Also, performance wise, will i really notice any difference in .5mm???

Help a newbie out, all ive been doin is researching and now its time to ask questions

 

up again, anyone???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dohcdelsol &raquo;</TD></TR><TR><TD CLASS="quote">
Also, performance wise, will i really notice any difference in .5mm???
</TD></TR></TABLE>

No not at all

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dohcdelsol &raquo;</TD></TR><TR><TD CLASS="quote">
I guess it really matters if im getting the block bored and honed or just honed right?? If i bore it and hone it, will i get a better ring seal or does it not matter??
</TD></TR></TABLE>

Take the block to an engine builder and find out how much taper the top part and the bottom part of the sleeve differ. If it's enough you're builder will tell you to go ahead and bore and hone otherwise sometimes you can get away with just a hone. It all depends on the condition of the block.

 

75.5mm
If your going to spend money on pistons and rods, do it the right way and get it overbore. Your block might be in good condition but just for that piece of mind go with the overbore. Just my two cents.

oh and forgot the other part of your question: no there will not be a noticeable difference between 75 and 75.5mm.

 

Peace of mind is in knowing your tolerance and EXACT measurments not just "getting an overbore to be safe" I'd rather save money and have more sleeve if there is no problem not getting an Overbore. Not my 2 cents....just how it's done .

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">Peace of mind is in knowing your tolerance and EXACT measurments not just "getting an overbore to be safe" I'd rather save money and have more sleeve if there is no problem not getting an Overbore. Not my 2 cents....just how it's done .</TD></TR></TABLE>

none of us knows the exact condition of his block..so my best advice was to go ahead with the overbore, if saving $50 is that important to you then dont do it.

 

^ i'm with him.

 

What I did was buy oversized pistons and then I took the pistons and block to the Napa machine shop. The machinist contacted CP and got the clearance needed for piston to wall, and bored accordingly.

 

make sure they use a DIA bore gauge to ensure the cyclinders are "perfectly" round.
you don;t want cyclinder walls with the middle looser than the top and bottom kinda liek this (_) uoi want l_l walls and make sure they also check for roundness as in you don;t want an egg shaped hole. like this 0 you want more of a perfect round like O.

I'm saying this because, most small shops like napa are NOT designed to work on specific hond amotors. Honda stuff requires much newer and speciialized machiens that can get the tolerances perfect. a lot of the otehr shops have older machiens that are worn or have a slight wobble and this are otu fo spec to even touch a honda block. They work ok for the old american iron sutf, but that's about it.

 

Normally if someone said this I would be shook up and worried, but I have confidence in Mark that his machinery is top notch, considering the volume of super high horsepower engines that they work on.

 

Thanks for the responces guys..

The cylinder walls are in excellect shape to the naked eye but ive tryed to contact Justice Racing in Maryland to see what they suggest. I went ahead and ordered the 75.5 just to be safe. I can always get the block sleaved if needed.

 

Regardless, anyone is worried about that, make your concerns known to the ppl doing the work, and have them sign a small agreement.

If they mess up, you can get a nice, shiny new block. I'd LOVE to get a brand-new block with perfectly round std-bore cylinders.