I am building a 1989 crx si and it is starting to use a little oil. good excuse to tear the block down anyhow I wanted some suggestions. I've already researched CP pistons and they are obviously popular right now. now for a build and considering engine wear (165,000miles on the engine) do i need to get 9.1:1 cmp 11.0:1 compression and standard or .5mm over, the noobness is oozing from this thread already be easy on me guys... i'm serious... and does anyone know what it takes to attach the 90-91 crx bumper on the 88-89?

 

why go crazy with it? stock works fine on a d16a6 unless your running 400whp.

 

I can only dream of a D with 400whp but i dunno i'm wanting to do a full build N/A. good point though. stock pistons = cheap and thats what i like. i just figured if i'm going to have the block down anyways might as well...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rangerxtrn &raquo;</TD></TR><TR><TD CLASS="quote">now for a build and considering engine wear (165,000miles on the engine) do i need to get 9.1:1 cmp 11.0:1 compression and standard or .5mm over, the noobness is oozing from this thread already be easy on me guys... </TD></TR></TABLE>

Before you go into this without knowing anything, you have to understand that you're intention for the motor is what will dictate what compression ratio you will want to use (compression ratio has nothing to do with how much wear your motor has already, it's independant).

Generally speaking, if you plan on going forced induction you'll want to lower your compression ratio. If you want to go all motor you'll want to increase your compression ratio. If you are just rebuilding to get rid of the oil consumption then changing the stock compression ratio is not necessary. Also, using different D-Series pistons will net you different compression ratios. This option may be a cheaper alternative for your particular application (check the FAQ and play with the compression calculator to see what I mean).

Also, here's a short explanation of standard vs over bore/sized: Take into consideration your particular application (D16A6). Standard bore on this engine is 75mm. When people say overbore or oversized, they are increasing the size of the piston (oversized) and as such, the cylinder bore will need to be increased (overbored) to accomodate the size of the new pistons. Now here's the question you'll have to ask yourself, "Do I need to do this?" If you are only looking to rebuild the motor to get rid of the oil leak, have the cylinders inspected to make sure they are still round and within spec. If they aren't, they will need to bored out and bigger pistons will be necessary. If they are still within spec, enlarging them is not necessary so bigger pistons will not be necessary. On the other hand, if your intention is to build a performance motor, then maybe you actually want to increase the size of the bore intentionally to increase the overall volume of the cylinders and combustion chambers. Again, it's your intention for the motor that will decide if you need to do this.

Hope this helped a little bit...

 

Thanks man. I am wanting to do all motor on the engine on a performance build. I am planning on doing a mini-me head swap so I figured why not yank the engine out. I have rebuilt domestic engines mainly vintage, so I have a pretty good setup, engine stands, hoists, etc. I have been reading extensively on the mini-me swap...