mustangsvo85

I'm thinking of rebuilding my d16y7 in my 97 civic dx coupe. I have heard wonders about the y8 head swap, but I don't want to wire and change too man things about it since it gets great gas mileage and its dependable.

I am trying to get a compression ratio of 10.5:1 or somewhere around it so I can still run cheap gas. I am just trying to do it cheap as possible, but I'll spend money on machining and tuning. My goal is to pick up some extra torque and a little more top end, but still pass an emissions test.

Anywho, I want to know what pistons I can run without deck height issues as well as connecting to the stock y7 rods? I've looked at many of these online compression calculators, looks like PM6 pistons are the best bet with the 2 layer y8 head gasket trick. One calculator claims this yields 10.25:1, which should leave me room for any head milling or block decking necessary. Will pm6 pistons attach to stock y7 rods without issues? any clearance issues? Can I run 87 octane with this compression ratio without issue? cast pistons should be fine right? I figure I'm just going to get some ebay specials or is that a crime? should I get OEM pistons and where would I get them?

Also I know a cam would help, does anyone do a cheap regrind designed for torque and midrange? will it require stiffer valve springs?

Are there any issues with losing bottom end with a mild bench top port job? I plan on port matching and maybe opening up the exhaust ports a tad depending on what it looks like when its all a part.

mustangsvo85

oh and also, are there any modifications I should do to the block??? ie anything to improve oil flow or any areas infamous for cracking?

mustangsvo85

or if anyone could just answer if pm6 pistons will fit onto the y7 stock connecting rods?

hondamark35

I can't confirm the piston rod combo first hand. hopefully some one else can.

don't plan on using 87oct with a high compression build. your goal should be pump gas... ie premium, as opposed to race fuel..

you can check out Delta cams for a cam regrind 260 and 272 would probably be good. contact someone on staff there, they're pretty knowlegeable and can suggest the best profile for your set up. there are others as well, but i think they're the best bang for the buck in this case.

honestly.. you don't have any bottom end to loose, haha. for real though i think just port matching- you should be fine. i wouldn't try anything beyond that without having use of a flow bench or professional assistance.

check out energy dynamics, theoldone.com for oil pump improvements and other great articles about building honda motors. one cam only dot com, no spaces (some reason you can't type that address in on this forum...) would be a great resource for you or anyone building a single cam.