Hi i am looking to replace my d16z6 i have, it currently has a rear main seal leak and pistons rings issues. I plan on rebuilding it later to turbo. I however found a d16y7/y8 mini-me fresh rebuild locally for 400 dollars. My issue with this being is that it is running p29 pistons with eagle rods and a .030 cometic. This is supposed to bring the CR to 12.91:1. Now i like the idea of a high compression all motor build swap while i build my turbo setup, but my use is for street only, and i want to fill up on pump gas. is this something i will be able to achieve without extensive tuning as currently i am on a budget and cant afford extra cost. OR could i just simply swap the p29 pistons out for something such as the pm6 and bring it to a 10.52:1 and run it safely on my p28 without any issues with the tune or pump gas. i have seen several people posting their mini-me builds and posting that the ecu doesn't need chipped and tuned. I am also open to suggestions people may have as i am still new. I feel comfortable rebuilding and swapping i just want my car running properly and leak free as quickly as possible with minimal damage to the wallet. I do have money to get an s300 and tune it as i know i will need to later if i plan on turbo anyways, i was just hopping to not have to make the investment yet. So conclusion will just replacing the p29 with the pm6 will that mini-me setup run safely and smoothly on pump gas without a tune. Any help is appreciated thanks, hopefully i can get some good advice before its sold

 

If they built the block, you can't just slap any old pm6 pistons in. You have to see if it's been bored out to over sized and then pay for the same oversized pistons, get the machine work done to get those pistons pressed onto rods, have the whole rotating assembly balanced to the new pistons etc etc etc. You say you are comfortable rebuilding so I figure you are well aware of this and the additional costs involved in doing it properly.

Shell out the 400 for the built mini-me, and then if you don't know how to tune (for street tuning) then contact your local tuner and see what systems he is comfortable tuning. You might get lucky and find someone who does crome tuning and for the mini me, it's a cheap tuning option as it only needs a chipped obd1 ecu. Then your tuner can tune and burn you the chip for pump gas on the high compression mini me.

I think that's cheaper then taking an already built block and changing out the piston/rod combo. I highly doubt the P29's are stock size being they are also on eagle rods. The block should have been built properly with blueprinting and balancing.

 

Thank you for the input. It is not overobred, why he went to the time of doing that and not overboring is beyond me, which is another reason why i didnt want to dump money into it, i want to rebuild my d16z6 overbored etc... the cylinders were just honed on the stock sleeves. my p28 is chipped, ive been contemplating getting the moates and burning it myself but i havent tinkered on the electronic side yet and dont know what im doing there, and would feel more comfortable finding a basemap on hondata. im assuming i wouldnt be able to easily find a basemap setup close enough to that to run it safely for a year or so untill i finish my build. i am looking for a bolt up replacement under 500 dollars ideally just to keep me on the road while i build mine. So the suggestion as of now is buy the motor swap it out and find a local tuner?

 

Well, that was assuming the motor was properly rebuilt. I suppose the out of round could have been in spec allowing just a hone and re-ring on the new pistons. But usually it's not and there is a fair amount of piston clap clatter on doing just a hone and re-ring.

If you are sure it's not oversize then going back to pm6's is rather simple as there is abundant supply of stock rods/pistons. If the pm6 is the stock piston combo for the block you can easily get away with a stock P28 ecu running the mini-me for a year and that would definitely be your cheapest option for the duration.