SR20DE - internal engine problem after head decking

Hi everyone !

I'm a new user here but i read this forum for a while. As you can see i own a Nissan Sunny GTi (known also as Pulsar SSS or in US as Sentra - it looks a little different). I bought it 2 years ago with 170 000 km on the clock, after i changed the oil to synthetic one - castro rs 0w 40 i destroyed my oil pump and main bearings so a nissan dealer told me to change whole bottom (engine block with pistons, crankshaft etc.) but they only had one from 91 p10 primera 2.0 SLX with single injection (in Poland it's hard to find sr20de engines because they were not popular) i agreed but in that time i didn't know that this engine i slightly different then my original one - it had 9.5:1 compression pistons. So after i visited the rolling road i was little suprised that insted of 143 HP i only had 108 HP and 158 Nm. Short visit in local nissan dealer ended with a verdict that my current compression is 9,2 MPa instead of 12,8 MPa so thats the main reason of power loss. Because i didnt change the head during my first engine repair and in meanwhile i managed to reach 214 000 km on the clock, the nissan dealer told me that the reason of incorect compression must be in the head (the bottom that i bought was only 80 000 km and in mild condition). So i bought new valves, springs, sealers, hydraulic lifters and some cool guys made whole headwork but they needed to deck the head surface by 0,15 mm because the surface wasn't straight. I bought new head gasket set and let nissan dealer assembly this thing, but after they managed to bolt the head with proper ;-)) cams setting they told me that they need new valve clearance regulation plates (i dont know their english name) but i couldn't fine one in Poland so they cut them to proper thicknes. i started the engine and after one hour they did a compression test and it still was 9,6 MPa :shit:, but that was only the begining, i went for a test drive and after 50 km of slow driving i heard a clatering noise from the engine and few seconds later the engine stoped, i tried to start it but the crankshaft didnt want to spin. Nissan Dealer told me that they think one of the pistons failed and need to be replaced.

So it's time for the summary:

is it possible that the head decking (0.15mm) was the reason of this mess or it's something totaly different, i know that nismo don't recomend decking but in nissan book i've read that if head isn't straight you can deck it max 0.2 mm

So know i have a big problem with the engine because i can't find new pistons for my baby here in Poland, even in germany or ebay there are none.

Try posting this at www.sr20deforum.com. You might have better luck there since that is an sr20 only forum.