I can buy a single brand-new ome piston pin + circlips 0.5 over from nengun japan for 155aud plus post. problem is it takes for ever to get, a month possibly. I think you right about reusing the old piston, for 155 I'll get a new one. I'm not sure what I'll do concerning the ds head, I'm reasonably confident its straight though, its the damaged Quench areas, that are concerning me atm. One side could be smoothed successfully, I think, but the other is pretty much shot. Those two flats (to my understanding) force the f/a mixture back into the centre of the dome in the head, where the plug has a better chance of igniting a strong clean burn.
Might be worth using some bearing blue on the valve faces to see how they mate with the seats. That will give you a clue if there any highs or lows. Not sure if you've ever had any head work done before; but its common for the machine shop to take of the sharp edge off (debur) the chambers with a die grinder as the sharp edge can create hot spots and cause detonation. If you're replacing the piston, I'd suggest taking the heads to a machine shop for a fix. If your in Melbourne, then Dandy Engines is the go.
Here's a picture of the combustion chamber from one of my heads that were done a while ago. Note the sharp edges removed from the chamber wall.
Looks like its coming together. You really want to spend some time cleaning the surface of those heads tho. You might get away using composite gaskets looking like that, but they aren't clean enough to use MLS. I always use copper coat on head gaskets. A little secret I learned from a few well know engine builders I've been lucky enough to watch as they build engines. Doesn't matter whether the gasket is composite or MLS. Copper coat will help improve sealing.
Those are stains mate, I've gone over the surfaces on the heads and block with a razor blade a few times and then with acetone and a scotch pad, there's nothing proud of the surfaces, short of a skim, those marks aren't coming of, although I'd like them gone. The new piston and block dowel pins ect, will be here on the 3rd 11, took three weeks. Short story, When I removed the conrod cap nuts from the from there journals, I remember thinking fk there tight, or at least tighter than the spec in the 1990 nissan manual, which is 38-44nm or 28-33ft lb. So I did a search, found a later 1992 manual and the spec was changed to 59-65nm or 43-48ft lb.
In bit more to show. I dissembled the heads again and did a better job on the mating surfaces, happy with that now. Cleaned the block decks also happier with that. Have a gasket kit from RSG, thanks Rob.
The pictures show my progress, happy enough. Atm I'm looking for turbo gaskets steering pump hoses and other turbo bits and pieces. Then I'll be tiding up the engine bay wiring and maybe put some heat shieling on the tunnel. I'm going to blackout the nissan emblem on the alloy-coloured cover, had the red cover on for ten years' time for a change, the black upper plenum is gone to, I've had the original plenum for years, it cleaned up nicely.
Sprayed and buffed graphite on heater pipes, came out really niece, going to spray the manifold heat shields to.
