big-phil Posted November 13, 2006 Share Posted November 13, 2006 How can I tell if they are forged? I will get some pics from the bottom. They are a very shinny aluminum. It has new "freeze" plugs, rear main seal. The guy I got it from said it was rebuilt, but did not know much about it. It has small dings in the piston like the timming was not set right at first try? The guy said he drove the car. It was running good the guy said, but the valves look dirty?? you can see the cross hatch still, and the top of the piston is marked "STD" On the bottom side, the skirt of the piston looks etched for the crank to clear, and it seems like the crank comes just mm from the pin of the piston. Does anyone know what I have???? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted November 13, 2006 Share Posted November 13, 2006 hmm...even another engine... the dirtyness pistons look like what mine did except worse. Just get some mothers polish and clean those puppies up! Makes me think the rings weren't a proper fit. Quote Link to comment Share on other sites More sharing options...
big-phil Posted November 13, 2006 Author Share Posted November 13, 2006 could it be the rings? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted November 13, 2006 Share Posted November 13, 2006 From that 4th pic it looks like a bunch of black gooey stuff so... I have a couple valves on my head that have a little of that white peely stuff...Not quite sure what it is though. Quote Link to comment Share on other sites More sharing options...
naviathan Posted November 13, 2006 Share Posted November 13, 2006 The pistons are definetely aftermarket, but they could be standard replacements. The cross hatching in the cylinders looks good, but doesn't look like it was machine bored. It reminds me of a quick hone job with a drill attachment. The white stuff is usually caused by coolant getting into the cylinders. My bet would be the engine blew a head gasket and the PO (one of them) rebuilt it himself using autozone parts and just did a crappy hone job to smooth the cylinders out. he probably slapped cheap rings in it and then ran the piss out of it before the rings had time to seat giving you all the nasty oil build up. The dings in the cylinders are definetely from the valves. It appears he caught it in time to keep from damaging anything though. Doesn't look like anything special. If it was over bored the pistons would have a metric number indicating the amount over sized they were on the top and I don't see anything like that. Sorry to burst your bubble, but they're not anything special and I would recommend rebuilding it as who ever did it last time probably had no clue what they were doing and used cheap parts. Quote Link to comment Share on other sites More sharing options...
z-ya Posted November 13, 2006 Share Posted November 13, 2006 Is it an L28, or L24? One piston looks like it has "STD" stamped in it, so the bore is standard. OEM flat top L28 pistons have "P79" stamped in them, so they are not Nissan. If it is an L24, then those are stock L24 pistons. The hone looks recent, and it also looks like the bores might have been ridge reemed. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted November 14, 2006 Share Posted November 14, 2006 thats how my victoria british pistons looked when i bought them, but new. std on top. btw, they were cast aluminum, nothing special. and that is definitely a hand drill hone. Quote Link to comment Share on other sites More sharing options...
big-phil Posted November 15, 2006 Author Share Posted November 15, 2006 Its an L28, but I am now finding spots in the hone where it did not hone through, low spots. Dammmmmmmmmmm!! I need to stop wasting money! The crank looks soooooo good too. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted November 15, 2006 Share Posted November 15, 2006 big-phil...You have enough motors now... get your best crank, best block(F54), best rods, and some custom forged 88mm pistons...yes, overbore it!!! don't worry about the little problems... I say you make it like a year long motor build and make it big...would you rather have a big chomper 3.0 turbo motor making 375+hp after sitting for a year? I would... Quote Link to comment Share on other sites More sharing options...
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