NewZed Posted September 28, 2014 Share Posted September 28, 2014 Leon just relayed a conversation he had with Isky about rocker arms. He said that new or mildly worn used was the way to go. Now you report that new Nissan rocker arms were "bad rockers". Any chance that they weren't actually new Nissan? What will you be checking on the rocker arms? Looks like a quagmire. Post #232 - http://forums.hybridz.org/topic/111062-leons-other-260z/page-12?do=findComment&comment=1122005 Quote Link to comment Share on other sites More sharing options...
madkaw Posted September 28, 2014 Author Share Posted September 28, 2014 Schneider says there is no such thing as new "nissan" rockers anymore-only after market. The kit I purchased was back in 2006, so they said more likely they were Nissans. No way to know for sure, unless someone can tell me. As far as checking rockers, I will be checking rockers for consistancy between the two surfaces to make sure they are truly parallel and flat . Quote Link to comment Share on other sites More sharing options...
NewZed Posted September 29, 2014 Share Posted September 29, 2014 (edited) I'm pretty sure that these are original 1976 rocker arms, pictures. From my old cylinder head, off an engine which appeared to all original. Either 150k or 250k miles. And here's a link with a few pictures of the ITM rocker arms. The used ones are different and the ones he replaced have a Z, instead of an X. No idea if that's relevant. http://forums.hybridz.org/topic/106910-loud-tickingknocking-noise/ Edited September 29, 2014 by NewZed Quote Link to comment Share on other sites More sharing options...
Leon Posted September 29, 2014 Share Posted September 29, 2014 I'll add that I also spoke with Ron about new aftermarket rocker arms. The new ones I bought earlier this year (Sealed Power brand) look essentially identical to Nissan rockers, at least from the manufacturing standpoint (2-piece with hardened inserts). He agreed that they'd work just fine, FWIW. Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 9, 2014 Author Share Posted October 9, 2014 (edited) What's going on here? Edited October 9, 2014 by madkaw Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 9, 2014 Author Share Posted October 9, 2014 So I have been doing some searching - could this be from dirt? I've never run this engine without a filter, but maybe I got careless and had dirt in my CAI? It's the only explanation I can think of that would score the bores ALL the way to the top of the bore. It would have to be wedged between the piston and bore. Quote Link to comment Share on other sites More sharing options...
NewZed Posted October 10, 2014 Share Posted October 10, 2014 How about during assembly? Dry rings and bore? Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 10, 2014 Author Share Posted October 10, 2014 Waiting to hear from the machinist since they assembled the short block. It's sad that the ZX block sitting in my garage with 100K miles looks better then this:( Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 11, 2014 Share Posted October 11, 2014 Is this cosmetic staining or actual scoring? What happens if you polish the area with red Scotchbrite and lacquer thinner? Carbon staining at the top from overheated combustion chambers comes to mind... Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 11, 2014 Author Share Posted October 11, 2014 A couple of the scratches can grab a finger nail and no I haven't tried any polishing. Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 11, 2014 Author Share Posted October 11, 2014 I will add that I looked at some old pics I had of the block fresh after hone I guess. I must have went to the shop right after they finished honed the block and before installing the pistons. Magnifying the pic as much as I could I swear I could see a faint hint of these marks under the cross hatching-weird. Quote Link to comment Share on other sites More sharing options...
Naptown Dave Posted October 16, 2014 Share Posted October 16, 2014 Steve that sucks, we did have a great summer. I'll keep my eye out for a good LS motor for you just in case. Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 16, 2014 Author Share Posted October 16, 2014 Not going to the dark side yet- but tempting! Quote Link to comment Share on other sites More sharing options...
Naptown Dave Posted October 16, 2014 Share Posted October 16, 2014 Your 2.4 hit hard I'd be afraid of what you would do with twice the displacement! Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 17, 2014 Author Share Posted October 17, 2014 (edited) I loved my little 2.4-maybe she will live again! I take the motor by to the builder tomorrow for his analysis on this -it ought to be interesting. I get the feeling he thinks I beat on that motor, but I really didn't. I drove it hard at times, but not abusive. Edited October 17, 2014 by madkaw Quote Link to comment Share on other sites More sharing options...
Xnke Posted October 20, 2014 Share Posted October 20, 2014 That looks like ring scuffing at the top of the bore...but then it doesn't look like ring scuffing because it is ONLY at the top of the bore. What are the current piston ring gaps, and are they ITM piston rings? Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 20, 2014 Author Share Posted October 20, 2014 I can't tell you present ring gaps because all parts are at the machinist. The machinist said I was concerned over nothing after a cursory look. With the block and pistons in hand he will mic everything out. He thought a hone and new rings would make things all better. I argued the markings traveled the length of the bore as if done by a machine, not rings. Maybe I didn't or couldn't see these marks with a cross hatch hone over top of them before? The shop did all the assembly work last time, but this time I will be doing the assembly. These were probably ITM pistons and rings, but can't swear to that either. We did go with SI valves and guides for the head. Still no word from Schneider on the cam. It gets a little old dealing with the lack of customer service anymore. I'll see how this motor goes second time around , I might be shipping to Rebello for the 2.8! Quote Link to comment Share on other sites More sharing options...
madkaw Posted July 19, 2015 Author Share Posted July 19, 2015 Almost a year later: where should I start. Block- as suspected, was overbored and wasn't properly honed . Aftermarket piston size was right at .030 over, so clearance spec put rings at large gap. After second hone piston to bore was .0045- too much. Head: uneven rocker wear causing uneven cam wear and side loading of valve guides. Since new guides were installed on the original build I would say the guides were not in perfect. Guides were off just enough for uneven wear. Intake valves showed extensive wear for 12000 miles. Exhaust valves didn't show same wear. All valves ( SI , I believe),we're installed on original rebuild. I also believe valve stem seals were not installed correctly leading to build up on back of valves. MACHINIST ADMITTED HE DID NOT DO A SWIPE ON THE LASH PADS.This would have all been prevented if he knew what he was doing. Another words - shitty rebuild. This time around I pulled the original block out and had it properly bored and honed. Replaced rockers,cam , intake valves with stock Nissan. Quote Link to comment Share on other sites More sharing options...
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