roninjiro Posted October 15, 2006 Author Share Posted October 15, 2006 well, guess i gotta drive it im going to do as daniel says then see what i result in. thanx guys, as i will keep you all updated Quote Link to comment Share on other sites More sharing options...
BIGJIM Posted October 16, 2006 Share Posted October 16, 2006 I have your EXACT symptoms with my rebuilt l28. Have an f54 block, n47 head, fresh rings, bearings gaskets. Honed the block , checked ring gap, everything is speced out and should be perfect. But no...it smokes like a mofo. Tried rebuilding the carbs, no help. Tried pulling the head and replacing the head gasket and putting on a whole new head that was on my other z (working perfect) didnt help. Put in different 3 quarts of 40w oil and 1.5 quarts of lucas oil stabilizer, still smokes. I havent run it much other than in the garage at idle, and smoke quick revs here and there. Only thing i can think of is to do like others have said, and to take it out and run it hard to break it in. BUT, my car is all apart ready to get body work and paint done. So until that stuff is finished it will sit as is. Let me know if taking it out and running the snot out of it helps. Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted October 16, 2006 Share Posted October 16, 2006 After you try the other advice that you have received "if" you still have the problem with smoking take it to a mechanic who can do a "leak down" test on it. Ask the mechanic to test at TDC (top dead center) and BDC (bottom dead center) of each cylinder (or as close to BDC as possible with both valves closed). If the mechanic finds anything out of the ordinary he should be able to explain it to you, if you do not understand what he is telling you come back here and tell us (HybridZ) what he says. Good Luck Dragonfly Quote Link to comment Share on other sites More sharing options...
naviathan Posted October 16, 2006 Share Posted October 16, 2006 Did you blow the engine or head gasket that prompted the rebuild? You could have oil left in the exhaust from before that's burning off. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted October 17, 2006 Author Share Posted October 17, 2006 Did you blow the engine or head gasket that prompted the rebuild? You could have oil left in the exhaust from before that's burning off. nope just felt like switching motors. Quote Link to comment Share on other sites More sharing options...
BIGJIM Posted October 18, 2006 Share Posted October 18, 2006 After you try the other advice that you have received "if" you still have the problem with smoking take it to a mechanic who can do a "leak down" test on it. Ask the mechanic to test at TDC (top dead center) and BDC (bottom dead center) of each cylinder (or as close to BDC as possible with both valves closed). If the mechanic finds anything out of the ordinary he should be able to explain it to you, if you do not understand what he is telling you come back here and tell us (HybridZ) what he says. Good Luck Dragonfly Ive built 6 L series engines so far and never had this happen. If i had the right tools to do a leak down test, i would do it myself. Most of the so called "MECHANICS" wouldnt be allowed to touch my kids bike, let alone my 240z. With every engine i ever built, including big block chevys to small block fords, to datsun l4 and l6's, i usually fire em up, run em up to 1500 rpm and break em in for 10-15 minutes. No problems ever. Did i not stagger the oil rings correctly this one time, maybe? But all 6 cylinders, i think not. Must need a good break in, but time will tell. Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted October 18, 2006 Share Posted October 18, 2006 Ive built 6 L series engines so far and never had this happen. If i had the right tools to do a leak down test, i would do it myself. Most of the so called "MECHANICS" wouldnt be allowed to touch my kids bike, let alone my 240z. With every engine i ever built, including big block chevys to small block fords, to datsun l4 and l6's, i usually fire em up, run em up to 1500 rpm and break em in for 10-15 minutes. No problems ever. Did i not stagger the oil rings correctly this one time, maybe? But all 6 cylinders, i think not. Must need a good break in, but time will tell. I understand exactly what you mean about not letting anyone else mechanic or not touch your car... but not everyone has access to a leak down tester or the air needed to use it, and if you have never used one before you are probably going to have some issues trying to make it work. I don't see anything wrong with the break-in that you did and I doubt that it would be the rings not lined up properly. What I have seen in the past is a head with a very small crack in it allowing water into the cylinder, a cylinder with a very small crack allowing water in and (not a water thing but a loss of power thing) valves that were bent so slightly you could not see it but a leak down tester found all the above and will help you pinpoint the problem. Dragonfly Quote Link to comment Share on other sites More sharing options...
280zx_sliding Posted November 2, 2006 Share Posted November 2, 2006 ronin the only thing i can think of is maybe cleaning some of the electrical stuff. i.e. the tps, swap the ecu, check vacuum lines... just do little things like that to get it all under way. i would like to come see ur z. since i am in killeen Quote Link to comment Share on other sites More sharing options...
naviathan Posted November 2, 2006 Share Posted November 2, 2006 Ahhhhhhh! Killeen! Oh God no. I was stationed there for 4.5 years. I cringe to think about that place. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted November 3, 2006 Author Share Posted November 3, 2006 it is indeed a hole in texas, i tried to move to phoenix,az and somehow i ended up right back here. Quote Link to comment Share on other sites More sharing options...
BIGJIM Posted November 6, 2006 Share Posted November 6, 2006 Did you ever get the smoking to stop? Im in the middle of the body work right now, so driving the car is a no no for at least another month. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted November 7, 2006 Author Share Posted November 7, 2006 nope, hadn't touched it since this thread started, b/c i too am in the middle of bodywork. but i will update when i get to it, i believe i just need to break it in is all. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted December 21, 2006 Author Share Posted December 21, 2006 bump, still smoking but just took it out for a drive last nite. drove it hard and big cloud of smoke behind me and it stinks from what my wife said. again, the car idles fine, has PLENTY of power, but this time i just rebuild the su carbs (running super rich, or super lean?). btw i have SM needle in this thing Quote Link to comment Share on other sites More sharing options...
naviathan Posted December 21, 2006 Share Posted December 21, 2006 I wonder if it's just oil or coolant or something left in the exhaust from the original engine? Quote Link to comment Share on other sites More sharing options...
Zmanco Posted December 21, 2006 Share Posted December 21, 2006 bump, still smoking but just took it out for a drive last nite. drove it hard and big cloud of smoke behind me and it stinks from what my wife said.What color was the smoke last night? Quote Link to comment Share on other sites More sharing options...
roninjiro Posted December 21, 2006 Author Share Posted December 21, 2006 white from what i can tell (shouldnt be headgasket b/c new head shave, new hg, block not warped). it just doesnt make sense i pull the plugs and they are black?? but it runs smooth, what gives!! Quote Link to comment Share on other sites More sharing options...
naviathan Posted December 21, 2006 Share Posted December 21, 2006 Black plugs? Oil then. How black? Light, heavy soot, wet? Quote Link to comment Share on other sites More sharing options...
Zmanco Posted December 21, 2006 Share Posted December 21, 2006 Black plugs could easily be due to a too rich fuel mixture, which is quite likely with SM needles. That by itself would not indicate anything is wrong with the engine - just that you're running too rich. Roninjiro, you sound like you're convinced that it can't be a coolant leak, but white smoke is most likely just that. If you're burning oil, it would have a blue tint. If you are much too rich, the "smoke" would be brown due to incomplete combustion. Perhaps you or your wife can look more closely at the color when you take it out again? Quote Link to comment Share on other sites More sharing options...
roninjiro Posted December 21, 2006 Author Share Posted December 21, 2006 gonna post a vid, smoke looks blue in the light, not totally convinced its not the headgasket as if it was that would be better then bad block or something. btw plugs are soot black now see post #42 Quote Link to comment Share on other sites More sharing options...
Zmanco Posted December 21, 2006 Share Posted December 21, 2006 Wow, that's a lot of smoke! On my monitor it does look blue. However, the way it rose up makes me think there is a lot of steam in it. It reminded me of the way my exhaust rises when the engine is cold. Was it cold when you shot the video? The bluish color makes me think a lot of oil is getting burned. I've only rebuilt a few engines, but I've never seen that much blue smoke before. Are you sure you installed the rings correctly? Perhaps you didn't get the oil scavenger rings (bottom set) installed properly? I've read that if the spacer overlaps itself too much, which is easy to do, they will not remove the oil properly and you'll burn a lot. Quote Link to comment Share on other sites More sharing options...
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