ms53_wagon Posted February 8, 2010 Share Posted February 8, 2010 Hey, This question relates to my nissan homy, z20 engine (8 spark). originally carbed but now dedicated lpg. question 1: with setting points i have normally just set the gap, but i read that it should be the dwell angle that you measure - is this hard to do/any better than just setting the points gap? question 2: I couldnt feel a timing mark on the crank wheel so whats the best way to mark the TDC point?? I could get it close but not sure how to get it exact. question 3: the old owner mentioned a timing of 10deg BTDC, can anyone confirm this. Also does anyone know what an acceptable increase in advance is for an lpg engine? or is it more trial and error? probably not fun doing trial and error with the twin spark haha question 4: I noticed the other day that the dizzy had no vacuum advance line - it was just blanked off (im guessing since the carb was changed to an lpg setup either you dont need it, or they were too lazy to hook a new one up???). anyway i hooked it back up - should i notice much of a change in the way it drives? question 5: not a timing one but - the muffler has some holes in the bottom of it, can these be welded over, or am i looking at a new muffler? Cheers! Dan Quote Link to comment Share on other sites More sharing options...
ms53_wagon Posted February 9, 2010 Author Share Posted February 9, 2010 ill answer a couple of these myself. 2 - found timing mark - sweet! however this twin timing shit is hard work! haha. can get inlet sitting about 10deg BTDC but cant retard the EX anymore within the dizzy and its sitting about 20deg...hmmm its a real mind bender trying to do both at once! then if i retard the whole dizzy i can get the EX back to about 10deg but the IN is about 0deg! argh. gonna have to have a bit more of a think about this one. 4 - when vacuum is hooked up it advances the mark way of the readable values, i was just mucking round and found a spare vacuum line (open) coming off the inlet manifold so i hooked it too this. but after thinking about it, does this need to be hooked up somewhere before the throttle plate? surprised i never noticed the open vacuum line off the throttle body - think thats why idle was slightly high haha. Will keep trying cheers Quote Link to comment Share on other sites More sharing options...
ms53_wagon Posted February 10, 2010 Author Share Posted February 10, 2010 someone was trying to trick me and the leads for In and EX where back to front, thats why my adjustments were not working properly and confusing the hell outta me! got both set at about 10deg BTDC now which is good. (this is with vac advance blocked off). at idle should the vac advance be working or is this only meant to work further up the revs?, mine seems to advance from about 10deg to more than 20deg even at idle. is there a way to test this is working properly? still not sure if i have hooked this up correctly yet either? Quote Link to comment Share on other sites More sharing options...
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