Lynton Posted October 16, 2007 Posted October 16, 2007 I recently drove my stock 77' 260z only when cruizing breaks down like someone has attached a caravan on the back of it, it will struggle to hold 100kmh flat out running like there is an electrical or mechanical or fuel problem the car goes from smooth running to almost like not on six cylinders lacking clean power it is choked up and bogged down. I have checked plugs and cleaned, no water in the oil in case of blown head gasket, idles ok, drives through the gears ok, checked distributor points, checked coil and cleaned contacts, no water loss in radiator. I can hear the fuel pump running on start up, I have not changed the fuel filter? Petrol does not have water in it. Questions, does anyone know what the symptoms are if the distributor is no good? Does anyone know what the symptoms are if the flat top Hitachi carburettors are finally breaking down. The car does not blow smoke except on choke on start up for a moment or two. Anyone got any ideas where to investigate or re investigate from here, Lynton Quote
chris240 Posted October 16, 2007 Posted October 16, 2007 sounds like a bad flat spot at mid-high revs. Have you had the carbies & needles looked at , or overhauled ? May need a electronic dyno service to see if something is causing the dizzy to lose efficiency / timming. Are you running headers or stock manifold ? Maybe time for a compession check. Quote
oldmates260z Posted October 16, 2007 Posted October 16, 2007 Bought my Zed in Albury and drove it back to Brisbane via Sydney. In the Sydney leg had exactly the same problem and noted that it was pinging a bit as well under load. Reset the timing by eye and drove it to Brisbane and did not miss a beat! Bought new points, dist cap, rotor, timing light and have used none of them and its still going well. Wish I had the time to work on it, too much fun driving it! Quote
pauly_adams Posted October 16, 2007 Posted October 16, 2007 yeh i have the same prob do you have flat top su's by any chance cheers pauly Quote
chris240 Posted October 17, 2007 Posted October 17, 2007 I replaced my flat tops with new pommy SU's 3 months ago...Now runs much sweeter. Quote
Lynton Posted October 24, 2007 Author Posted October 24, 2007 Yeah I run flat tops, but I have decided to pull them off, just done that, I have pulled off the standard dizzy, now I am going to put 240Z carbies on, extractors and electronic dizzy off a 280ZX, replace the coil, and replace exhaust pipe, so far I have lots of vacuum lines running to nowhere, a water system that's a bit cruddy, water pipes leading to nowhere, two broken studs (I am going to have to drill out got any good ideas,) I think I shall replace thermostat and housing while I am at it, Then I will be I hope, a happy boy??? Lynton Quote
260Coupe Posted October 30, 2007 Posted October 30, 2007 Lynton It sounds like classic emission control carb issues (they have plastic diaphragms that distort with heat and age) I had a similar issue 17 years ago with my then stock '76 260 Coupe , drive for 1 hr and the car would die............wait an hr and it would drive fine yaddah yaddah. As you have suggested ditch the airpump and exhaust gas recirculation and flat top carbs, install 240Z carbs, 280 elec ignition and headers and 240 A grind cam shaft you will have years of trouble free motoring and 90 kw at the wheels from the standard low comp L26. regards Al. Quote
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