NotMe

Hello all.
I think it is time to ask for a little help. I bought a 1974 260z last spring and have ben picking away at it off and on. So far I have replace the flat top hitachi's with a set of three screw dome top su type. New electronic fuel pump and hoses plus filters.
Ok so here is my dilemma when I line up the engine to set my timing ( crank pulley at 0 my cam notches are lined up in the # 2 position ). I continue to set my timing at 8° BTDC, I can barely get the engine to run, the Idle is low, and stumbling with no power. Now when I advance the timing the engine Idle started to pick up I maxed out the rotor adjustment to about 24° BTDC, (I'm guessing because the timing marks don't go that far they stop at 20°). With the timing set to 24° my Idle is steady and vacuum holds at 16 VGI (I live at an elevation of 4200 feet and I'm not sure what my vacuum should be but that is another issue). Could anyone tell me why the engine would run like this, any Ideas would help.
Thank you. P.S. The original radio works great

theramz

At this altitude (I live in Dayton, NV) the carbs need to be leaned out quite a bit. Turn your mixture screws on the bottom of the carbs in until the idle comes up and work from there. Make sure your vacuum advance is working freely. Those old dizzies get gunked up inside.

NotMe

Thank you for the reply. I bought a color tune plug and have set my mixture to a pretty blue with a little yellow when I throttle up. Last Saturday I had set the air flow and was ready for a test drive when I noticed bubbles in the fuel filter, I ran out of gas. I was checking fuel pressure and found that with the fuel return line connected I get a whopping .5 PSI, so I disconnected my return line and put the pressure gauge in it's place and now hold a steady 4 PSI.
I'm still trying to figure out why the timing won't line up properly, If my cam timing was off the notches shouldn't line up with the crank pulley at 0°. Unless maybe someone put the wrong timing plate on the block, is that even a possibility?
Dayton is right down the road, let me know if you want to get together some time and through some ideas around and see if any stick.

theramz

Maybe your timing chain is stretched. Your fuel pump is not supplying enoungh gas and could be leaning out one or both carbs. Compensating by advancing the timing that far will burn the valves. I have some timing covers laying around to compare and several books. Contact me via PM and we can talk Z.
Tom