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My Z runs horrible and I’m unable to locate my timing marks when the #1 piston is at TDC.
Have a 1970 240Z 5speed, with 139K (engine rebuild at 134K). Performance modifications: Fujitsubo Legalis R Exhaust and Trust GReddy JDM Exhaust Headers.
PO installed a Mallory dual point distributor, which I changed to Pertronix version 1. During the ignition change I found the timing before at 1-2 degrees ATDC with points and 20 degrees BTDC after Pertronix install. I’m sure that change had something to do with the electronic pickup.
I was unable to retard the timing much due to adjustment limitations on the distributor, so I adjusted the timing by drivability and the ping test. It ran decent enough.
Fast forward to last week, original carbs were impossible to adjust, so I installed replacements from ZTherapy.
Prior to carb installation I checked and re-gapped the plugs, adjusted the valves and checked the timing. With the new carbs, the car ran great with full choke, but horrible once warm. The lowest idle with the car still running was 1300 rpm.
I knew the timing was off, so I checked the oil pump shaft and found it at 1:35 (rotor at 12:00/#1 plug wire), instead of 11:25. I set the engine at TDC; timing marks/pointer, cam lobs and piston at “what I thought was” compression stroke, based on the manuals.
Reinstalled oil pump shaft to 11:25 and bolted down distributor so I would have room for adjustment. The Mallory rotor now installs after the 12:00 position, so past the #1 plug wire.
(I’m at 620 feet above sea level, so I found out last night I was running the carbs too lean at 2..5 turns out. So my mixture should be 3-5 turns out based on elevation.)
Car still runs horrible, even with the mixture screws out to 3.5 turns. In addition, when using my timing light I cannot find the timing marks and I have no more adjustment left on my distributor.
Today, I pulled the #1 plug and inserted an old rubber plug to find the compression stroke. The plug popped out like a champagne cork, but I do not see my timing marks.
I’m stumped. Will appreciate advice on getting my car running right with these new carbs.
Thank you!
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