ZAutobahn

The original 240-Z tachometer will work just fine with the 280ZX electronic ignition and a high performance coil IF you don't bypass the Ballast Resistor. The original 240-Z ignition uses a Ballast Resistor to reduce the voltage from 12V down to about 8 or 9V in order to protect the points from burning. Note that when the key is twisted to the Start position the Ballast Resistor is bypassed in order to provide the full 12V to the Coil and Points. But as soon as the key is released the circuit is directed through the voltage reducing (performance robbing) Ballast Resistor. The 240-Z tachometer uses an inductive loop to sense voltage changes on the positive side of the circuit - but it is designed to work properly with the reduced voltage provided by the Ballast Resistor. It can't handle the full 12V it receives if the Ballast Resistor is eliminated from the circuit (and the "bouncing needle" on the tachometer is the result). The 280-Z tachometer on the other hand is of the more common design that senses pulses on the negative side of the circuit and it functions just fine at the 12 volt level. So if one wants a 240-Z to function at the higher level of ignition efficiency provided by bypassing the Ballast Resister in order to provide the full 12 Volts to the Coil AND have a functioning tachometer, they must retrofit a 280-Z or an aftermarket tachometer. I converted my 240-Z (L28) engine to the ZX Distributor / High Performance Coil setup 14 years ago. When I did it I bypassed the Ballast Resistor and of course got the "Bouncing Tach Syndrome". So I wired the Ballast Resistor back into the system and my Tach's schizophrenia disappeared. I decided I prefered having a stable Tach even if it meant a slight performance hit while I waited for the day I got up the wherewithal to buy and install a 280-Z Tach. Fourteen years later and here I am still procrastinating... :-)

Back in the day, we used the standard system here exclusively so bolt patterns were in inches. I think various parts on early Z cars are standard and others are metric (could be wrong). But the standard 4 - 4.5 bolt pattern (4 Bolts spaced 4.5" apart) works out to 4 - 114.3mm, given that there are exactly 25.4mm in an inch.

Actually, the second lever was a (crude) cruise control. I either read this in my owners manual or the factory owners manual (can't remember which).

Hey it's an old thread but I'll reply to it anyway. I've always been pretty OCD about checking mileage (always try to fill from the same pump so car is at same angle, and I always top it to the rim of the filler - easy to do in an early Z). Like the Johnny Cash song, "I've been everywhere, man" - and so has my Z. When I lived in Germany I typically used: Around 8 to 9 liters per 100km on pure Landstrasse driving (rural highway, approximately 90-100km/h or 55-60mph). This works out to about 28mpg US. Around 12 to 14 liters per 100km pure city driving (about 17 - 20 mpg US) On the Autobahn at slower speeds (120 km/h to 140km/h or 75mph to 87mph) about 10 liters per 100km which is about 24mpg US On the Autobahn balls-to-the-wall (200km/h to 220km/h or 125mph to 137mph) about 18 liters per 100km (about 13mpg US). This was the most fun mileage check of all - I'd fill up at one Tankstelle on the Autobahn in the middle of the night with little or no traffic, and drive it floored to the next fill-up several hundred kilometers down the road. Whoooo--EEEEEEEEE!!! :laugh: My usual mix of driving in Europe usually resulted in an average of 11 liters per 100km (about 21 mpg). Moved back to the US in 2004 and since then I've been averaging around 23 mpg (I tend to take the car out less in city situations, plus out on the interstate I don't get the chance to drive all that fast anymore). Best tankful in the past few years was 30.1 mpg and that was at a steady 65mph gas station to gas station on an interstate. Worst was 14.5 mpg, all city driving in traffic jams. Three things that kill mpg in these older tech cars: short trips, traffic jams and cold weather, especially in combination. My Z's setup: 2.8 Liter (not high compression), 5-Speed, ZX electronic ignition, K&N Filters, Z-Therapy Carbs, MSA Cam (fairly mild), 6 into 1 Headers, 2-1/2" Exhaust System with a FlowMaster muffler, Tokico Shocks, Lowering Springs and Antiroll Bars, all suspension and steering rubber replaced with urethane, and 16" Wheels with 225/50-VR16 tires. It's hibernating right now (that reminds me, I've got to go put the trickle charger back on it - had to charge up my Jeep's battery pending installation of a new Alternator yesterday). Best wishes, John

Mazda Miata seats work GREAT in a Z. I bought a set of used seats from a kid that upgraded his Miata to leather. The seats bolted into my '72 with just a little bit of modification (if I remember, I only had to drill a couple holes in the mounting area for the seats on each side of my Z). I used standard washers as spacers to raise the seats a little and also to adjust them to get the correct tilt. Best wishes, John

Make sure all the connectors on your coil and ballast resister (and the - lead going to the Distributor) are good and tight. The blade connectors on these can get loose with time and also corrode. I would be VERY surprised if you have a vapor lock problem. I've had two 240-Zs and neither of them ever had such a problem (and I lived in Southern California for years with them, and even now in Chicago, I drive in 100 degree heat in City traffic in the summer with no starting problems). When everything is right with the SU carbs and your ignition, an early Z will start as if it is a new computer controlled, fuel injected car. When it is cold and hasn't been run in a while, it might take a few seconds of cranking to get fuel to the carbs and then fuel vapor into the manifold, but then it should start right up and run great. And when the engine is warm, it should start instantly. In either situation you should never touch the gas peddle. There is no reason to. Just use the choke in cooler weather when the engine has been off for a few hours or more. Another thought: If you have the original points type distributor, the problem might be with it. When I had the original distributor, the car become very inconsistent. It would run great, and then run terrible, constantly missing on various cylinders. And every time I checked the points gap and dwell, it would be different than the previous time. It turned out that the distributor's drive shaft was worn and the shaft was wobbling about, causing totally inconsistent point gap. I solved the problem by buying a used 280ZX Electronic Ignition Distributor - one of my best investments ever. Good luck to you!!! Best wishes, John ZAutobahn