Mark Maras

Have you trained him to do anything else?

I'd start with a new battery and retest. I suspect the alternator or voltage regulator is bad, too. It may be as simple as overworking the alt. while trying to charge a battery that won't take a charge.

A good battery will be about 12.6-12.8 volts; 12.2 is very low and indicates it might not hold a charge. A good alternator will read 14-14.5 volts.

I'm not saying you're wrong about the vibration source, but many years ago, a friend had a '56 Ford pickup that someone had slopped a 302 ci engine into. The engine was visibly out of alignment both vertically and horizontally, and it ate u-joints every six months, but it never vibrated at speed.

Your vibration description is identical to one I had in my early 71, except mine came on at 80 mph +. I described it as having a 500 lb. bumble bee in the car. The vibration was too fast to be half-shaft u-joints. I tried new u-joints, but they didn't improve the vibration. After carefully cleaning the shaft and upon closer inspection, I found a bit of scuffed paint and the slightest hint of a dent. The dent was only visible in bright sunlight and at the right angle. Off to the local drive-shaft company it went. They retubed it and installed new Spicer u-joints. The only brand of u-joint they would guarantee to not screw up the balance at the time, I reinstalled tyhe shaft and never had any more trouble with it for the next twenty years..

I wouldn't want to be on the lean side of 14.7 at any time.

I believe there are two different snake oils for injection. One is a solvent that breaks down corrosion. The other is a lubricant that frequently uses mineral oil to lube the injectors. The one you've shown is a lubricant. Some products may contain solvent and oil but the little I've studied them, it appears it is either one or the other.

IF, (big if) the problem is electrical and is isolated to #4, it has to be located somewhere in the dist. cap, rotor, plug wire, sparkplug, and or any of their electrical connections. I'd pull the dist. cap (wires intact), and pull the plug wires. Using an ohm meter. check the resistance in the circuit between the contacts in the cap with the corresponding spark plug wire at the boot end. They should all be similar. Let's hope you find high resistance in the #4 circuit.

Depending on the mechanic's expertise, I'd lean towards the mechanic with a shop. If you have a Z repair manual, it will guide you through the head removal and replacement process.

I like the fact that they want to inspect the head before quoting a fee. I'm assuming you'd have to take them the cyl. head. Who will be removing and replacing the head?

Don't cut the choke cables. Loosen both cable attachment screws at the carbs. Push and pull the choke lever a few times. Is it easy or difficult to operate? If it's difficult, lube the cable and lever mechanism with oil. I pulled the carb end of the cables up, and sprayed WD 40 or CRC lube into the cable sheath ends and let gravity pull the lube down along the length of the cables. Then I looked to see if both nozzles were all the way up, pushed the choke knob forward and connected the cables to the carbs. Good luck and tell your Dad not to worry about the Canal.

When my nozzles started sticking in the down position, I removed the carbs and found the #1 bar warped. The ends were not parallel to their attachment points. A slight twist with two pairs of pliers on the bar realigned the ends of bar #1 with their mounting points. That ended the problem with the nozzles.

How's your knee doing?

It looks like something a pellet gun could cause. Is the paint original or a re-spray?

I too am guilty of using Series 1 &2. but using Type A &B is going to launch the same discussion by the same people because Nissan didn't use that designation either. I'll continue to use the Series designation because it is descriptive enough for U.S. Infidels.