Mark Maras

Although I don't own a Pertronix set-up & know virtually nothing about it, I've repeatedly read about this little problem of leaving the key on & and frying it, I'll leave the question of why anyone would sell or buy this product, to anyone who would like to educate me. The thing I'm curious about is, does anyone know how long you can safely leave the key on? Everyone writing about the problem seems to have a vague idea of the time frame. I'd be afraid to buy one for that reason alone. I really am curious about the positives this system offers because Pertronix was one of the options for an upgrade.

Congratulations Geoff How many times did you pinch yourself just to make sure it wasn't a dream? Assuming your Z is now running great, as the burn-out would indicate, two questions remain #1 Is it going to be your daily driver? & #2 Will your daughter ever trust it or want to be seen in it again? Enjoy this next week, Temp. near 80 Wed. Perfect Z weather in the NW.

Hi Geoff, While you're under the car, disconnect the clutch slave cylinder spring & see if you can move the clutch release arm for & aft. I adjust mine so there is about 1/4"-3/8" of movement. This will ensure the release bearing separates from the p-plate. If the r-bearing has been pushing on the p-plate, pushing on the clutch may not change the noise. My first impression while "listening to the video" was serious valve train noise. Pull the valve cover take a look & a listen. I think you'll find it there. Then I listened for the whirring noise & heard it. I think you'll find it in the valve train but I'm going to listen to it a few more times to take a shot at that one. Give me a call if I can help. Meanwhile, Fawlty Towers, John Cleese screaming at his car. It will make you laugh. Guaranteed

If & when you are going to change them, I recommend Spicer u-joints if you're not going to use Nissan. Cheap u-joints can cause or aggravate driveshaft vibration. A fairly common problem on Zs. The local driveshaft shop I use insists on Spicer joints when balancing.

Sus get leaner as the fuel level drops. The fuel level is supposed to be just a little below the top of the jet which is determined by the float level. Easy to test the vapor lock theory, test drive it with the hood cracked open. My previous 71 Z & I shared 20+ years as a DD & despite not having insulated f. lines, only a heat shield, I didn't experience V. lock once.

I'm going to take a shot at this. If we start with the normally dark plugs, idle was set with a rich mixture. As the engine starts to run low on gas the mixture leans out & the idle goes up. No power under load is classic low fuel supply to the carbs. There is plenty of fuel in the filter up front seemingly the problem exists from the filter to and including the carbs. Check the f. lines, filters in the banjo fittings on the float bowl & fuel pressure & volume test. There may be a filter in front of the gas tank too.

Ouch, it hurts a little more when you remember the price of gas pre 1973. At least we can enjoy our miles of driving.

I know little of the complexties of FI, being an SU guy, but there are basic similarities. I doubt the problem is fuel ratio related. The only way any engine will run at higher RPMs is increased air supply. More fuel is needed to sustain the higher revs but it starts with the air supply. Something is controlling the butterfly and preventing it from closing. Most carbs have a dashpot,(vac. diaph.) that allows the revs to fall normally, until just above idle. Think of it as a rev cushion. Whatever is causing this problem is attached to the throttle shaft or linkage and is temp. related too. Just out of curiousity how do your plugs look? It is possible running a very lean A/F ratio that an increse in fuel will raise the revs.

A good rad. shop can re-core it. I've always used Mac's in Portland but there must be a good shop in Bend or Redmond. Here's my tip. Pick up a mechanics pad at Harbor Freight. It's a trifold cushion about 5' long that makes everything much less painful. It also works great for under dash work if you remove the seat.

Take a look at the front carb.The likely culprits for the first three sooty plugs are; sticking fuel nozzle, misadjusted choke cable, mixture screw adj. or float level.

It sounds like valve train to me. I'd pull the valve cover, start it up and use the prev. mentioned hose to find the source of the sound. I've used the hose for years. AmaZing tool. Works well for checking the carb. balance too.

There is one more vac. line from the base of the front carb to the vac. diaphram on the dizzy.

The hoses into the back of the air filter aren't vacuum lines. They all vent fumes from the float bowls and the engine to be burned. Vacuum lines are usually found coming from the base of a carb or the intake manifold.

It sounds like valve train noise to me, I'd pull the valve cover & see if the oil tube is squirting, drooling or leaking. It should be squirting oil out uf 12 holes in the tube. The lower compression on #s 2 & 4 would have me rechecking the valve adj on those two.

The tic tic sounds lindicate the plugs are firing. I'd pull #2 or 3 plug & ground it to actually see what, if anything, is going on. Compression? Recheck the valve adj. & compression to eliminate that possibility. That leaves FI. I'm an SU guy but basic injector function must be easy an easy test. I'd guess disconnecting the injectors one at a time.

Check the inside of the dizzy cap boots & the spark plug boots to see if the connectors have pulled back. If this is a consistant no fire in two cyls. it is isolated to the wires, cap, rotor or plugs all of which are new. Swap #1 & #2 plug wires & see if the miss changes to #1. This problem is usually a poor elec. connection, especially when you have new components.

Assuming you've done a recent complete tune up, the front carb sounds like the problem. Check the following; fuel nozzle sticking in the down position when the choke is off. cable adjusted to allow nozzle to return, float level ( you'll need a new gasket), compare piston drop in both carbs(oil cap in & out), everything OK then turn the mixture screw clockwise 1/2 turn, this will lean the mixture in that carb. clean the plugs & drive it. Check back.

The ratcheting, You can hear it, can you feel it as well? What part of the car is it coming from? Can you feel it in the shifter, the body, the seat or the pedals? Also, have you noticed any changes in the car previous to this noise? Any info you can share, no matter how trivial, will be a big help.

A couple of questions. Are all the windows up when this happens? Can you change the noise using windows or vents? The reason I ask is my Camry thuds my eardrums above 60 mph with the left rear window down. Yeah, left only.?? This may be the same noise as the Audi prev. mentioned. My answer is as simple as rolling up a window. Is it possible you have air leakage into or out of the cabin that could be causing it?

Point Float. Racers back in the 50s & 60s would cut a small piece of neoprene rubber & wedge it behind the movable point. This was a common way to eliminate point float from the list of things that could go wrong, or at least it did no harm & made them feel better. The neoprene usually came from a wet suit back then.

Nice find and welcome to the club. The members here are eager to share their knowledge with others. Check out the forums on whatever Z topic you wish. You'll find hours worth of reading there.

OK, I haven't researched them, just repeating what the PO told me. I obviously have some homework to do, If they're not DGV's, what are they. Anyone recognize them? They came as extra parts with my 74 & are set up for a Z.

Here are the pics of the DVGs The PO said 1 carb has a bad diaphram. Unfortunately he didn't remember which carb it was. I assume it's probably an accelerator pump diaphram, but that's just a guess on my part. I don't have plans for them at this time, Maybe way in the future but I have plenty to work on before I start swapping carbs out of boredom.

I'll post a pic of my DVGs tonight when I get home from work.

Having experienced clutch seizure, The noise is a lot like small plane prop. & HP drops about 25%. I drove my Z with a flex fan (no clutch) over 100k miles and had no complaints. Mine has a 2" spacer which sets the fan 1" from the radiator instead of 1 5/8". Fan diam. is 15" & acually gets quieter at higher RPMs. If you watch it as you rev the engine the blades flatten out. The individual blades are quite large 3 1/2" x 5 1/4". At the time I thought I would add a shroud but didn't need it after all. My orig. fan had steel blades & weighed a lot. with the FF, the engine reved noticeably quicker. TomoHawk, I don't ever remember my fan clutch, for the few years that it lasted, cycling as you described. Confession, I drove the car daily without a fan in the summer time for 2 weeks. This is what I learned. RPMs are heat. Duh! Keep the revs low and shut it off instead of idling. I found that at 10 MPH or above I could keep the car at the normal temp. this way. I came to realize that it doesn't take much speed at all to make a fan useless. i wasn't entirely sure if the FF would solve my overheating at idle but i was totally satisfied.