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I need to go study up. On my '73 when I depress the pedal I hear a hissing sound and the pedal effort is much higher. In some ways I kinda like the increased pedal effort as it seems like I have better control. Will the effort required get even higher if leak gets bigger? It affects idle speed. I assume that its not worth the headache to take appart and rebuild myself. Are the different sizes you talk about tied to a month of manufacture? Perhaps time to join AAA. I am a member of Good Sam towing. They advertise unlimited towing but its unlimited to the nearest shop so that is not very useful if you are far from home. I have an '81 zx parts car but it looks like that booster is way too big.

OK, well I guess the brakes don't need them. I'll put them in my collection and save for the future. Never know when you will need a copper crush washer. ON a sadder note, now that I got the brakes fixed I think my power booster has a leak. When I come to a final stop I notice the pedal effort gets pretty high and I can hear a slight hiss. bummer. Actually, I don't mind the extra effort as it seems like I can control better but I guess the leak will get worse. This will probably be another thread. Don

I just replaced my calipers with some rebuilt ones from AZ. In each box there were 2 copper washers. They do not work with the mounting bolts (smaller diameter on washers). Does anyone know what these are for? My Z is an early 73. Perhaps they are used with other year models? Don

I think the electronics in those modules is pretty generic. I remember reading a Motorola linear parts manual that actually gave the specs of the detail part. Applications listed were auto ignition, obviously. Moto makes a lot of this stuff for oems. So I think many of the mfgs just used that small piece of silicon inside their own package. I've used the Nissan and a GM version with no apparent difference. I think that I will move mine off the dizzy and put a heat sink on it. That's a pretty hot location on that dizzy that must lead to higher failure rates. I have had the Nissan fail in the typical manner intermittent. Interestingly, the symptoms are similar to that experienced when the bearing at the bottom of the dizzy gets worn. Totally different thing, but similar symptoms.

tks Wade, looks like I can save 30$. I'm gonna get the master as well. Last time I did a rebuild on it I had a hard time getting the rubber seals to the right spot on the piston. I'm getting old enough that I just don't have the tolerance for fooling around with stuff anymore. Hopefully that doesn't lead to getting rid of the 240 after having it 35 years. don

I should say a bit more about why I'm not interested in rebuilding. Not sure what the problem is but the left caliper totally froze up. :ogre: No amount of pedal effort will make the piston move out. So I'm expecting that could be a headache to get it appart. So I'm gonna chicken out and go recon for now. Totally recond'd and ready to go is only $17 more than the rebuild kit. Yeah, I figured they all come from the same place. Amazing that there is still a big enough market to keep the recon business going. Lately, going to the Advance shop has been a bit more pleasant. They are willing to dig for miscelaneous parts not just want the year model etc. I needed a fuel filter for my boat and he went thru all the frams and found a nice one at a low price. Kinda like the old auto parts places. Don

My callipers are sticking on my 73 240. I remember rebuilding them a long time ago and it was a pain. This time I'm thinking about just using them as a core and buying a pair of rebuilts. Anyone have any experience with the rebuild callipers from Autozone or Advance? tks

just fyi, long time ago I was working around the alternator (engine was off) my wrench brushed against the +12 terminal. There was of course a huge spark and then the inductive kick. That inductive kick blew out the diodes on the alternator.:stupid: So net is always remove -terminal to battery when fooling around in that area. This was before lifetime warranties at AZ. Don

for those of you who want an mp3 input and don't want to monkey with the radio take a look at these things. http://cgi.ebay.com/Car-FM-Transmitter-USB-SD-MMC-SLOT-MP3-Player-Remote-PP-/160522604716?pt=Other_MP3_Player_Accessories&hash=item255fe490ac I know that the earlier versions did not work very well. I bought one of these for my daughter and it works extremely well and has its own SD mp3 player built in to boot. The earlier versions did not have a strong enough transmitter so the signal quality was poor. they fixed that. AS a matter of fact adjacent cars may pick up your mp3 signal. Don

I switched out my ammeter in my 73 to a voltmeter from a 280. To me the voltmeter tells me a lot more about battery and alternator condition. and yes. It shows on all the time. Just lately my autozone lifetime alternator went bad. I've got a zx one that I'm going to go back with. its autozone lifetime too. came from my rustbucket 81zx. don

Being an old EE nerd I (of course) have an old storage scope that goes to 2 ghz. After I get things running again I'll take a look. I want to do this anyway since I plan to modify the tach so its reliable yet doesn't reduce the spark. I really do think that its the heat. Even if firmly mounted on the dizzy that area gets pretty hot and heat is the biggest killer of electronics in everyday use. So once mine is running I'll probably move the module onto a heat sink and mount it on the fender well next to the coil. I still have the 240 alternator but I am going to replace it with the one from my 81zx parts rust bucket. BTW, I was in the middle lane of IH35 going about 70 when that dizzy bushing gave out. I quickly got over to the right side and got off the road. Not a pleasant situation trying to figure out what's wrong while 18 wheelers come blazing by. The huge whoosh and my cap flies off and I'm 70 miles from home. The odd thing was that it would start up and cough and die like fuel starvation. I was all set to blame the alcohol in the fuel. Don

That's what mine did with my zx replacement after a while. I replaced the module and then the bearings all blew up leaving me stranded. So I am starting all over with a remanu like you did. However, I had a similar experience with the original points dizzy where mechanical wear of the bushings would cause some jumping of timing to the extent that the motor would shut off. I doubt that's your problem if your dizzy was remanu'd properly. And you are correct the sudden shutoff does provide a sudden mechanical shock not to mention shock the mind if you are crossing a busy intersection. If I have similar problems with my newly rebuilt dizzy I will try a honda module or hei from GM. I have collected a few of these from the junkyard. I wonder if the problem is that there is not enough heatsink compound between the module and where it mounts so it may be overheating? This doesn't seem right. My original beater 81 ZX went over 250K miles until the dizzy bushings wore out. Never had that module problem.

it shouldn't be difficult to do this. I did this same thing on my 73 240. I had to transfer some mounting plates from the points version to the zx version. Did you do that? One thing you can do is just eyeball it to make sure that the rotor is pointing to the correct cyllinders as it rotates. Does it matter what year model 280ZX dizzy is used? Reason I ask is that mine just went bad and I don't remember which zx year it came from before. I am going to go with a remanu one from Autozone this time. Don

I have the 4 wire tach on a 73 240z. These tachs are wired such that a one turn loop on the back of the tach acts like a one turn transformer. The current through the points runs up into the dash and thru that loop. So the spiking current going thru that loop inductively couples to the other side of the transformer inside the tach. This is a pretty bad design as it routes that huge noise current spike through your dash. I guess back then people didn't care about radio or other electronics interference. I told a hot rod friend about this setup and he mentioned that the tach on the old Jags were also that way. A poor design copied apparently. Previously I used an old capacitive discharge electronic ignition and of course the lower current through the points rendered the tach inoperative. I was able to make it work by replacing that one loop with many turns of wire to get the coupling increased. Since then I have gone to a ZX dizzy setup. I connected that same tach to the negative lead thru a 30 ohm resistor and .01 uf capacitor and grounded the other lead and it mostly works I suspect that I need to add more turns of wire since the current is even lower. If I find the right combination I will post the results. Currently, my Z is down. I went on 60mile trip down IH35 and wouldn't you know it, the dizzy bushings gave out stranding me down there. I had it towed home, $230 ouch. I decided to do that when the mechanic I called asked me if the "check engine" light was on. I see someone here on the thread is from Austin. I need to send you a PM as I'm in Georgetown. I want to fix the tach but honestly, after driving this car so long I can tell when to shift from the engine noise. have fun Don

Living in central Texas I had lots of vapor locking problems when the fan clutch got the least bit weak. I solved the problem with a metal flex fan eliminating the clutch. Have had it this way for 20+ years. It was a significant improvement for me and made the ac better at idle too. Don

On my '73z when the engine is off the sending unit measures infinity ohms. If someone had told me this I would not have believed them but that's what I measured. This is with the sending unit disconnected of course. At idle the resistance goes to about 50 ohms and then when I rev up to like 2k it drops to about 30 ohms. these gauges are very slow in responding since the meters themselves utilize heating of bimetalic strips to drive the indicator. Furthermore, the voltage regulator circuit for these gauges consists of pulses of voltages again from heating of bimetalic strips. If you measure the resistance of your gauge with the motor running be sure to connect the ground lead of your ohmeter back to your battery. If you connect it to the alternator ground terminal you may get a wierd reading due to the high charging amperage that can cause a ground bounce on the alternator. To confuse matters more, don't use a digital meter. When I tried mine it indicated nothing at all. Apparently there is enough electrical noise from spark plugs etc that the dvm got confused. I remember 25 years ago in the winter panicking when the oil pressure showed zero. I had to remove the sending unit and clean it out with kerosene as some sludge had blocked it off. I did the same thing you did. I got a cheapo mech oil pressure gauge just to double check that I really did have oil pressure. Right now, I use a T fitting so I can connect up the sending unit and a switch. The switch is to turn off the electric fuel pump in event of no oil pressure in case of a crash. Don

I read thru the forum and I have about concluded that I can trade out an 81zx 2+2 5 speed for my 4 speed 73 240z. Keep the same drive shaft but use the diffy from the zx as well. Does all that still sound good? I saw some scares about shifter holes but apparently that only applies to the early 240s. I've talked about doing this for years but now that my clutch is slipping in the 240 the tranny has got to come out anyway and I'm retired now so I should have the time. Not really looking forward to being covered by grease but I guess that's the price. Only gotcha may be the speedo gear. Anything else? 73 240 bought in 76 (daily driver) 81 zx rustbucket no longer a daily driver regards Don

I've fooled around with lots of batteries in boats, rv's etc. On my RV it has a continous charger (like a tender I guess but more oomph if necessary) it charges to like to 13.2 and holds it there. If I disconnect the charger in a few hours the battery voltage will drop to about 12.75 volts. If the battery is on its last legs it will show like 12.5v. However, the real way to find out is to l hook up a headlight for 30 minutes. If it runs down to less than 12 v then you know that battery is on its last legs. For trickle charging on my boat I just picked up a wal wart that says 12vdc. Open circuit it may be 16V. Then I hook it to the boat and it will slowly bring up the voltage to like 14v. To keep it from going too high I put some diodes in series with the lead. Each diode drops it about .6V so you can customize it. The charging current is probably only about 200ma. I've been using something similar on the Z as the 73 alternator doesn't charge it all the way up. Once I switch to my old rust bucket zx alternator I'll probably not need the trickle charger anymore. Don

I'm an EE so I couldn't agree with you more. However, most mechanical types and people with grease under the fingernails know them as condensers so that's what I called it. I had already used one of the old fashioned capacitive discharge type electronic ignitions. It used the points to trigger the discharge of a high voltage dc-dc converter. In that case the points saw very little current. So.......I removed the tach and added lots more loops of wire and it worked. So the plan now is to use the hei circuit to trigger a transistor to drive some small current thru those same loops of wire. If I figure out something that works reliably I'll post it. tks Don

I dug around and found my old actual ZX manual and found the answer. To answer your question, it looks just like the ordinary dizzy condenser. However, what they do is connect it between the +12 terminal on the coil to ground. So the purpose is to reduce noise going back on the 12 volt circuit to reduce radio interference. So its not really needed functionally. Now to figure out how to make the tacho work. I really don't want to route all that high switching current thru the tacho as that is really a noise generator and puts the tacho in the functional loop. BTW, Mike, I grew up in Baytown and got my first view of a Z back in '70 when I was going to UH. I had to have one but I didn't get it until I got my first real job in '73. I've still got it. You must garage yours to keep that rust away in Houston. Don

Hello everyone, I've been out for a while. Finally getting around to Z car improvements. I've moved the ZX dizzy to my 73 Z and it runs fine. Only thing is I can't figure out why the ZX ignition had a condenser. Does anyone know its purpose? On a conventional points system the condenser is there to save the points and return some energy back to the coil. With the new pointless hei I don't think its needed for that but the condenser did something on my old rust bucket 81zx. Was that how they coupled the signal back to the tacho? Reduce radio interference? I looked at some of the reference html on the old points style and the hei style and they don't even show the condenser at all.:stupid: tks Don

I realize this is a bit of shade tree engineering, but I had one of those adjustable thermostats from Jc Whitney with the bulb on the end. I put the end of that bulb into the radiator hose on the engine side and then used 2 clamps and lotsa gasket sealer and it did not leak. This provided me with an adjustable thermostat, albeit kludegy looking. Since then since I live in Austin Tx I went with a flex fan and I've used the thermo switch for an idiot light in case I stop paying attention to the gauge some hot day. don

FWIW, on my '73 I only use the electric pump. I blocked off the mechanical port. I did this in my quest to eliminate vapor locking. Its bad here in Texas in the summer. I could hear the fuel boiling inside the mech fuel pump. For shutoff, I used a oil pressure switch. Don

I thought about that one too. So far the control seems to keep hot water from flowing in pretty well. But its on my list once I tackle all the other high hitters . tks for the suggestion. Lately I've taken to moving that control on and off periodically just to make sure it doesn't get stuck. You know how it is in Texas. We don't need the heater much.

Wow, if you feel that much vibration and loading I think that something is big time wrong. Maybe as simple as an overcharge and the pressure is getting way too high. Or you may have a clogged expansion valve or orifice tube depeending on what's in there. I remember now the location, its the same location that they put ac compressors on the 280zx. If you don't have ac experience, be careful there are some very high pressures involved and freon if let go suddenly can burn or blind you if it hit you in the face. yes, Lake Travis looks just like a snakey river now. don