240ZMan

Marty, when you came off the track did it have problems idling? I ask because I had the exact same symptoms as you at our last track day where it was at least 95. First few laps of each session were great, but after about 10 minutes I had to short shift. Turns out for me the front carb is percolating the fuel. Event though I have a large home-made heat shield over my header, the front gets too hot. I've been able to recreate the issue at home on a warm day letting the car idle in the sun. The fuel level in the front float rises, and sometimes the fuel percolates. One time I quickly pulled the domes off the carbs and I could see the fuel spurting out through the nozzle. I've checked and double checked my float levels, and I have a fuel pressure regulator turned down to about 2.5 psi. What surprises me is that I can put my bare hand on the carb when this is happening and while it's hot, it's not so hot I have to pull my hand away. So far I haven't found a way to solve this completely. I've tried routing the fuel lines around the front of the engine compartment (over the radiator support) as an experiment to see if it was heating up too much on its way to the carbs. Made no difference. I did find that stuffing some fiberglass insulation between the carbs and the heat shield slowed down the rate of the problem occuring, but I get the same problem when I come back to the car after driving and letting it sit for a few minutes. I've confirmed it is NOT vapor lock. Taking the cap off the fuel tank makes no difference either. I'm going to be switching to some Weber DGVs to solve a tuning problem and am hoping that they aren't as sensitive. FWIW, I have a 4 core radiator, fan shroud, and splash pan. Part of me wonders if removing the shroud might help by blowing the air in a different path under the hood? Haven't tried that yet. What drives me crazy is that I read about people driving their early Z's in Arizona in July with no such issues while where I live in CO 90 is a hot day! Anyway, I don't mean to hijack your thread, just letting you know you're not alone (in case that makes you feel any better). Daniel

No, the wires are a dead giveaway IIRC, a mechanical should be less than $50. If they want more and you're interested in a used one, PM me.

http://www.classiczcars.com/forums/showthread.php?t=10305 When I did my conversion I wasn't aware of anyone who had made a harness already otherwise I would have gone that route. I will tell you that I measured the voltage across my headlights before and after and saw an increase of 1.5 V. I forget exactly what the values were, and since it was November in Colorado it was pretty cold so the battery voltage was lower than usual as well. But the point is that just changing the wiring in my case resulted in nearly a 35% increase in POWER for the lights. Even if I hadn't changed to H4s things would have been much brighter. I highly recommend upgrading your wiring for anyone with a 73 or older Z.

The PO of my '73 had put that model in. I couldn't get it out fast enough as I couldn't stand the harsh tapping sound it made. No amount of rubber mounting would get rid of it. In fariness, I don't know if it was just my unit or that's just how the Facet's are. I think the "rotary" models are quieter, but also more expensive. I can't tell if the second one you listed is rotary. I found a generic (not for any particular car model) at Autozone for about $30 that was much quieter. You can still hear it a little at idle with the windows up, but otherwise I don't notice it.

I have done it with my Enki92 14x7 rims. It's tight though. I think it depends on the wheels. I had wanted to do the vented disc swap at the same time, but that wasn't going to clear my rims either. And yes, you have to cut the dust shield as the new caliper is bigger than the original. I used a dremmel and cuttting wheel. Took just a few minutes.

I experienced the same thing unti I realized I had forgotten to put the metal washer on the fitting before threading it in. Once I did that it sealed perfectly. The SS lines give a very nice firm pedal.

They look like 4 screw round tops from an early 240. But I doubt they have never been used. Look at the side of the piston. Looks like the usual accumulation from gasoline. Also, I'm a little confused by the banjo fitting. I haven't seen that on SUs before, especially since I already see the rubber fuel inlet connected as well as the breather. On mine there are only 2, not 3 connections.

As said above, the 81-83 has the best ratios. Pair that with a 3.90 diffy and you'll have a great touring car. Use a 4.11 like I did, and it's very lively . Do this if you like to shift a lot and like revs. If you want a more sedate ride, I think the 3.90 would be a better choice. Of course, I know some people just swap the 5 speed and leave the stock 3.36 diffy in the car. If all out acceleration isn't your objective I suppose this might be a nice option. Certainly would keep the revs down! Or swap a 3.54 from an early automatic. They are a lot easier to find, and not expensive at all. That would get the revs up a little. Again, as GunnerRob suggested, http://www.geocities.com/z_design_studio/transmission.html is a great tool to figure out how the different combinations would affect your speed in gears.

I think that's only true for the early 5 speeds (75 - 79?). On the 81-83 all 4 of the lower gears are different from the 4 speed (that's why you should also change your differential) but most importantly, the gap going from 2nd to 3rd is much smaller so that the engine can still be in its power band.

I have a 73 and did the 4 piston swap last year myself instead of using the MSA kit. I've been very happy with the results once I put Axxis Metal Master pads in. I have the stock rotors too. The improvements were much easier modulation at the limit of brake lockup on the fronts, and a slight improvement in fade resistance, but that's probably more a function of better pads as I didn't change the discs. BUT... my system was functioning properly before I did the swap. In your case I think you need to determine why you're not getting lockup in the fronts before the rears before you do any swaps. Many people claim that a properly functioning stock system is just as good at stopping the car as the 4 piston swap. (go to hybridz.org for some very heated discussions on this topic.) I will also say that if you want to buy more performance oriented pads, there are more choices for the stock calipers than the 4 piston. Keep in mind that the 4 piston calipers come from a 4x4 truck and hence the pads offered are oriented towards a truck. Again, the improvement for me was in the ease of controlling or modulating the brakes. You really don't get any significant improvement in fade resistance. Now if you do the 300zx vented rotor swap and go with the wider 4 piston calipers as suggested above, then you'll get a significant improvement in fade resistance as well. I wanted to do that, but didn't have enough clearance with my current wheels and didn't want to get new ones. At least not right now Good luck!

I've read the answer is "yes" but that it will hang down low in front. In other words, the 75 is taller than the 72. Haven't tried it myself...

Thought I'd share my experience. When I put the L28 (all stock) into my 73 I upgraded to the MSA 6:1 header and their 2 1/2" exhaust with Dynomax muffler. I found I loved the sound, but it really was too loud to drive where I live. So I put an 18" glass pack in just before the bend over the rear half shaft and the results were a really good comprimise. Later I upgraded my cam to a mild performance cam. The result is noticeably less exhaust note at low/mid revs, and it doesn't have the "warm" tone it used to. It's not bad, but if I were to do it again, I would have put a shorter glass pack in. My point is that it really helps if you know where you plan to end up with your mods so you can (hopefully) get it right the first time.

Actually, in this case this isn't true. If you are seeing a significant voltage drop before the coil (in other words, the voltage across the coil is much less than 12V, it's because there is additional resistance in the circuit elsewhere. That means the TOTAL resitance of the circuit is higher, which means the circuit's current is LOWER. This really works against you with the coil because you have both a lower voltage across it as well as lower current flowing through it. Power is equal to the voltage times the current. In this case you will have significantly less spark energy. Where your statement is true is IF the total POWER of the circuit is to remain constant, THEN it will take a higher current with a lower voltage to generate (or consume) the same amount of power. That's the idea behind low voltage lighting in your backyard. EE class dismissed BTW, what is the gap of your spark plugs? I think stock is supposed to be .035" (going from memory) and you can open it up to .040 with a higher voltage coil.

There are some who have advised me to get rid of the vacuum advance all together. You don't have to have it, although you may see some reduction in mileage if you drive at steady speeds on the highway. To try it, put a plug on the nipple on the front carb where the vacuum hose connects and just remove the hose from the dizzy. Now you can dial in more advance at idle without as much concern for pinging at part throttle accceleration. Try it and see. Just listen carefully to your engine for pinging in which case you need to back the timing off.

On my '73 there are two spade connectors connected via a bent piece of metal onto the one spade connecter on the starter. When you turn the key this is how the voltage is applied to the starter's relay. Sometimes I would turn the key and nothing would happen. I finally traced it back to these connectors. No amount of bending and cleaning would make this intermittent problem go away. Just this weekend I cut the old connectors off, crimped both wires into a new spade connector, and life is good again. I'm not saying this is what is the problem with yours (I'd suspect the battery first), but it's pretty easy to check this out none the less. Good luck!

Did you by any chance note the timing before you started the swap? My own experience is that if you have a lot of advance, the engine feels like it responds to the hit of the throttle more sharply. You can always try adding more advance at idle, say 5-10 degrees, and take a test drive. I'm not saying you won't run into pinging problems with too much advance though. One of the things I like about the Z is that you can experiment with these settings and as long as you don't go overboard you won't damage the engine. And you can learn a lot. That's the fun part! Good luck.

The way you have it currently set up (bottom picture) is correct. You won't see any vacuum until you crack the throttle plates, which then gives you the advance you want at part throttle. As for initial timing, I'd be surprised if you could feel any differnce between 7 and 10 degrees of advance. What really matters is how much TOTAL advance you land up with. At this stage in the life of an engine, there are many factors that can determine the max advance you can run. Regular vs. Premium fuel is also one. Unless you are going for absolute maximum power, I'd set it at 10, listen for ping, and if you don't ever hear any, you're probably fine. As for being down on power, why do you say that? Are you comparing it to some earlier time, or perhaps you just expected more? Hard to advise without knowing more.

Rebuilt alternator is installed and so far all is good. Opening beer now...

I'm thinking along the lines of Carl. Either way I'm going to replace the alternator. I did pull it out this morning. It spins quite freely. The only play in the bearing/shaft is front to back, and very little. I can't feel any sideways at all. The only thing stopping me from just replacing it with a rebuilt (besides needing to finish mowing the lawn:) ) is that a few weeks ago I had problems getting the engine started (my mistake in setting the timing) and eventually the battery needed a boost. It's not a new battery, and I can't help but remember reading people who replace one of the two and then later found out the problem was the other. And given the problem is intermittent, if the alternator tests good on the bench, then I don't know anything more. I did measure the voltage across the battery while the moaning sound was present, and it measured about 12.8V. That makes me think the problem ISN'T with the battery as a dead cell would likely drop it further, don't you think?

I agree, that was my first thought on the sound. But I don't understand how that would affect its ability to charge? When the sound is present the alternator can barely power the ignition. As soon as I turn on the headlights the ammeter shows I'm discharging the battery.

I've got an '80 alternator in my '73 240 and for the last year it has worked great. But last night I noticed the headlights dimming now and then and the ammeter showing a slight discharge when they dimmed, even when the engine was at reasonable revs. When I got home I checked the wiring all around, wiggled everything and the problem dissapeared. That is, until today when again it intermittently showed up. I noticed that when it dims, there is a slight growl or hum from the alternator that you can hear in the cabin as well as with the hood up. Also, there is a smell while it's making the noise if I put my nose down near that part of the engine compartment. I've smelled that smell before, but can't quite place it. But it's not insulation burning. In any event, I suspect I'm going to need to replace the alternator, but my question is if anyone has experienced the noise? Mostly out of curiosity, I don't understand why it's making a speed dependent noise when it's not putting out enough current? Anyone experienced something like this before?

I just had my flywheel lightened. Before we started it weighted 23.5 lbs. I paid the machine shop for 1.5 hours of work to use a lathe to take offenough material to get down to 16.5 lbs. To go further was going to require them to switch to a milling machine to take material off between the studs that align the pressure plate. I didn't want to go that far or spend the $$$. Then I had to find another shop to balance it. Then I had to find a last shop to refresh the clutch disc surface. In the end I spent about $150 total. I do think it was worth it, and was very pleasantly surprised that it didn't make starting up in 1st gear any more difficult. On the positive note, the revs drop much faster on shifts. I can't say I found any improvement in acceleration that others have claimed, but all in all I think it was well worth it if you're going to have the tranny down anyway. I don't think I'd suggest it for a street driven car if that's all you're going to do.

Good luck Mark, I will say that of the many projects/fixes/rebuilds I've done on my Z so far, this was by far the least-fun. I don't like pounding on hard-to-get parts that are supposed to operate precisely, and can cause really bad things to happen if they fail. With luck I won't be doing this one again. Daniel

Found the problem: although I had driven the seal about 2 mm beyond the edge of the hub, I guess the inner flange was rubbing on it a little when I fully torqued it down. I pulled everything out, drove the seal further in, and all is well. It had been a week since I pulled the old one out and I didn't remember how far in it had been. And the FSB and Haynes manuals don't say how far to drive it in either. Now I know

Mark, you're thinking along the same lines as I am. After sleeping on it I'm sure the issue has to be that one of the bearings isn't seated properly. I made sure by looking through the hub that the inner was all the way seated. As you point out, there isn't any way to confirm the outer is seated. However, the whole axle stub assy slid in easier than I thought it would. To get it in the last bit I used a mallet on the wheel flange and heard the sound change when I thought the outer bearing had been seated. I hit it a few more times for "good measure". At this point I guess I'll have to pull it out and try again tonight. Perhaps it just needs a few tries? Still looking to hear from others who have done this job before. Thanks.