Jennys280Z

If it's a driver, just stroke it and hone it? Regarding power it seems to me that upwards of 300HP should be more than enough for most people needing a speed fix on a <2500lb car. Just how much traction do people intend to lose? But maybe I'm underestimating most people. But based on a lot of Z owners I know, I doubt it. An L28 in the junkyard is a no-brainer for the budget. And I think that's really the biggest answer here to my question. Conversely, if building out the L24 was the cheaper alternative, it'd be popular.

well you are very certainly excused, based on your story!

Turbocharge that 2.7L then. Maybe there's a niche in the market out there that does this but I've never heard of it before.

Okay I can understand using a 280Z or 280Z-ish head on a rebuilt/modified L24 for power and torque. But I don't understand why so many people get rid of their original blocks. Other than, I guess it's cheaper to just slap in an L28 from a 280Z or ZX...it's kinda sad to me though. It would seem to me that a 240Z with its original but well-rebuilt L24 would be a very desirable car to have in this market.

Is there something intrinsically inferior about the L24 block? I've heard about the siamesed cylinder bores of the F54 block but does that really make that much of a difference? An L26 is a stroked L24. An L28 is a bored-out L26. So why not just keep your original engines and just rebuild your original engines already in your cars? It follows that this would be a good idea for the car's resale value as well.

OT: Wow your dad's cars are wonderful!

Here's a video of a 260Z with a horrible case of run-on.

I'm going to do this soon on my rear too. I still have my bumpers minus the rubbers and I would sell them with the car. Removing all four bumper shocks shed another 20 pounds off the car. It's another one of those things that adds up and makes 280s so heavy compared to 240s.

Thank you Anthony!!! You have good numbers reading according to spec. My car was mfg in 11/75 FWIW Well it would seem that when I started this thread, I needed a new Thermostat, Brake Booster, Air Regulator, Distributor, Air Flow Meter, Clutch hydraulics and possibly a Coolant Temp Sensor. Considering my remaining issues, my car is running well. I'm going to see if I can bark the tires in 2nd on a dry flat road and if I can I might consider this good enough. My car could always do it before on 14x6" wheels and 215mm retread tires. With these 16x8" and ZR 225s, it might be harder for me to lose traction, everything else but tires held constant.

OMG and they wonder why I love you? Silly boys!

Wow okay since I have to do a test from the ECU again I'm going to make a long list of a lot of other stuff I'd like to test while I'm in that thing again. I only tested the stuff the bible told me to test for conditions of loss of power in the engine the first time. Resistance at the AFM, voltage at the fuel injectors, etc. Yep I will have to look which is which again...I think that's how I remembered it too, that the thermotime connector box is the larger of the two. It sounds like your AR is functioning mostly, maybe better/similar to how Eric described his old one. One thing I've been learning the hard way all along is that it's a lot worse having a toast AR in the wintertime than summer. I'll test it before presuming it's bad though, because it is around $100 after all. I wonder if tightening the hose so tight like I had to do, to kill the whistle from the vacuum leak, is symptomatic of that thing staying closed when I'm cold idling. That is, if there was vacuum flowing through there, it'd be a bit easier to make the hose "tight" enough as the air is kindof "taking the path of least resistance" similar to flow in an electric circuit. Thanks for the wonderful advice I'll follow it all. :kiss:

Here's the Air Regulator for the 1976 280Z: BOSCH Part # 64402. It's only $83 at Rockauto. Having a bad AR could cause a rich condition and give me idle issues to boot. Sarah and Eric you guys pointed out very early on for me to fix one known problem at a time, and you've helped me peel off the layers of mystery and solve my car's problems and I am so thankful. Y'all knew that multiple problems could be at play with my car and you were totally right! I have another issue: Now I'm worried about my clutch master cylinder that arrived today...cozye can help me for sure on this one. The rod (at the pedal end of the MC) is LOOSE. I'm able to move the rod about 20 degrees (edit: 15-20) in different directions. Is this normal? *pant pant*

Hi Sarah thank you! It's because of you guys that I've gotten along as well as I have. xx Coolant temp sensor? My temp gauge reads just right if that's what matters! Setting the idle air is a way I could go...but shouldn't I just test/fix or replace my AAR? If my car had a few minutes of 1200+RPM while it warmed up I'd consider that another problem solved! A lot of benefits with that...my car warms up faster, plus the idle would already be high enough to drive well when it kicked off. My daily driver (Camry) always starts off at 1500RPM and drops down slowly. I love that! I want my Z to do that too

Wow thanks Zed. Sure I'm not blaming my idle problem on the lack of vac advance, just the noticeable gargle/miss I still hear from 1000-2500 RPM on the road. Is this correct thinking? The idle problem is something else. And my car was likely running too rich (but why?). In fact I remember experiences driving the car in the past when plugs would foul resulting in dead cylinnders and a bad running car. We put over 50,000 miles on the car ourselves (well, me and my ex ) and I really started exploring the repair bills and trying my best to remember the history I've had with it myself. OT: The air regulator is where I heard a whistle (vacuum leak!) right after I changed those lines/clamps. So that popped my "vacuum leak" cherry when I accidentally made one myself hehehe The surface of the connector(s) on the Air Regulator are slightly conical, making the standard style hose clamp I replaced necessary to be tightened very tightly to stop the leak. And now this drive today had the benefit of a new cap and rotor for what that was worth. I'm definitely firing on all cylinders now at least! It feels like a straight six now and not a straight five. I've never seen a used dist cap up close before last night. The rotorhead was blackened and had a tiny notch in the metal where I presume the "spark" crossed. The six contacts on the cap were all blackened on their faces too. I don't have any experience to know better, but I suppose it's possible that the new cap and rotor singlehandedly made that much of a difference in the way it drives, and my adjustment direction on the AFM is incorrect. I just don't know how much difference 4-5 teeth of the AFM makes having no experience with them at all. For at least the first minute or three, your Auxiliary Air Regulator should keep your idle up (around 1200 to 1500 rpm, slowly dropping as it warms up). OMG Zed I'm going to have to do my homework on those now. ty

Little update: Just got back from a long test drive after leaning out the AFM 5-teeth from where I was before (two teeth leaner than ever). Outside temp here is over 60degF. Idle was awful warming up. 550RPM though a steady putt-putt otherwise. When the temp gauge was almost fully warmed up I got in to drive...idle was probably 650-700 at this time. I put it in reverse and released the clutch pedal, it shot backwards with no threat of stalling despite no throttle. After driving it pretty hard for a half an hour, my idle speed was 800RPM, if that. Never heard a backfire, from a few full throttle runs, a few full throttle hill climbs in 2nd and 3rd, to revving to 5000RPM and back to idle (with no load). The car has better much pickup now! (much better sorry ) It still has a gargle at part throttle/low RPM but this might be attributed to having zero vacuum advance from my distirbutor. I think the moral to the story is becoming this: I had a bad thermostat. I ran the car several times in the cold without it warming up...and not driving it either. Not addressing this problem immediately made me focus on how bad the idle was prior to replacing the thermostat. After doing that, I still didn't have an opportunity to rightly "drive" it in warm weather. And now that I think of it, the last time this car ran this good was last summer/fall when the weather was this warm. There is a divergence here, between how the car idles and how the car drives. I've sacrificed my idle speed for a much healthier road performance. For whatever reason this is the case. Still know my vac advance is shot on my dist. Am still wondering whether my AFM has a chance of being alright (and if this leaning out process is actually just a way of dealing with the failed/failing AFM without replacing it). Thoughts?

Okay I hear you but...Generally, they were all dirtier than in the photos before I cleaned them up the first time. And we're not really talking about enough miles put on them after that--- 25 -30 miles if that. You can see on the metal in the photos where I sanded them. I think in the case of the #5 cylinder's plug - the dark one- I didn't clean the insulator but only the electrodes.

If the notch I've identified isn't the marker for stock, and if that notch at 12 o'clock with a pristine glue blob isn't nothing but a coincidence, then I was at the stock setting yesterday and now I'm about 4-5 teeth lean. Nobody's paid much attention to that to either confirm or deny it for their own AFM, but I'm convinced of it myself.

Not to me, it looks too low. That's lower than it normally reads (has read) for you, right? I guess the gauge reading low is a possibility, but Are there any other symptoms? Changes in the way the motor's running? If it gets cold outside at night there you might take it out around the neighborhood to warm it up and see if the heater can blow hot air out the vents. It'll be more obvious if you're very lightly dressed. At least that's what I'd do. :classic: Or if you have a cooking or candy thermometer, it's also easy to take the coolant's temperature under the radiator cap. Being careful opening it when hot, as always.

Little update: So now my car has new plugs, plug wires, cap and rotor. I'm timed 12 degrees BTDC. I haven't driven the car yet but will tomorrow I hope. But I moved my AFM wheel two teeth leaner than it was before I adjusted it in the first place. I'm doing this so I can get a more likely feedback tomorrow during my test drive what these changes will do to my car. Until tonight I only adjusted my AFM wheel once, moving it about 3 teeth CCW, and then I lost a half inch of vacuum, and my car ran no better than before, even with new plugs and air filter. The case for running rich: Despite the high smooth idle with my TPS enriched, I didn't run any better on the road and probably ran worse (less pickup, more helicopter, more smoke and gasoline smell) AND, after adjusting my AFM those three teeth richer, combined with moving static advance back to 10 BTDC, I had some light popping out my tailpipe while driving. These observations, combined with cozye's opinion about my old spark plug photos is causing me to believe that I have a rich-running issue. A rich condition, that my former mechanic may well have been trying to deal with at my last tuneup. When he leaned out my AFM and put in hotter plugs. Anyhoo, I'm looking forward to my "extra lean" road test tomorrow. I'm about two teeth leaner than ever and I am so hoping my car responds positively to this change. And I really hope a few of you lovely 280Z owners will check your AFMs this weekend. Then by Sunday I'll have a much better bearing on what is wrong with my car. Something is telling me that a bad AFM might be causing these "lean like" or "rich like" symptoms. And even frustrating me and making me chase after them the wrong way. But I'm still hoping for a 280Z owner to post a 126 and 226 and tell me I'm okay. I've been reading a lot about how some of these Z's seem to wander into a state of leanness, whether by ECU-fade or whatever else, but maybe my car's gone the other way?

14 different model numbers of AFMs across nine model years '75-'83 http://www.thezstore.com/page/TZS/PROD/11-3040

I don't think that high resistance comes from the connectors, it comes from the resistive elements that make up the potentiometer. Yup I don't either. *sigh* Zed, when your AFM readout like mine, did your car seem to miss when you drove it, even audibly at low RPM? Did it feel like it was at a loss of power, almost like it was running on five cylinders? Was it intermittent? Was it sudden? Did the problem come, then go, then come back again do you remember?

I will guess that the CSV wouldn't come on for the 8 seconds after startup like it normally does. But if it's leaking, I'm not sure whether or not unplugging it is going to fix the problem.

Got the cap and rotor from MSA today. They are Daiichi brand parts. Not what they told me over the phone but they fit right. Installing those right now. I love how NGK numbered my spark plug wires for me. How thoughtful!

How the ohmage effects the unit's function...that'd be nice to know. Perhaps 126 and 226 are points that the unit intentionally rises to, to still be functional on the car, but yet also communicate a universal signal that it's gone bad and needs replacing/fixing. The test you posted has the "standard" and "approximate" resistivity measures. 126 could be considered "approximate" to 100 depending on what kind of range in Ohms we're scaling with imho. It would be nice if we could form a validated consensus on this here. I'm still suspicious of units all falling back to 126 and 226 if gone bad, and if so, it's even more suspicious that this fact isn't in the EFI Bible. Anyhoo, if three or four of you with good running stock 280s can all flash your 100s and 180s at me then I'll surrender, and go get the harness and straps because that's how I'm going to feel having to go through all this again. AnthonyG: please do! If you could run at least the four tests that I ran in the table posted above that would be so good. The 100 and 180 values are for the 1976 AFM for sure. In general, the AFMs are not interchangeable except for a few years. I think that 1975 and 1976 are the same, maybe 1977 too. Zed...okay. I was thinking of the part numbers changing for different year 280s and then I read your post again...