Tony D

It's not that Nissan wouldn't ever...it's THAT THEY NEVER DID! Your Y70 is a NORMALLY ASPIRATED HEAD. Period. End of story. If there was a turbo hung on it, it was done ex-factory. Period. End of story. Move on.

Read what I wrote, it is exactly as stated and there is absolutely no disparity in the two statements. They are congruent in every way. You are mixing up what someone in the field does with what an OEM would do in an ultra-conservative planning session with lawyers present. THERE WERE NO LINERED TURBO ENGINES FROM NISSAN ON THE L-SERIES, PERIOD. What someone changes out of expedience EXACTLY makes the point I was making: on stock engines it's likely not going to make a difference. But From a LIABILITY STANDPOINT the OEM just isn't going to do it. The function of the liner is defeated by the turbo! Linerless Heads are CHEAPER to make as well...BTW. I'm not arguing with anybody on this point. You want to pick pepper out of flyshit and make an argument twisting things areound you can go hop the flying express to buggerville. I'm not having it.

"The only thing I have waisted would be time." Not only yours, some people are taking time to answer your questions. Don't ever forget that! Personally, I don't have the time to waste with that kind of minutiae, I'd have done a head swap and have been driving the car learning about it...while I made a 'good head' out of the P90 to be used at a later date. Different paths, but understand not driving the car sucks.

Keep in mind the Bosch System defaults RICH. That's safe. And the cars run GREAT when rich. So many times people think they have a 'great running car' but have multiple failures in components resulting in rich conditions which give poor mileage. additionally, the way you drive DRAMATICALLY affects the numbers. The 27mpg should be possible if you steady-state run the thing on flat land at between 35-55 mph with gradual throttle applications, and never, ever exceed 60-65. Which was the test conditions used to get 27mpg!

Have you seafoamed the injectors and cleaned the fuel system? dirty and damaged pintle caps along with backside valve deposits wreak hell on mileage as well. but you needed to have all items in the basic tune up proper first. You are WAAAAY down the line skipping the basics. Valves out of adjustment cause low vacuum which causes higher fuel pressure which causes poor mileage. Ignition timing (centrifugal or vacuum -- PARTICULARLY VACUUM -- advance malfunctioning can affect mileage similarly with a double whammy of low vacuum and more throttle angle required due to running retarded from optimum. Do a basic tune up according to shop specs FIRST, then move on to the bizarre and obscure stuff. Don't start there!

You most likely have the bad pump check valve as stated.... To further isolate it, you can clamp the feed line immediately after shutoff, and if it leaks down then it's on the FPR return side. To go the next step, clamp both the feed line and return line Immediately after shutoff. if it leaks down THEN, it's in the injectors. The troubleshooting steps I've posted before. No need to take anything apart a gauge and a couple of vice grips or fuel line clamps are all you need to zero in on the section of the fuel system responsible for your bleed down. Aftermarket check valves are available, and have been posted previously.

What the hell was that last 4 lines again? You bought a non-running car? It states it "started and ran"....why would you change wiring if it was running and starting? Something is missing in the story here. When you say "81 Style Distributor" you mean with nothing inside it and a crank trigger? If so, I'd lay money if you simply switched to an 82/83 Distributor/CAS assembly you would have been fine. Likely the 81 CAS went out -- but you haven't given us ANYTHING to troubleshoot the issues which were present in the car.

You mean you can't find one of these? Really?

What have I done? People talk about me in a positive way behind my back.... Oh.... The SHAME!

The title of the post was 'JUNKYARD BUILD' -- It was not '1,000 HP Electramotive Replica Turbo Build' so I'm betting any amount of money you would like to wager you will not get to a point with this build that the Exhaust Liners will in any way come into play, nor will your cam selection amongst the stockers you seem intent on using. I think the proper word to use on the 'burn out over time' should be more like "was feared that they MAY burn out over time" -- Remember Engineers were looking at 300,000 mile reliability and the elevated temperatures of the turbo engine on the exhaust side MIGHT cause an issue. But... for most people not running in Europe...they weren't on boost long enough to damage anything!

Because they're internet dweebs stuck on what everybody else tells them and can't figure out the data that shows them what I say is true. As for 'why didn't Nissan' do this or that, I'm not getting into an in-depth engineering discussion on why the liners are there, but suffice to say the glowing hot liner markedly helps the HC Emissions if the ECU farts at all, and normalises the O2 Content by combusting those HC's before they hit the N/A O2 Sensor. Keep in mind they didn't have P79 heads on the JDM Cars... Why? Uh...because the emissions requirements weren't there? Why were there N42 CLOSED CHAMBER heads overseas, with NO EFI Bolt Pattern on them? Don't use false logic based on incorrect thinking to justify a parts choice. I simply said you are making a LOT of work when there was a perfectly good head complete (from what you say in your posts) that you could have had off, and on to your car already without all the interim steps and failure points introduced. I'd need to SEE a head with a 'burned out liner' from turbo use, because the ZXT I got had a P79 on the ET Bottom End, and the owner told me he replaced the head at around 150K when the original turbo went out and they found cracks in the P90 that was on it. He put a USED P79 on it and when I bought it there was 225K on it and those liners looked JUST FINE...and were in there same as any other. So in at least 75K of turbocharged application on a P79 that started with 150K, those liners were holding up darned good. I just haven't seen it. I've seen loose liners but not one that came out and went anywhere, nor one that 'melted down' or 'burnt out' as some tout. Doubt it would do much if it did. It's a Nissan Hotrod Book root...and the guy writing it may have simply wanted to steer people towards stuff that was easier to modify---though Bryan Blake's work on the P79 showed very good results comparable to the P90 in terms of ultimate flow. "The Restriction of the liner just wasn't what everybody seemed to think it was..."

The timid run at the slightest bit of basic work required to fit a part these days... this is not rocket science.

The sensor curves are identical. The output from a 1968 L16, a 1972 L24, a 1983 L28ET, 1989 VG30, 1999 VG30DETT, or any Nissan for that matter is the same. The harness and connector is more suspect (changes the reading by skewing the resistance higher) and causing gauge reading error. Note your resistance in the meter loop from the gauge, and at the sensor to local ground---that will tell you how far any gauge has been affected by harness or connection resistance.

Honda: labor of lock change exceeds value of car," total it and get another!"

Nope, no meaningful performance nor flow differences. The P79 takes the turbo exhaust manifold just fine. You're making a lot of work nd introducing variables in assembly for nothing with all the parts swapping, IMO.

It appears the plates have small holes in them. THAT is your idle air. Close the throttles and affect balance/synch at idle throughout what I (think) is your bypass line (black tubes?) Off idle synch is a mechanical issue and needs relatively rigid mounting. Probably not an issue in this problem though. That it does it at idle AND off idle...but who knows where in the rpm range. Give specifics... Hold it at 1500, then 2500, then 3500 and look on your tuning map....is the dot bouncing around the cels? If so equalise their values and see if AFR Stabilises and then determine why the MAP is jumping around so much. It should be relatively stead off-idle, and NOT A FACTOR AT ALL in Alpha-N. Indeed, something is being left out here as switching ITB's to Alpha N should stop all MAP-Based AFR jumping about. And off-idle for sure!

I can't tell too much from your photo as the fuel bar covers everything I need to see. A shot from straight down overhead would be helpful. You don't REALLY mean "RRFPR" do you? You just have a standard 1:1 Manifold Vacuum-Referenced unit correct? With MS you DO NOT use a rising-rate FPR, it totally defeats the purpose of having programmable injection! Anyway, here goes: Balanced the ITBs with a carb syncrometer to 4 Kg/hour Used a caliper to set the plates to open within 0.25mm. The above two are basically mutually exclusive. You set your balance how? Bypass screws per barrel? CLOSE the throttles it idle and adjust your balance with the individual bypasses. Check off-idle balance separate from idle. Fixed a few small vacuum leaks I found using ether or by listening with a hose. Use water or some sort of spray. No leaks are permissible. Any present will screw with you forever. Replaced plugs several times Why? Are they gapped properly? Readjusted the valves What is idle vacuum? Alpha-N should give you a ROCK STEADY idle as it discounts MAP Spikes in the ITB setup. This may be your issue, look to see if your idle kPa values are sufficient to keep you in ONE LOAD CEL. If it's jumping between four cels at idle and they all call for different fuel you will constantly be chasing it. Make all cels at idle that it jumps through identical and see if your AFR settles out. Fuel pressure looks good. Nix Several compression tests, open and closed throttles, all good. I doubt that from the above synch and setup concerns. But likely they are not an issue if you standardise their setup.i. Terms of throttle angle and relative position / reaching WOT. Swapped in a set of GSXR 240cc The 450's may have had latency issues, they were also high impedance?

Should have pulled the P79 head and run it...same in all respects to the P90 save the liners in the exhaust

Haven't seen a "leaky injector" YET that wasn't an EXTERNAL leak. If you don't see it, they're not leaking. FPR seat is far more likely BUT... THE FUEL EXPANDS due to heat soak after shutdown. As it does the FPR dumps pressure. (This can happen from 5-15 minutes after hot shutdown)---after that point, the fuel cools and contracts. Maybe a 10% volume change of a hydraulic fluid in a closed container can make for a big difference in the pressure that remains. Do this: tomorrow morning with the engine STONE COLD, crank up the car with your fuel gauge in place. Once it's started and the fuel pressure is stabilised shut it off. We're talking maybe 30 seconds of run time max. Then repeat your checks and please post the results. Use the same gauge and same tming intervals for best comparison. THEN... Without starting the car AT ALL...rig up your Fuel Pump to run "key on"... You may have to move the AFM Flap, jumper the Oil Pressure Switch, etc... Run the pump ONLY until pressure stabilises, the repeat your test as above at the same testing intervals. Remember this: in a RUNNING CAR with the shown 17" HG idle vacuum, fuel pressure will be FPR set point minus 8.5psi. AS SOON AS YOU SHUT OFF THE ENGINE the FPR changes to a 3X pis regulator. So the car WAS running with 24-27 psi, then rises to FPR set point and relieves, and then cools and contracts and as a result the pressure will drop dramatically. As soon as you crank the car the pressure should be 24, and the initial pulse of the cold start injector may be killing your pressure if it's slightly low. That's why they ran the pump to prime on the ZX's, to prevent extended cranking and flooding of the engine! You will see (should) marked differences in the two tests above between where the car starts running vacuum, and funning straight upon the FPR. From your starter test, your fuel pressure is FINE! Smelling gas on the dipstick is VERY subjective. I don't know if I would jump off that bridge just yet!

Never understood using Jaguar Terminology on a Japanese Car...but some guys started it and it infected others.

I got 330's on the E88. They go thicker. Bryan Blake was also an advocate of buying the thick pads and cutting them as needed, rather than stocking every size under the sun.

I haven't cut roof skins in years. A circular saw with abrasive cutting wheel, BELOW the solder joint on the "C" Pillar about 2-3" and anywhere on the front "A" Pillar to make it sit level when on the floor and allow multiples to be stacked on top of it! I take the whole roof, headliner and rear light and all when possible. Makes drilling the spot welds out for a correct panel transfer easier later on... And yes...my 71 had.... A SUNROOF INSTALLED ONTO IT! This is why you keep six roofs in the shed. Yes, honey, I may need one, and I think someone else needs one...so there are really only four stored. And we may have them sold if I put the word out...

Yeah, 4/74 will be the same as a 73. That should give you the sheetmetal you need to get a stock shifter placement back in the car. Give yourself PLENTY of extra metal, and you could actually "slide" the 74 component around a little bit to give you a nice factory hole right where you need it, that might not be exactly where the factory intended. You should be golden with those donor parts!

Check out his photos on Anglefire -- "Extreme 280ZXT" that should give you some ideas.

Really, if you have a good running (dyno pulled) N/A jetting setup, using modulator rings will get most people where they need to be. Higher fuel levels in the jet well SIGNIFICANTLY increase AFR under boost. Many times you wont have to increase main jet size at all.