Syncro Posted May 17, 2012 Author Report Share Posted May 17, 2012 Just a question but. How different were the n42 nd n47 fuel systems? My friend has an n47 car and the manfold looks somewhat similar to mine but it. Has this round thing that bolts on top of it that some vac lines go to, my car has the spot for it but lacks the lines and part. On a side note I got a free n42 motor complete with 4 speed accessories and its got good compression from what I've been told, friend just needed it gone. I admit I have been slacking on all of my cars as of late, but I've had a hectic schedule the past couple of days. Quote Link to comment
Syncro Posted May 20, 2012 Author Report Share Posted May 20, 2012 There's the photo's of the bad temp paint job its got for now, alos, I was looking at my 240z and noticed something I didn't when I first got it, does the stock exhaust mani normally look this cool? Quote Link to comment
Syncro Posted June 1, 2012 Author Report Share Posted June 1, 2012 I had one hell of a great day at the junkyard today. Quote Link to comment
Syncro Posted June 1, 2012 Author Report Share Posted June 1, 2012 thats a urethane air dam, fiberglass ducktail, guess how much? Quote Link to comment
I'm BLUE Posted June 1, 2012 Report Share Posted June 1, 2012 Just a question but. How different were the n42 nd n47 fuel systems? My friend has an n47 car and the manfold looks somewhat similar to mine but it. Has this round thing that bolts on top of it that some vac lines go to, my car has the spot for it but lacks the lines and part. On a side note I got a free n42 motor complete with 4 speed accessories and its got good compression from what I've been told, friend just needed it gone. I admit I have been slacking on all of my cars as of late, but I've had a hectic schedule the past couple of days. Part in question is probably the EGR. pic ? Quote Link to comment
ggzilla Posted June 1, 2012 Report Share Posted June 1, 2012 EGR system, not needed to make the engine run. Quote Link to comment
Syncro Posted June 2, 2012 Author Report Share Posted June 2, 2012 EGR system, not needed to make the engine run. niether of those are on my car, and the problem isn't in making it run, the thing fires up and runs great before warmed up, then it just starts bogging when you floor it. there's a puff of smoke out of the exhaust on start up, pretty sure its running rich. Quote Link to comment
ggzilla Posted June 2, 2012 Report Share Posted June 2, 2012 Sounds like a fuel pressure issue. It is adjustable. Quote Link to comment
k-autic Posted June 2, 2012 Report Share Posted June 2, 2012 Had similar issue in my 620 but its not EFi I'm running su carbs, but it turned out to be rust in my fuel tank was making a nasty mix of fuel and plugging up my fuel lines. Quote Link to comment
ggzilla Posted June 2, 2012 Report Share Posted June 2, 2012 there's a puff of smoke out of the exhaust on start up, pretty sure its running richThe two are not the same. Smoke on startup is not a "running" condition. The smoke could be from the valve seals (very very common), or a start-rich condition. Bad fuel causes a lean condition, fuel starvation. You can lose power, even if it idles OK. Other times is causes the engine to stop. On an EFI z-car they use a large filter. If it's bad fuel, the filter may be plugged, and if so it will show up in the Fuel Pump volume test. So there's no reason to replace the filter if the test is good. Do both tests, Volume and Pressure. Overly high pressure causes it to run rich. The 280Z factory service manual covers all this. Time to stop talking and start testing. Quote Link to comment
Syncro Posted June 4, 2012 Author Report Share Posted June 4, 2012 The two are not the same. Smoke on startup is not a "running" condition. The smoke could be from the valve seals (very very common), or a start-rich condition. Bad fuel causes a lean condition, fuel starvation. You can lose power, even if it idles OK. Other times is causes the engine to stop. On an EFI z-car they use a large filter. If it's bad fuel, the filter may be plugged, and if so it will show up in the Fuel Pump volume test. So there's no reason to replace the filter if the test is good. Do both tests, Volume and Pressure. Overly high pressure causes it to run rich. The 280Z factory service manual covers all this. Time to stop talking and start testing. your right, but I think I'm about to dicth the fuel injection system anyway, not cause its trouble some, just because I've got a header and a holley 39cfm carb and manifold and feel like using them. plus, I don't have money to buy a fuel pressure tester right now, all I've got are the parts to throw at it. Quote Link to comment
jalen Posted June 4, 2012 Report Share Posted June 4, 2012 My advice is to research Z's. Research the EFI system, carbs, suspension, and wiring because I guarantee you will have problems with one of these. And it sounds like you have bad gas. Drain your fuel and run some gumiut through. My z did the same thing but now it runs perfectly Quote Link to comment
ggzilla Posted June 4, 2012 Report Share Posted June 4, 2012 The Holley 4-barrell sounds like a fun swap! Let us know how it goes. Quote Link to comment
Syncro Posted June 5, 2012 Author Report Share Posted June 5, 2012 The Holley 4-barrell sounds like a fun swap! Let us know how it goes. It'll be a headache, but atleast i already have the linkage and everything else to make it work. Quote Link to comment
Syncro Posted June 5, 2012 Author Report Share Posted June 5, 2012 My advice is to research Z's. Research the EFI system, carbs, suspension, and wiring because I guarantee you will have problems with one of these. And it sounds like you have bad gas. Drain your fuel and run some gumiut through. My z did the same thing but now it runs perfectly I'll try this, I understand carbs a bit better then fuel injection, I have problems with all but the suspension so far. I'll drain the fuel but I'm doubting its bad gas, here's to hoping though. Quote Link to comment
Syncro Posted July 14, 2012 Author Report Share Posted July 14, 2012 Alright so I've got the exhaust and all off my 280z, I"m gonna start taking the intake off, I was wondering if you still need the ecu after swapping over to carb, would simply hooking up a switch fuel pump work for bypassing the ecu and fuel pump relay? I've got like 3 or 4 relay's and ecu's there all good, was just hoping I could get rid of those and sell them for more parts, hopefully I'll have the holley carb and my header on soon. Quote Link to comment
Alex Datsun Posted July 14, 2012 Report Share Posted July 14, 2012 you do not need the ecu when swapping to carbs for all i know Quote Link to comment
Syncro Posted July 14, 2012 Author Report Share Posted July 14, 2012 yeah, didn't seem like I would need it, so thats another part for the for sale bin. Quote Link to comment
jalen Posted July 15, 2012 Report Share Posted July 15, 2012 You know you can change the name of the build, right? Quote Link to comment
ggzilla Posted July 15, 2012 Report Share Posted July 15, 2012 Normally when swapping from EFI to carbs, you will replace the fuel pump with a carburetor fuel pump. But if you use a 3-psi fuel pressure regulator and the return line, the EFI pump might work with carbs. Quote Link to comment
Syncro Posted July 15, 2012 Author Report Share Posted July 15, 2012 Normally when swapping from EFI to carbs, you will replace the fuel pump with a carburetor fuel pump. But if you use a 3-psi fuel pressure regulator and the return line, the EFI pump might work with carbs. got this covered, the parts car had a holley pump for the 4barrel, wonder how much the injectors and 3 fule pumps I ahve are worth, those pumps gotta be atleast $50 working and used, and the injector came from a low mile 280zx. Quote Link to comment
ggzilla Posted July 15, 2012 Report Share Posted July 15, 2012 Not worth much. Guys remove them to fit carbs. Quote Link to comment
I'm BLUE Posted July 15, 2012 Report Share Posted July 15, 2012 Injectors are worth what you can prove what they are. fuel pumps are a toss up ... some may bleed back and not hold pressure ... but pump adequete pressure ... again its what you can prove :) Once converted over to 4-bbl ... depending on size of engine ... (2.8 im sure lol ...) *You will want to get it running (obviously) **BUT more likely than not you will have to re-jet *I have currently #48 primary/secondary Jet in my 390cfm on my L24 ( I may go with a #50 for secondary) *I put a slightly smaller accelerator pump discharge nozzle *and put in a "new" red/white? Accelerator pump cam (more aggressive discharge curve) *Your 390cfm holley wil want a minimum constant of 5.5-6pThe si of fuel pressure. *Torque down the carb hold down bolta to no more than 5ft-lbs (literally) *Make sure to wire up your choke (+) *If electric* to key on source ... (if mechanical no worries) *The greater the tension on your throttle "return springs" the more likely throttlw shaft bushing wear will occur/or bend! ! *Make sure float bowl fuel levels are below the sight plug ( even a sqoosh is good ! DO NOT buy the clear sight fuel level bowl plugs ... they are shit ... nuff said lol) *Always ... always have fresh fuel filter change outs! *when setting your electric choke position ... loosen the (3) screws and dial it to either "richer" or leane as you see fit. (Ideally you will start in the center of the adjusment indicated dial) *Measure vacuum at idle ... if between 12-18lbs of vacuum your stock power valve will be good! *you shouldn't need to mess with the secondary spring at all unless its been altered. *I also use a *Lokar* throttle cable BUT I will be making solid/ball linkage for it in the future. (*Make sure you take a close look at your PCV routing system as it will change (depending on your manifold) and get this right or suffer vacuum leaks! *When setting Idle ciircuits ... turn them very gently all the way ... then 1 full turn out each ... connect a vacuum gauge ... start it up and keep turning it back as evenly as possible matched for both circuits! You want to acheive highest vacuum @ idle ... go towards a touch rich instead of lean ...Too give you an idea ... I am sitting at about 1.5-1.75 turns out each. ----IMPORTANT: ---- *** Before doing conversion .. Make sure your distributor vacuum advance mechanism is 100% functional... and not jammed or rusted! Or you will be fighting it/trying to fix a thought to be "carb" problem when it is indeed not. Check the overall condition 3x over !!! Seriously :lol: *** Before running 4bbl make sure to check throttle shaft bushings for play ... if evident ... they are fixable but usually faster/easier to get a new base plate. ***Make sure your fuel pressure is a close to optimum as possible and meets minimum requirements! ( do not use EFI Pump with restrictors/regulators as it will cause spikes and wreak havoc on your system) ***Install largest Air filter you can fit under your hood. *** Holley machining tolerances/castings are ... questionable at times lol ... make sure bolts/springs/screws arn't going to fly off down the road (my mechanical adjustment screw/spring backed out and fell off even with Blue thread-lock lol *** Be ever so gentle when tightening/opening a carb ... very little tightening pressure is optimum ... too much will ruin things/air leaks/warp baseplates etc ... *** Own or have access to a Timing Light ... *** Own or have access to a Vacuum Gauge *** Own or have access to a 1/4" - 3/8" Torque Wrench My old F54/P79 L28 engine w/390cfm holley (stock flow + header) = #53 jets ... was too rich IMHO... #51 was still a bit rich ( bit better rich than lean) I believe Holley provides Jets from #40-#110 ? I bought mine from baxter's A lot of people are afraid of re-jetting .. don't be (its easy older production are stamped 2digits and new production jets are 3 digits... be afraid of going lean or the fuel bowls starving! Quote Link to comment
Syncro Posted July 15, 2012 Author Report Share Posted July 15, 2012 I'm not afraid "oh you will be, you will be" moment. Alright well I have no fear when it comes to carbs. so what, go with #50 jets? I have all but the vacuum gauge. Well I'm guessing this carb is jetted for the turbo the guy had, course he was a bit of an idiot, blew a hole out the side of the block on the old car, and while the intercooler was present, was not piped. Quote Link to comment
I'm BLUE Posted July 15, 2012 Report Share Posted July 15, 2012 Start Fat. I'm guessing #51 and go leaner as you see fit cam/port work/climate/sea level/gearing/driving etc Who knows you may just want to go fatter on the secondary or something Jet kits local to me are $8 a pair. Accel pump cam kits are about $25 local (8-10 variety) discharge nozzles vary in cost I personally like to "Lucas" or "Marvel Mystery Oil" for top cylinder lube = works well ... I notice a difference Quote Link to comment
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