porkbun

Took some shots of the plugs today at 17° initial timing. I just cleaned up both electrodes before I reinstalled them last time. The white/grey looking stuff is anti-seize (especially on #6!) that managed to get on a few plugs but wouldnt wipe away entirely Plugs 1 and 3 ClassicZCars you saw it here first. Ive managed to run a Holley lean!

Zed Head, your post caused me to look up how my distributor actually works . I read a couple places that advancing the timing a bit more could get me better fuel economy around town but I think it made it worse. This car has NEVER gotten very good gas mileage(compared to some of the numbers I see posted), I think the best ive ever gotten out of all the carb setups Ive tried was 22/15(shifting at 2k) with the ZTherapy carbs but I have no idea how much the cam/close ratio 5sp/3.90 affects it. Maybe I should take closer look at the distributor? Interested to see if the timing can really change the color of my plugs With that super wealthy and advanced setup I had before I was getting ~10mpg but its also hard not to floor it with the pedal/throttle response (probably my favorite part of the swap). I think I might get this carb tuned up as well as I can and put in a super stiff secondary spring if my fuel economy isnt where Id like. My car is my daily driver and only car so I have to worry about these things

Ive had everything installed for a week or two and I think ive got the whole tuning thing down. Went from having to turn 2-3 screws on the SU's to 7+! Notice the sweet return spring setup! Much easier to install with no balance tube in the way (I had to do it twice since I had to tighten the coolant fittings on the bottom and my header was in the way). Most difficult part was the throttle cable install. The BSR manifold has the throttle linkage posts which just got in the way of the recommended spectre install hardware so I had to cut that up. The stupid black plastic piece that goes on the end of the sheath cracked as soon as I installed it and then I had to pull everything apart and bore out the plastic piece because it was preventing the cable from moving freely I love the setup pulled the plugs and they were uneven and so dark!! This explained my fuel economy and gave me some info about my mixture but it also happened to be the complete opposite of what people told me I would see, 3 and 4 were the leanest! Yesterday I cleaned the plugs, lowered the floats and also brought my timing down to 15 degrees from 20(so much for that supposed increase in fuel economy). Pulled the plugs again today and saw all the plugs were a light brown but 3 and 4 were a little richer than 1 and 6. Im hoping that by going to the FSM recommended 17 degrees (Not the random sources on the internet :stupid:) Ill have a nice even mixture across the board. 0-60 run will have to wait until there isnt as much snow on the ground and piled on the side of the road.

Bob Sharp manifold arrived today. Theres a little rib inside intake before the 3 & 4 runners that is not on the Arizona Z Car manifold that I think was put in there to prevent cylinder distribution issues? Just a guess but it looks pretty restrictive. Any ideas? Heres the inside view and the bottom view. You can see where it juts out on the inside view and its looks nowhere near as narrow from the bottom.

Do you remember what kind of adapter/intake you had when you installed it? Not that I can diagnose your problem or anything, just curious. The guy I bought the BSR manifold has run a number of different 4bbl/intake combinations on Z's before and he said the Arizona manifold is made better than the BSR manifold which is why he was selling the BSR manifold. He reckons that with a bit of porting the AZC manifold could make more power than the BSR manifold which is exactly what hes going to do. Aside from that and the throttle linkage mounting on the BSR, they are the same. A couple years ago on hybridz, the owner of AZC made a thread addressing the usage of a 4bbl on a Z. He was definitely right about "junkyard" carbs, trying to return everything to stock would put a massive hole in my wallet. BSR manifold should be installed on Friday!

There are a few stories of 4bbl success but you rarely hear it over the hubbub. I sold my all original 260Z to get a project so I could learn more about car and this car has taught me a bit and has gotten me more comfortable with working on cars. Learning how to weld is high on my list of priorities but it hasnt happened yet so I think itll be a while before Ill be able to build my own manifold. Not sure if you want a picture of my theoretical manifold or my setup but this is what my car looked like the day I drove it home. I think its a pretty clean look

Im not trying to say that one is better just that the mods that have been done to my car react to the 4bbl very well contrary to what ive been told and what I have read (which is why im making this post). My speedo appears to be pretty accurate but im not sure what an acceptable method of testing it is. Its been "verified" at different times via GPS, "Your Speed" signs, in comparison to the flow of traffic, and comparison to newer cars. Perhaps next run Ill have some GPS on board? I think the main reason people dont do it is because in theory it sounds like a horrible option. Had my car not come with a 4bbl I NEVER wouldve bothered putting it on since people talk about poor cylinder distribution, 90° angle air and fuel bend etc(no coolant lines hooked up btw so my atomization should be poor). and it all makes sense...but the overwhelming majority of people regurgitating these "issues" dont have or have never had a 4bbl on their car. The weird part is that pretty much everyone who has 4bbl parts wont part from them without a sizable chunk of money. I say try it out if you can, get your hands on an adapter. Its a quick swap removing the SU's and if you buy used its easy to sell your parts for close to what you paid for them. If Im understanding this correctly ZTherapy carbs dont offer any additional performance but just assures that the throttle shafts never leak and that you get a better than new set of carbs with no vacuum leaks or problems that could affect old used SU's. That said my car may have been able to make use of SM needles but when I tried swapping in some 'SM' needles I got from a british shop, the car could barely idle it was so rich (even with the mixture screws bottomed out). For all I know when I install the Bob Sharp Racing manifold I may encounter all the problems I heard about

Thats not quite what I was trying to say so I should probably clarify about my history of carbs on this car. I bought the car with a Holley 4bbl and misdiagnosed a failing distributor and poor gas mileage as a problem with the Holley(I had only had experience with SU's up to that point and didnt really want to or know how to mess with a 4bbl). Turns out on top of the failing distributor the previous owner had it at ~30degrees of advance at idle. I bought a set of ZTherapy SU's and ran those on my car and I got 15/22mpg(averaging 80mph with both windows down). Traded the ZTherapy SU's for a non ZTherapy setup since I was short on cash and ran those for a short while while the 4bbl adapter and swap parts were on the way. Im assuming thats what you mean by poorly tuned SU's since I pretty much just slapped those on the car before I sold them. The two videos are NOT meant to be a comparison which is why I didnt bring it up...but if we are talking questionable tests my car with a poorly tuned Holley is faster than the 71 240Z with an L28 "a Racer Brown cam, competition valves and springs, triple Mikuni 44PHH, Header to a 2.5 inch pipe with a Supertrap, and 'fat sticky Yokohama A001-R in 225-60-14e'"(I literally have the second cheapest all season tires Town Fair Tires offered. Big mistake I know) tested in an old car and driver magazine Why did I switch back? The 30 degrees of advance and failing distributor explained the poor gas mileage on the Holley. Everything else but that was great. No choke cables and I fire up in any weather like I have EFI (7 degrees was no problem this morning!). Throttle cable is butter smooth and the performance bump makes in town driving(which is what my commute is now) a lot more fun. Plugs were all identical. I switched back to find out what kind of fuel economy I get with a good distributor and proper timing and to see if the Holley was as nice as I remember. I should also add that the Holley was a used eBay carb and the adapter a pretty beat up cartech example. That video was the same day I bolted the carb on and the only adjustment I made was the pump cam position. Since then ive learned that the power valve was the wrong size, the accelerator pump arm was not setup properly, floats werent setup properly and who knows what else had been changed but it was still good for ~6.4s 0-60 and ~14s 0-90. I only made this post because everyone seems to think that 4bbls on Z's are unusable and inferior. I dont want to start another theoretical debate since Ill bring more proof in the form of another video when all the new parts are bolted on

The preferred carburetor of classiczcars and S30's all over the world! Ive run used SU's and ZTherapy SU's but they have never come close to the level of performance that my car was on when it had the 4bbl on it (when I first got the car). Ive got a close ratio 5sp, cam, clifford header, and a Crane XR700 ignition so it was pretty fast with the SU's but the 390cfm takes it to another level. Lightning fast startups with the electric choke is the cherry on top since this is a NE car and my daily driver(and only car!). I have the cartech adapter bolted onto the SU manifold but I have a BSR manifold on the way which should be a more permanent setup. Definitely not the fastest it couldve been since Im new to Holleys and my tune is nowhere near perfect, the tires were spinning through ~30mph and I shifted late but it does show the Holley is certainly no slouch! 0-60 was in ~6.4 seconds and I plan on being well into the 5's once my manifold arrives and I take another video(hopefully!)

I was doing some searching on exhausts and all this time I thought I had an ANSA setup but I think Im pretty sure I have the Clifford/Datsun Competition(?) exhaust setup. One of the glasspacks broke off and I thought Id work on changing the sound since its VERY raspy. Here are some pics of the exhaust on a car I believe has 55k original miles

Finally got someone to crank the engine when I was watching the engine bay. Engine kept cranking and cranking until I covered the vent hoses with my fingers and started to start up. When I took my fingers off I heard air rushing out, not from the carb side, but on the other side of the engine bay. The gas is not leaking from the hose, but from under the filter bolt. Could this be because I dont have the filter screen on it? Took the carbs off again, rechecked everything, all the passage ways are clear, my floats are the right height, needles are straight, but I dont know if theres else something that could negatively affect their performance.

I tested my needle valves by blowing through the inlet hose and it closed as the float got closer to the top and theres no way it would be overflowing since the gas in the float bowl is nowhere near the top. I never took them off since the appeared to be working, but there isnt even that much gas in the float bowl in the first place, so the gas isnt coming out of the overflow hose. Its almost as if the gas from the fuel line makes it through the bowl cover and most of it just finds its way down the hose side of the outside of the float bowl. I know the fuel is getting into the float bowl, the floats arent drowned, but gas spits out of the intake side of the carbs (When I pump the gas pedal. It seems as soon as the suction piston rises enough, itll spit out gas and drop like a rock. Manually rising the piston after the spit will greet me with white fumes), but doesnt seem to be getting into the engine since I can some of the spark plugs firing. As soon as I plug the overflow hose (the only action they have gotten is venting fumes, gas has never actually overflowed) everything seems to right itself and it fires up right away like it used to, except the rate that the gas pours down the side seems to increase also.

Ill check them again when I get home, but the choke mechanism behaves as it should and the nozzle pulls out and goes back into place when I take the choke off. The gas is coming from the crack between the float bowl and the float bowl cover and when I cover the vent hose, the carbs appear to behave properly, but continue to spill gas. Might have to get the Z therapy video after all.

I recently swapped some 240Z Carbs onto my 260Z, capped everything according to the other swap thread in this subforum (the only things that are unplugged are the PVC valve which im pretty sure has been unplugged since I got the car and the overflow hoses which arent connected to the air cleaner). I cranked the engine maybe 5 times before the car started and revved to 4000rpms and stayed there. I tried rearranging hoses and plugs and it did the same exact thing. the next day it wouldnt start and the engine would start going at very low rpms and would die at the same time the carbs spit gas out of the intake and would also have gas dripping from the fuel delivery line and the side of the float bowl. I havent been able to start it since then and have checked: The fuel return hose, still has the pressure cap on the end and gas moves through it. Checked the floats, the needle valve works, the needle is straight and the suction chamber moves freely The sparkplugs fire and I recently had the timing done. The gasket on my float bowl was shot, so I took it off (temporarily until I can get it running and the gaskets come in the mail) and it stopped the leaking on the front carb, but the rear carb continues to spill gas on the exhaust. There is only maybe an inch MAX of gas of the float bowl so I know its not flooding, but I dont know what else to check/replace. As a last ditch effort and because I dont know what to do, I capped the overflow lines, and the car started showing some semblance of its old self and started up as it usually would although a bit slowly, but there are a ton of warnings all over the forums saying NOT to do this. Are the float bowls pressurized? Any idea what else I can check/ replace to narrow this down?

Sorry I forgot to attach the picture: My power valve is the bottom right corner. Im pretty sure the hose goes back into the top of the radiator. I plan on replacing that hose since it doesnt seem like the most reliable fit right now, but its no longer leaking and the smoking is whats worrying me (diagnosing a car problem online is like trying to diagnose an illness online). Im pretty sure its the droplets in the air cleaner, but ill have to check that tomorrow before I put it into the garage before the storm. Im looking at buying some 240Z carbs, but they have the individual air cleaners. What happens to all those things connected to the air cleaner if I go the dual air filter route?

While checking the power valve on the font carb, I put too much pressure on this hose (in the middle of the picture) and coolant started streaming out. I loosened the radiator cap, the streaming stopped and I readjusted the hose and tightened the clamp. Now im noticing that my car likes to blow out white smoke when pushing it through low rpm in 1st and 2nd gear (up until about 3). I did notice some coolant in the airfilter which im hoping is from when it was spraying when I loosed that hose, but if its not, its from the valve cover breather hose which means theres coolant in my oil. No overheating problems that day I drove it, but right now its parked. Going to try and get a ride to autozone to get a coolant pressure checker and hope its not my headgasket.

I got the car back, took the power valve off the front carb and the diaphragm was intact, and nothing looked like it was in need of replacing or repairing. I didnt get a chance to check the rear carb (closer to the cabin) behind the air cleaner, but what should I be looking for when I take it apart?

The shop says my carbs are dumping fuel into the engine, so it wasnt that there wasnt enough gas, but that the car was flooding. Theyre going to give me a price for rebuilding the flat tops, but Ive got my eye on a pair of round 240 carbs and im doing the research to find out how much itll cost and what other work needs to be done. Just realizing now that I was only getting 13mpg the past 2000 miles.

When I start the car, it idles just fine, but after driving it for a bit, it will die if im not nursing it on the gas. When it dies, im cranking the starter for up to 10 seconds and pumping the gas pedal before any action happens. Its going to a garage that I sort of interned at over the summer which sees a ton of vintage cars (always a different Citroen SM there). Ill have them check everything else while its there.

Changed the fuel filter and driving it has gotten a little better, but I think the problem is the fuel pump and its getting worse. Any recommendations besides this universal pump: ( http://www.autozone.com/autozone/parts/Spectra-Premium-Fuel-Pump/1974-Nissan-Datsun-260Z/_/N-iopilZ8vcz2?itemIdentifier=191528_173884_4967_ ) f

Found a hidden part of my car this evening. It currently has clear filter on it, and I can see a large chunk of rust sitting at the bottom. Ran to autozone since they had one of the white filters in stock, but couldnt get the hose clamp screws off. The clamps are marinating in PB blaster right now and hopefully tomorrow Ill easily be able to pop off the old filter and install the new one. Ill be sure to get better pictures tomorrow when I get the old filter off. Plastic filters are the only kind Ive seen for these cars. By metal filter, do you mean like the oil filter like filters?

Guess I should start saving for rustproofing. Im noticing most of the "issues" and "symptoms" I notice are one off instances or are bad descriptions of whats actually happening. The pinching was after high RPM acceleration and highway driving which is when the car is most likely to die if im not nursing the gas pedal. I couldnt recreate the situation after letting it warm up the next morning. After further inspection, the air pump has been capped off and it seems that I bought it as it is now. While that hooning in that parking lot taught me a lot about the cars handling (and saved me a couple times after that), it seemed to take its toll on the car. Cars will keep their distance at a stoplight to avoid my Zs toxic fumes and Ive had people at school ask me if my car is diesel. In tunnels and near dividers on the highway, I can hear my acceleration stuttering through my exhaust. The exhaust will flow freely and then putter whenever my acceleration stutters.

Today after getting a good look at the engine bay in the daytime I noticed that the belt that was supposed to be on the smog/air pump had broken off which im pretty sure explains the horrible exhaust smell that I occasionally get complaints about. I got the engine to idle and pinched the EGR hose. Nothing happened at first, but a few seconds later, the RPMs started to drop and the car turned off as I was describing earlier. When I bought the car I fully intended to learn all about its inner workings, but it seems my lack of time in the fall and the approaching winter is going to cut that time short . Two cars isnt an option for me and if I left it in the garage, it would be filled with spiders and chipmunks come spring time.

Looks like all my fuel lines have been replaced by some heavy duty hoses already and im pretty sure the only braided hose coming from the air cleaner is the valve cover hose. The only hose thats visible from the top of the engine that looks like it needs changing is the EGR hose which feels like play-doh. Im trying to make it until the weekend and ill take it to that mechanic, but my starter is trying to stop me. Im thinking about maybe trading it because I dont want to ruin a not-that-rusty, pretty low mileage Z by driving it in the NE winters

You can actually see the spill in the picture. The only reason I was asking was because all the other braided hoses are greyish and dry and this one is jet black and seems to be getting oilier everytime I check. I checked everything but the distributor cap and float bowl levels, and things were going well until those couple of donuts I did. My car wastes so much gas between the horrible smell of the gas and me having to keep the RPMS up at every stop. Itll be completely normal driving it until a few stoplights and signs into the trip and the car will try to die on me at a stop and hiccup when trying to accelerate from a stop. Im not even sure where to start with replacing the vacuum hoses. All the hoses seem pretty baked and hard, so I think itll be better to just change every hose then to just locate the current problem(s), but are the hoses all the same size? Or will I have to measure out each hose that I replace?