Carburetor Central
If you have questions about the SU Carburetors, this is where you can find the answers.
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I'm a scientist by training so I can't resist the chance to gather data and over analyze things when I get the chance. To that end, I picked up a wideband O2 meter... Wide band It's not my intention to leave the wideband installed permanently but rather just hook it up for tuning or trouble shooting. I installed the sensor in a bung in one of the down tubes in my header. The bung had always been there, just nothing but a bolt in it till now. I left the bulk of the wiring zip tied under the hood and only ran the necessary wires for the gauge which I zip tied to the steering column for easy viewing. The installation went quickly and smoothly. After calibration I sta…
Last reply by madkaw, -
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- 3 replies
- 2.1k views
Greetings all -- The pump on my '73 (rear electric pump, standard SU's, pretty much stock except for 280-Z distributor) has effectively given up the ghost - car ran great, then silence, followed by cursing. Dropped a new see-thru filter in and the pump could not fill it (and the pump was turning over - sound was "normal" and there was a tiny amount of gas bubbling in the filter). So -- what should I ask for - specs / makes /etc. Any info would be helpful. Steve Bloom
Last reply by Steve Bloom, -
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- 1.6k views
My 4 screw carbs are in need of some ZTherapy therapy; sizeable vacuum leaks, etc. While I am accumulating funds to make that happen, I picked up a pair of 3 screw carbs locally to have as back up, or to play with, or what have you. I took them apart, cleaned them up (followed the Just DVDs video) and decided to replace my rear carb (biggest vacuum offender!) with the 3 screw alternative. I was stunned how much better the car ran, idle was able to drop down to 700 to 800 rpm (could never get it below 1100), smooth acceleration, etc. Well, being reasonably stupid, I thought I would replace the front 4 screw carb with the 3 screw and make it run better, right? Wrong!! …
Last reply by Duffman, -
- 4 replies
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WoHooooo There may be hope for my su's yet. After struggling in the fall with various problem with my 4 screw su's. I had to run them rich so as to get rid of a surging at constant throttle and miss at wot then the car smelled of exhaust at idle and low speeds. When it was missing at wot if I just backed off on the throttle a little it would pick up and rev to 7000 ( I have a fairly modified 2.8). I looked at converting to injection or holley 4bbl and had discussing this with some of you. When I got the car it had dvg's on it. I converted it to 4screws that I rebuilt with zero play in the shafts. For air breathers i took the small elements fron the dgv's built flat bases…
Last reply by Travel'n Man, -
- 15 replies
- 8.6k views
As I continue to learn the many joys of tuning and balancing SU's, I got the thinking about my dashpot oil. I have always used straight 20W motorcycle fork oil. It seems way too difficult to lift the dashpots (enough force that my wife couldn't lift them) when the engine is cold. My most recent tuning/tweaking attempts have me running very strong right through the powerband, up to about 5,500 rpm, but I have the slightest bit of hesitation when I back off the gas (for cornering, etc.), then get back on it. Could this relate to the viscosity of my dashpot oil? I have read recently about some people using a combination of 20W or 30W oil cut down 50% with light oil. Con…
Last reply by Bruce Palmer, -
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Ok Here's a new one on me, I can only get the car to take 1/2 a tank of gas, like 6 or 7 gallons. At that point the fuel is topped off at the neck. Anyone see this before? 73 240Z, standard 15.9 gal tank with all new tank plumbing to expansion tank and motor. I understand that new doesn't mean good, and I may have missed something. Any ideas before I have to dig through the hole hose thing again would be appriciated.:stupid:
Last reply by Darrel, -
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I have a 72 with the surging accelerator problem. I got a new bellcrank and throttle rod so I could perform this modification. I'm not a welder and was wondering how anyone else has done this mod without welding? It looks like I can use my Dremel and saw the arm off the weld but I'm not sure how I would attach a washer to the bellcrank. Attaching the arm to the washer I can see, but I don't see what I would screw to with the washer. Any ideas?
Last reply by zKars, -
- 12 replies
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Hi Got my 240 today and it seems to be idling high and very rich and smelly How do I adjust the idle and will this in turn adjust the mixture?? Or how do I adjust both idle and lean off the mixture? You help would be greatly appreciated. Will post up pics soon...car now registered here in the UK having spent its 41yrs in CA.
Last reply by Vipergts, -
- 8 replies
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On my 73 240z, I'm having problems keeping it running. Starts up fine but dies after it warms up. Acts like vapor lock. Anyway, I have new fuel filters front and back, new mechancial fuel pump and stock electric pump in the back. I thought the return line might be clogged so I blow air thru the return fuel line and after the pressure built up fuel started coming out of my fuel rail from the spot I removed the return fuel line. So as the air goes into the tank it forces fuel back thru the feed line. I did not think this is a closed system. Oh yeah I have z therpy 3 screw roundtop carbs. Any ideas on what to check next. Can not drive the car now and spring is here.
Last reply by manny1973, -
- 7 replies
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I just installed a MSA 3-2 header and exhaust system on my 1972 240z and now my idle is too high. It used to idle around 800 rpms, now it idle around 1200-1300 rpms. Overall it seem to run great. Just idles high. Is there a quick idle adjustment on these SUs ? Any help would be greatly appreciated. I know there is tons of info. already in this forum, but it is very hard to find any specifics... Thanks again in advance
Last reply by LeonV, -
- 13 replies
- 2k views
First of all, I know zero about carbs...my motto was that I always wanted to know a good carb guy, but never wanted to be one...except my carb guy retired and moved to the lake, so here I am. I put triple mik 44's on my stock 72 240z for show purposes. And it worked, I was in six shows and got six first places. Mission accomplished. But I gave up the fun of driving, in order to have a car that looked and sounded pretty sweet. I'm now going to remove the Mik's and put "something" else on. Don't know what the something is. I see a lot of posts about Z-Therapy, but I also see these Weber's on Zcar parts: http://www.thezstore.com/page/TZS/CTGY/PFFC02 What's the diff between…
Last reply by Hybridz-KY, -
- 8 replies
- 3.9k views
I'm trying to plug the 3 ports on my crossover tube to delete the smog stuff on my 72 with a 75 engine and mix of SU carbs. Can't seem to find what will go into these and close them up.
Last reply by mr mikey,
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