Viva Datsun Posted September 13, 2014 Share Posted September 13, 2014 So my 240z is currently 800 miles away in California and my friend and I are trying to swap a set of SUs in place of the junk Holley on there now. Obviously this is a bit difficult for me cause all I have to go by is what I'm told over the phone and the wrong pictures my dad sends me. Can someone tell me what part this is? He sent this picture to me with the rest of the intake/carb parts, so I assume it's in that system. It's probably from a 73 240 or maybe a 280zx Turbo, though anything's possible. Thanks for any help Quote Link to comment Share on other sites More sharing options...
Miles Posted September 13, 2014 Share Posted September 13, 2014 http://www.classiczcars.com/forums/su-carb-discussions/33472-su-carb-advice.html Quote Link to comment Share on other sites More sharing options...
Viva Datsun Posted September 13, 2014 Author Share Posted September 13, 2014 Are you saying it's the balance tube? That was my first thought but I guess I don't recognize it or something. And thanks for that link, pretty informative. Quote Link to comment Share on other sites More sharing options...
Miles Posted September 13, 2014 Share Posted September 13, 2014 I removed all of the smog crap from mine and plugged all of the holes with brass plugs. A Haines manual will tell you what each component is. Quote Link to comment Share on other sites More sharing options...
Viva Datsun Posted September 13, 2014 Author Share Posted September 13, 2014 Cool, I see it now. I guess the picture is at a funny angle and I couldn't see the parts that would mate to the intake manifold. Quote Link to comment Share on other sites More sharing options...
Leon Posted September 13, 2014 Share Posted September 13, 2014 Look's like a '73 or '74 balance tube (EGR). Quote Link to comment Share on other sites More sharing options...
Miles Posted September 13, 2014 Share Posted September 13, 2014 (edited) Go here and download a Factory Service Manual: http://www.xenons30.com/reference.html Edited September 13, 2014 by Miles Quote Link to comment Share on other sites More sharing options...
Mecha Posted September 21, 2014 Share Posted September 21, 2014 Getting a manual and the various books = good advice, searching here and at zcar.com will also answer a lot of your questions before you post something that gets you yelled at by Tony D. As far as removing the smog "crap", consider how important the PCV valve and system are to engine cleanliness and longevity. Don't just slap a plug or breather on the block. Just because a lot of people do it, doesn't make it smart. If you are debating between intake and carb options as you mentioned in another thread, here is my $.02 - take it or leave it. I got a late 260z that ran with flat-tops, I tried to "upgrade" to a worn out set of round-tops that I got off eBay. After cleaning and installing the round tops, balancing, adjusting, etc etc etc I was nothing but frustrated so I started researching other options. ruling out EFI I came to this; Ztherapy or 4 barrel. Both have advantages, both have disadvantages, many people have VERY strong opinions but most of that is based on ass-dyno and "friend of a friend" information. Polished SU carbs look amazing and when they are working properly they work very well. A properly sized 4 barrel (Holley 390) is available brand new with an electric choke, is a single device to tune, and while maybe not the best performance upgrade when everything is at 100% it will get you running reliably with easy starts as a simple bolt-on. My decision came down to luck and money. I had some spare PayPal funds that I used towards the Clifford manifold and gift certificates to a site that carried Holley carbs so I decided to drop the 40+ year old SU tech and install a slightly more modern 4 barrel setup. I still need to replace my fuel pump (partly to blame for the poor performance with the flat and round tops?... sigh) and re-do the fuel lines so I haven't actually driven it yet but I'm looking forward to driving directly to an exhaust shop while it is just blasting out of the new header. Hopefully there are no CHP around for that. Quote Link to comment Share on other sites More sharing options...
Viva Datsun Posted September 21, 2014 Author Share Posted September 21, 2014 Yeah, I get the searching, and I got the FSM and a manual months before I even bought the car. Sorry for the dumb question, It's hard working on a car you've never seen through the phone haha. Was just trying to get a better inventory of the parts I have. I just couldn't tell exactly what part it was, and you guys cleared that up, so thanks. As for plugging the smog junk, I never did get why people plug up the PCV... Just seems like a bad idea. The new plan is to have my friend rebuild the Holley and get the car running good, then once I have time from work and school, I'll head down there for a week to finish up a bunch of reliability work on it to prep for the 800 mile drive back. Then I can really get to wrenching on it myself. Quote Link to comment Share on other sites More sharing options...
Mecha Posted September 21, 2014 Share Posted September 21, 2014 Sounds like a good plan, will you have a "chaser" car with you? If not, add/upgrade your roadside assistance Before you invest time and materials into the carb make sure it is a good size for the engine. 390 CFM is the smallest one currently offered by Holley and it is actually bigger than necessary; putting a 600 or 750cfm unit on there will not be a positive experience. Quote Link to comment Share on other sites More sharing options...
Viva Datsun Posted September 21, 2014 Author Share Posted September 21, 2014 For better or worse we won't have a chaser haha. Just me and my buddy. We have both worked on all our own cars and he's currently a Porsche mechanic, and I worked as a mechanic briefly as well too. So we'll see how well that goes... I'm not sure what size the holley is actually, I would assume the 390 but I can't really go out and check. My intention is to freshen up the SUs when I get the car back and replace the holley with those. I know it's probably not necessary but, hey, I like twin carbs and could sell the holley for more than the SUs (I would think, It's the AZC intake). Since you mentioned it, what spares would you take along for my drive back? Obviously I'll be trying to replace whatever parts may give me trouble before hand (brakes, cooling, suspension and steering parts, big tune up, clean fuel tank, get some gauges working...). Would converting to the elect. distributor be worth while? Quote Link to comment Share on other sites More sharing options...
Mecha Posted September 24, 2014 Share Posted September 24, 2014 The distributor is an easy upgrade and since you would probably be adjusting points and timing anyway it sounds like a good time to do it. Make sure you get/have the right mount; the 240/260 dizzy has the screws way off from the 280zx. Here is a nice little write-up: http://www.atlanticz.ca/zclub/techtips/distributor/index.html I'd try to check and/or replace as many fluids and as much rubber as possible before you go, and bring some extra with you. The accessory belts are easy to replace and likely to be old/worn. Obviously make sure the fuel lines are safe, especially the ones that were added/changed with the Holley. Speaking of changed lines for the Holley... Check to see how the brake booster is connected to vacuum and that it has a (working) check-valve. The PCV system might be hacked as well so check the block vent and make sure it isn't capped, a breather isn't ideal but at least you won't blow a seal. Something that may or may not need to be addressed are the shifter bushings, 40 year old plastic tends to disappear but there is a brass option (http://www.atlanticz.ca/zclub/techtips/shifterbushing/index.html) based on my experience... then research it isn't uncommon for the ignition switch or combo-switch to go out and cause starting or electrical problems, some wire and a momentary switch are a short term fix - I'm not endorsing that as a permanent solution but if you really want to make it home a little ugly might just get you there. Regarding spares... other than your spare tire, jack, tools... wheel locks? A healthy supply of fuses, electrical tape, zip-ties, bailing wire (aka, custom exhaust hanger), maybe some duct tape, and some road flares. I'd bring the old belts, spare hose, extra clamps, and all the common fluids as well as at least a few gallons of water. If the car overheats -water for the car, if you break down in the heat - life sustaining moisture for you. Snacks are good too, you can have a picnic on the side of the freeway if things go South but if you plan ahead you shouldn't need to. I'd highly recommend using/borrowing/getting a GPS to accurately tell your speed and give you directions. Since you will be driving over at least one mountain range and across some desert on you epic journey I'd bring plenty of water and check/replace the thermostat as well as do some serious flushing of the whole cooling system. One last piece of advice; install a disconnect or just unhook the battery if you stop overnight. It isn't like you are going to reset your ECU and a lot of old cars have power drains that could leave you with a dead battery in the morning. I'm surprised that nobody else has chimed in on this, you might want to search or create a new thread for more advice. Quote Link to comment Share on other sites More sharing options...
Viva Datsun Posted September 24, 2014 Author Share Posted September 24, 2014 Cool. I'm already planning on pretty much everything you said, so I think I got it covered. Good tip on the battery though, thats something I wouldn't have thought of, thanks! Quote Link to comment Share on other sites More sharing options...
bfg Posted September 24, 2014 Share Posted September 24, 2014 This was my "breakdown kit" after I finished re-installing my rebuilt suspension. What you can't see is a full set of ratchet wrenches, spare fuel pump, and a bottle of brake fluid. I would also recommend bringing a few inline fuel filters to put between the gas tank and fuel pump. I replaced my filter once a week before I cleaned the gas tank and i still need to replace it once month even after flushing it out the best I could. Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 24, 2014 Share Posted September 24, 2014 "so I decided to drop the 40+ year old SU tech and install a slightly more modern 4 barrel setup. " I'm going to chime in on that one to say the following: The Holley is 50's technology at best. That 4150 390 was available used when I was a kid, and that was 35 years ago! The SU was used into the 80's on Hondas in the USA. Don't think 'old' means "inefficient or obsolete"... Generally the separation between systems is due to a person's willingness to learn about what they have. Personally, I'd gut either system, put a TPS on it, and make it EFI. I've dealt with enough carburettors to know I don't need that hassle in my life, digital is easier to quantify than analog any day of the week and twice that on Racing Day! Quote Link to comment Share on other sites More sharing options...
Mecha Posted September 25, 2014 Share Posted September 25, 2014 (edited) ... That 4150 390 was available used when I was a kid, and that was 35 years ago!... yeah... but probably not with an electric choke Even if the core design is ancient, the materials, minor design improvements and production process are slightly updated over the years. Plus, my main motivation was the fact I could get a NEW one without 40 years of wear and tear and have ONE to tune. It is odd though, I'm in IT and have experience with electronics and fabrication but I just don't want to go EFI right away. I totally understand the concept and see many benefits but I just know I'm not taking my car to a level where it would compete with something like a Subaru BRZ/Scion FRS anytime soon so I don't want to change it in that way... yet Edited September 25, 2014 by Mecha Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 25, 2014 Share Posted September 25, 2014 I watched as GM clung to carburettors using pwm controlled solenoids moving metering rods... Dismal. When they went to TBI, while some carb holdovers existed (stalling when cold some times) it was a huge improvement, and used legacy wet runner technology good enough... TPI came along, and dry-runners...and woah! The GM Tuning world hasn't looked back! If you think carbs are "easy", you don't know carbs! Quote Link to comment Share on other sites More sharing options...
Viva Datsun Posted September 26, 2014 Author Share Posted September 26, 2014 Going EFI means that I've also built some kind of beast of an engine, at least to me, that carbs just couldn't handle. Obviously EFI is factually better, but for the average, or even above average Z, I don't see it being worth while. This is a 40 year old car, it'll never be perfect and that isn't my objective with it anyways. Quote Link to comment Share on other sites More sharing options...
Mecha Posted September 26, 2014 Share Posted September 26, 2014 (edited) I would say that going EFI is going to make your engine more efficient and more consistent, regardless of the performance level. You can find EFI in a Geo Metro and Carbs on some full-on racecars (that mandate it); NASCAR did pretty well with carbs up until what, like 2012? Anyway, back to the... uh...second... topic of the thread. Do you have your route planned out? I'm just curious if you are headed my way (I-80 North East of Sacramento). Edited September 26, 2014 by Mecha Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 26, 2014 Share Posted September 26, 2014 (edited) "Going EFI means that I've also built some kind of beast of an engine, at least to me, that carbs just couldn't handle." Educate yourself, this is an inappropriate mindset. Yep, that's EFI on a 71 Triumph! Not a 'performance' build this gent was after by a longshot, check out his car here: http://triumphowners.com/registry.cgi?sectionID=111014&vehicleID=108&i=8 or another high profile Triumph here: http://tr6.danielsonfamily.org/index.htm He makes a nice synopsis here http://tr6.danielsonfamily.org/TBI.htm EFI has been in the USA mass produced on low-performance vehicles since 1968 (Not much lower performance than a 1968 VW Type 3!) The technology has advanced so much that the self-tuning capabilities, and wear adjustments make for a car that doesn't need much of anything over it's lifetime. It's nothing about performance at all, other than 'trouble free'... Not perfect, just driveable any day of the year, anywhere, anytime. I converted my SU's to TBI some time ago, more and more are doing it and singing the praises of troublefree starts, superior mileage and performance out of otherwise bone stock cars much older than our Z's. Look at http://www.pattonmachine.com/ I supplied him with SU's to pattern his drop-in conversions so all SU's on Datsun, Toyota, & Isuzu 64-78 were covered! Latest blog was Andrew Jennings who drove from British Columbia down to Vegas in the heat of summertime (can you say "SU VAPOR LOCK"?) for the meeting of The Z Bastardz in his Patton-Machine Converted SU'd PL510. It's about driving the car from -40C to +40C and never having to worry about anything, from Death Valley to Denver and never having to get out and pull a vacuum hose off to make it over the hump! Been there, done that, don't miss it one BIT! Edited September 26, 2014 by Tony D Quote Link to comment Share on other sites More sharing options...
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