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Thread: How to get 260Z to daily driver status?

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    Registered User porkbun's Avatar
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    Question How to get 260Z to daily driver status?

    Not only is this my first post in this forum, this is will also my first Datsun, and also my first car! It has a well documented 83k, starts right up, drives great, and has rust on the passenger side wheel arch and a bit on the driver door sill. It hasnt been driven much in the past few years and I would like to get it up to daily driver status. Ill have to travel at least 15 miles a day or 28 miles at most (round trip). What should I be checking/replacing to ensure reliability and healthy driving? Are there specific parts that commonly fail on these cars, or should I just bring it to Meineke to have it inspected? Cant wait to pick it up tomorrow!

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    Congrats on the new Z. Your screen name might have scared people away, it sounds unhealthy.

    You said it starts right up and drives great. Is there some reason you think this won't last? The more detailed information you share the better. How much is "not much" in the past few years?

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    This could be a novel...
    Flush the cooling system and put in new coolant.
    Inspect the brakes and replace any worn components. Also replace the brake fluid.
    Flush the brake fluid in the clutch hydraulics (manual) or replace automatic transmission fluid (automatic).
    Inspect the tires to make sure they have adequate tread and are less than 6 years old.
    Inspect the u-joints and driveshaft bolts. Tighten, lube or replace as necessary.
    Inspect all suspension components and steering components. Be prepared to replace worn rubber bushings and boots. Replace the shocks if worn.
    Look into adding relays to power your headlights and possibly H4 lights.
    Replace running lights with LED bulbs. This reduces the chance of burning up wires.
    Clean and lubricate the wiper arm mechanism.
    Replace the old seatbelts or at least replace the webbing.
    Inspect/replace coolant hoses and water pump.
    Inspect the horn and replace the horn relay if the horn is weak or nonfunctional.
    Replace the fuel filter.
    Inspect/replace spark plugs, plug wires, distributor cap, & rotor.

    Finally get a beater for the winter or your Z will rust to pieces.
    73 240Z
    74 260Z

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    Registered User porkbun's Avatar
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    Theyre not that unhealthy!

    I know that cars are meant to be driven and a low mileage garage queen may end up presenting a lot more problems in the future than a car that gets more action regularly. I got a ton of documentation with the car, so I have the window sticker from ACME Motors in NJ where it was serviced a bunch of times (anyone else?). I can see that in 04/13/02 it had 81,843 and had some hoses and the water pump changed. In 07/11/06 It got an oil change and had 83,389. In 08/11/08 it had all the hoses replaced, repaired the choke and cleaned out the carbs and had 83,520. I bought it with 83,760 on Friday.

    I was shopping for C4 Corvettes before and generally the rule was mileage doesnt matter as much as the previous owner taking good care of the car and there were certain fluids to replace when you got it. There was also the preventing the optispark ignition system from getting wet in the later models by avoiding puddles, heavy rain, and making sure the water pump didnt break. Are there similar warnings for the S30 or 260 in particular?

    Im going to the DMV to get temporary registration so I can drive it!

    EDIT: Left this open in a tab and SteveJ posted before me. Procedures like those is what I was looking for
    Last edited by porkbun; 08-20-2012 at 05:58 AM.

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    Welcome to Z-Land and the addiction.................be prepare to spend that bacon on this baby

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    Oh, and download a copy of the FSM from xenonS30.com. Take pictures, especially of the engine bay. It will help us help you to figure out modifications done to it.

    Also beware of the seatbelt interlock relay. Most likely it has been disabled, but you never know. This relay is a 260Z only issue (as well as any other 1974 model year car).
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    Inspect/Replace/Repair:

    - All fluids
    - Entire braking system
    - Cooling and oiling systems
    - Clutch hydraulics
    - Fuel filters
    - Throttle return springs
    - Valve adjustment
    - Carb sync
    - Ignition timing
    - Headlights, tail lights, brake lights, turn signals

    etc...

    Good luck and enjoy!
    2/74 260Z

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    Quote Originally Posted by SteveJ View Post
    Oh, and download a copy of the FSM from xenonS30.com. Take pictures, especially of the engine bay. It will help us help you to figure out modifications done to it.

    Also beware of the seatbelt interlock relay. Most likely it has been disabled, but you never know. This relay is a 260Z only issue (as well as any other 1974 model year car).
    Ill have to get pictures and a video tomorrow because its too dark here.

    Also forgot to mention this is the second time I drove a manual car.Drove it 70 Miles back home today. Today I learned: My brakes could wake up the dead, other people really like the car, it doesnt have a casette player but it does have an 8 track player, one of my headlights stopped working, the wipers stink, theres a clicking sound at higher speeds and theres a bit of surface rust like everywhere. I already have the FSM, and the owners manual, going to get duplicate keys made tomorrow and do most of the stuff that LeonV listed.

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    A picture I took earlier from inside my house through a dirty window
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Okay, from that picture we can tell you have a "late" 260Z. The bumpers are a dead give-away. You'll find it has a lot of parts in common with the 75 280Z. You might find that there are components in the engine bay that are in different locations from the FSM, too. What is the build date on the door jamb plate?

    Edit:
    The clicking sounds at higher speeds could be u-joints or loose bolts in the driveline. It would be good to check that out sooner than later.
    Check the fuses for your headlights. See if the bad headlight lights up when you switch it to bright.

    Like I said before, you could write a novel on getting a 40 year old car of unknown pedigree up to being a reliable daily driver.
    I tried to do that with my 73 about 20 years ago. That did not go well. I tried to do it on the cheap, and I didn't have near enough knowledge to get it in good shape. I'd actually have a better chance of getting the car in shape now.
    Last edited by SteveJ; 08-20-2012 at 06:24 PM.
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    Quote Originally Posted by porkbun View Post
    Are there specific parts that commonly fail on these cars
    A lot of people complain about the 260 carbs. They are commonly known as "flat tops" because of the shape, and most people don't like them.

    Parts availability for the flat tops is difficult. You can get a "rebuild kit" easy, but if that doesn't fix the problem, then you're out of luck. The support structure just isn't there to supply other parts if necessary.

    If it's running fine, then don't poke that nest. However, if you have carb problems, unless you find someone in your area that is willing to work on the "flat top" 260 carbs, then you may have to switch to the older "round top" 240 carbs used from 70 through 72.

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    Its dark outside now and pretty late to be closing those doors, but I will have pictures and videos tomorrow. Clicking isnt really the right word to describe it. To me the noise sounds like if you stick the edge of a piece of paper into a house fan. I also hear it when I pop the hood and idle. The closest comparison I can make without sounding like a complete and total idiot is that it sounds sort of like a diesel engine. Im going to sound like an ridiculous if I try and describe it any further, so I hope the video will help reveal it tomorrow.

    As for the carbs, since they arent broke, I wont go try and "fix" them. I was thinking about switching the, out for 240 carbs or other popular options that people go with, but after the maintenance and the new lights, I want to focus all my funds on rustproofing.
    Last edited by porkbun; 08-20-2012 at 08:49 PM.

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    Rustproof is a must.

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    Okay, I misunderstood your description of the noise. It sounds like it's a valvetrain issue. I don't claim much knowledge there, but I know there are several threads on here that go into issues related to that knind of noise.
    As for rustproofing, make sure you get rid of the existing rust first.
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    Quote Originally Posted by SteveJ View Post
    Okay, from that picture we can tell you have a "late" 260Z. The bumpers are a dead give-away. You'll find it has a lot of parts in common with the 75 280Z. You might find that there are components in the engine bay that are in different locations from the FSM, too. What is the build date on the door jamb plate?

    Edit:
    The clicking sounds at higher speeds could be u-joints or loose bolts in the driveline. It would be good to check that out sooner than later.
    Check the fuses for your headlights. See if the bad headlight lights up when you switch it to bright.

    Like I said before, you could write a novel on getting a 40 year old car of unknown pedigree up to being a reliable daily driver.
    I tried to do that with my 73 about 20 years ago. That did not go well. I tried to do it on the cheap, and I didn't have near enough knowledge to get it in good shape. I'd actually have a better chance of getting the car in shape now.
    I think the fact that the original wheels are there is a good sign that it probably hasn't been modified, which will make it easier to diagnose known issues.
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    Could be an exhaust leak, the ticking noise you hear...
    1971 240Z HLS30-38691
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    Click image for larger version. 

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    Thats a picture of the engine bay, but whats kind of worrying me is this:
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    It may just be the angle of my driveway and the shape of the car, but it seems a lot of other cars engines also tilt the same way.
    Full album here including the trip on the way back

    The video I took today is huge and will take a while to upload (like tomorrow night). Things I noticed today: The oil is filthy, the car will sometimes try to start itself up after I shut it down (I read this is because I put in 87 as opposed to 91), not to trust mechanics when they say they have time and to come back later(trying to get my brakes changed), the car will occasionally shake a bit and the RPMs will bounce a bit when at a red light (need carb tuning?).

    Tomorrow I want to pick up some oil and coolant, but I have no idea what to get. Im not very interested in all the arguing about oil, but I would be interested in what works in your car. Right now im looking at Valvoline VR1 20W-50 and a K&N filter, but im not sure if thats the right oil for me. Ill only be doing 6k a year MAX, so Id keep the oil in for at least half the year, but I read that 20W-50 is more for summer driving and theres not much summer left. Im heading to autozone tomorrow, but I have absolutely no idea what coolant to use. Any names I should look out for?

    About the diesel noise, Ive narrowed it down to this area:
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    I can hear it in some form on nearly every Datsun engine bay video and shouldve captured it today on video. Not the fans like I thought. Any ideas? What is that covered by that cap?
    Last edited by porkbun; 08-21-2012 at 03:23 PM.

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    Quote Originally Posted by bpilati View Post
    I think the fact that the original wheels are there is a good sign that it probably hasn't been modified, which will make it easier to diagnose known issues.
    I found at least one modification. The oil pan drain plug on my car is 7/8" and stuck to the oil pan pretty good, so the oil still has yet to be changed which means no no driving the Z . BTW I went with Valvoline VR1 10w30. When it get lighter out ill have to check out the carb dipsticks again, because one dipstick felt much goopier than the other, so either one has the wrong/old oil, or one has oil and the other doesnt(which would explain the occasional shaking). Seems like all my problems are oil related.

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    Before I start poking around with the carbs, I was wondering if there could be any other cause for this problem. I just changed the oil to VR1, but Im still having some starting problems. My car doesnt like to start early in the morning, but has no problem starting in the afternoon when it gets much warmer. In the morning I crank it up, the rpms will go to about 500 and then it will die unless I pump the gas (read: flooring it then taking my foot off). When I floor it, the RPMs will go up like normal, but something will click while I pump and will temporarily make me lose power until I come off and pump some more (feels like the slight resistance in the gas pedal goes away until I come all the way off). Once it stops this hiccuping, Ill keep it at around 1.5-2k until it will finally idle at about 1.1k.

    At first I thought the ancient oil that was in there needed to warm up (whether by pumping the gas and keeping it at 1.5-2k or waiting for the day to pass, but the oil has been changed, and its still way easier to start it up the second time in a day, or after it has sat in the sun for a while (Itll fire right up and idle at about 1.1k after sunning for a bit or if I drove it earlier). Applying the choke makes my RPMs drop until the starts shaking, or just shuts the engine off. Does this sound like a carb issue to anyone else? Will it be solved if I follow this: http://www.classiczcars.com/forums/thread41940.html ?

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    Download the FSM at xenons30.com and look in the Fuel System section. Now that I look at it, it's a bit blurry, so you might have better luck with the '73 manual. The carbs are similar. "Round top" SUs ('70-'72) are different.
    2/74 260Z

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    Quote Originally Posted by porkbun View Post
    Before I start poking around with the carbs, I was wondering if there could be any other cause for this problem. I just changed the oil to VR1, but Im still having some starting problems. My car doesnt like to start early in the morning, but has no problem starting in the afternoon when it gets much warmer. In the morning I crank it up, the rpms will go to about 500 and then it will die unless I pump the gas (read: flooring it then taking my foot off). When I floor it, the RPMs will go up like normal, but something will click while I pump and will temporarily make me lose power until I come off and pump some more (feels like the slight resistance in the gas pedal goes away until I come all the way off). Once it stops this hiccuping, Ill keep it at around 1.5-2k until it will finally idle at about 1.1k.

    At first I thought the ancient oil that was in there needed to warm up (whether by pumping the gas and keeping it at 1.5-2k or waiting for the day to pass, but the oil has been changed, and its still way easier to start it up the second time in a day, or after it has sat in the sun for a while (Itll fire right up and idle at about 1.1k after sunning for a bit or if I drove it earlier). Applying the choke makes my RPMs drop until the starts shaking, or just shuts the engine off. Does this sound like a carb issue to anyone else? Will it be solved if I follow this: http://www.classiczcars.com/forums/thread41940.html ?
    To answer your last question first, no, it won't.

    Are you pulling back on the lever to apply the choke or pushing forward? Your description sounds like you are taking off the choke. What do your plugs look like? Are they fouled?
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    It has been sitting outside cooling down with the night on the street and I went out to bring it into the driveway. The engine fired right up, but my rpms dropped to at about 500 and I had to get my gas pedal pumping routine going, but it wasnt as nearly as difficult as in the morning. Tomorrow morning Ill have to go out and do a conclusive test with the choke. Whats confusing me is starting it the first time in a day is always the hardest, but starting it the 2nd, 3rd, 4th etc. time it just fires right up. When I try and start it in the morning(during the gas pumping phase), the choke only makes it more difficult to get the engine going (pulling it back towards me activating the choke light), it causes my RPMs to drop and the car to get a bit of a shake going. Just now when I was bringing it in, I pulled back on the choke and it brought my RPMs up a bit and made the engine run a little smoother. Tomorrow I will check out the plugs, the choke, and my carbs( the 73 manual is a loooot easier to read!) and report back.

    EDIT: A couple of other details that may help narrow down this problem: I never smelt the exhaust before (I always keep my window down), but with this recent gas pumping routine, the strong smell of gas and ripe exhaust usually greet me in the car and the family in the house. Another phenomena that happens is when I shut the car off, itll shake for a couple of seconds, perhaps try and start back up, and then die (dieseling as ive heard it called). It happens no matter which octane I use (87, 89, 91). Is this indicating something about my air/fuel mixture?
    Last edited by porkbun; 08-29-2012 at 05:45 PM.

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    One thing I'd suggest is to change oil again relatively soon. I would have thrown in some cheap-o 30 wt. to dissolve residue left behind after sitting for years on old black oil. Having just changed oil what does the new oil look like already?

    And do try and get a read on those plugs pretty soon. They can tell quite a story.... We do sell a pretty decent dvd which covers engine related issues that would be a nice addition to your library.
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    Just tried starting with the choke fully pulled and it fired right up, so the error was me confusing all the things I had been reading. With the choke pulled in, the engine fired right up, and idled very roughly and shakily at about 1.1k with the horrible exhaust smell pouring in. I took the choke off after about a minute and the engine could idle, but it was still very rough at 1k and I felt that at any moment I might have to give it some gas to keep it from dying(but the exhaust smell disappeared).

    I pulled the spark plug wires off one by one and the idle dropped the same bit for each plug. I cant find my spark plug socket, so I cant actually pull them out now. I did check the dampers and the back (closest to driver) carb has a lot more transmission fluid than the front at the fluid is also a bit lighter than the front carb. The rear carbs fluid covers the bottom plumb and makes a squishing noise when I replace the dipstick, the front makes no noise when I replace it and I can literally feel there is less fluid. Is the single notch on the dipstick the level I should aiming to reach? Oil is still pretty golden although it is a bit dirtier than when It was poured in.
    Last edited by porkbun; 08-30-2012 at 08:07 AM.

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    Your cold start and running issues don't surprise me at all:

    "In 08/11/08 it had all the hoses replaced, repaired the choke and cleaned out the carbs and had 83,520. I bought it with 83,760 on Friday."

    Sounds to me like the previous owner was chasing a performance problem with the car... He had all the hoses replaced and the carbs taken apart and cleaned out four years ago, and then put less than 250 miles on it since. I assume it's been sitting with the same gas in it for those four years? I'd be happy that it runs at all!

    If you're looking for significantly better performance that what you're getting now, you're probably going to have to get inside the carbs. Or open your wallet and find someone near you who's got a handle on the infamous flat tops and hope that it's something simple that can be addressed by the anemic rebuild kits. If you were closer to me, I'd be happy to help you with them, but I'm several hours from you.

    Also, from one of your previous posts, there's a question that hasn't been addressed:

    Quote Originally Posted by porkbun View Post

    About the diesel noise, Ive narrowed it down to this area:
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    What is that covered by that cap?
    Under that cap is your EGR valve.

    I'll second the guess that you've got an exhaust leak. Probably at the rear of the engine back by the firewall.

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    Speaking of EGR, one of the things that can cause the problems you're describing is if your EGR valve is active when it shouldn't be.

    The EGR valve should only be open after the engine has warmed up, and if it opens before that, it can cause rough running.

    To check for that, pull and cap the hose running to the EGR valve (the thing with the large round cap) and see what happens.

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    In 08, the car wasnt starting, the alternator wasnt charging, and all the fuel lines were replaced at Acme Nissan in NJ, so it sounds to me like they were trouble shooting and happened to notice the state of the fuel lines. According to the receipts, it seems that it was a daily driver until the 80s (70k in 83)and then the mileage per receipt interval starts dropping down to a couple hundred in the 00s. I have no problem with the performance, but sometimes in first, ill experience a bit of a hiccup under heavy acceleration like the car is just realizing how hard im pressing down on the gas (like an automatic transmission changing to a lower gear for more power. carb lag?). I also feel like I could be getting better MPG since I do mostly highway driving, but I do enjoy the acceleration in town.

    I would like do work on the carbs, but it all seems to be a bit over my head. Would just replacing them with the 240 SUs or another carb make maintenance easier? I havent called around yet, but I feel like getting different carbs would be cheaper than always having to rely on someone else to take hours to get everything right.

    This is the clacking diesel noise I hear when I start the car and the hood is up, but its definitely coming from the area in the photo. I havent even noticed it anymore because I can hear it in nearly every other engine bay video (or its could be stuck now that I think about it)so it doesnt really seem like a problem to me: http://www.youtube.com/watch?v=mcCV7ooaovk . Ill try covering up the EGR tomorrow to see what happens

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    It would totally make maintenance easier, there is tons of info about round top SU's here and they are most reliable carburators i have ever stumbled across. I had them tuned by a pro and i havent touched them since (2 years). There is good quality sets for sale if you keep looking, im sure many of our forum members have extra pairs waiting for someone to buy them
    -72 240Z "Goldie"

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    Problem is that you've got no "baseline". You don't have any portion of the car verified, tested, proved positive, that you can be completely confident is working as designed. What I mean by that is, for example...

    Quote Originally Posted by porkbun View Post
    sometimes in first, ill experience a bit of a hiccup under heavy acceleration like the car is just realizing how hard im pressing down on the gas (like an automatic transmission changing to a lower gear for more power. carb lag?).
    Stuff like a short lived dead spot, "bogging" on heavy acceleration as you described above could be caused by a whole bunch of things. Some carb related, some not. Could be anything from lack of oil in the carb dampers, to a clogged fuel filter back in the electric pump, to a distributer problem. Might be fuel related, might be ignition related, might be air related. Could be anything. Point is, either you better get good at opening your wallet, or you better get good at finding and fixing your own issues.

    So back to the carbs... The flat tops work great when they're working great. I'll even risk poking the hornets nest here and go out on a limb to claim "Better even that the round tops." Problem is, as with many other "better" systems, that improvement comes with the down side of complexity, and that complexity provides more avenues for problems to work thier way into the system.

    The bottom line is, either carb choice works great if done properly, but the round top system is boatloads simpler than the flat top system. That simplicity makes it much easier to keep the round tops working properly and also to troubleshoot problems when they do occur.

    I know the flat tops pretty well. But reaching that point is much easier to achieve if you aren't behind the eight ball working on your daily driver!

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    Quote Originally Posted by Captain Obvious View Post
    Problem is that you've got no "baseline". You don't have any portion of the car verified, tested, proved positive, that you can be completely confident is working as designed.
    I see what you mean. The only other detail that I can give is that the problems go away after the car is does some "work". This morning it was pretty chilly and I was experiencing some of that lag and my rpms were threatening to drop below 1k. 3 Hours later (7 miles away), I start it up with the choke, but the RPMs dropped to 8-900, but when I took the choke off, it went to a normal idle.

    Ill pick apart the FSM and see if I can get anywhere tomorrow with the carbs, and maybe that set of appliance rims that came with the car will help soften the blow of switching/tuning the carbs if I cant figure them out. I cant just pour money into the car all at once, because I still have to pay taxes for it and get some new tires which is already about $800, so what do you recommend me doing first? Its pretty predictable right now, but I want to get it in good mechanical shape so I dont end up on the side of the road.

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    Quote Originally Posted by porkbun View Post
    I see what you mean. The only other detail that I can give is that the problems go away after the car is does some "work".
    Apologies ahead of time if I'm wrong, but I'm gonna go out on a limb and make some age related assumptions. I don't know how old you are, but I'm guessing that every car you have ever seen or been in to this point had computer controlled fuel injection systems and no choke. You got in - turned the key - and went off down the road without a hiccup.

    Well let me tell how it used to be in the old days...

    There was no electronic fuel injection or computers of any kind in cars. Cars had carburetors and chokes. When you first started your cold carbureted car, it ran "OK" if you were lucky, and "poorly" if you weren't. If you were lucky, you could let it sit at high idle for a minute or so to warm up before you went off down the road, and if you weren't lucky, you had to sit there for a minute and nurse it to keep it running. Then once it was running well enough that you felt confident that you could pull out into traffic without stalling in front of someone, you could get moving on your way. As you put a few miles behind you and the engine continued to warm up, it gradually got better and better until it ran "good".

    The best you could ever hope for was that it started easy, idled smooth but tentative while cold, and improved quickly to the point where you were safe to leave your parking spot.

    So what would I do? With the FSM as a guide, I would start with the easy stuff:

    Ignition - Install new distributor cap, rotor, plug wires, and spark plugs. While you're in the distributor, check your ignition pickup gap. Once you have installed new components and verified your pickup gap, check your ignition timing and adjust as necessary.

    Fuel - Check and adjust your damper oil as necessary (yes, you have a fill-to line on the damper stalk). Check your float bowl levels. I would assume that if your float bowl levels are OK at idle and you aren't running out of power on the highway that your fuel filters are not clogged (yet).

    Air - Replace the air filter and inspect all the vacuum hoses and lines in the bundle of snakes and compare against FSM for correct locations of all the tubing. Vacuum leaks are not your friend, and because of the complexity of the 260's system, there's lots of opportunity for them to occur.

    Keep in mind that this is just the simple non-invasive stuff. Beyond that are more invasive tasks like setting the valve clearances and replacing the fuel filters. Also keep in mind that I'm focusing on simple "performance" based stuff, and there is a lot of "safety" related stuff suggested earlier by SteveJ and LeonV like brakes and suspension inspections.

    Keep us posted!

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    Quote Originally Posted by Captain Obvious View Post
    I don't know how old you are, but I'm guessing that every car you have ever seen or been in to this point had computer controlled fuel injection systems and no choke.
    That assumption is spot on. This car is more than double my age and Ive never seen a choke on anything besides gardening equipment, even those are disappearing now. It seems like most of my worries were just part of the operating instructions that arent in the manual. My Moms mechanic is biiiig on Volvos, and now that I think about it I actually remember seeing a couple of Zs and ZXs at his garage over the years. Hopefully he will know a thing or two about the SUs if I cant figure them out

    That list will be added pretty close to the top of the growing list of my Zs to do list. My wallet and schedule will be taking a beating, and I havent even touched the body or the electrical yet! Its a good thing I wasnt looking for a car that would be perfectly reliable and never give me a reason to get my hands dirty. Thanks to everyone for helping me diagnose and plan a course of action and take the first steps on my Z journey!

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    Well let me tell how it used to be in the old days...

    There was no electronic fuel injection or computers of any kind in cars. Cars had carburetors and chokes. When you first started your cold carbureted car, it ran "OK" if you were lucky, and "poorly" if you weren't. If you were lucky, you could let it sit at high idle for a minute or so to warm up before you went off down the road, and if you weren't lucky, you had to sit there for a minute and nurse it to keep it running. Then once it was running well enough that you felt confident that you could pull out into traffic without stalling in front of someone, you could get moving on your way. As you put a few miles behind you and the engine continued to warm up, it gradually got better and better until it ran "good".

    This is the exact same routine I went through in the winters of 77 to 79 in order to get to college class on time, 73 with flat tops.

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    Quote Originally Posted by porkbun View Post
    My Moms mechanic is biiiig on Volvos, and now that I think about it I actually remember seeing a couple of Zs and ZXs at his garage over the years. Hopefully he will know a thing or two about the SUs if I cant figure them out!
    I believe they used SU's on some of the Volvos, so if he's got old Volvo experience, he should know his way around the Z carbs. Only question though would be is he capable of making the leap from the round tops to the flat tops like what you have... They are the same carb in theory of operation, but there are a few differences.

    That list I put together was assembled with an attempt at "all things considered". By that, I mean, I tried to put together a list of things that wouldn't cost much, wouldn't be very difficult or require special tools or equipment, and wouldn't take too much time at any one sitting so you could still use the car as your DD while working on it.

    My intention was not only to get you some possible improvements in how well the car worked, but also an expectation that you would get some experience and knowledge while doing that work. You could spend hours and hours and hours on making things perfect, but I know it's probably not the right time for that. Once you know your way around the car and have a handle on the FSM, you get to spend countless hours working on everything else! If it's running well once warm, isn't billowing black clouds, and has decent power, then you're doing as well as a lot of Z owners.

    Quote Originally Posted by Bonzi Lon View Post
    Well let me tell how it used to be in the old days...

    This is the exact same routine I went through in the winters of 77 to 79 in order to get to college class on time, 73 with flat tops.
    Haha! It's amazing to think how "spoiled" we are with todays cars... You get in, turn the key, and hit the road. I typically start the car cold in the morning, and have wheels turning no more than ten seconds after the starter has stopped spinning. No muss, no fuss... It just starts and goes.

    We take it for granted now, but when you think about it, it's really amazing!

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    Put 1k on the car and it had been running just as it had when I got it...until my friend brought me to a large open parking lot to do donuts. I couldnt pass up the opportunity to do a few donuts, but Im kinda regretting it now. It was really just turning hard in first in a sandy empty parking lot, but my car did not like that at all. My car suddenly started experiencing jerky hard acceleration (like I was pumping the gas pedal) and would randomly threaten to die at stoplights (putting down and running rough until I gave it some gas). Accelerating from first always feels like im just using the clutch completely wrong and I feel a ton of rubbing as the car starts move (from idle or above the usual 1.2ishk, the RPMs will drop to maybe 700 and then go up as the car starts to move). I also feel more of this rubbing when I try and accelerate and turn from a stop, but that might be because its harder to move with the wheels turned.

    I decided to check out the air filter and though it wasnt that dirty, I did find a TON of tree nuts inside the housing. I cleaned those out and noticed a ton of play in my throttle arm linkage (id say a little less than half an inch).
    Does the little boot of the arm coming from the pedal act as a spring? The one on my car is brittle and opened up. Does the play even really matter? I feel as if the throttle response is perfectly fine, but dont know if its contributing to the jerky acceleration.

    From what ive read about vacuum hoses, it seems like theres a leak somewhere (my rpms will also drop if Im on the brakes hard for very long (like an exit ramp). I hope its just that and not my steering and/or clutch. Any recommendations as to replacing the hoses or learning more about them? Ill be a LOT less busy in a month and have plenty of time to pay attention to the car, but right now im so busy.

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    I just noticed while under the hood that my valve cover breather hose(?) is saturated with oil and the valve cover has marks that show that some oil spilled/spurted out of the hose a while back. It also has some tape on it which seems to show that it isnt the first time this has happened. My mechanic should be back from vacation, so ill call him and see how much he knows about these cars

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    I wouldn't worry much about some oil in the valve cover hose. It's part of the PCV system and it's gonna happen. However, with that in mind, you should add checking/replacing your PCV valve to the maintenance suggestions provided earlier.

    Speaking of which... How much have you done with the car? Looked into any of the stuff mentioned earlier?

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    Quote Originally Posted by Captain Obvious View Post
    I wouldn't worry much about some oil in the valve cover hose. It's part of the PCV system and it's gonna happen. However, with that in mind, you should add checking/replacing your PCV valve to the maintenance suggestions provided earlier.

    Speaking of which... How much have you done with the car? Looked into any of the stuff mentioned earlier?
    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?

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    The small hoses are 1/4 and 5/16. Between those two sizes you'll have all of the small stuff covered. The bigger stuff (the braided stuff) is more difficult. The hose on the top going to the valve cover is straight enough that you can easily find a replacement at the parts store. The problem is the braided stuff from the air cleaner to the carbs and between the two carbs. Of those, the one between the two carbs is the highest priority since it's at the highest vacuum and will such the most air if it has a leak.

    I'm thinking that you should visit that guy who knows the SU's.

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    Been gone a while and just saw this tread...What a "barn" find! Like the car has been frozen in time. Definitely a lot of maintenance things to do as outlined by the forum. You'll never make it a driver till you do things methodicaly. What intrigued me was it is real close to my original 260 in all aspects except color. You manufacture date is 11/74, mine was 12/74. Your VIN 66522; mine 69276. O fcourse I've owned mine since new so know everything about her, but you've got a real classic there and hopefully some good bones to keep her on all fours.
    Late 260Z; 2005 Daytona Blue paint; Triple Webers 40DCOE; competition springs w/Tokico HP shocks; Koenig 17x7 Crosshairs w/ Yokohama AVS 215/45 WR 17; Original owner; Show car w/ many awards

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    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

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    The 260 system is complicated. There are lots of tubes and wires and hoses and valves. It was the culmination of Datsun's efforts to provide good cold driveability, good fuel economy, and good performance all while meeting ever tightening emissions standards. That complexity works great when everything is perfect, but once it starts to fall off that razor's edge of performance, finding the problem(s) can be difficult. And that's where you are.

    You've got a forty year old car with unknown history. It's got dry rotted brittle tubing, solenoids that are probably frozen in place, sensors that might not work, valves that should be shut that are leaking, valves that should be open that are clogged, vacuum leaks, a dirty fuel tank, carbs that probably need a rebuild or more, and a questionable ignition system.

    Simply... The 260Z is not a car for the feint of heart. If you want it, you gotta want it bad. You have to be willing and capable enough to dive in yourself and learn how it works. Download a copy of the factory service manual and study it. Learn the terminology and where the components are. You've got to be able to point to something and call it by the same name that the manual calls it and have at least a basic understanding of what it's supposed to do. Without that level of knowledge and standardization of language, remote troubleshooting doesn't work.

    I know the 260 system pretty well, but I'm not close to you. If you bring the car to me and leave it with me for a month along with a stack of $100's, I'll fix it. If that doesn't work for you, then you need to find someone else closer to you, or learn to do it yourself. I'll do what I can from a distance, but diagnosing problems based on vague description is very difficult, especially when you've got so many places that could be causing problems.

    I'm not trying to scare you off. In fact, it's the opposite. I'm encouraging you to embrace ownership. Unless you're willing to pay for someone else to do it for you, you're going to have to learn a lot about the system yourself.

    My bottom line suggestion would be to buy something else to use as your daily and work on the Z in your heated garage in the meantime. If you drive the Z through the winter in CT, there isn't going to be much left.

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    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.

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    I don't know if you would be able to actually smell a difference if your air pump is working or not. I do know that there are plenty of other reasons for a 260 to have a horrible exhaust smell. But as a data point... From my experience, a well tuned and proper operating 260 doesn't have a horrible exhaust smell, even without an air pump installed.

    As for the EGR tube, I'm not sure what you're talking about. The only tubes involved in the EGR that are soft enough to pinch are on the control side and pinching any of them could only result in the EGR becoming disabled (which usually improves performance, not degrades it).

    Quote Originally Posted by porkbun View Post
    if I left it in the garage, it would be filled with spiders and chipmunks come spring time.
    Spiders and chipmunks are better than floors and rocker panels with rust holes in them.

    To be honest? Dude, it's October. And you're in Connecticut. And this is your only car? You gotta do something quick.

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    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.

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    Captain O. mentioned checking (cleaning) the filter on the rear fuel pump. Did you do that? It's by the frame at the right rear wheel well. Use a channel lock to take off the filter. Doing donuts could stir up nearly 40 years of gunk & debris in the gas tank, clogging up the works. You can put a clear filter before the pump to diagnose a dirty tank - replace it with a metal filter later for safety.
    If a few donuts blew out the clutch it was time for a new one anyway.

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    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?

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    Just a steel fuel filter, about the size of a frozen orange juice can, with a 5/16 I think hose barb each end. About $6 or so. Probably made for a big V-8 but who cares, just so it's free-flowing enough. One of those big filters like a mallory competition would be cool but they're like $45 or so. If there's a stock electric pump back there it's got a removable filter too, in the body of the pump, the filters are available from msa, got one a few months ago.

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    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/par...8_173884_4967_ ) f

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    I don't have any input into which fuel pump is the best, but you might be able to tell if your having a fuel delivery problem by checking your float bowl levels.

    Is the problem at idle, or somewhere else?

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    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.

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    Heh. Sounds like a typical "old car sat for a long period of time and now it just doesn't run right sometimes". Still could be just about anything.

    Taking it to the shop that has some familiarity with vintage stuff sounds like a plan. Let us know what they find?

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    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.
    Last edited by porkbun; 10-22-2012 at 03:19 PM.

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    Yup. From what little I've heard from others, that's the typical failure MO with the flat tops. They fail rich more often than failing lean. There are lots of things that can cause them to run rich, but not all of them will be addressed by rebuilding the carbs. Depends on what's wrong. If the problem is with your float levels or your power valve, then you stand a chance that it will be better when they're done. If the problem is with the needle or the nozzle, then you're scrod.

    You can (and should have already) checked the bowl levels yourself. I assume they're OK. My theory would be that you lodged a goober in one of your power valves when you were doing full throttle donuts. Now the goober is making it stick partially open all the time and dumping fuel into the engine.

    You might see if the garage would rebuild the power valves first before they took the carbs completely off the car. You can get the power valves off the sides of the carbs while the carbs are still on the manifolds. You have to get a bunch of plumbing out of the way to get access, but it's the same plumbing that would have to come off anyway if they were to pull the carbs completely.

    They could also use a flat plate of metal to completely eliminate the power valves if they wanted to try that. You would lose some full pedal performance, but it might narrow down the problem area.

    I'm sure the garage wouldn't be interested in either suggestion, but it's just a thought.

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    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?

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    Been a while since I looked at one of these so please forgive... I'm going from memory here.

    There is a tiny slotted head screw with a nut on it. I believe the screw passes through the diaphragm. Under the head of that slotted screw is a small (maybe 1/2 inch diameter?) rubber washer. That washer is the seal that prevents fuel from flowing through the power valve when it's not supposed to. In other words, when the valve is closed, that rubber washer provides the closing seal. I've found that those washers either turn to dust or turn to goo. Probably because of the ethanol added to today's fuel.

    Basic function of the power valve:

    Vacuum behind the large diaphragm provides the closing force.
    The spring behind the diaphragm provides the opening force.
    The washer under the little slotted screw head does the sealing.

    In order to test the system without the power valve, you can cut a new round gasket without any of the "functional" holes in it and install it between the power valve and the carb body. Cut yourself a round disk out of gasket material and only put in three holes for the three mounting screws. Let the gasket disk block off the small fuel and vacuum holes. (Does that make sense?)

    For a more permanent modification, you can make a flat block-off plate. Here's what I did:


    You might not want to leave it on forever, but it helps narrow down rich running issues. If you completely block off the power valve, then there the only way fuel can get to the engine is through the main jet (or the choke nozzle, but I'm assuming that's not your problem).

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    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.

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    I'm not sure what hose you're talking about. If you're talking about the inch or so diameter hose in my picture here:


    then I don't have a good explanation for that... There should be nothing in that hose except air. If you've got coolant streaming out of that hose, then you got real issues.

    There are other hoses in that area that are supposed to have coolant in them, but I removed them from the car with that block off plate. The stock setup has coolant running into the carbs to heat them up, and I disabled that feature as well. Are you sure you're looking at the same hose shown in that pic?

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    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?

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    That hose in your pic makes a whole lot more sense. That hose is the coolant input to the front carb. From there, the coolant passes through the front carb - comes out of the front and goes into the rear - passes through the rear carb - comes out of the rear carb and connects back to the hard lines at the brake booster corner of the engine.

    If you decide to go the 240 carb route, search around this site and the other Z sites. There is lots of good conversion info available. Will probably answer most of your questions. Not all, but most?

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