ritchie

Ok everybody, definite improvement happening. After noting the front 3 plugs were lean, I decided to check the float bowls. Interestingly, the float bowl associated with the lean plugs had a lot less fuel in it than the other float bowl. Anyway, didn't see any foreign matter in there, so screwed back on. Started the car and wallah! Idling sound far better, opened up nicely on acceleration! Can't really explain it, but maybe there was some obstruction of the float that I fixed (somehow) by simply removing and replacing the lids. Weird! It would explain the problem though - float bowl obstruction could keep float low, letting less fuel in. Under acceleration, float bowl empties before it has a chance to refill And hence can't deliver fuel to front three carbs. Only issue now is the carbs are backfiring every minute or so when I really get going (starts around 60km/h). I adjusted the timing (reduced advanced), it now accelerates even better but there is still the carb backfiring/popping. I hear this is because of a lean mixture. I was thinking about trying to adjust the SU's myself, but I figure it's probably worth getting a pro to tune them - will probably save that much on petrol in the long run... Thanks again everyone for your suggestions - definitely a learning experience!! Cheers ritchie

Alright, timing light indicated we were at about 18 degrees BTDC. I experimented with various levels of "retardation". Setting it to around 12-ish made idle smoother & lower revs, but the same stumble happens on acceleration (it's an electric distributor, by the way, so it can't be points related either). Now, we replaced the spark plugs about a week ago as the first step. I decided to look at them, and interestingly, the front most plug is brown, maybe a little on the lean side. The rear most spark plug is charcoal black already. So now I'm thinking maybe the carbies are out of tune. Would that cause the stumbling under load we're talking about? I don't believe the car is "pinging" - there are definitely odd sounds, but it's more of a rattle that increases in frequency as I accelerate. My best guess is that 3 cylinders are firing (the rear three, considering they're rich), and three cylinders aren't. Hence I get a good sound out of three, and low/empty clicking sounds (maybe sparks going off with no fuel?) on the front. But this is just a theory. The other thing is that this problem happened all of a sudden. Everything was fine, could get the car up to 140km/h no problem when we were in Tasmania (doing a fair bit of driving). Then came back, the next day drove 10 kms absolutely fine, got out of car, got back in 15 mins later, then this stumbling thing started. Basically I'm trying to say that it happened all of a sudden, rather than a gradual decline. Hence I'm thinking something somewhere is blocked or busted. Any advice appreciated... at wits end! Cheers, AR

Thanks for everyone's advice/input. Come to think of it, it is idling a bit higher than normal. I will check the distributor rotor, points etc and check the timing tomorrow. The following threads seems to describe a similar problem, and in the end it was always ignition related: http://www.viczcar.com/forum/index.php/topic,2297.0.html http://www.viczcar.com/forum/index.php/topic,2448.0.html http://www.viczcar.com/forum/index.php/topic,1848.0.html I'm struggling to understand exactly *why* this would occur though - surely if it was a spark timing issue, the issue would be apparent at idle too? Or is it to do with the speed of rotation - issue becomes more apparent when revs are higher? Cheers Ritchie

It's an electric fuel pump, and I've already changed the fuel filter. Suction feels relatively the same with my hand, but that's not very scientific.

Thanks for your advice guys. 1. The engine idles at higher revs with the choke on, but regardless of choke on or off, the engine always is bogging down at ~ 2,000 rpm. The engine then has a distinct "click click" sound, my guess is that it's because it's so lean it's only running on 3 cyclinders (one carby working, one not) - although I could be way off. 2. Took off the air filters, no change. 3. I've taken apart the bells / damper domes, and checked the fluid. One did look quite low - any idea exactly how much fluid to put in? (i.e. with the bells on, should the damper screw thing face 'resistance' when plunging?) I've given the bells & piston a good clean, replaced with transmission oil, sounds a little better than it did but no real change. I've also added ~ 10L of premium petrol to the tank - it was running low, so I thought maybe some crud had got in somewhere. I'm going to experiment with more / less transmission oil, but if that doesn't work, I guess I have to move onto the floats chambers... Cheers, Ritchie

Hi all, I've got a Datsun 260z (purchased a few months ago) which seems to be fitted with twin British SU carbies (bell top shape, 4 bolts to manifold, suspected HS6 model). At the moment the car is really struggling when accelerating - like, struggling to the point where 20km/h I now consider fast. It seems to stumble - revs up, then drops all of a sudden, revs up, bogs down, etc etc. It isn't running ideally at idle, but it certainly is a significantly better. In neutral revving up the engine by opening the throttle works fine - revs all the way up to 6,000+ without bogging down. The problem is only really apparent when under load. We first thought it was electrical, so replaced the sparks/leads, checked the points (fine), checked the dizzy (fine) and checked the coil (fine). So now we think that it's fuel/carbie related, especially as the problem is only present under load. Fuel filter looked fine, we replaced it anyway - no change. Before I take apart the carbies, does anyone have any advice on specific things to look for? I'm thinking there might be an issue with one of the floats, or there might be some crud in the float chamber that got past the fuel filter. Alternatively the damper might be getting caught... but this is just speculation. The only other observation I have is that the car isn't blowing smoke, which indicates to me that there's a fuel supply issue, as opposed to a problem relating to air supply. Any advice at all would be so much appreciated! Cheers, Ritchie (ps. It seems odd to me that the problem doesn't appear when revving in neutral, but does appear when in gear - anyone got any ideas on why this might be?)

Hi all, Bit of a problem with my auto 260z. When I push down the accelerator, especially under load (i.e. not in neutral), the revs will move up but then soon after drop down, even with the same pressure on the accelerator pedal. Even pushing the pedal to the ground is often not generating a response from the engine, it just coasts along at 15 km/h, around 2,000 revs. If it gets any speed, it will "bog down" at random times... every 5 or 6 seconds... where the revs just drop of their own accord. I don't think it's a transmission problem as the same thing happens in when I select second gear. In neutral/idle it seems fine - or at least a whole lot better. We first thought it was an ignition problem, so did the basics of replacing the spark plugs and the fuel filter. Problem is still there though. The ignition leads look in good nick, and there's no obvious issues with the distributor. Our next possible culprit is the carbies. Trouble is, neither my mate or I have much experience with them. Anyone had a similar experience before? Or know common issues with the original 260z Hitachi carbies that we should particular look out for when we take em out and inspect tomorrow? Any help would be appreciated... Cheers guys, Ritchie

Sweet! Thanks guys. Seems the high beam only goes on when the standard lights are on, *and* the engine is running... I was trying to switch straight to high beam from the parkers with the engine off. I will post some pics over the weekend. At the moment I just like sitting in it and listening to it purr. And for some reason I really want to take it over the Balti bridge... maybe that big curve on ramp thing, followed by letting it rip up to 100 ks....

Ok, these are probably really basic questions. I'm new here, just picked up my Datsun 260z 2+2 last night. And I love it. But, in order for me to safely drive at night, I should probably work out the following.... How the hell do I put the high beams on? Pressing the little button on the indicator seems to turn them on whilst I hold (and a blue light appear behind the speedo), but as soon as I release they turn off. (The interior light isn't currently working in the car, so finding things at night is a little harder!) If anyone can point me in the direction of how to turn them on permanently, that would be ace. Also, the dashboard/instrument lighting seems quite dim. I've turned the lighting knob to full. Is this pretty standard? Or is there possibly an issue with the variable resistor? And last question... I should probably replace the globe in the interior light - hopefully it's just blown and it isn't a wiring issue. Are they pretty standard globes? Should I just be able to pick one up locally, or will I need to specifically search for a non-standard globe? Thanks all, Ritchie

Hi all, I'm Ritchie, from Melbourne, and I'm picking up my Datsun 260z 2+2 tonight. Very excited... not only is this my first Z, it's my first car full stop. It's already road worthy, so can't wait to take it for a spin. Will post some pictures over the next few days, and no doubt ask you all for your opinions on what I do with it (aside from drive & enjoy it, of course). I'm not all that mechanically minded, but am keen to get my hands dirty on some small restoration pieces, learning as I go. Cheers, Ritchie