Murph

Just tried starting it cold with no choke....fired straight up.

On this topic, are there any ways to make your zed more secure, that are specific to old school zeds?

Cool cool. I'm going to start building a mild L28 soon still using the SU's. The SM needles are definantly on the list of things to get.

These carbs were complelty disassembled, cleaned and kitted a few months ago, so needle/nozzle wear shouldn't be an issue. Got another question. What's the effect of taking these carbs that were meant for a 2.4L motor, and then chucking them on a 2.6L? Is it simply a case of the engine using more air, therefore the carbs will provide more fuel and always keep the correct A/F ratio? What if you put these carbs on a motor that was considerably larger or smaller?

Hehe....it's summer all year round up here. I recon I'll lean them out a little again, to where it originally had them, and try giving it some choke if it's hesitating too much. I always use the choke to start it when it's cold pretty much out of habit, because it always needed it. No idea if it does now. Next time it's cold and I remember I'll see how it goes with no choke. With choke it always fires imediatly.

Just found out it aint run quite so well when fully cold. It was hesitating quite badly for the first few minutes....maybe even 5 minutes or so. Drove it for about 20min or so like that and even then it still felt a bit weak. Ritchened them up 1/8 turn, ran better but seemed a bit on the ritch side again. Lean them off just a tiny bit again, seemed ok. I'll have to see how they go in the morning when it cold again. So why is it that it will hesitate when it's cold? Is it running leaner when cold?

Still a bit lumpy, but it always has been. Mind you it is a lot better than it was, eg it will comfortably idle at 700 rpm now whereas before it seemed quite unstable.

Well I've just given it the full tune up by ear, and I'm quite happy with the results! I actually had a go at making my own flow meter, just a simple U tube manometer type design, but unfortunatly didn't get the sort of resolution needed. Maybe another time I'll sit down and design it properly. Anyhow, I balanced it by ear which wasn't too difficult at all but I can see that it's never going to be quite as accurate as doing it with a flow meter. Adjusted the mixtures, rebalanced and reset the idle, checked mixtures again. At this stage I kept it quite conservative (ritch) and while it ran strongly on the road it did blow a good bit of black smoke. Leaned them up a quater turn, still on the ritch side of things, but you could feel on the road that it had lost some power. Came back and ritchened then a 1/8 turn and like this feels great and doesn't blow any smoke. Took it for a 15min fang in some nice open areas near my place and it performed quite strongly. When I got home I checked all the plugs and they look great too, nice browny sort of colour as a pose to the jet black they have always been. So does this sound about right to everyone? Anything I've done wrong or should do differently? Thanks to everyone for your help! I'd be buggered without you all! Justin

I'd say my best bet with balancing them, will be to playwith the idle screw adjustment on one of them so I can learn how the sound changes/what difference I am listening for. I'll post up tomorrow with how it goes.

Excellent! Well that clears that problem up then. Tomorrow I'll pull the carbs open and visually inspect the needle height, then take it from there. Thanks for all the advice everyone! Justin

Oh righty. Just went a turned out the mixture nuts out 2 turns while cold, then fired it up. Pushing up on the piston lifting pin, the rear carb was at stoich, and the front one was a bit ritch. I turned each out another quater turn which had them both running ritch. Took it for a drive and it felt quite good. Pulls quite strongly though the rev range although maybe a little doughy at low revs in higher gears. I left the rear mixture as is, and leaned the front one of a quater turn at which point it's still running ritch. The car seems to drive quite fine like this. Would I guess correctly that the balance (idle screws) is out if they're getting different mixtures with the same number of turns on the mixture nut? Btw the other balance screw (so they open at the same time) is set correctly, and I adjusted the vavles last weekend. havent' looked at the timing yet.

Thanks Matt. That's a great help. I'll have to give that a whirl when I get my hands on a flow meter. Alternatively I'm thinking of just making somekind of flow meter myself. I just had a look and as is the mixture nut is a bit over 2 turns out. Another question. Say, if I go an adjust my mixtures now, with out changing the balance, am I likely to have any problems, or stuff something up? I would have imagined it would most likely be ok as long as I keep the mixture fairly conservative?

Ultimately I'll buy the vid etc and a unisyn etc, but I simply can't afford it atm. I can't afford to get it tuned by someone either. I've been asking around to see if someone has a unisyn around here that I can borrow.....but nothing yet. One main question. Can people confirm for me from their personal experience, how far ritcher than stoichometric they run their carbs? Is it one "flat" as all the tuning guides say? Oooo....another question. If I were to have it tuned a little too lean, is it just going to mean a loss of performance, or will it start pinging and kill itself? When my mechanic last tuned it, he said it needed to be tuned fairly ritch in the bottom end to keep the right amount of fuel to it in the top end. Is this normal? This's my main concern really. If I'm tuning for mixture at idle, how do I know it's getting the fuel it needs in the top end? Thanks, Justin

When my 260Z (with 240Z SU's) was last tuned it had a vacuum leak on the balance tube, so I'd say it was tuned around that problem. When I fixed that leak, it was running ritch as hell. Now, I've never tuned the SU's before but have read plenty about how to do it. Anyhow, as a quick fix I leaned both carbs off by half a turn which helped quite a bit. Still runs quite nicely other than hesitating a bit when cold (any ideas why?). Anyhow, I had another play with it today and found the the rear carbs mixture adjustment is two and a half turns on the ritch side of stoichometric. (I assume it will be the stoichometric mixture, where you will get the highest idle speed and lifting the piston wont alter engine speed?) So...you'd gather from this that it's still running really really ritch? All the guides say to back the mixture off 1 flat (1/6th of a turn) fom the max idle position. I was going to have a go at doing the full tune up procedure the other day, however I don't have a unisyn. Instead I decided to try the hose in ear trick, however for the life of me I couldn't hear any difference between the two. Of course that could just mean they were properly balanced? What is the differnce in the sound that I should be listening for? Is is the pitch, volume or something else? I suppose I'm mainly just in need of some general advice on tuning these things. Thanks, Justin

He may, but I don't have any. But seriously, it look pretty much identical to mine (but perfect), so you could show your mate a pic of mine to give him an idea.

Virginblue do pretty cheap airfares here. 16 hour drive home. Bring a mate and do it in one hit.

Not really.... but will keep an eye out. Actually there is another 260Z 2 seater around here, looks almost identical to mine but far better in everyway. L28, big cam, brand new tripple webbers, retrimmed interior, racing buckets, harnesses. It's mainly used at a track car. It's run a 14.4 on our very slippery drag strip too. Anyhow when I last spoke to him he said he was thinking of selling as he'd rather something with 4 seats he can fit the wife and kids in. Not sure what sort of money he'd be after, but it'd be (at least) that sort of ball park considering its totally imaculate condition. I can ask if your mate is interested.

Didn't realise it was you kalium. How much is he willing to spend?

Afraid not. My mate seems to only be able to get at a computer over there every few months or so. Still waiting for replies. He's coming home in a month or two, so I'd expect we'll hear from him soon.

From what I've heard, the VQ30's aren't capable of as much power as the VG30's due to flex in the alloy block. Of course we are talking big figures here, higher than you or I are likely to ever be shooting for. If I remember correctly the VQ35 block was made quite a bit stiffer. I'm sure that could make some bulk HP with the stiffer block and the extra displacement.

Been a while since I've looked at the figures, but I'm pretty sure the VQ is more compact than the VG's (98SEblackmax?) and of course having an alloy block, is a good bit lighter. A mate has perfectly good VG30DETT sitting at his house atm from his Z32 parts car. Ohhh if only I had the money!

G'day joe! Hmm been a while since I've thought about the VQ idea, still love to do it though. I have heard though that the piping for the turbo on the VQ30DET would clear the strut tower on the zeds. This requires either the manifolds or piping to be modified...... or to modify the strut tower. Maybe one day when I have some $$$ to build up a nice zed I'll go the VQ.

The head is an E88 with a lot of km's on it.....not exactly sure but were talking ~500000km. From another forum we pretty much worked out the tight clearance on the inlet valves was due to valve recession into the soft bronze seats, whereas the exahust vavle seats are steel, so don't suffer the recession problem. The large clearances on the exahust valves were just due to general valve train wear. As is that valve I can't get within spec has a clearance of between 0.1mm and 0.15mm. I'll only be running this motor for another few months and it isn't causing any problems, so I figure I'll leave it well alone. Compression test before doing the vavles came up with 150 130 110 135 120 120. I'd say it's no coincidence that no.3 inlet vavle clearance (or lack of) was the tightest, and no.3 has the least compression. I'm planning on doing another compression test some time soon.....should be interesting to see how it changes.

Just out of interest I'll try starting it without the choke tomorrow morning.

I do still use the choke to start it cold. The thing was, before, even with the choke, it wouldn't fire up straight away. Did the original single carb on the K have an automatic choke?