Stanley

Maybe the problem with using the British SU needles is that they're bigger (leaner) at stations 1 & 2 (0.099" vs. 0.095). My car, stock 240 displacement with some mods, was going lean at top end WOT with N-27's, stock and modified, so I put SM's. That fixed the top end miss, but to get it to run at low rpm under load I had to lower the mix nuts about a half turn from where they were with the N-27's. This causes it to run too rich at lower mid-range swhich is usual for around town. Every few weeks I need to un-foul the plugs. It might be OK just polishing down stations 1 & 2 on the SM's. That should allow the mix nuts to be raised to get better A/F ratio at low end and better gas mileage around town. It would lean out the top end though, so the WOT miss might come back. Another idea would be to push the SM's a little further up in the piston, so station 2 becomes station 1. Haven't heard of anyone doing this, though. Maybe unmodified SM's would work correctly on built 280's with SUs. It would seem to make sense since they'd need more gas at low end too. Anyway, there are a bunch of British needles available and they can all be modified, so there should be something that will be perfect for any size and tuning stage of engine and for every driving style. Stock N-27's should be right for a stock (including stock air cleaner and exhaust system) 240z. I had planned to do a 3-D graph of all the applicable British needles in some unknown way that would be useful to myself and others, but it's a huge amount of work and I'm busy, so it might not ever get done. Maybe someday...

If I can find my old Clifford catalog I'll check. Seems like it couldn't hurt to put a gasket. The auto parts store or a muffler shop could probably find something that would work. Make a paper pattern before you go. Congrats on first post. Not a hijack if it's pertains directly to the thread. Better to have a photo of the headers and car though.

Won't help though if it happens sitting in traffic.

Summer's coming. Is it overheating ? If so, please don't install an oil cooler. Then we wouldn't be able to keep reading about the overheating problems.

After finding little bits of black debris in the float bowls I changed all the hoses to USCG rated marine hose. Costs 8 times as much but you only need a few feet. It has an ethanol resistant liner. Also fire resistant. Didn't check pressure rating since it's not an issue with carbs. It's thicker and stiffer than ordinary non-F.I. hose, so F.I. style clamps required.

I have very slow internet, so don't usually see ads. 2 melons for 5 sounds ok though. Crap, just signed up for faster isp. Guess I'll get them now.

Various springs, that go in the domes to restrict rise of the pistons, are available for the British SU's. Some will work with Hitachi's. The red springs are intermediate, considerably stiffer than the previous ones in my carbs, which were probably the stock ones. They have blue, red, yellow, and green, in order of stiffness. According to the "Just SU's" book, the needles and springs can be selected by measurement and testing to provide the best performance. Stiffer springs are said to reduce gas mileage, except that very stiff springs increase gas mileage and reduce performance. I sort of understand it, but not well enough to give a clear, in-depth analysis of what springs are best (and why) for a particular application. My car goes better when I stomp on the gas with the red springs. APT has needles and springs.

That hesitation after the new engine installation might have been due to the carbs not keeping up with fuel requirements due to bigger engine. According to official SU publications from years past, even putting aftermarket exhaust and air cleaners can require carb needle changes. When I made those changes plus a non-stock head, couldn't tune out WOT miss at 4000-4500 rpm until I installed SM needles. The SM's plus red springs from APT immediately cured the top end lean-out, and gave me a low rpm rich condition that fouls my plugs instead, and hurts my gas mileage. Pretty sure I need to mod the SM's to get things right. Other option is mod the N-27's. Looked up your new pump:http://www.jegs.com/InstallationInstructions/500/510/510-12-802-1.pdf Your fuel pump is 14 psi, regulator is 4.5 to 9 psi. Don't remember FSM recommended pressure but 3.3 to 4.2 psi is close. I read that regulators with a return line are better and more accurate. Possibly the regulator is bad.

What happens when it's idling and you turn the idle adjustment screw on the rear carb ? Also, while idling, if look into the throats of both carbs can you see atomized spray of gas coming out of the nozzle in front carb but not rear carb ? The glass filter I had for a while, Specter from pep boys, was on the suction side near the mechanical F.P. I kept seeing air bubbles in it. As experiment, put a piece of clear yellow Tygon tubing (not recommending Tygon, it gets soft when it heats up) in place of the glass filter, and no more bubbles. Guess the filter was sucking in air. Those filters have 8 places that can leak. Maybe some brands are better. IIRC the package said don't use for fuel injection. Handy to see if the gas is clean though. Illegal for NHRA - no glass allowed in engine bay.

Mine is from MSA, looks like the one posted by 7tooZ, except it's eaten sh#@ a few times on curbs, has a few cracks and a bandaid decal. Glad it's carbon fiber and not fiberglass, or it would have had to go in the dumpster. Looked beautiful when new.

After reading this link below I think I'm going to put this off. Planning an engine rebuild and valve job as soon as I find the right shop to do it, so they can do it then. Not supposed to be doing anything other than minor maintenance here and don't have another place to work on it. Looks like and all-day job, at least the first time. Did a hot adjustment on my old dodge van with the engine running, also on my chevy, but that's a different can of worms. Should learn to do it though, since it's basic. I watched the mechanic adjust the valves after they installed the Y-70 (from a respectful distance), took about ten minutes. But I go slow and careful when I don't know what I'm doing. Looked up 280z spec, same as 240z. Looked up 1982 280ZX, it said 0.007 and 0.009 cold, 0.010 and 0.012 hot, FWIW. If anybody ever reads this and can post a link for specs or a manual for L20aET or Y-70, I'd appreciate it. Maybe I need to relieve the valves a little or something to reduce compression, to run more timing with Calif. pump gas.

When my corroded, stock '73 240z cylinder head needed to be replaced, the mechanics installed a new-looking Y-70 head assembly. I think someone else had ordered it for an engine mod and changed their mind. From what I've read it's from a 1980 - early 81 Skyline with L20AET engine, and various other Nissan models. I like it, especially with the AT, not much top end but great mid-range torque. I read Ozconnection's threads about it here and on HybridZ, searched and searched but never found a manual or other specs (that I can trust). So how do I adjust the valves ? No experience so rather not just wing it. Hear some ticking when it's cold but maybe that's normal.

I agree with C.O. in post 19. Also, due to engine tilt, the fuel level in the front bowl needs to be a couple mm lower than in the rear bowl. For me, the thing that makes setting the floats a hassle, even with a sight glass, is bending that tang on the float to adjust the level. Fuel level is too low so you bend it down, then it overflows so you bend it up, repeat and repeat to get it more or less right. Took me about 10 tries last time. Adjust, remove/replace the lid and run the engine each time Seems like it would be fairly easy (OK, maybe difficult) to put a small captive screw between the tang and plastic float. The tang would be initially bent in a low position, turning the screw would raise it. You could figure how many turns would raise it one mm. Need to look at on old float to see if it would work.

Right, Arizona.... The M-C ones are glass, otherwise I would have got them. Probably not for automotive. Kind of big, too, probably wouldn't go behind the K&N's. If these would go behind the K&N's maybe I would just leave them there, with a cap or plug or something.

You still have the stock exhaust pipe ? Didn't think anybody did that. I was told to use a 2 1/4" pipe. I have no idea which is best, but I went to a local independent muffler shop and they hooked one up, with a "turbo" muffler. Sounds good and took a full second off my zero to sixty, according to many runs checked with a stopwatch.

Never saw that before, wonder if it's from England. Nice packaging, etc. I would rather have the glass extend up a little higher, so it a bowl overflowed (it can happen while adjusting floats) the gas would run out the vent on the lid (through a hose routed to a catch can or container) instead of out the glass. Also, looks like it would obstruct an air cleaner, stock or otherwise. A sight glass has other uses besides setting the floats. It can be useful sometimes to verify that there's the right amount gas in the bowls (that the valves are working properly), while doing a test drive. There's also a nifty sightglass from M-C for about the same price that has the right thread I think; it would probably obstruct an air cleaner, though. I bought a low-tech version from ZTherapy for about half that price. Had to modify one of them so it wouldn't leak (maybe i got a bad one), but it can set so the plastic tube outlet is higher than the lid vent. Also, it can be used with an air cleaner, K&N's anyway. Pretty cool, though.

One way to get a faster response from stop is to let the engine rev to yellow line BEFORE transmitting it's power to the rest of the drive train.

Bought a condenser for it, can't find it, will get another one. Found a bunch of corrosion in the socket in the coil for the wire to the cap and cleaned in, might be corrosion in the cap too. Will check or replace the cap tomorrow if it's not raining.

Checked the dwell with the digital timing light a couple weeks ago, dwell was 35 deg which is about where I set it two years ago when I put new point, cap, rotor, and condenser. Will check it again though to make sure I had the light set for six cylinders. Didn't have the instructions in front of me and it's more complicated than the old light. Does more stuff, though. Need a microscope to read the instructions. Looked at the points cap and rotor with magnifying glass, points looked perfect which surprised me. Saw corrosion on cap and rotor. Cleaned them with Deoxit and bought new ones, installed the rotor, haven't put the new cap yet. Car ran crappy yesterday, might run great today.

Have points. Now I see why no full voltage with engine off. This stuff should be in the book. Don't think it's fuel related, fuel pressure is good and carbs are maintained, running rich at low end (SM's) but don't think that causes the intermittent problem. When I first started the car, the coil to ground voltage kept dropping off to 3 or 4 volts every 5 seconds or so, but after a running few minutes it was steady. No clue on that one.Gotta work today but will try to repeat that tomorrow. Found a 0.5 volt drop across the positive battery cable connector to post, doubt if it matters for this but I'll clean it before it gets worse.

Sometimes it starts right up, sometimes have to crank it 10 seconds or more before it starts. Hot or cold doesn't make a difference. Today for example, ran some errands, 3 easy starts including the first one, and one where I had to crank it a while. Only other problem is intermittent right turn signal. Shouldn't it have about 8 volts coil + to ground with engine off and key "on" ? Battery is strong I think, at least it doesn't slow down any when I have to sit there cranking it.

Yep, got 9.2 volts from coil positive to ground at the body with the engine running. About right I guess. Still got the 4.5 volt from coil + to ground with the key to "on" and engine not running, though. That might mean something, but don't know what. Also, the 9.2 volts dropped down to 3 or 4 volts briefly a few times. My recent book learning needs some more experience to back it up. At least I understand it a little better after reading post #2.

Will try that tomorrow.

Basic question I know but basic's where I'm at. It should be about 8 volts across the coil right ? I'm getting about 4 volts across the ballast resistor which seems about right, but only 4 to 4.5 volts max across the coil. If it's supposed to be 8 there must be a resistance somewhere that's hogging about 4 volts. Not the only electrical problem of course. One time, got zero volts across coil. Cranked the starter accidentally and turned the key back to "on" engine still off, then I got the 4 volts again.And with the engine running, still got the 4 volts or slightly less, but every 5 seconds or so it dropped to about 1 volt. Maybe there's a vibration-related intermittent resistance too. Wish the engine harness drawings in the FSM were drawn better, and showed clearly what wire went to what component.

Thanks, looks like vintage connections has the right multi-connectors and terminals. I'll print out the catalog page so I can have it in front of me while I'm checking out the engine bay and other areas. Might get a kit or just individual parts. Called Fry's; they've got that crimper; need a better one than what I've got now that likes to bite terminals in half. Might use shrink-wrap instead of OEM sleeving though, or maybe liquid "tape". I see they've two sizes of extractor tool, probably cheaper than buying a set, unless Sears has a screwdriver set I need that has it. Read somewhere Sears is selling Craftsman. I like the lifetime guarantee; they gave me a free 12 mm combo wrench last year when I messed one up, no waiting.