Bcalvosa

NJ Area Z Enthusiasts: We will have our next Z meeting at the Green Knoll Grille on Sunday, July 10th at 12 noon (645 Rt 202/206, Bridgewater, NJ 08807). The meeting is open to members and "not yet" members alike, and is also a great time to join. So far, the agenda is: Talk Z's in the lot among friends. Grab lunch at the Green Knoll Grille Review the calendar for the rest of the year, and set future meeting dates (with the goal of not conflicting with holidays and other car shows). Brainstorm other activities -- this could be a great opportunity for our South and North Jersey members to suggest North and South based activities (like Diego's Harriman Park Photo Shoot (see images linked near the bottom of the post http://njzclub.proforums.org/viewtopic.php?t=140)). Come out in force, and let's set something up! Getting the word out -- Ideas to let other Z enthusiasts know they are welcome to join us (flyers we can slip under windshield wiper blades, leave on our own cars at shows, etc.) New Members - As you know, you are entitled to a NJ Z Car Club tee shirt. Peter will have them at the meeting. Talk Z's in the lot as we depart... Reminder of upcoming events: 1) The Annual NJ Z Club Picnic is tentatively set for July 30th or 31st. Final details will be set at our meeting, and we will post on our website & forums afterward. Save the date! 3) Cruzz Nite in Somerville NJ - is set for Friday, August 12, ~4:00 PM - 9:00 PM. Come out to play after work and have a blast! This is always a fun night, with many awesome cars in downtown Somerville on Main Street, great places to eat, music, etc. We will be the featured Car Club, with reserved parking right in front of the old court house (5 East Main Street, Somerville, NJ 08876). See details at http://www.findsomerville.com/pub/gen/event/896/fulltext and http://hillsboroughnjjournal.blogspot.com/2011/05/somerville-cruise-and-concerts-2011.html 4) Our 13th Annual Z Car Show will be held on Saturday September 17th, at the Hilton Gardens Inn, Bridgewater NJ (500 Promenade Boulevard, Bridgewater, New Jersey, 08807 (732) 271-9030). The rain date is Sunday September 18th. As always, participation is key to a successful show. Last year we all showcased a record number of our Z cars, and are looking forward to fantastic show again this year (complete with trophies, raffles, and lots of friendZ). For more information on upcoming NJ Z Car Club events, check our web page http://www.njzclub.com/ complete with links to our Event Calendar, our forums (featuring NJ Z Car Club events section and other Meets/Events/Cruises in the area), our facebook page, and more!

Attached is a write up with some pics of how to do the smoke testing, and a method of using a hose to pinpoint the exact source of the leak. It also shows and notes areas where I found leaks... http://www.classiczcars.com/forums/showthread.php?t=34205 Good Luck, Bob

The Z wiper motors have less torque when on high speed. If the windshield is wet, you will probably see them move a little faster on high speed, but it isn't much different. When the windshield is dry, they will typically move slower on high speed.

Some SU tips: As mentioned prior, first tune up the car (adjust valves, synchronize the air flow through the carburetors, check for vacuum leaks, etc.). With the air cleaner off, and engine idling, you can reach a finger into one carburetor and slowly lift the large vertical suction piston. Lifting it all the way up disables that carb at idle (the vacuum across the fuel nozzle drops to atmospheric pressure so no more fuel will be drawn out). This makes the engine run on just one carburetor (the one you are not lifting the piston on). Sometimes you may need to raise the idle speed a little (on the linkage by the vacuum log) in order for the engine not to stall, but most Z's I've tuned haven't needed to be raised. There is a little spring loaded rod sticking out of the bottom of the carb on the float side that raises the piston around 8mm to achieve the same effect, but I usually raise the piston all the way directly with my finger. Doing this gives you a good sense of how each set of three cylinders is contributing to the engine speed. Lift one piston, let the engine settle to an idle speed (lower than normal, since the engine will be running on three cylinders), let the piston drop, then lift the other and let it settle. This should yield the same (lower than normal) idle speed. If one carb idles higher than the other, (assuming they are synchronized, valve adjustment, ignition and compression are OK) the lower idling carb is not tuned properly. Start by adjusting the large mixture screw on the bottom of the carb to get best idle. If the adjustments between front and rear carb are significantly different (ie. more than a quarter turn), the float levels are probably off, or the nozzle head / choke tube is sticking (ie. push up on the black plastic fuel nozzle sticking out of the bottom of the carb (the tube with the fuel hose from the float chamber going to it) to ensure it is snugged up against the idle mixture adjusting nut. If the nozzle is sticking, pull the choke, and clean brass tube surface (above the black plastic end) with carb cleaner (appling a light lubricant (oil or thin film of grease) may help). Regarding the float level, 23mm front and back is spec for the 70 & 71 240Z's, but later Z's used 25mm front and 21mm rear (the measurement is from the inside top of the float chamber down to the fuel level, including the space taken up by the gasket, so a higher number is a lower fuel level). Later Z's had different length float valves and different length stands on the float tops for the float pivots. If your car is a 72, I don't know of anyone offering the different length float valves anymore, so it is possible they are misadjusted (trying to set them with a gauge to measure the distance from the float to the lid will be inaccurate, if the replacement needles are not the stock lengths. Last time I did one, I added an extra washer under the front float valve to make up some of the difference, and adjusted the floats by removing the float bowls from the carbs, hooking them up to an electric fuel pump pushing the same pressure as stock, hooking a clear hose to the bottom of the of the float bowl, and marking the side of the floats with a mark around 4mm less than the spec level (the spec is from the inside of the top of the lid down to the fuel level (includes the thickness of the gasket and the recess under the lid). I then held the float chambers level (outside the engine compartment and over a drip pan, held the end of the clear tube vertical higher than the top of the float chamber, and had an assistant turn on the electric fuel pump. This let me observe the level where fuel stabilized in the plastic tube relative to the mark on the side of the float chamber. Disassembling the float chamber and bending the tab on the float (as normal) adjusts the fuel level. The reason the float specs changed for 72 is because the engine is tilted on all Z's from the factory, and since the front and rear float bowls are forward and rearward of the carb centers respectively, the only way to get the same fuel level at the nozzle is to have a lower float level (bigger distance from the lid to the fuel) in front and a higher float level in the rear. Since all Z SU carbs have this issue, there is some benefit to fudging even the early carb float levels in this direction. The Hitachi carbs are very reliable when tuned properly, but it is rare to find people familiar with tuning multiple carbs. If you are new at carb rebuilding, I'd seek out a specialist (like Z Therapy, a local Z specialist, an English car specialist, or someone familiar with multi carb motorcycle tuning) to assist. Good Luck.

The knurled section is not a separate part of the brake booster push rod. The acorn bolt threads in the end, and there is no lock nut to secure it. Each of the ones I adjusted did give some resistance to turning however, almost like the threads were intentionally deformed to act like a nylon locking nut's threads.

By referencing the fuel pressure regulator to the intake manifold vacuum, this ensures the fuel pressure is always a constant pressure above the air in the manifold. This simplifies the fuel injection logic since they do not have to adjust the pulse width to account for a smaller pressure difference (and thus slightly less fuel injected) when the engine is under load. Newer fuel injection systems accommodate this in the fuel map.

If you don't already have it, grab a copy of HPBooks "How to Modify Your Nissan/Datsun OHC Engine" -- very helpful book. The below formulas are gleaned from there. A narrow band oxygen sensor in the exhaust can help you tune idle and cruise jetting, a wide band can help with power settings. Dyno time is extremely helpful, albeit expensive. 40mm carbs are small for best high RPM performance on an L28, but are streetable. 44 or 45mm carbs would be better. Main Venturi size should be around 36mm. An initial main jet choice would be .04 times the main venturi size (or 1.45 in this example) An initial main air correction jet should be .2 larger than the main jet (1.65 in this example). Search the forums for jetting recommendations for Mikuni, Weber, Solex, or Dell'Orto (they all work off of the same principles). For reference, my jetting is: 2.4L w/ triple 44mm Mikuni's, header, headwork, etc. 34mm Main Venturi 1.50mm main jet (note that the initial recommendation formula gives 1.36) 1.80mm air correction jet (still tuning this - I may need to go a little larger to maintain high RPM mixture). .65mm pilot jet .45mm pump jet 1.6mm starter jet (rarely use the "choke" system, so not that important) Idle air ports enlarged from 1.2mm to 1.3mm to give better mixture under light cruise acceleration. Some examples of jetting I've noted from other posts: A Nissan Tech with an L28 was using: 37mm Venturi 160 Main 180 Air 55 Pilot Mikuni default jetting for the 44mm carbs (seem set up for an L24): 34 Venturi 150 Main 200 Air 57.5 Pilot 40 Pump Nissan Motorsports 16010-E4620 carbs came set up for an L28; 37 Venturi 175 Main 250 Air 55 Pilot I believe Jon Mortensen noted he was once running an L28 with: 37 Venturi 155 Main 210 Air 67.5 or 65 Pilot 50 or 45 Pump Good luck to you

When air flows into a square edged tube, the edge creates a large disturbance or boundary layer that reduces the effective diameter of the tube by a significant percentage (depends on tube diameter, edge profile, fluid viscosity, and velocity). For a Z carb, assume about 20% at full throttle. A radiused opening (aka venturi, air horn, snub stack) smooths the air entry, reduces the boundary layer, and allows a greater percentage of the actual carb diameter to be used. The difference is significant enough, that one should always provide a smooth radiused entry in the direction of flow (be it intake, exhaust gasses, coolant, etc.). An optional secondary benefit is the ability to use different length venturi tubes to extend the overall manifold length to tune the intake to a lower RPM.

Polk shows 2,056 Datsuns 1973 and older are registered in Canada. If the same 43% were 240Z's, that would be 884 additional 69-73 240Z's.