zcarnut

Plug them. Do not loop! The heater core is in parallel with the radiator. Replacing the heater core with a loop of hose means that you be bypassing your radiator and returning a good portion of the heated water back to the engine. I can’t think of how many people I have seen make this mistake.

I appreciate you taking the time and effort to post your detailed instructions. However, at the risk of sounding argumentative, I would like to make a few points: Other makes using the R180? Who are they? If you are alluding to Subaru you should realize that they used the smaller R160 diff. Well, here’s what I did to use the R180 CV axles in a 240Z: Unbolt the stub axle companion flange and swap with the CV companion flange. Tighten bolt. What part of that is not easy or cheap? I wonder if you are confusing the R180 CV axle with the R200 CV axles? You may be confident, but you’re incorrect. The torque for the ring gear bolts is different. It’s 50.6 to 57.8 ft-lbs for the early (240Z) R180 diff and it’s 65 to 72 ft-lbs for the later (like the Maxima K type) R180 diff. I would recommend getting one of the 1981-84 Maxima FSM’s as well.

True, alternators will put out the same current regardless of the direction of rotation, but they do make alternators for reverse rotation applications that have the pitch of the cooling blades (either external or internal) reversed. It is more efficient to cool the alternator by flowing air through it from the front to the back of the alternator.

No need to yell at me.... I was only trying to help!

You need to look at the later R180 u-joint axles. The 240Z R180 axles have a flange on both ends and mates with a separate flange piece that fits into the differential (where it is secured with one bolt). The 1974 260Z and later R180 axles do not use this separate flange piece. The diff end of the axle just slides into the diff where it is secured with a single bolt. Here's a pic of the later R180 axle from a 280ZX FSM: http://home.comcast.net/~zcarfan/AxleShaft.jpg I’m pretty sure it will be long enough to cut a grove for the c-clip.

The 1981-84 Maxima only used CV axles which snapped into its R180 diff. All the Z cars that used the R180 diff and the u-joint axles used a single bolt to secure the inboard axle flange into the diff. Although the R180 u-joint axles will fit into your K type R180 diff, there is nothing to secure them unless you machine a grove in the spline section of them for the internal C-clip in the R180 K diff. So, here’s an opportunity to use CV axles instead of the u-joint axles. You can use the CV axles from a 81-84 Maxima along with the splined companion pieces that will connect to your 240Z stub axles. The CV axles are made with the piece that fits into your diff, hence there is no separate flange piece. If you can’t find a Maxima, then look for a 280ZX 2+2 automatic which also had an R180 diff with CV axles. As you noticed, the R180 requires symmetrical axles, and indeed the R180 CV axles are the same, so there is no “left side†or “right side†axle, unlike the R200 CV axle. Using a R180 with CV axles in an early Z car has been well discussed here before. I’ll see if I can find some of my previous posts on it.

Did you see this thread? http://forums.hybridz.org/showthread.php?p=522983

Low mileage ZX’s are not uncommon. Just here in Knoxville I looked at one with less than 100 miles on it and another with under 10,000 miles. Both cars sold for less than $15K, much less than the original asking price of either.

In terms of monetary value I have seen the E31 head fetch up to $135 (“as isâ€) on eBay whereas the E88 goes for as low as $25. I have both a spare E88 and E31 head on my spare parts shelf. I always keep an eye on these heads when they appear on eBay.

At your friendly local Nissan dealer. PN 25251-37700.

If this is true? You seem to be doubting basic mechanics! As my Statics and Dynamics instructor always told the class, “to begin the solution, draw the free body diagramâ€. A sketch of the crankshaft throw, the connecting rod and the piston will illustrate the problem. Kidding aside, the error is a function of “where†(relative to the crankshaft angle) the “stops†are. Because of this I created a spreadsheet program where you input the “stop†locations from the degree wheel and the program determined the location on the degree wheel where the mechanical TDC location is. The error is also a function of the rod length and the stroke of the particular Nissan engine. I’ll see if I can remember where I put the program (that was a few computers ago).

This page is fairly useful and appears to be accurate: http://www.ozdat.com/ozdatonline/enginedesign/

I have always found it necessary to elongate the mounting holes of the tensioner and the curved side guide as outlined in the “How to Modify your Nissan/Datsun OHC Engine†book. According to the FSM (and other texts) it is very important not to have any of the tensioner piston exposed. If modifying the mounting holes does not accomplish this then you can shim the piston shaft. I have found that spark plug washers are the correct size for this. I also recommend re-drilling and tapping the curved guide mounting bolt holes to 8mm. I have seen the stock 6mm bolts shear off on some engines.

The plastic ball bearing retainer plate on my 810 distributor (same as the ZX) was also badly deteriorated. As you may have discovered, this piece is NLA from Nissan. All the used distributors I looked at had the same problem. I gave up trying to repair mine and simply got a reman distributor. I was able to get one without the ignition module for only $80 from Advance Auto. It appeared to have a new retainer plate installed in it.

Often heard quote around race tracks: “Here is an easy way to remember the difference between oversteer and understeer: If the front end hits the wall, it was understeer. If the rear end hits the wall, it was oversteerâ€.

Just don't get the 810 head: http://forums.hybridz.org/showthread.php?t=105198

The very early 240Z’s had a hand throttle lever next to the choke lever. It operated a cable that was connected to the top of the accelerator pedal. It was not a cruise control which is much more complicated (speed control via feedback, brake switch cutout, etc.). It’s purpose is just to raise the idle speed for faster engine warmup. A lot of 1960's and early ‘70's European cars had a throttle lever. I even had one on my 1975 Fiat X19. Nissan removed the throttle lever in sometime early 1970 due to possible legal litigation but the slot remained in the console until the 1972 console redesign. It’s interesting to note that the early 1970 owners manuals had pieces of paper glued over any reference to the throttle lever. My Feb 1970 240Z did not have the throttle lever but I got a NOS one on eBay a few years ago for only $200. I have seen them go for over $400 since then(!) As usual, any questions about early Z cars are best answered at the Classic Z Car website forums: http://www.classiczcars.com/forums/showthread.php?t=19094&highlight=hand+throttle and: http://www.classiczcars.com/forums/showthread.php?t=10229&highlight=hand+throttle

Some info here: http://www.classiczcars.com/forums/showthread.php?t=19277&highlight=bedliner

Get the Echlin brand at NAPA. It’s only brand (including your Nissan dealer) that uses brass contacts instead of aluminum. Aluminum contacts wear out much faster. http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=ECH&PartNumber=EP663&Description=Distributor+Cap

I have installed the 90A Maxima internally regulated alternator in my 260Z. I removed the external regulator and its connector and rewired the alternator so that the A terminal is connected to the battery positive terminal through a heavy gauge wire, the S terminal is connected to the battery positive terminal through a smaller gauge wire and the L terminal is connected to a +12V switched (IGN) source through a diode (so it can be energized at engine start up). However you have to do more. The problem with the 260Z with regards to the elimination of the external voltage regulator is that it has an electric fuel pump shut off relay and it also has the seatbelt "interlock" module. Both of these circuits require an electric signal input so as to be able to determine whether or not the engine is actually rotating. This signal is supplied from a connection on the external voltage regulator. On the 260Z there are two fuel pump relays in series with the rear-mounted electric fuel pump. One of these relays will not allow the electric fuel pump to operate when the engine is being cranked over when starting. I don’t know the purpose of this feature, but since the stock 260Z also has a mechanical fuel it can still supply fuel to the carbs when cranking. The other relay is to shut off the electric fuel pump if the engine stops rotating. This is a safety feature in case of an accident where you could rupture a fuel line. Although the engine may stop, you would not want the electric fuel pump to continue to feed a potential fire. The early alternators have an "N" terminal which is the common connection to the three stator windings. When the alternator is rotating there is a positive voltage induced at the "N" terminal. This is used to operate the "cut out" relay in the external regulator. However, Nissan also used the "N" terminal voltage as a sense voltage to determine if the alternator and therefore the engine was rotating. The "N" terminal voltage operates the fuel pump relay and also sent to the seatbelt interlock module. This is done via an electrical connection off the external regulator (which has it's own connection to the "N" terminal of the alternator). On my 260Z I elected to defeat both the electric fuel pump relays. So, the electric fuel pump operates whenever the ignition key is in the ON position. I have triple Webers and I like being able to prime them before starting the engine. These relays are located in the passenger side kick panel area. However, I don't feel comfortable instructing someone to disable this safety feature. So, do what you want to. I surmise that the seatbelt interlock module needs to know if the engine is running so you can unbuckle your belt while the car is moving without the engine being shut off by the interlock module. I also defeated the seatbelt interlock module, as I don't need to be reminded to fasten my seatbelt. Nissan stopped using the interlock module in '75, and even told dealer service departments to defeat it on the 260Z if the customer had problems or complained about it. It is probably possible to design a circuit that would have an "engine rotation" output signal when using the later internally regulated alternators. On the later Z cars Nissan used a special oil pressure sending unit (with two terminals) that supplied a voltage when the engine was rotating and generating oil pressure. The fuel injected Z cars needed this because it is possible for a fuel injected engine to operate even when it is upside down, say following an accident in which the Z rolls over on its top. However, in an inverted position the oil pressure would fall to zero as the oil would flow from oil pan to the top of the engine.

One more thing then I’ll go back to lurking Nissan started adding the “installed†pinion preload spec in the late 1980's Z31 FSM. Since the Z31 used the R200 diff this info is useful to the S30 and S130 diff rebuilders: R200 pinion bearing preload spec without diff carrier: 8.7 to 11.3 inch-lbs R200 pinion bearing preload spec with diff carrier: 13.5 to 20.4 inch-lbs

Fortunately Nissan specs the Z32 front pinion bearing preload with and without the differential carrier installed. Without the carrier the pinion bearing preload is speced at 9.5 to 12.2 inch-lbs for the R200V and 16 to 23 inch-lbs for the R230V. With the carrier installed the preload meassurment should increase no more than 2.6 inch-lbs. This makes sense as the total side bearing preload is reduced by the gear ratio when it is measured at the pinion. It’s all in the FSM: http://300zx-twinturbo.com/cgi-bin/manual.cgi?list=pd&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=32&design=default&total=43 and http://300zx-twinturbo.com/cgi-bin/manual.cgi?list=pd&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=34&design=default&total=43

It's interesting to note that the R200V used in the Z32 uses shims to set the pinion bearing preload (like the R180 and early R200's) but the 230V uses a collapsible sleeve: http://300zx-twinturbo.com/cgi-bin/manual.cgi?list=pd&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=15&design=default&total=43