Zed Head

Good point on general wear. More wear puts more load on the bearings as things get out of alignment. Here's a thread on the 71C bell housing swap, just to round out the discussion. You can see the one sealed bearing in the picture on the second page. Probably not really a factor in noise. http://home.comcast.net/~zheimsothtn/Transmission2.htm

Oops. Nomenclature fail on my part, clearance, not tolerance. Thanks for clearing it up, I can't tolerate mistakes on my part (pun :sick:). I think that the "roughness" of the noise suggests the ball bearings instead of the needle bearings. At least for the noise I've noticed. It has a grindy bad bearing sound to it. If I recall correctly, there are only seven balls, of relatively large diameter compared to the needle bearings, in each bearing assembly. There are a lot of needle bearings in each cage. In Post #4 above when I said "same bearing noise" I meant within the group of four transmissions. I couldn't hear anything in the video either. Anyway, might as well drive it and see if it gets worse.

Looks like you've read up on how to make power. Why hope when you don't have to (this could be a campaign slogan!)? You listed all of the stuff that you should work on, so it also looks like you already know it's not going to work. The injectors and size of the throttle body really only serve one purpose - to supply the fuel and air demands of the engine. Without increasing the demand, with a different cam, or intake/exhaust port work, or exhaust system work, for example, the bigger injectors and throttle body will be wasted. You'll probably feel a difference in throttle response because the same amount of throttle blade movement will let more air in with the bigger body, just like pushing the throttle pedal farther. Basically, you'll have less throttle control that gives a feeling of more power, that's not real. Just one opinion. I can't recall a single thread or post in which someone said they got more power with bigger injectors and/or throttle body alone. I have read some accounts of people removing the big throttle body because it just made the engine hard to control, but no more powerful. The SDS will probably allow you to reduce injection duration so that it performs like a small injector, so you'll probably get away with that modification without noticing any ill effects.

I've had four used transmissions in my car and they all make the same bearing noise that goes away when the clutch pedal is pressed. The noise doesn't get worse over miles run though, and it seems to be just a noise, it doesn't affect operation. I've also read an account from one of the more experienced members here (can't remember who for sure) about rebuilding a transmission, installing it and having the noise come back within miles. The bearings used in these transmissions are C3 spec., which is a loose tolerance to allow debris to flush through. Maybe it's normal. The later 71C transmissions, in the 300Zx and the 240SX, used sealed bearings which are probably tighter tolerance (haven't checked), maybe as an attempt to make them quieter.

Did you adjust the rod to the master cylinder to make sure that you're getting full travel? You can do it with a pair of pliers and a wrench without removing the rod if you're good at contortions. Loosen #2, and twist #4, in the diagram.

The fifth one is in-line in the EFI harness, is green, and consensus seems to be 40 amps. They went to two fusible links in 1978, still in-line. The stock setup is to have the link(s) clipped on to the metal relay bracket by the battery. Forgot to say that they are described in the Body Electrical chapter.

It is most likely the dimmer, or high beam/low beam, switch at the base of the turn signal stalk. It's happened to me on two cars. You can spray contact cleaner in to the guts of the switch and work it back and forth and that will probably fix it. It did for me both times. Or you can take it apart and clean it. You might even find that it's stuck and one click will fix it.

Your AFM numbers look great, ~100 and 180 ohms. I wouldn't mess with adjusting the AFM at all until you get the ECU connector to read the same as the AFM. From your previous post, it looks like you might have corroded connections between the AFM and the ECU. The ECU connector numbers should match the numbers directly from the AFM within an ohm or two. Until you have the electrical connections between your coolant temp. sensor and the AFM cleaned up, don't touch the insides of the AFM at all. You'll be getting way ahead of yourself.

I don't really know if this would make a difference, but it might. The "How to Rebuild..." book by Monroe says to install the rear main cap first. Your statement above suggests that you are installing it last, unless by "last" you mean last in line from front to back.

Fusible link? They melt on the inside so it's hard to tell when they've failed (succeeded).

This 1976 Service Bulletin sheds a little light - http://www.xenons30.com/files/Datsun280Z_1976Supp.pdf -, page 8. There was either an intermediate, more durable, material used before the N47 intake seats or the change happened sooner than thought. Or maybe the the intake valve was changed before they got to the exhaust valve. They don't really say what the new material is.

That's probably just water and carbon. Both combustion byproducts, running a little rich will produce more carbon. No biggy, they all spray a little back gunk after starting a cold engine. $250 is over $40 per injector. Almost 1.5 times the Rock Auto price. Let him keep them if he doesn't stick to the initial quote.

Ace Hardware has a good selection of metric screws. You could probably find one that will do the job and replace them later if you want the hex head factory screws. A Phillips head screw isn't going to corrode in place and bind up in a few days.

I've never actually tested the ignition module but there is a procedure. Here's a piece. www.xenons30.com/reference

Typical mis-matched injectors on an older Z. If they flow at the same rates the mis-match in pintle caps (the plastic cover on the ends) won't matter. How long has the car sat in the past? It doesn't take long to build up gas tank crud and get a little moisture in the injectors. The set that were on my car when I got it had a mis-match in flow rates of about 15-20%. A few of the cylinders were running pretty lean. Only the small seal on the end seals to the intake system. The big one is an insulating mounting gasket. The rubber pieces are cheap and available at most auto parts stores.

You can replace the hoses on the injectors. It's even described in the FSM as a standard maintenance practice. The injectors have a specific "one-way" barb style that allows the hose to go on and seal but not come back off. The old hoses have to be cut off. I've used the 5/16" Gates hose and it seals fine. You do need a good tight hose clamp on the rail because the new hose is kind of slippery and will tend to loosen up on the rail barbs over many heat cycles. Check the clamps as regular maintenance. The injector barbs don't leak.

There is one fuel rail bracket that's bolted to one of the four big intake manifold bolts across the top of the manifold. Looking down from the driver's side (left side) it's underneath the rail so essentially invisible. That's probably the force. Several of us have been stymied by it.

$106 for a "DIODE ASSY". Probably the plate with the three positive diodes installed. At least I have a part number now. (I found a new parts site also: nissan4u.com) - Part #19 - http://nissan4u.com/parts/280zx/us_s130/1978_7/type_2/engine_electrical/alternator_fitting_and_alternator/illustration_2/ You have to insert a dash before the letter in the part number for Courtesy's site to find it - http://www.courtesyparts.com/diode-assy-p-281882.html Edit - I think that this is the right number for 1978. Still $106. The above is for 1979. http://www.courtesyparts.com/diode-p-281880.html

Posting for my own amusement now but also to fill in - turns out the sub-diodes are available from good ol' Courtesy Parts. $10 each. Found the number on carpartsmanual, but the main diodes aren't shown. http://www.carpartsmanual.com/datsunS30/DatsunZIndex/Electrical/Alternator/12V60A/tabid/1641/Default.aspx http://www.courtesyparts.com/diode-p-281902.html Edit - Thanks Steve. We posted at the same time. I'll bet Courtesy has them but I would also bet that they aren't cheap. Edit 2 - I wonder if the part is called out on the classiczcar CD that I've heard about. I've not bought it, so don't really know what's on it.

To test the main diodes you have to desolder all of the connections to the stator and at least one to one of the diodes. Then pry the stator (the metal ring with all of the windings) out of the case to get two of the studs out. Pretty much deconstruct the whole thing,just like they show in the FSM. I did find one bad main diode. Now if I could just find a new set. Added pictures just because you don't see these that often. For anyone that's on their third or fourth try with an auto store rebuilt and looking for an alternative. Edit - I guess that there are diodes out there - http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_x_5260086-P_x_x?cm_mmc=CSE-_-Shopping-_-VALUE3-_-VALUE4&srccode=cii_13736960&cpncode=32-189062079-2#utm_source=cse&utm_medium=shopping&utm_campaign=value3&utm_content=value4

My expedition in to the world of cheap alternator repair is on pause. It must be one of the main diodes that's bad, they did look a little crusty. A fail on the lamp/diode part of the test at Autozone. From what I've read, people used to actually replace these diodes without too much trouble, three are pressed in to the case, and three more or are pressed/mounted on the diode plate. The FSM even says "replace if faulty". I'll probably take them out and test them when I get back in to it. There has to be some old stock out there in a warehouse somewhere.

I think that purpose to opening the throttle blade is so that the closed intake manifold vacuum doesn't affect the pressure readings. After one cylinder pulls a vacuum and closes its intake valve, the next cylinder to open its intake valve will be pulling on the previous cylinder's vacuum. Less air to pull in will be less air to compress leading to lower pressure readings. In theory, I haven't practiced it. On an EFI car there won't be any fuel to flood with if the main distributor wire is pulled,or if a remote starter is used. The EFI injects based on pulses from the spark events. No spark, no fuel.

Deep and loud implies something with a lot of mass and/or relatively low frequency. Tires and wheels come to mind. What happens if you shift in to 4th at 65, besides the higher RPM? Does the vibration change? Push the clutch in and see if it changes too, this will separate the engine and flywheel from the wheels and drive shafts. Might tell you something.

The variety of testers and the various hoses and adapters that come with them can have a large effect on the numbers. I've measured 180 psi without an adapter and 120 psi with. The volume of the gauge and the hose and any fittings "count" as combustion chamber volume when the measurement is taken. More volume results in a lower pressure reading.

I'm starting to get it Mike. The diode trio has more functionality than I had thought. I would guess that the specs. for those three diodes are fairly important, so my Radio Shack diodes are unlikely to be long-lasting even if they do work. Still good to know that if I had the right diodes I could get them installed correctly. If the alternator windings are in good shape, rebuilding an alternator is not really very difficult, if you have the parts. I can source all of the parts individually except the diodes. Regulator, brushes, bearings and diodes are about it.