Captain Obvious

DRBall, Is the .pdf that black gold man linked to the same one that you have, or do you have something different?

I'm interested in a copy of this... Is there a place you can just upload the file? What format is it in?

Gotcha. That's a good point.

Bummer. I don't know what the offending ingredient is, but in thier FAQ: Pine-Sol® Ingredients, How to Use Coupons & Other FAQ's

Yeah, that's why it seemed like the same thing to me as looping the heater hose. Sure, you'll get some convection currents in the air in the box where the core is, but that's gotta be negligible. Makes me hope you were right about this: I agree, and based on the empirical data of "we don't hear from lots of stock owners with overheating problems" I would guess they did OK with the margin of safety. Still makes me wonder if I may have complicated matters with my fancy schmancy heater flow valve...

And at the risk of typing a bunch of stuff you knew already... There are two things that control how much fuel will be pulled in. First is the gap around the needle, and the second is the speed of the air through the venturi. The bigger the gap, the more fuel. Simple. The faster the air through the venturi, the more fuel. Not as simple. The trick to the damper is that when you punch it, the engine sucks a lot more air, but the piston will not rise instantly because of the damper. Because of the slowed damper rise, that "lot more" air has to funnel through a smaller opening and Bernoulli says that will cause a lower pressure. That lower pressure pulls more fuel in even through the smaller neeedle gap. Once you have reached steady state, the gap is the only thing controlling mixture, but in transition if you slow the piston rise enough, you can actually create a transient rich condition EVEN RICHER than the steady state will be. That's the simplistic beauty of the SU design!! So in short, a thicker oil will slow the damper more which results in a richer transient mixture.

Counterintuitive as it may be, it really is true. There are lots of sources to cite, but here's two that should carry the most weight around these parts: First is from Skinner's Union's themselves: SU Carburetters The S.U. Carburetter Second is a snippet from the Datsun factory service manual (1973 pg EF-9):

Actually it is stagnant. There is an air intake control flapper door on the input to the blower motor that selects either outside fresh air, or recirculated. You get that air intake door into the recirc position with the fan off, and it's dead stagnant (or at least as stanant as your sealing foam on the door will allow). I don't know about the 240s, but it's easy on the 260 and 280. Without A/C, if you move the top lever (the "AIR" lever) to "OFF" this will put the air intake door in the recirc position. No fan, and you're stagnant. (260 FSM BE-46) (260 FSM BE-48) And if you do have A/C, you're running in recirc any time you have the lever on "A/C" or "REC HEAT". Put the lever into either of those two positions with no fan, and you're stagnant. (260 FSM AC-6) (280 FSM AC-6) Good point about the coolant flow valve. I have to remember that my modified flow valve provides pretty much no resistance when wide open. Something I should probably keep in mind... When wide open, I bet I'm sending a lot more hot water back to the water pump than stock. I'm going to consider adding a restriction to that line. It's not like I need more heat in the interior. I get plenty. Between that and the fact that my PO took off the heating pad under my AAR, I'm thinking I should install some sort of small thermostat bypass just to make sure I get some flow into the thermostat housing to keep the thermostat up to date with the rest of the engine. Thanks for the help!

Here's what was suggested the last time we were talking about pin21: "a" isn't gonna happen without the ECU even making connection, so I'm sticking with "b".

Excellent. As stupid as it seems, there's a lot to be said for little details like this. Snappy, positive, predictable operation. Satisfaction in liking the way it works every time you use it. Corny, but it's the little things...

I can't even figure out what you're trying to say. What does ebay have to do with anything? There's a guy on HybridZ (FricFrac or something like that) who does a lot of work with the FI harnesses. Why don't you just buy one from him? I think he offers everything from connector "kits" to turn-key harnesses. S30 and S130 Wiring Harness repair kits. You NEED this if you have an L28E or L28ET! - Parts for Sale - HybridZ And I believe he does have some of his stuff on ebay... Is that what you're talking about? Are you saying that you're planning to actually SELL rebuilt harnesses on ebay? If so, that's not a "hobby", that's a "business".

Wade, Don't know about your ZX, but on the Z The cold start valve is not tied into the ECU. I believe you are referring to the mysterious "pin 21", and if that's the case, then remember that while there is a wire going from the cold start valve to the ECU connector, that signal does not actually make it inside the ECU case. That pin location is not populated. No pin at all, just a blank hole. That signal makes it to the ECU connector, but it doesn't go any farther than that. Would be interesting for you to take a look at your ECU and find out if your ZX populates that pin location. Maybe they started using it in later years? :bulb:

Haha! Yeah, I remember those times as well. Don't remember which family car it was, but I remember Dad turning the heater on full blast in the middle of summer and then trying to explain to me why. As for the looped heater tube, I really don't think there will be much heat rejected by the core in completely stagnant air, but granted, it will be non-zero. Same situation for the resistance to flow... I suspect there's not much, but, non-zero. Oh well, just curious if I was missing something simple and there really was some big reason why those two situations were different.

Haha! Ya think?? Makes me wonder if ads like that help or hurt our Z community. Stuff like that ad irk me because I think it makes the collective "us" look like crackpots... [/Threadjack]

Well, if you got 15K to spend on a Z, you could buy this beauty currenty for sale in NYC! 1974 datsun 260z with low miles For that money, I think I'd rather have the one from San Diego... :stupid:

I also believe you have the flow direction through the carbs going the wrong way in Figs 1, 2, and 3. Not sure about the direction in Fig 5... I don't know what would happen there. So about looping that heater hose as shown in Fig 4. I understand the concept about it short-circuiting the radiator and sending hot coolant back to the water pump inlet, but here's my question... With a completely stock setup, how is that any different than driving around with the heat selector control slid all the way to HOT and putting the air selector lever to OFF so there isn't any air flow through the heater core? You're doing the exact same thing, right?

If you want something self contained to the console, there ought to be something hot at all times going to the flasher switch.

It's supposed to be hard to lift the pistons. 15W40 is higher than the manual recommends (and higher than I've had success with) but if it works for you, then go for it? Are you blowing black clouds on acceleration? Are you fouling the plugs? Is your gas mileage really low, say below 17 mpg? If your answer is "no" to all of the above, then are you looking for something more than that?

The dampers are not just for WOT operation. They are for any time the throttle valve is transitioning from a more closed position to a more open position. All that damper does is slow down the upward movement of the piston. The thicker the oil you use, the more it will slow the piston rise. The more you slow the piston rise, the richer you will run on throttle transition. The important detail is transition. Not WOT. It is supposed to act like an accelerator pump... It's purpose is to temporarily richen the mixture on throttle transition from more closed to more open. And this isn't the way the multi-vis oils work. They are not thinner when cold. They are thicker when cold, just like any other oil. The trick to the multi-viscosity stuff is that they don't get as thick as they would get if the modifiers weren't added. For example, think of 10W-30 like this: "When cold - It will be as thick as a 10 weight would be when cold" "When hot - It will be as thick as a 30 weight would be when hot" That cold 10 weight is still way thicker than a warm 30 weight.

Never had one of those off, but I assume that tube is just a straight piece of tubing with flares on the ends. Not sure if they are single, or double flares, but flares of one sort or another. If that's the case and you have the means, you could replace just the tube part by using the correct size of tubing, moving your flare nuts to the new part, and then flaring the ends. Is the part is NLA at the dealer? You can't just buy a new one?

Thanks! I wish I had known how that mirror went together before I heated the crap out of it and blackened the paint. I may have even heated it to the point where I messed with the metal as well. Like I said... Nothing to lose. Trying to prevent someone else from making the same mistakes. I'm not a shutterbug guy and wasn't looking for a lot from my camera, and accordingly, I didn't want to spend a lot. I ended up with a Panasonic Lumix and I continue to be absolutely satisfied. I bought it a few years ago, and I continue to think that it was one of the most satisfying purchases I ever made. That says a lot...

My Z came to me with the "racing style" door mirrors, and like so many others before me, it fell apart because after years of adjustment, the ball stud pulled through the hole in the adjustable shell part. This left me with the shell housing part completely off in my hand and the mounting half still attached to my door. So with nothing to lose, and for the trivia, I figured out how it originally went together. First, I took the mirror off the door and disassembled it. Looks like this: Typically like so many others, my failure is that ball pulled through the hole: But the tricky part is... How do they get that spherical ball stud installed in the first place? The whole mirror assy operates on the principal that the ball is supposed to be larger than the hole in the mirror body and NOT pull through. So after twisting (even twisting with heat) did not work, I discovered that it is simply splined and pressed together. Duh. Like this: To assemble, you put the ball stud through the mirror body like this: And then press the ball stud into the mounting arm: Of course, mine is going to pull through again, but it opens up some repair avenues like putting a steel washer behind the original stud or making a larger stud. And of course, the trivia.

Haha. Yeah, mine (like so many other parts on my car) was bead blasted by the PO. Looked great for a week and then started to rust because he blasted off all the plating. The plan would be to eventually have a batch of parts replated and chromated.

mgood, That reminds me... There's a story about the whole reason I even ever noticed the difference between the different ashtray designs. It goes like this: I use the ashtray not for ashes, but as a small storage compartment for change, etc. I also put my cell phone in there, but it didn't fit quite comfortable, and I decided that it would be better if the "snuff out shelf" wasn't in the way. With that in mind, I unscrewed that shelf from my ashtray and used pop-rivets to re-attach the spring retainer on the outside of the tray. After doing this mod, I did find it easier to get stuff out of the ashtray, but I discovered a problem... Without that shelf in there to grab on, the ashtray was difficult to get out of the console. There's nothing to hook a finger tip under. It looked like this: I was content with the trade-off of more space for the phone, until... I came across an OLDER ashtray with the little grabber handle that I had never seen before. So, I undid my previous pop-rivet mod and moved the little grabber handle from the older ashtray over to my newer style with the light window. I used slightly larger screws and tapped the grabber handle for threads. Looks like this: And here's the inside with the handle installed. Now I've got the best of both worlds... No shelf in the way, but a little lip to grab onto to pull the ashtray out of the console: It's the little things....

Hahaha!!! :laugh: Thanks for the laugh!