Zed Head

Most manufacturers call out the changes in the new model year when they introduce it in their sales literature. They almost never say "it's so good we haven't changed a thing!". Does anyone have a 1971 240Z sales brochure?

It's an old topic that's been examined, apparently, of course. But the BAT guy got more views probably by claiming 1970. Still has questions to answer in the comments. Here's Carl Beck from 2006. https://www.zhome.com/History/1970or1971.html

So, @zspert is a 12/70 build date a 1970 model or a 1971 model? What is the difference between a 70 and a 71? That's the question.

Found another 12/70 build "71" with 70 belts. What's it all mean?! https://bringatrailer.com/listing/1971-datsun-240z-218/

The belts in the listing seem to be of 1970 style. The lift to unfasten lever instead of the push-button. Therefore it must be a 1970 model. The seat belt latch tells the story. Undeniable!

One more small fact would be that 1978 got rid of the ballast resistor and opened up the spark plug gap. Implying that they were using current limiting technology like the GM HEI module. 74-76 used the ballast and the smaller gap. 1977 is odd though because they kept the ballast resistor but opened up the plug gap for USA models. Weird, don't understand it. Might be a typo because in the Engine Electrical chapter they show the big gap for Canada models. Engine Tuneup shows otherwise. But 1978 seems clear.

What type of seat belt do you have?

Here's one of those Owner Manual things. Nissan defined one as 1970 and the other as 1971, apparently. Not arguing for the sake of arguing, just trying to solve a puzzle.

The answer is probably in the Owner Manuals. There is a separate one for 1971 and 1970. If the Owner Manuals are identical then the cars are probably identical. The Owner Manual features should match the car. It's really just stuff the BAT seller should have done. Sellers need to understand the potential customers. https://www.classiczcars.com/files/category/17-owner-manuals/ They show a 1970 manual but who knows where they got it.

$27,000 was not enough.

That's not how things are done today. As somebody pointed out above, the model design is completed and built in the latter half of the year preceding its introduction to the market. The only question here is about what Nissan was doing in December of 1970. Are the 1970 and 1971 model year designs identical? If they are then a 1971 is a 1970. And a 1970 is a 1971...cause they're identical. If I was selling on BAT I'd just put the VIN in the title. That's what the collectors look for anyway. One of the commenters tried to place the VIN in a model year range but it's been discussed many times that the VINs could be produced out of sequence in the early years. Who knows. It's HLS3015316. The funny thing is that the error, if it is an error, generates interest. Too bad it has that huge dent in the fender. Looks like something large and heavy fell on it in the garage.

Here's a good one. Ends tomorrow morning (West Coast). https://bringatrailer.com/listing/1972-datsun-240z-239/

By your description you think that one of the flanges has excessive runout. You said that you think something bent when installing new bearings. The only force that could put a side load on the shaft or the flanges is the nut and washer pressing on the inner flange, pulling the parts together. The only thing resisting the force is the bearing. If you put the nut on when the parts are out of the casting it should spin right on. I'm just proposing ideas about what would cause a bend of any of those parts. Here's other thoughts though - the half-shaft is not properly seated on the centering ring. Or the half-shaft itself is bent or binding. Or the differential is damaged. There are a lot of moving parts back there. Can't really tell because all you have are impressions from driving. Sometimes it helps to just lift the car, throw a cushion under it, crawl under there, and take a good look at things as you spin them. Grab things and shake them, see if anything is loose.

Is a 12/70 build a 70 or 71? Controversy... https://bringatrailer.com/listing/1970-datsun-240z-82/

Your description sounds more like the bearing is not seating properly in the strut casting. The bearing is cokced. Or the "distance piece" is distorted which also would cause a cokced bearing. There are several surfaces you can examine and measure to find out what's not right. You'll have to take it apart though. When those 5 parts clamp together they basically form a solid tube though the hub. The two inner bearing races and the distance piece are the tube, and the flanges are the clamping surfaces. The outer races get pulled along by the balls and inner race.

There's always the hands off the wheel test. Find a level road, get up to cruise speed, take your hands off the wheel - see what happens - hit the brakes - see what happens. If nothing bad happens then everything's right .

@Terrapin Z The turtle man has a lot of stuff. Worth an ask.

p.s. ritrebor is the seller. He's a member here. @ritrebor

Probably easier to tell if the axle and flange are off the car. I did a quick Google and these popped up. You can see that the guy is sliding the flange on and off the axle by hand. Has to be for the pictures. Type "Datsun 280z 27 Spline Stub Axles W/Companion Flange " in to eBay and they should pop up. $350 for the set. (eBay tags so much stuff on to their web page links that I'm afraid to share the link. Who knows what all of that extra stuff means).

Off the splines or out of the hole? I think that the outer bearing race is an interference fit (could be wrong). Might be that the strut casting has a problem.

Did you post about this before? Seems familiar. A dial indicator, or even a stick on a brick, might tell you something. Set it up and spin the various items in question.

This is the typical sign of a lean situation, except that it happens under load. If it happens with no load that's pretty bad. Worn out cam lobes also cause popping back through the intake manifold. I've had it on V8 engines. That happens with no load. You might pull the valve cover and see if you have any loose rocker arms/damaged cam lobes.

Don't overlook the EGR system. Sometimes it leaks internally. The smoke would just head down the exhaust pipe. Even if you removed it and put a plate over the holes (I assume that you did, if your engine's had it), the passage walls sometimes rot out. ckurtz2, you could be here for quite a while. If they won't even put the vacuum line on the FPR, flow-matching injectors seems quite a stretch. Good luck though.

They're in the Distributor section of the Engine Electrical chapter of the FSM.

I don't think that anyone can really tell what you guys have installed on your engines. Ogs said he put his hand over the AFM, things changed, he installed the stock air box, things changed. "Normalized". Not sure what any of that actually means. The vacuum line reference to the FPR is a basic of ALL electronic fuel injection systems, not just early 70's Datsuns. The computer programs are designed to work with fuel pressure that varies with intake manifold pressure. You need that vacuum line. Just because the engine runs doesn't mean that it will run right. The best way to learn about early EFI is to get everything spec'ed in the way that the engineers intended. Then mess with it and see what happens. Messing with a messed up system just makes more mess. No offense. ckurtz2 wrote a whole page describing his experience with early EFI and you guys just blew right past it. Everything that he wrote is true. The fine details make the difference. There are many many stories on the web from people who just gave up and put carbs on. It's a challenge.