motorman7

Got my Z in a short promotional piece by NBC for the La Jolla Concours http://www.nbcsandiego.com/video/#!/the-scene/events/La-Jolla-Concours-D-Elegance/145159165

I love the pictures. This is a re-post, but this is my Z at the 2011 Dana Point Concours. Entered in the Post WWII-pre 1972, sports cars under 3 liters class.

Hi Bob, No, I was not discouraged at all by your comments. Actually I was really glad you prepared me for what to expect. I just laughed and realized that you really knew what you were talking about. As some have mentioned here, each Concours is very different and judges are looking for different things. In hind sight, I just brought the wrong Z to that event. They would have loved the yellow one. And honestly, the awards are not really a big deal, it’s the atmosphere, environment and conversations that are the best part. I have met famous and well known people at these events. And, it’s amazing how many of them have owned a Z at one time in their life. Always makes for good conversation and a great experience.

They do, that's what keeps me hooked to this thread. Perhaps we can drag this on for years .

I do get the impression that the major shows are starting to give the Japanese cars a bit more recognition. Last year the Palos Verdes Concours had a Japanese car category which I thought was quite significant. It was definitely out of their norm, but nice to see. Espirit placed well in that show. Even with the upcoming La Jolla Concours, I was not planning on entering until I spoke with Les Cannady at Classic Datsun Motorsports. He mentioned to me that someone from the show had talked to him about entering some of his cars. That was definitely a pitch for the Datsun brand, so I went ahead and applied – even though there wasn’t a Japanese category. It will be interesting to see what happens over the coming years. Hopefully, by the time the Z approaches its 50th birthday, Japanese car categories will be common place at the higher end shows. Time will tell.

The purpose of this thread is to discuss Z-cars at Concours events. I know that individual Concours events have been mentioned here on classiczcars.com, but I was hoping to set up a thread that might encompass all of them so that the subject is not so scattered. The goal is to have a Concours thread where people could offer tips, voice their thoughts and opinions, promote local Concours events, and of course show some awesome pictures. First off, entering your Z car in a Concours show is really a mixed bag for us Z owners. I remember excitedly talking with bobc about this subject the first time I was accepted into a Concours show. With sage advice, he told me not to get too excited about it. He told me, “most Concours judges have no idea what to look for in a Japanese vehicle. If you tell the judges that the Z cars came from Japan with blacked out engine bays and V-8s, they would believe you”. Of course I dismissed this comment. Lo and behold, at my second Concours show, the winning Z car entry had blacked out engine bay, a lot of chromed engine parts, and was not even painted a standard Z car color. Oh well, I was warned:ermm:. I still enter the Concours events but try not to get my hopes up too high. The other side of this coin is that Concours events can be quite a wonderful event for the Z owner. At one local Concours event, I was one of the few individuals personally interviewed at the event (broadcast throughout the show on the golf course), I received a car identification placard (brushed aluminum) that is nicer than just about any trophy I have received, and the people that I met and spoke with were great. Not to mention an exceptional goody bag, first class photos and web PR, parking on the fairway with an ocean view, and car positioned near the show entrance so that virtually everyone in attendance would walk by and see the car. I thought I had died and gone to car show heaven:bunny:. Doubt I will ever be in a better show than that. Along with the great shows and bad shows, there is one issue that us Z-car owners continue face with car events. This issue seems to be….…should I say it…..discrimination. Take a look at the judged categories for most major Car shows. Of course you have a wide array of US car categories; Ford, Chevy, muscle cars, etc. There is typically a European car category or specifically German and Italian, or Jaguar, Porsche and Ferrari . But do you find Asian or Japanese car categories? Rarely. It’s almost as if Nissan and Toyota don’t exist. I find that very odd, and they have been selling cars for quite some time. Anyway, not sure if we will ever get a clear answer as to why Asian cars are not in the mix, but definitely feeling a little discrimination. Along this line, I will be displaying my Z in the upcoming La Jolla Concours. The only category that my car fit in was the “Preservation” category. Oh well, whatever it takes. Anyway, just thought I’d set this up and see where it goes. Rich

That statement helps a lot. Was trying to figure out Leon's statement (which is your same point) and this clarifies it. Thanks! (such the educational thread )

I would think that with the needles moved flush with the bottom of the piston that you would correspondingly return the seats to just two turns. As your needle shoulders were beyond the base of the piston, your seats were corresponding lower, 3.5 turns out if I remember correctly? These move hand in hand to provide the correct fuel ratio at idle. This seems to be the opposite of what you really want to do. Given this last bit of information, you do not have a fuel delivery problem; you have a fuel ratio problem. I will propose the KD needles once again. As you can see in the pic, they allow more fuel at the higher RPM's, more than the SM's which don't seem to be doing the trick. KD needles would be a pretty cheap item to check. Best of luck, Rich PS: This is easily my favorite thread on this site.

From the looks of it, that one won't be available for too long. Original owner - that's impressive

OK, got one signed up for the car show. Will probably add the other later. Should be a great time. Looking forward to seeing all of the Z's and Z people.

I like this. Use it some of my motor parts. http://www.por15.com/POR-20-ALUMINUM/productinfo/P2H/

Of course, if you live in Mayberry, they will go "Shazam!"

I think on this test you would want to run it without the dampers. The dampers just effect your ramp up and ramp down. At constant speed, the dampers don’t do much other than maybe minimize oscillations. They mask the difference in the ‘blow-by’ on your test. I was wrong on the springs not helping, kind of. If you were to put a spring with a higher K value in the dome with the better (assumed) seal, this could compensate for the Delta P within the chambers. This really is a GREAT thread by the way. Engineers love this stuff….seriously. Best regards, Rich

My Theory: The needle and seat relative position at steady state condition at 4500 RPM+ is not the same for your two carbs. One is running too lean. The other may be just right. I do not think new springs will fix the problem. So what can cause this disparity? There are a number of items. Difference in float bowl height would cause this assuming both SU pistons rose the exact same height. From earlier posts, it looks like the float bowl levels are equivalent, so this most likely is not the issue. The piston height in the vacuum chamber can vary based on the amount of air that escapes through the piston/wall interface with uniform manifold vacuum. An SU piston with a weaker seal will ride lower than one with a tighter seal at this interface. There are no ‘piston rings’ on this interface so there should be some very real blow by. My guess is that there is too much disparity there. The piston with the tighter seal is ‘riding high’ and running lean at higher RPM’s. That’s why car still has some power, although diminished as you are running 3 nominal cylinders (either forward or aft SU set) and 3 intermittent cylinders as some fire with the higher fuel ratio and some don’t. There is a balance tube on the manifold between the two SU carbs, however, at the higher RPM’s I do not think it has much effect on fuel mixture balancing. Actually It probably has no effect at all on fuel mixture balance. It is more for pressure/vacuum balance. This leads us to the Oxygen sensor. The sensor measures the product of the six cylinders and cannot differentiate between the forward three cylinders and the back three cylinders. It can provide an overall result, but cannot tell you whether the front set (of 3) or rear set is too lean. Based on the assumption of SU piston height disparity, an increase in the oil WT will improve your short term steady state RPM runs; but as the carbs manifold maintains a steady state condition, the pistons will again offset. This also helps to explain the poor performance of the low oil WT as the pistons achieve their offset condition quicker due to the reduced damping. Solution? That’s a tough one as there is probably some difficulty in determining what piston chamber combo is running lean or rich. Maybe you can tell by plug color. Assuming this was evident from plug color, the lean SU piston edge could be lightly sanded (1000 grit) to help equalize the blow by. This would be a trial and error process. Pistons could be swapped within the chambers, this might prove easiest and easy to check. Those are just a few ideas off the top of my head. Anyway, this is my theory. It has kept me pre-occupied a bit here so I thought I would write it down and send it forth. Please remember, this is a theory and not a law. Best regards, Rich

Very nice engine compartment! And I love the flat tops, they are so retro. They do clean up nicely.

I have always installed the SU needles with the base of the unmachined portion flush with the base of the piston.

Or maybe you get a set of the KD needles which would be better at the high end. I used to have a pair, but I think I may have put them in the '73 that I recently sold.

There are quite a few of us here from SoCal, always working on the Z's. And, like most, we are looking forward to the MSA show in April. I have a couple 240's here. Not as familiar with the 280's. Best regards, Rich

The suspense is killing me :paranoid:

No Vacuum advance. Very similar to Zedyone, with just 3 degrees difference. Manual says 17 for non-smog equipped cars, so not too far off.

Yes, I was surprised because my fuel filter (made in Israel) was pretty new. May have been some remnants of debris from the earlier fuel tank mess. I also got a new fuel pump several months ago, but that made no difference when swapped out with my old one. May put the old one back in as it is the original Nippondenso (?) pump. The new one is that cheapo stamped sheet metal type. (Looks like the old one would pump more fuel as the diaphragm diameter is larger. Of course the lever arm fulcrum would need to be compared to verify). I thought this may have been part of my earlier popping problem, but I never did switch back to the old one. May do this when I get some time. You may also want to try the timing advance and a run or two without the air cleaner to see if that makes a difference. For me, with the ZX dizzy ‘over-advanced’, I get a bit of ping at the lower RPM, but the car is VERY happy at 3K. Car pulls very nicely from 3K-6K now. And, no popping at all. Best regards, Rich

After experiencing what sounds like the exact same popping issue, as I noted earlier, I can say that I did very little adjusting to my SU’s to fix the issue, other than minor mixture adjustment. I even had the popping at idle at one point and then again at 3K. My SU mixture nuts are now at about 1.5 turns. I could adjust these either way ¼ turn and not make much difference in the way it is now running, which is just about perfect. I think the fuel delivery/fuel filter was the issue. I thought what I had installed originally was pretty new and clean, but apparently it was not. I installed the new filter (made in China) and did the 20 degree advance on the timing and that seemed to do the job. As I mentioned before I also punched some holes in the air cleaner housing. Not sure if this was a contributor; the car just seemed to pop at higher RPM’s when I tested with the air cleaner off (when I was having the popping issue). Another problem I had with the air cleaner housing (a couple months earlier) was I had somehow accidentally flipped the cold/hot baffle on the front of the housing to “cold” (I live in SoCal so never need this setting). Anyway, the Z was really dogging and popping at about 3.5-4K in this condition. Flipped this back over to hot and made a big difference. Anyway, Just thought I’d pass this on. Definitely a very frustrating issue.

I'm running 10W30

Fuel filter? Finally got the car running great, but not sure if it is the same issue that Zedyone is dealing with. Changed out the fuel filter (I think that was the main issue), moved my 280ZX dizzy to 20 BTDC, Vacuum hose not attached, and drilled five 1” holes in the underside of my air cleaner housing (not sure if that was necessary but I had been wanting to do that). Seemed like it ran better with the air cleaner housing off. No popping at all now. It revs and runs nicely at over 6K rpm. Testing this can be dangerous. I am doing over 90MPH in 3rd gear at 5.5K. Fortunately traffic on freeway was light today. Doing around 60 MPH at 6.5k in second. Was not paying careful attention on one of these runs and locked up wheels when light turned red. No accident, but lots of smoking rubber. No ABS on this vehicle. Anyway, glad to be back to normal. On a side note, I do have to say, I rarely take my car over 4K RPM. My typical shift point is 3K. Nice to know that it will do it, but can’t say it is very useful Rich