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vairter

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  1. Using this port on the intake manifold: My only concern again is what will happen every time I briefly let off the throttle as I upshift. The manifold pressure will abruptly drop into the zone in which vacuum advance is programmed to occur (see the green curve pressure dips at time = 9030, 9220, and 9390), so that maximum advance of 43 degrees will suddenly be applied. I'm not sure this is what you want during an acceleration phase... Jim, regarding the absolute pressure readings, I think there is an offset error of about -10kPa in the reading on this distributor. I left the port open once and it read 90 kPa instead of full atmospheric 100 kPa. So all the pressures in my plot are probably about 10kPa lower than reality. I'm surprised that the error is present on a brand new unit.
  2. I switched the vacuum source to a port on the intake manifold and blocked off the ported vacuum source on the 32/36. Here's what the trace looked like while cruising at 70mph: The black lines are the pressure limits that you suggested, jimk. It looks like 35-65 kPa may be a better range to maintain the vacuum advance while cruising. Here's the trace under accleration conditions: The suggested 55-85 kPa band will lead to full vacuum advance during the accleration. Shifting the band down to 35-65 kPa will prevent this. At each shift point, the pressure decreases because the throttle is released while the shift is executed. This will llikely lead to the a sudden increase in the vacuum advance, even with my revised 35-65 kPa band. When I compare the deficiencies of ported vacuum vs. manifold vacuum, it seems as if ported vacuum has a weakness of frequent vacuum advance dropouts, while manifold vacuum has the weakness of sudden surges of vacuum advance at each shift point. You can pick your poison. Anyone else have any thoughts about the selection of vacuum source? Terry
  3. After getting some direct advice from board members and reading past threads, I started with these advance curves programmed into my desmogged 4-speed 1975 2002 with Weber 32/36. Here are the advance curves I tried: Under acceleration from a stop, here is a typical set of Total advance (red curve), Ported Vacuum Pressure (green curve), and engine RPM (blue curve). The gear I was in during acceleration is marked by "1", "2", "3", and "4". While cruising on the freeway at close to 70mph, here is the logged data: After seeing this data, I'm inclined to widen the allowed band for vacuum advance to be applied (it is 30-60 kPa in this trial), to keep the distributor from hunting back and forth between 36 degress (maximum centrifugal, no vacuum advance) and 43 degrees (maximum centrifugal and vacuum) while attempting to cruise. It looks like every time I put a small amount of pressure on the throttle (so that the vacuum port pressure decreased), the distributor cut out the vacuum advance (dropouts in red curve). I've seen in various threads that the 123 won't allow you to set the lower limit below 29 kPa, but I can't see this documented anywhere in their literature. Can I set the lower pressure limit to 20-25 kPa to eliminate the cruising dropouts? The other issue I can see with this setup of vacuum advance is that the upper pressure cutoff limit of 60kPa allows the advance to creep up above 40 degrees during the extended acceleration in 3rd gear (see the acceleration plot), as the pressure drops into the range when vacuum advance is programmed to be applied, though this is for a fairly short period of time. Am I wrong to be thinking that the goal for programming vacuum advance should be to make the allowed pressure band as wide as possible (to eliminate advance hunting during cruising by allowing vacuum advance to be applied almost all the time), without causing excessive advance during either: (a) acceleration from a stop, or (b) strong acceleration while cruising? Or are there other operating conditions during which too-easily-applied vacuum advance could be a problem? Terry
  4. Yes, I'm sending $ to Holland to tide them over thru Covid-19. From what I've read, the provided installation directions for the 123 are....not so good. Does anyone have some links to instructions that are clear and helpful?
  5. love, love, love that tobacco interior. if that is what it is....
  6. and social distancing probably precludes throwing my 164 into the neighbor's pool...
  7. oh, that one might be headed to Minnesota for rehabilitation as a backup. I'll keep it on my nightstand so I can sleep at night, despite all the concern about vacuum advance....
  8. Steve- Is this "mimicking" feature availabe on the USB version as well? Or is it just on the Bluetooth version?
  9. although I think 7502 used the "wrong" vacuum port...
  10. Mark92131's experience above makes we ask the question: Has anyone been successful at building a MAP curve using either: (a) direct (non-ported) manifold vacuum or (b) the ported vacuum port on the 32/36? Sounds like 7502 may have been successful. Anyone else successful with a 32/36?
  11. Stevenola- Sorry for not answering your question about the other vacuum hose. One leg of the tee is connected to the port on the manifold that is right under the ported vacuum port on the 32/36 (the blocked-off lower port in 7502's picture). Another leg is connected to a grey canister in the engine compartment that I'm guessing has to do with fuel-tank vapors. The final leg of the tee goes to a hose that enters the air cleaner and opens up right beside the throat of the carb. Previous owner set this up, so I'm not sure what the rationale is for this plumbing. So, yes, this line also looks like a candidate MAP port. If manifold vacuum is indeed the correct port to use, which seems to be in question. Terry
  12. yes, Weber 32/36, so I assumed that the current "ported vacuum" port being used with the old mechanical distributor would NOT be the appropriate port to use with the 123.
  13. Is it necessary with a 123 distributor to put a pulsation dampener between a manifold vacuum connection and the distributor?
  14. Regarding the longevity issue, yes, I know they're electronic, but there are still mechanical moving parts that must wear and eventually fail. And if the electronics are really that good, then a mechanically worn shaft, bushing, washer, etc. will end up being the limiting factor. It would be interesting to know how long people have run these in the field without failure. I found one guy on Youtube who had run one 100,000 km, but it eventually did suffer an electronic failure.
  15. OK, I know many will roll their eyes and wonder if this is yet another thread about this distibutor. But I'm at the cusp of having to decide if it's worth spending $500+ on this, so I get to put my focus on this question. Let me look at it from the perspective of what the potential downsides are to this unit (my wife says I always like to take a negative outlook...): (1) the installation and documentation information from the vendor is sub-par: not a deal-killer since there are lots of accounts online about how to do it. (2) the longevity of the distributor: will the units last 50K+, 100K+, 150K+ miles? The mechanical structure is simpler than a conventional distributor, but does the vendor really know how to make units that will last a long time? Will the vendor be around in 10 years when the units start to fail either mechanically or electrically. I haven't found much about this online... (3) the ambiguity about how to handle vacuum advance: not a huge problem, but there is a lot of confusion online and it is still unclear to me if MAP sensing does as good a job as ported vacuum advance in a conventional mechanical distributor. (4) the oil intrusion problem: seems to afflict a non-trivial number of the units and the vendor doesn't seem to be willing to modify the design to fix this for all users. Could be a big problem having to get the units rebuilt ever 15K miles. (5) if it fails, it's a black box and can't be readily troubleshooted by a typical user. You have to send it back to the vendor (if they still exist) or toss it and start over with a new solution. Anything I've missed? Am I being too paranoid about this expensive solution? Terry
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