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pdp8

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About pdp8

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  • Gender
    Male
  • Location
    california, bay area
  • Cars
    1979 210 wagon,1980 510 wagon, 1972 1200,4 Saabs,2XE350,2XCVR(T) if those count
  • Interests
    Older cars, old computers, CVR(T)
  • Occupation
    telescope technician

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  1. The carb is on the passenger side and the valve cover says NissanZ, so I'm thinking Z... Pink slip says 1980 but VIN starts with WHLA10. Newer than any Datto I've ever owned so I'm in new territory here. When I ran it in the driveway and looked down the carb, slowly revving it I do see fuel coming out of the primary venturi but you raise a good point in that one of the only orifices I didn't verify was the primary jet. My smog machine suggests the HCs go really high before it dies like it's dumping fuel, but of course that's completely inconsistent with running pretty well until the choke opens. Made me question the ignition but honestly I'm a little bit intimidated by anything that drives 8 spark-plugs using 2 coils!
  2. pdp8

    12" tire options?

    I know it's hard to get performance 13" but I just bought a 1200 with factory wheels and am now challenged to find tires. I know there are several options out there from manufacturers I've never heard of and pretty much all 155/80. I'd love to know of some just ever so slightly wider tires from a company I'd have some trust in. Otherwise, how have people been fairing with their Nanking, Federal, Americus, etc. tires? Are they actually decent or is it just time to steal some 13s from my 210 pile?
  3. Symptom is this, car runs great when it's cold but as soon as it warms up it idles strong but dies when you give it throttle. It's particularly bad when you come off the brakes and try to start moving after a stop. I did kit the carburettor since the accelerator pump wasn't working, it wasn't that dirty at all and I took pains to make sure I blew out every passage with compressed air. I did find the main venturi to be loose so replaced the O-ring and tightened it in. If you accelerate *very* slowly you can get up to some sort of speed. Automatic and factory carb. Hose routing looks stock but not sure things are working as they should be.
  4. So, I like the idea of a turbo A-series motor but I don't understand why people make it more complicated than it has to be. I see lots of people trying to make it work with carburettors and of course that's just not something that is naturally going to work out. Seems like it's either the extreme low-buck crowd or those folks who don't want to mess with a megasquirt setup. Then the megasquirt folks, seems like a good way to do it but gets complicated with all the bits and pieces. What I haven't seen is people doing it the easy way: The first mass-produced turbocharged car was the Saab 99. They used a Bosch Jetronic mechanical fuel injection. In it's essence it just uses a spring-loaded plate the air flows by as an air-mass sensor that moves a plunger that meters fuel to the injectors. Very like a variable-venturi carburettor but with the fuel added downstream, a natural fit for a turbo! You can make it work with just one wire to the fuel pump. Bonus points for a warm-up regulator (think choke), it's nice to have a fuel accumulator to aid warm-up, and a cold-start injector (also nice for dumping fuel during heavy boost) but it's really simple overall and you can grab the parts off any old Saab, Volvo, VW or whatever European car from the 70s or 80 you care to. No need to tinker with your ignition or so much as own a computer.
  5. I love the wrench with the hole drilled in it, great idea. I have a tappet wrench I cut down to size and ground the head to narrow it as well. My contribution is this, before you put the carb back on make sure to get in with a die-grinder or Dremel and open up the recesses where the nuts live as much as you are comfortable with. Giving you a little more room to work makes the process a whole lot better during the re-installation and future removal.
  6. pdp8

    1980 210 floor pan

    I just hacked the back third off a wagon in a yard near me, clean California car. Shipping would be rather spendy I suspect but I don't think the pan would be hard to cut out. PM me if you want to discuss it further.
  7. 510 wagon 1980, automatic, 2L. Located in the south bay area of California. Well, since there is a place for these, this one might as well be here. It's a project I shouldn't have taken on. The PO swore it was a 210 and by the time I drove 150+ miles with the van and tow dolly with the final hour and a half out in the sticks with unpaved one-lane roads, I'll be damed if I was going home empty. I figured it needed rescue and was bound to be worth more in places with running water so dragged it home. https://sfbay.craigslist.org/scz/cto/d/santa-cruz-1980-datsun-510-station-wagon/6884780261.html
  8. Leave it, it's just a leftover defect from the casting process. Welding on it will just risk cracking down the road. The casting process for these blocks was fairly imprecise so there is a large amount of extra material sitting around.
  9. This should be the more-or-less final note I have for this thread: I reduced the orifice on the primary a bit too much (like 18.5:1 too much) and then opened it up a touch (#55 drill) so my lean cruise seems to be in the low to mid 16s. I've removed a few more coils from the power valve plunger so I can cruise at 75MPH on flat land but the moment I hit a grade it kicks in. After the first time I learned my lesson and left the diaphragm in the top cover and just cut the spring one coil at a time with a dremel. I lost count but one coil at a time was really unnecessarily gradual, two at a time is plenty fine I think and I lost count but I'd say I'm about 8 coils down from factory. It's still too rich on the power valve but enough of that is altitude and fuel variation that I'm not positive I'm going to chase it down. In the end, it's much more tractable than the factory carb in terms of usable torque but it's still pretty imprecise. I set the idle to a nice 14:1 and the next day it's at 12:1 or 15:1 depending on engine temp, where I bought gas, the barometric pressure, etc. I see less variability at steady throttle but accelerating and decelerating both show wonky irregularities and if I pull a hard corner while doing a hillclimb I really see how fuel slosh is hurting me. I considered a computer-controlled air-bleed solenoid but really I fear if I want better it might be time for some sort of EFI. Oh, mileage... too soon for real data but it looks like I'm back in the mid-30s, not great but it's almost as good as the Hitachi. I'm interested to see if I can break 40 on a road-trip like I could on the Hitachi.
  10. Well, it's progress... "You can make adjustments to the power valve by shortening the rod that protrudes into the float bowl. I hit them on a belt sander and knock them completely off." I thought about this and started shortening the rod from the power valve, I cut it to about 1/2 it's length and then stopped. If I knocked it flat off, I would have had no power valve action which isn't what I was looking for. I tried it with the shorter pin and it helped a very tiny amount so I worked the other end, I considered shortening the plunger out of the vacuum-housing but decided on reducing the spring pressure instead which has worked pretty well. I cut about 3-turns off the spring and I can now cruise carefully at almost 70 or climb a *very* slight grade without going into the power valve, I'll take another 2-turns off and that should be good. If I were going to do it again, I'd leave the diaphragm housing attached to the top cover since it's small and thin, I got it assembled with a slight crease the first time and then it was on the power valve worse than when I started. OK, so the sensitivity is about fixed but it's still way too rich. Sounds like it uses the same nozzle as the power valve? Oh, When I started both jets were #140s which is .0535". I altered the secondary to .0465"(#56 drill) which nets me a cruise A/F of about 15.2:1, I could go a touch leaner.
  11. Blueprinting can help a fair bit: A good 3-angle valve job, undercut the stems for better flow while you're at it and balance the c**p out of it... pistons, big end and small ends of rods, etc. It will run smoother and make more power, with some better valve springs you can rev it higher to get more power yet. Even if you don't do a real port job, cutting down the valve guides can make some nice room. Especially if you have a swirl-intake head, porting can help improve power without hurting emissions much. Fancy coatings in the exhaust stream will aid in scavenging and flow. If you have the original catalytic converter, change it out for a new one, they will flow better and help you pass smog with your other modifications. I found some joy with mild flow work on the Hitachi carbs, a dremel and time will allow you to re-contour the venturis and smooth the throttle shaft. It's no Webber but every little bit, right?
  12. I've lost my notes temporarily. I think the jets were #140 though there is a tiny chance they were #145. I measured them and the one on the secondary was a bit smaller but I had looked up the date and they weren't individually gauging them at that time so I'm not too surprised. OK, I'll try shortening the rod a bit and see how I come out. Is there a length to pressure ratio I should know? I'll have to look at the carb for the sub-model but it's progressive mechanical secondary, single-pumper, electric-choke. Is it really the case that the accelerator pump and power valve share a nozzle so to change I wind up changing the other as well? Unfortunate but I can cope. I'll shoot for "best lean torque" in the mid 13s then. What about primary/secondary cruise? I'm at low 15s now and I thought that was pretty thin but I did some looking and I gather newer cars are running mid 16s. I'd worry about exhaust valves but I guess you aren't really making any heat or power at those loads so it's ok?
  13. Based on idle and lower-speed cruise I'm convinced my primary jet size is good. I reduced the size of the secondary by about 20%(by area) and now my higher speed cruise values look good as well. That helped me see my other problem, if I tip the throttle it still just dumps fuel. I'm talking ratios as low as 11:1 here at the slightest grade or acceleration. So, I need to both decrease the sensitivity of the power valve and also reduce the flow. I know there are theoretical A/F ratios for ideal power but I also know that the type of motor matters a fair bit, what have people found with the A13 motor to be a good power-making ratio that stops short of just converting fuel into smoke? thanks,
  14. Thanks for the input. Well, based on that recommendation I've changed the secondary from a .0535" down to .0465". I left the primary alone because it's running pretty right-on in that range. Test drive tomorrow and we'll see.
  15. I got the car with the Weber and had to swap to a Hitachi, well I've moved and the Hitachi got balky so I dug out the Weber. It really makes more low/mid power which the poor little motor needs so that's a win. Idle is good, power is fine, low to mid cruising is lovely. The issue is that if I tip the throttle my A/F plummets from 14-15 down to about 12:1 and pretty much stays there. I'm having a really hard time deciding if it's a power valve issue since it's a big carb for that little engine or if I'm opening the secondaries and they are well to the rich side. There is only the slightest difference in throttle position and I sometimes see the ration change with no throttle movement so I'm suspecting power valve. Secondarily, what's a good A/F for power without just turning fuel into smoke on a tiny N/A motor like this? Thoughts anyone? I'd rather buy the likely parts before cracking the carb since I don't live anywhere near a parts shop. Thanks all,
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