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rcv

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About rcv

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  • Map Location
    Sherman Oaks, CA
  • Occupation
    CTO

My Cars

  • Zcars Owned
    240z
  • About my Cars
    1970 Series 1 240Z

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  • Website
    r-c-v.com

Zcar VIN Registry

  • Zcar 1 VIN
    HLS30-15257

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  1. Yeah, I'm really hoping it's just the exhaust hitting some resonant frequency and banging into something occasionally. I've got a big piece of 1.5" tube that I've been putting to my ear and trying to hunt down the sound - I'm sure my neighbors think I'm a crazy person. I haven't been able to pinpoint it yet, but it's comforting to not hear you say "that sounds like pinging and your engine is about to blow up." I'm still waiting for the DMV title transfer to go through, but I've been on a few questionably legal burns up and down my street and it feels great. It feels like there's plenty of power, and there's no hesitation as far as I can tell. I'm hoping I'll have legit plates and registration in a few weeks, and I'm really looking forward to working up to a drive down Mulholland here in LA. I'm running the "SU Carburetor Oil" from MSA right now - it's advertised as "the best dampening fluid for SU carburetors" but I have no idea what it actually is. Probably just plain 20W oil.
  2. Just a quick update - I bought some new SM needles from Joe Curto over at British Superior and dropped them in. The car immediately runs much better. I think I've got it tuned just about right - the ColorTune is showing a nice blue color, and slightly raising the piston by pressing on the little maintenance pin makes the revs go slightly up and then back down. I'm occasionally hearing a "rattling" sound from the engine now. At first I thought it was just all of the tools/WD-40/junk I had on the fenders, but I cleaned that all off and I still occasionally hear it. I've tried to track down where it's coming from, but I haven't found any loose bolts or anything else that looks like culprit. I've heard that detonation can sound like "a ball rattling around an empty spray paint can" so now I'm paranoid that I'm getting detonation. Can one of you experts give this a listen towards the end and let me know if I should be worried or not?
  3. Yeah, but I really just eyeballed them separately. I'm mostly concerned about getting the engine to idle correctly right now as an experiment, so I figured that the drop rates wouldn't be too big of an issue until I start fluctuating the throttle. I'm keeping things organized on my bench so that it will be easy to re-match things once I feel like I have an idea of what's going on. Absolutely - I texted Jeff already but I'm planning on giving him a call in the next day or so when I get a moment. He advertises a "1 year warranty" and I bought the carbs last October, but I'm hoping he'll be reasonable about it. Let me know if you decide to incorporate BruceTech - I may be in the market soon.
  4. Just the pistons. I want super rigorous about testing their drop rates like the ZTherapy dvd recommends, but they seemed roughly ok.
  5. Good idea. They don't have them listed on their site, but I'll give them a call and see.
  6. Well I may have celebrated a little prematurely. I had only color tuned the rear carb before my last post. I just went out and tried tuning the front one and it’s still rich, even with the mixture cranked all the way in.
  7. I just tried pulling the needles out of my old SUs, but both needles were stuck hard in the cylinders. I ended up just dropping the old cylinder + needle combo into rebuilt carbs on the car and ... drumroll ... it runs much better! The car won't start anymore with the mixture screws all the way in, but runs great around 2 turns down with a nice blue-ish spark from my colortune. I'm very pleased. I'd like to get a new set of needles if possible - does anyone know a good source these days? It looks like MSA is out of stock on their N-27s. By the way, here's what the needles I pulled out look like - the pitting is worse that I had thought, and I'm guessing that was effectively "thinning" the needle causing the rich condition:
  8. I got the carbs and intake manifolds from Paltech and just bolted them on as-is. I really have no idea what their history is, as I just bought the full set from him rather than having him restore my originals. I’m assuming he aligned the nozzles. The pistons drop freely with a nice solid clunk at the bottom when I pull the oil damper out, so I’m assuming the alignment can’t be terrible right? I’m going to swap those needles in an hour or two and I’ll post an update.
  9. I’m going to text him tomorrow and see if he’ll get back to me. I actually have the stock needles from my original carbs now that I think about it. I’ll try swapping them in tomorrow while I’m waiting for Jeff to get back to me.
  10. The needles looked ok to me when I pulled them out today. No pitting or scratches as far as I could tell. I didn’t see any markings on them to indicate what kind of needles they were though. It was getting dark though, so I could check again in the morning. Should they be marked on the shoulder?
  11. Ok, so I replaced my OEM ignition coil / ballast resistor today with a Pertronix Flamethrower coil and new resistor. The car seems to run a bit stronger, but the mixture is still way too rich. My colortune is showing bright orange even with the mixture screws all the way in. Backing them off at all just causes the motor to bog down and run like junk. I also tried re-seating the needles according to the Z-Therapy DVD instructions, but that made no difference. I'm not really sure where to go from here.
  12. My set point is 23mm down from the roof of the lid, which comes out to 14mm up from the base of my Float Syncs. I'm actually maybe 1mm off from that, but if anything I'm a little low so I can't imagine that's my problem.
  13. As always, I've got some good news and some bad news. The good news is that I installed a new K&N fuel pump, and the process couldn't have gone better. The float syncs are now showing near perfect fuel levels in the bowls, with the bonus feature of being able to tune the levels without Hoover's ladder. The bad news is that something is still very off with the mixture. Using the standard 2 1/2 turns down on the mixture knobs the car will barely start, runs very rough, and pours enough dark smoke out of the tailpipe that people on their afternoon strolls cross to the other side of the street. Good thing they're already wearing masks. As I turn the mixture knobs leaner and leaner, the car runs better and better. I bought myself a Gunson Colortune, and verified that even with the mixture knobs cranked all the way up I'm still running rich (see video below). I made sure that the chokes are pushed all the way up, so I don't think that's the problem. I suppose the next thing to check is that the needles are seated properly in the carb piston, or possibly the needles are just totally wrong themselves. Anyone have any other debugging advice I could try? Is it possible that my timing has something to do with this? I'm pretty sure I'm somewhere between 15-20deg advanced, but this is honestly my first experience with a timing gun so it's possible I'm screwing that up. I tried shifting the timing around a 5deg each way and didn't see an appreciable change in the spark color. EDIT: I just had another thought. I have no idea what the story is with the coil on this car, but it looks like it's the factory original one. Is it possible that my mixture isn't actually rich, but I'm just not fully combusting because of a weak spark from an aging coil?
  14. Ah yeah you're totally right, I was just setting the fuel levels with my funnel while my gas tank was in the shop. I re-adjusted yesterday during the brief period that my fuel pump actually worked, and and had to make minor adjustments as you'd expect. Just out of curiosity I calculated how high that vertical hose would be to get to 4psi: p = ρ g h p = pressure in liquid (N/m2) ρ = density of liquid (kg/m3) g = acceleration of gravity (9.81 m/s2) h = height of fluid column - or depth in the fluid where pressure is measured (m, ft) Using ρ=750 kg/m3 for the density of gasoline and 4psi = 27579.04N/m2 for our pressure we get a column height of ~3.75m = 12.3'. That's a lot of hose!
  15. Sorry, not sure I follow. I've been using Randalla's Float Sync's during all of my tuning, which were really helpful in immediately diagnosing that my float bowls were drying out.
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