duragg Posted October 14, 2011 Share Posted October 14, 2011 QUESTION:Is this type of system (Crane XR3000) as stable as any other, or are their better? 1973 240. F54 / N42 / Triples / 10.3:1 / L490-290 cam / Fairly new engine for me (<3 months). Crane XR3000 on my old L24 Dizzy that I had recurved for +20 mechanical advance only. Spins up pretty quick to full adavnce. New slotted wheel, new rotor, cap, wires, and an MSD Blaster 2 coil. I zoom the car around on weekends and to car shows - nothing critical here. Some say the optical thing isn't all that great. I've been told some kind of GM HEI thing would be superior. What is the short-course on the most stable hi-power ignition at a reasonable cost ($100-$250) Thanks all. Quote Link to comment Share on other sites More sharing options...
Leon Posted October 14, 2011 Share Posted October 14, 2011 I'm converting to crank-trigger ignition using EDIS 6 and Megajolt. It cost me in the range of $400, but it can be done for $200-250 with time and ingenuity. It's also fully programmable, which is what I was looking for. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 14, 2011 Author Share Posted October 14, 2011 Crank trigger is the ultimate in stability is that right? Gets rid of the gearing in the dizzy? What are you replacing? What issue made you want to upgrade? Thx., Quote Link to comment Share on other sites More sharing options...
johnc Posted October 14, 2011 Share Posted October 14, 2011 Well... my race engine ran to a 7,500 shift point and a 7,900 redilne and we ran an optically triggered distributor wheel. That's with a full Motec M48 setup, 14 to 1 CR, etc. Ignition was rock steady. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 14, 2011 Author Share Posted October 14, 2011 Were you running the "Crane" wheel setup? I worry that the dinky plastic pinwheel in the Crane system is not reliable enough. In fact I notice that around the 3000 rpm range my tachometer needle wiggles a bit (1/- one needle width). That signal is directly off the coil. So either its a problem with the new tach, or the tach is telling me that at times the output from the pinwheel is marginal. The pinwheel doesn't sit rock steady on the shaft. If you grab it with your fingers it can easily be pulled off. Same with the rotor bug for that matter. Even though both are new. Maybe they just need to be modified to sit down nice and tight. With triples especially, seems the ignition needs to be ultra stable and I don't get the feeling that mine is. Help / advice is appreciated. Tj Quote Link to comment Share on other sites More sharing options...
Leon Posted October 14, 2011 Share Posted October 14, 2011 Crank trigger is the ultimate in stability is that right? Gets rid of the gearing in the dizzy? What are you replacing? What issue made you want to upgrade? Thx., Yes, it should be a hell of a lot more stable than a distributor since the sensor reads right off the crank. I'm replacing the stock 260Z distributor which has an undesireable timing curve for my triple Webers. I get 26 degrees of mechanical so I can only run about 10 degrees static, max. I have a 280ZX electronic distributor with 17 degrees of mechanical, going off of my memory, but I decided to quit screwing with distributors and go with a fully programmable system. Being able to create my own map is a big plus, because not only will I have an optimal timing curve at WOT, but also at cruise. A load-sensing timing curve (MAP sensor) also enhances throttle tip-in. The accuracy, tunability, and great price made the choice to convert to EDIS easy for me. Additionally, it allows me to keep the triples while having an awesome ignition system! Quote Link to comment Share on other sites More sharing options...
z-ya Posted October 14, 2011 Share Posted October 14, 2011 QUESTION:Is this type of system (Crane XR3000) as stable as any other, or are their better? 1973 240. F54 / N42 / Triples / 10.3:1 / L490-290 cam / Fairly new engine for me (<3 months). Crane XR3000 on my old L24 Dizzy that I had recurved for +20 mechanical advance only. Spins up pretty quick to full adavnce. New slotted wheel, new rotor, cap, wires, and an MSD Blaster 2 coil. I zoom the car around on weekends and to car shows - nothing critical here. Some say the optical thing isn't all that great. I've been told some kind of GM HEI thing would be superior. What is the short-course on the most stable hi-power ignition at a reasonable cost ($100-$250) Thanks all. Question: Does it run OK? Does it feel like it is missing? What plugs/gap? There is nothing wrong with triggering from the distributor. I've not hear bad things about this system. It is most likely better than the HEI retrofit. I run a 280ZXT distributor in my vintage racer with an MSD. The timing is rock solid. Sure, a crank trigger is more stable, but if what you have is working, I'd stick with it. Quote Link to comment Share on other sites More sharing options...
johnc Posted October 14, 2011 Share Posted October 14, 2011 Were you running the "Crane" wheel setup? I worry that the dinky plastic pinwheel in the Crane system is not reliable enough. In fact I notice that around the 3000 rpm range my tachometer needle wiggles a bit (1/- one needle width). That signal is directly off the coil. So either its a problem with the new tach, or the tach is telling me that at times the output from the pinwheel is marginal. The pinwheel doesn't sit rock steady on the shaft. If you grab it with your fingers it can easily be pulled off. Same with the rotor bug for that matter. Even though both are new. Maybe they just need to be modified to sit down nice and tight. With triples especially, seems the ignition needs to be ultra stable and I don't get the feeling that mine is. Help / advice is appreciated. Tj We used a ZX distributor body and a Motec stainless wheel with a Motec optical trigger. Instead of relying on your feelings, hook up a good meter and watch your actual ignition timing and firing. If there's any variation its far more likely in the distributor body then the trigger wheel. Quote Link to comment Share on other sites More sharing options...
johnc Posted October 14, 2011 Share Posted October 14, 2011 Yes, it should be a hell of a lot more stable than a distributor since the sensor reads right off the crank. At least in my situation there was zero measurable variance in ignition timing or firing up to 7,900 rpm with a distributor trigger. That was measured using Motec data logging and we tracked the firing of each cylinder from 4,000 to 7,900 rpm. Dead nuts accurate. (EDIT: within 1 degree of crank angle) Forgot to mention that we had a separate crank trigger on the engine at the time (on the engine dyno) which was used by the dyno software. Comparison showed the distributor trigger matched the crank signal that the dyno was picking up. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 14, 2011 Author Share Posted October 14, 2011 We're running "ok" and lots of other changes in the car so I am not sure what is doing what all the time. Hence my desire to lock down timing and eliminate it as any potential variable. NGK BP8ES right now. I am ordering some BP8ES-11 (bigger gap). Sometimes I am steady state at mid-rpm say 3000 and I can feel some slight missing. Wideband shows fuel flow is appropriate which makes me wonder about ignition. I have timing back to 25 total right now because my pulley slipped and I want to wait for the new one before I retime and put the big balls back in it. I am running a mix of 100LL and 91 pump gas. Perhaps I will start by shimming the pinwheel and rotor bug to be much tighter on the shaft. Lastly, Appears my system is firing right off the very far tip of the rotor bug versus the center. Need to fix that. Sorry for the big data-dump. Quote Link to comment Share on other sites More sharing options...
Leon Posted October 14, 2011 Share Posted October 14, 2011 (edited) At least in my situation there was zero measurable variance in ignition timing or firing up to 7,900 rpm with a distributor trigger. That was measured using Motec data logging and we tracked the firing of each cylinder from 4,000 to 7,900 rpm. Dead nuts accurate. (EDIT: within 1 degree of crank angle) Forgot to mention that we had a separate crank trigger on the engine at the time (on the engine dyno) which was used by the dyno software. Comparison showed the distributor trigger matched the crank signal that the dyno was picking up. I don't doubt that, and I'm sure a fresh, well-built distributor can be very accurate. The difference here between crank-trigger and distributor is that there is no shaft, bushings, bearings, etc to wear out. As those parts of a distributor are wear down, timing will be less and less accurate. It really comes down to what you need. Do you need something that works with minimal time and money put in? Do you need to follow a certain rule-set? Do you need full programmability? A distributor is fine, but I much prefer to trigger my spark off the crank and change spark advance with a keystroke than play around with advance springs and breaker plates. Edited October 15, 2011 by Leon Quote Link to comment Share on other sites More sharing options...
duragg Posted October 14, 2011 Author Share Posted October 14, 2011 Summary: Crank trigger or a fancy machined wheel in a perfectly new Dizzy is best. A well running Crane or other dizzy based system for a hopped up street car should be fine perhaps. Thinking about all of this I will go back and re-do the "phasing" and make sure everything is tight in my current dizzy and see how that goes. Appreciate the input. Tj Quote Link to comment Share on other sites More sharing options...
duragg Posted October 15, 2011 Author Share Posted October 15, 2011 I am almost embarrased to share this video. I just now took a video of my rotor bug. Something tells me the motion is excessive (please don't hammer me... I'm kinda new). Am I toast with this? Quote Link to comment Share on other sites More sharing options...
johnc Posted October 15, 2011 Share Posted October 15, 2011 Its got some extra slack but you're not toast. Remember, the slack is taken up under acceleration so keep that in mind when setting the timing. The rotor will lag. You'll see variation at idle because of the light load and people assume that variation is constant under acceleration. Its not. It just varies at steady throttle. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 15, 2011 Author Share Posted October 15, 2011 Seems under full power the thing is pretty stable. But idle and part throttle - say holding 3000 and waiting to stomp I can hear a little messing around. I wonder if that is in the helical gear on the crank or the half-moon higher up? Worth trying to tighten up? I think I can find a way to tighten up the middle joint easier. Quote Link to comment Share on other sites More sharing options...
z-ya Posted October 15, 2011 Share Posted October 15, 2011 Seems under full power the thing is pretty stable. But idle and part throttle - say holding 3000 and waiting to stomp I can hear a little messing around. I wonder if that is in the helical gear on the crank or the half-moon higher up? Worth trying to tighten up? I think I can find a way to tighten up the middle joint easier. Are you sure it is not fuel? Do you have a wide band O2 sensor on there so you can see what it is doing at 3000RPM? BP8ES is probably too cold for street use. I would not use a projected tip either. I would try B7ES and set the gap to 35 thousands. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 15, 2011 Author Share Posted October 15, 2011 I'm not sure of anything with 3 DCOEs. I am running a mix of 100LL and 91 pump gas (50/50). Wideband shows low 12s at that time. This motor just seems to pull hardest in the low 12s. Starts sneezing in the mid 13s. Could be one carb over or under contributing, but all plugs look similar. Could be the O2 sensor getting funky from the lead in the 100LL Could be just the way triples run and want to be richer. So, today I will recalibrate the timing again and do the phasing procedure on the Optical wheel again. Will also hunt down some different plugs and gap up to .040 or something. Appreciate the help. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 17, 2011 Author Share Posted October 17, 2011 Today: Pulled valve cover and verified Cam mark and piston #1 at TDC. I made a more distinct white ZERO mark on the pulley and indicator to line up #1 TDC mark. Switched to B8ES at .041" gap plugs. Started the engine and set timing max advance at 34btdc (elevated RPM). This gives me about 14 Initial. I then phased the rotor to the Cap and shot this video. What you cannot see: * Using a Snap-On variable timing light to keep the white marks on the pulley aligned at Zero. * Then reading the timing from the dial. * Then shooting the light at the cap and you can see the rotor alignment is better (without touching the dial / same rpm). At idle and up to maybe 2000rpm the timing marks are rock steady. From maybe 2000 up the timing marks starts to jump around quite a bit. Much higher rpm is steadies a little bit, but not rock solid. Rotor cap for testing. Felt a lot better driving after this. But still concerned about those marks jumping around. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 17, 2011 Share Posted October 17, 2011 ANY spark scatter you are experiencing is NOT a function of the Optical Trigger. It's an e-gate which is on or off and nothing in between. ANY spark scatter you are experiencing is DIRECTLY a function of several factors which come into play when using ANY system NOT directly fired off the crankshaft. 1) Crankshaft to Drive Gear Backlash. 2) Any Key Shearing that may have happened. 3) Possible loose pulley bolt letting drive gear on crankshaft 'work'. 4) Friction fit of drive gear on distributor shaft which lets is rotate freely when hot. 5) Slop in the Drive Tang of the Distributor. ALL the above factors (these are the quick ones I can think of) contribute to timing that 'changes' while the engine is running. The optical triggers are good to over 12,000rpms DISTRIBUTOR speed without fail. JeffP has made a test bench to check this on an O-Scope, similarly the input speed for the Nissan Distributor (Z32) components is similar. The trigger only fires when gated. WHERE the gate is relative to the crankshaft is dependent on the above 5. There is no rotational inertia of the plastic disc relative to the metal components. I will posit the 'scatter' you see is from the metal parts which have a lot more inertia 'rattling around' and as the disc is relative inertia-free it sticks to the shaft it's pressed onto and triggers reliably relative to it's original position. Take that same optical trigger wheel, chuck it in a direct driven dremel tool powered test stand and you see there is no variation in trigger events. It's rock solid. In the digital world, it truly is GIGO---the mechanical slop leading up to the triggering point is where its changing. It moves relative to the crankshaft for any number of reasons. The stock mechanical distributors do the same thing. You can't make a silk purse out of a sow's ear, but you can make a damn good looking pig. Short of going to crank-fire, the only thing you can do is what guys have always done to get better, more accurate distributor spark timing. Ultimately that meant removing the distributor and it's complex drivetrain components and triggering off the crank directly. That is the ultimate solution. The question is "do you need it?" From what your described use of the car is currently....I would say "No". Quote Link to comment Share on other sites More sharing options...
duragg Posted October 17, 2011 Author Share Posted October 17, 2011 (edited) Very helpful, thank you. So I will pull the dizzy and drop off at the machine shop to get rebushed. Or do I just buy a new one, and install my eyeball in there? Not opposed to spending some money to have nearly perfect ignition as reduction in variables only contributes to Triple DCOE performance. (edit: $150 ish to fix a dizzy is fine (my machine work is free). SPending over $150 makes me think crank fire.) ... Yet again, building an entire car around 3 italian carbs! I wouldn't have it any other way. Unless I win the lottery and install: www.imagineinjection.com Edited October 17, 2011 by duragg Quote Link to comment Share on other sites More sharing options...
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