Crashtd420 Posted March 23 Report Share Posted March 23 29 minutes ago, 510_dreamin said: Unfortunately I have no idea. They’re the same model carbs (40dcoe) but that’s all I know. I was surprised to see them changed out by the shop in the first place. I asked for the ones I had to serviced and it turned into a swap out since mine allegedly needed a rebuild. That could be some of the reason why it feels different when driving.... It's definitely tougher when you question 2 items as an issue.... Have you done anything lately with the carburetors or are you just playing with the distributor? Quote Link to comment
Crashtd420 Posted March 23 Report Share Posted March 23 Also did you catch the question about your vacuum source? Are you in fact using the map curve? Quote Link to comment
alfa7kar Posted March 23 Report Share Posted March 23 I have a 123 on my 510 with a l20b with a weber 38. Your ignition map looks really close to mine I also do not run the map/vac i just zeroed it out and it is not conected. I run just regular unleaded 87 with no pinging even in the summer. maybe you got some bad gas it happens also i had a 521 with a l20b that would ping and deisel i just ran chevron 91 and it solved the problem. Quote Link to comment
alfa7kar Posted March 23 Report Share Posted March 23 (edited) also can you confirm with a timing light that you are close to what the curve says at idle. it would really be confusing for you if it was off that might be a problem if it was set advenced say like 25 deg at idle but the curve says 15 Edited March 23 by alfa7kar 1 Quote Link to comment
Crashtd420 Posted March 23 Report Share Posted March 23 1 hour ago, alfa7kar said: also can you confirm with a timing light that you are close to what the curve says at idle. it would really be confusing for you if it was off that might be a problem if it was set advenced say like 25 deg at idle but the curve says 15 This is actually something good to verify if you haven't... I remember having to adjust the timing slightly after following the setup instructions to get the 123 to read the same as the timing light... Quote Link to comment
510_dreamin Posted March 24 Author Report Share Posted March 24 8 hours ago, alfa7kar said: I have a 123 on my 510 with a l20b with a weber 38. Your ignition map looks really close to mine I also do not run the map/vac i just zeroed it out and it is not conected. I run just regular unleaded 87 with no pinging even in the summer. maybe you got some bad gas it happens also i had a 521 with a l20b that would ping and deisel i just ran chevron 91 and it solved the problem. I don’t have anything set up for the map I should probably zero mine out as well. I have dieseling too most time. I just filled up with a fresh batch of chevron 91, usually all I run or shell 91. California gas though. timing light is a good idea. I’ll look into that. I might work on adjusting the carbs too and see if I can smooth them out a bit. thanks everyone for all the help. I feel it’s getting better and better with each suggestion you all have, what a great community! 1 Quote Link to comment
datzenmike Posted March 24 Report Share Posted March 24 Dieseling on shut off? Try setting 12 degrees just for idle. Quote Link to comment
510_dreamin Posted June 29 Author Report Share Posted June 29 Hi Everyone, finally got the ignition dialed in and carbs tuned. It was a combination of carbs needing some adjustment, user error with the 123ignition app, and trial and error with the advance to get it dialed in. Now that it runs well my next question is the factory tach doesn’t rev up much since the 123ignition was installed. It also has an MSD Blaster 2 coil. I believe the tach pulls the signal from the coil. Is the Blaster 2 the wrong coil for the tach to work, would switching to like a Pertronix Flamethrower help? Quote Link to comment
510_dreamin Posted July 4 Author Report Share Posted July 4 (edited) After the coil replacement, carb tuning , and following all the tuning suggestions it appears to now run a bit hot and still struggles with hills. Any other suggestions? At 30 degrees total advance by 3k rpm Edited July 4 by 510_dreamin Quote Link to comment
datzenmike Posted July 4 Report Share Posted July 4 All the advance mechanical and initial in, should be about 32 degrees total. The L series seem to like 32 degrees at full throttle. As the 123 is adjustable, try 13 or 14 degrees initial timing and 18 degrees total mechanical as this adds to 32 total when revved up and WOT. You could experiment with bringing in the total sooner see if that runs better. Is there a provision for vacuum advance on the 123? Stock '71 vacuum advance is 18-22 degrees at 14-16 inches of vacuum. If that helps. Vacuum advance is load dependent in that light throttle is high and full throttle is very low to non existent. Quote Link to comment
510_dreamin Posted July 4 Author Report Share Posted July 4 In reading the manual It uses a MAP Curve as opposed to Vacuum advance. I have no idea what this means but trying to learn. Local tuners indicated they can tune it for $700-$1000 on a dyno but I feel that’s how I got into this mess so trying to learn how to do it myself. Regarding the vacuum curve, this is a little bit more complex. 123ignition works with absolute vacuum in stead of relative vacuum. The advantage of absolute vacuum is, it works also when you drive the car on high altitudes. In case of relative vacuum, you have to adjust the ignition manually. The values in the original Bosch graph are given in mmHg, 123ignition works with kPa. First we convert the values to kPa and crankshaft degrees instead of distributor degrees. You can type in Google: 80 mmHg to kPa 0 deg @ 11 kPa 10 deg @ 27 kPa Now we have to convert the relative values to absolute values. Atmospheric vacuum at see level is 100 kPa. So 100 kPa is our base point. Al values below 100 kPa is vacuum all values above 100 kPa is pressure. in this case we have a vacuum curve, so our result will be: 0 deg @ 100 – 11 kPa = 89 kPa 10 deg @ 100 – 27 kPa = 73 kPa Quote Link to comment
Crashtd420 Posted July 4 Report Share Posted July 4 9 hours ago, 510_dreamin said: In reading the manual It uses a MAP Curve as opposed to Vacuum advance. I have no idea what this means but trying to learn. Local tuners indicated they can tune it for $700-$1000 on a dyno but I feel that’s how I got into this mess so trying to learn how to do it myself. Regarding the vacuum curve, this is a little bit more complex. 123ignition works with absolute vacuum in stead of relative vacuum. The advantage of absolute vacuum is, it works also when you drive the car on high altitudes. In case of relative vacuum, you have to adjust the ignition manually. The values in the original Bosch graph are given in mmHg, 123ignition works with kPa. First we convert the values to kPa and crankshaft degrees instead of distributor degrees. You can type in Google: 80 mmHg to kPa 0 deg @ 11 kPa 10 deg @ 27 kPa Now we have to convert the relative values to absolute values. Atmospheric vacuum at see level is 100 kPa. So 100 kPa is our base point. Al values below 100 kPa is vacuum all values above 100 kPa is pressure. in this case we have a vacuum curve, so our result will be: 0 deg @ 100 – 11 kPa = 89 kPa 10 deg @ 100 – 27 kPa = 73 kPa I have never gone back to try to add a map curve, I wanted to but I'm connected to the manifold and have always been confused about what to add when and how with the curve.... Quote Link to comment
Crashtd420 Posted July 4 Report Share Posted July 4 10 hours ago, datzenmike said: Is there a provision for vacuum advance on the 123? Stock '71 vacuum advance is 18-22 degrees at 14-16 inches of vacuum. If that helps. Vacuum advance is load dependent in that light throttle is high and full throttle is very low to non existent. Can you add to this for me.... Say your cruising at 3000 rpm light throttle so your already at 32 total timing.... Does the vacuum advance add to that 32.... does that mean you could be running as much as 54 degrees of timing depending on load? Quote Link to comment
510_dreamin Posted July 4 Author Report Share Posted July 4 12 minutes ago, Crashtd420 said: I have never gone back to try to add a map curve, I wanted to but I'm connected to the manifold and have always been confused about what to add when and how with the curve.... do you have any issues with your 123 setup? Mine feels sluggish at times, runs a bit hot, and spark knocks uphill where it’s slow lol Quote Link to comment
Crashtd420 Posted July 5 Report Share Posted July 5 22 minutes ago, 510_dreamin said: do you have any issues with your 123 setup? Mine feels sluggish at times, runs a bit hot, and spark knocks uphill where it’s slow lol Not that I can say.... But I don't have a before comparison... As for heat I have a 3 row aluminum radiator and it's always just on or above the center mark... even if I run my ac it doesn't get to much hotter As for sluggish or spark knock I don't think so.... I have some steep graded hills I travel up going to work.... I can usually keep cruising up the hills even in 5th, this is usually going about 60 to 65 mph. If get stuck behind someone and slow down I definitely have to down shift but I feel that's normal .... I do get a wierd sound I hate if my rpms are low and I try to go full throttle climbing a hill in 5th.... I have always felt it was a lugging sound not a spark knock since I'd get the same sound starting from a stop at idle if I'm too light on the throttle and too quick off the clutch pedal.... I also have dome pistons, I don't know if I read about issues running them in a street application but I forget exactly what that was.... I'll be honest I have never heard a true spark knock to say oh that's it.... My last issue I blamed on the distributor and it was my carburetor... In the end I feel the distributor does it's job correctly, for me my engine setup is what needs to be adjusted to make more power.. more carburetor or possible efi and some head work, bigger valves waiting on the shelf for when I can do a port job... Quote Link to comment
510_dreamin Posted July 5 Author Report Share Posted July 5 (edited) 8 minutes ago, Crashtd420 said: Not that I can say.... But I don't have a before comparison... As for heat I have a 3 row aluminum radiator and it's always just on or above the center mark... even if I run my ac it doesn't get to much hotter As for sluggish or spark knock I don't think so.... I have some steep graded hills I travel up going to work.... I can usually keep cruising up the hills even in 5th, this is usually going about 60 to 65 mph. If get stuck behind someone and slow down I definitely have to down shift but I feel that's normal .... I do get a wierd sound I hate if my rpms are low and I try to go full throttle climbing a hill in 5th.... I have always felt it was a lugging sound not a spark knock since I'd get the same sound starting from a stop at idle if I'm too light on the throttle and too quick off the clutch pedal.... I also have dome pistons, I don't know if I read about issues running them in a street application but I forget exactly what that was.... I'll be honest I have never heard a true spark knock to say oh that's it.... My last issue I blamed on the distributor and it was my carburetor... In the end I feel the distributor does it's job correctly, for me my engine setup is what needs to be adjusted to make more power.. more carburetor or possible efi and some head work, bigger valves waiting on the shelf for when I can do a port job... I am running a Koyo radiator with dual electric puller fans. I’m running between 3/4 of the temp gauge to the end but with the IR thermometer it seems ok. I had my carbs tuned and adjusted and it definately helped. I just can’t figure this thing out Edited July 5 by 510_dreamin Quote Link to comment
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