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| Edelbrock 500 too lean https://slantsix.org/forum/viewtopic.php?f=19&t=64475 |
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| Author: | slantsix64 [ Thu Feb 06, 2020 2:03 pm ] |
| Post subject: | Edelbrock 500 too lean |
Hey guys I got an eddy 500 Avs on my slant six, she's running lean, I'm trying to get a nice tan color, my set up with 9:1 comp Howard's camshaft .473 lift clifford tube headers offy intake carb pointing towards to passenger fender, I currently have primary's .89 65x47 rods and .98 in the secondary's What kind of jets you guys running? |
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| Author: | Joshie225 [ Thu Feb 06, 2020 5:25 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
Tuning by plug color is obsolete. A wideband oxygen sensor is far superior. If you do get the plugs to be tan you're wasting a lot of fuel and are far richer than peak power. |
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| Author: | kesteb [ Thu Feb 06, 2020 8:41 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
The out of the box jetting is just fine. You may want to adjust the hanger springs for the metering rod. The problem is that you don't have enough fuel volume. You need to update the fuel pump. The stock fuel pump is marginal for a 1bbl carb and it can't keep the fuel bowls full on the Edelbrock. I would suggest an electric pump and a regulator set at 5 psi. Been there, done that, have the discarded parts. |
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| Author: | Greg Ondayko [ Fri Feb 07, 2020 5:42 am ] |
| Post subject: | Re: Edelbrock 500 too lean |
I agree that tuning by reading the plugs is a usable yet archaic method. I diddled with the vacuum springs on my 500 on the 69 dart for driveablity etc.. although I never did install an O2 Meter on that car, I just did it more by seat of the pants feel. If I wanted more reliable / accurate / repeatable results I would get an O2 Sensor for that car... but I have my reasons. I never had a Problem with the Stock Fuel pump supplying enough fuel volume on 2 of my High RPM Carter 4bbl carbbed engine builds however. I am not saying Kesteb is wrong on this, just offering my perspective as all builds and parts can yield different results. I had stock Mechanical slant 6 parts store fuel pumps supply 500 cfm and 750 cfm Carter / edelbrock on slant 6 builds to 6200RPM and 6800 RPM respective with no leaning out. The latter on a drag car that at the time was running ~12.30's or so. One more item to consider is that you have an AVS so you might have to play with tuning the secondary air valve as well. Greg |
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| Author: | GregCon [ Fri Feb 07, 2020 9:33 am ] |
| Post subject: | Re: Edelbrock 500 too lean |
I agree...it seems a lot of car run near-white plugs now with success. I used to run a stock mech pump on my 440 cuda. One day I put a pressure gauge tap right at the carb and ran it to the cowl so I could see it. At the beginning of the 1/4 mile it had 7 PSI. By the top of the run, it would be flat zero. The car ran 'fine'. I went to an electric pump and larger lines and the car still ran 'fine' but picked up a few MPH. I guess if you are running a Carter 500CFM on a Slant Six you must have a bad-dude engine. So might as well have a bad-dude fuel delivery system. too. |
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| Author: | 69val6 [ Fri Feb 07, 2020 8:10 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
I have nearly the same combination in my Valiant with a Mopar Performance 268S cam. I'm running the 500 edelbrock performer AFB. I run the .089 in the primary with the .0715/.058 metering rod. I have .083 secondary jets. I have a wideband 02 sensor. I run 14.5:1 a/f ratio on the primary side at highway speed. It runs 12.6:1 at W.O.T. It runs sooo much better at all rpm's after I got the A/F ratio straightened out. All of the hesitation on acceleration went away once I got it tuned well. I also noticed that changing the ignition timing has a small effect on the A/F ratio. Make sure your ignition timing is where it needs to be before you start making adjustments or you'll get led down the wrong road on A/F ratio. Lastly, take a micrometer or caliper and measure all of your metering rods on the two steps and make sure they're made accurately. I found many of mine varied in diameter up to .002" on the exact same size. You'll probably find you jets aren't perfectly accurate either. Since you have the AVS version I'm not sure your secondary jets will be the same or not. I highly recommend getting a wideband O2 sensor. The fuel distribution is much too varied from cylinder to cylinder with this combination to be able to read the plugs accurately. On mine even with a good reading on the wideband, cylinder # 1 and 6 are bleach white, # 2 and 5 are sooty black while # 3 and 4 are a nice light tan. Hope this helps. Joel Harris |
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| Author: | kesteb [ Fri Feb 07, 2020 8:35 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
Greg you must have very special part store fuel pumps, because the stock pumps I have tested can barely maintain 4psi of pressure. I believe that NAPA rates them at 19gph, which can't support the HP required to run 12.9s. Just saying, they didn't work for me. I could drain the fuel bowls before the 300' mark. |
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| Author: | Dart270 [ Sat Feb 08, 2020 8:36 am ] |
| Post subject: | Re: Edelbrock 500 too lean |
I have not had trouble with stock-type mech pumps running the carb out of fuel up to about 230-240 HP engine build (low 14s in 1/4 mile), UNLESS the fuel pump eccentric was worn on the cam. Then, you can run the carb low with only 150 HP (Lemons car). Joel has good advice there. If you don't have a WB O2 sensor, get one and you will save plenty of hours and heartache. Lou |
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| Author: | kesteb [ Sat Feb 08, 2020 8:35 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
A quick search on the web shows that it takes 1gph to support 10hp. So if we are to believe NAPA. The stock fuel pump should be able to support 190hp. The purported weigh of the "ruster" is 2200lbs. So yes, the stock fuel pump could support that 12.90. But it would be on the ragged end. My experience is that is not the case. I have a box of replacement fuel pumps that didn't measure up. But if you are maxed out on the jetting and still running lean, it may be a fuel flow problem, not a jetting problem. I took me a while to figure it out. And I develed into some interesting sites while searching. The guys that go fast and turn right have some interesting insights. |
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| Author: | GregCon [ Sun Feb 09, 2020 12:29 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
A big factor in pump output is the inlet....a kinked up 5/16" line will result in less flow than a good 3/8" line. Pumps...all pumps...like to pump. They don't like to suck. If you installed a gas tank 20' above your engine and let it gravity feed the pump, you'd find it can put out all sorts of gas. |
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| Author: | slantsix64 [ Tue Feb 18, 2020 11:03 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
Update! i found that i was getting a lean mixture due to my AVS have a factory electric choke, its been converted to manual choke, so there is a little hole that pulls in air creating a small vac leak too adjust the choke, i had it plugged up but i guess the plug came out! and i wondered why i always has a hiss WOT anyways now i checked my plugs got way more color but rich, probably lean out the secondaries to .92 see how she runs |
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| Author: | slantsix64 [ Wed Feb 19, 2020 12:13 am ] |
| Post subject: | Re: Edelbrock 500 too lean |
69val6 wrote: I have nearly the same combination in my Valiant with a Mopar Performance 268S cam. I'm running the 500 edelbrock performer AFB. I run the .089 in the primary with the .0715/.058 metering rod. I have .083 secondary jets. I have a wideband 02 sensor. I run 14.5:1 a/f ratio on the primary side at highway speed. It runs 12.6:1 at W.O.T. It runs sooo much better at all rpm's after I got the A/F ratio straightened out. All of the hesitation on acceleration went away once I got it tuned well. I also noticed that changing the ignition timing has a small effect on the A/F ratio. Make sure your ignition timing is where it needs to be before you start making adjustments or you'll get led down the wrong road on A/F ratio. Lastly, take a micrometer or caliper and measure all of your metering rods on the two steps and make sure they're made accurately. I found many of mine varied in diameter up to .002" on the exact same size. You'll probably find you jets aren't perfectly accurate either. Since you have the AVS version I'm not sure your secondary jets will be the same or not. I highly recommend getting a wideband O2 sensor. The fuel distribution is much too varied from cylinder to cylinder with this combination to be able to read the plugs accurately. On mine even with a good reading on the wideband, cylinder # 1 and 6 are bleach white, # 2 and 5 are sooty black while # 3 and 4 are a nice light tan. Joel Harris Oh cool, yes i have the .89 primaries .98 seconds with 65x52 rods i think my seconds should be leaned out to .92 to .89 maybe swtch rods to 67x55. see how she does then, after i fixed that vac leak at the carb checked plugs have alot more color but looks like plugs running rich on the secondaries. |
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| Author: | 69val6 [ Wed Feb 19, 2020 10:28 am ] |
| Post subject: | Re: Edelbrock 500 too lean |
I also found that the primary jetting has more effect on WOT af ratio than the secondary does. For instance, if you change the primary jetting by .003", the af ratio changes by almost a full point. If I made a .003" change in the secondary jetting, the af ratio only changed about 0.25. Since you have the avs version you may have different results. Joel |
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| Author: | slantsix64 [ Wed Feb 19, 2020 6:55 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
69val6 wrote: I also found that the primary jetting has more effect on WOT af ratio than the secondary does. For instance, if you change the primary jetting by .003", the af ratio changes by almost a full point. If I made a .003" change in the secondary jetting, the af ratio only changed about 0.25. Since you have the avs version you may have different results. Joel Cool, also whats your initial timing and Compression ratio? your combo pretty close to mine, thank you for the replys |
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| Author: | 69val6 [ Wed Feb 19, 2020 7:28 pm ] |
| Post subject: | Re: Edelbrock 500 too lean |
I run 10 degrees advance at idle. I run about 34 degrees advance at 2500 rpm and higher. That's all mechanical advance. I have the vacuum advance hooked up but it doesn't do anything at WOT. Mine likes a little more advance than what the experts recommend. I did check true TDC way back when I built it 22 years ago. It may not be accurate anymore. I recommend that you check yours to be sure. Compression ratio is a little under 9:0 :1. It's just .060" over bore with .090" shaved off the head with stock replacement sealed power pistons. Joel |
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