FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: 390owner on April 05, 2021, 08:24:35 PM
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Any one else using a edlebrock 600 on their 390. Mine seems to be running too rich,but if I lean it down one jet size it runs too lean and surges. I have a hei dist. and have set the plug gaps to .45. My tail pipe is black and it smells rich. Any ideas
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You're still too lean. That "rich" smell is hydrocarbons from incomplete combustion. An authentic rich mixture is carbon monoxide, which doesn't have that eye-watering stink. If you are super rich, like the choke is stuck full on, then you can get that stinky exhaust. What's happening is that the mixture is too lean to burn completely and it gets exhausted. Many times you can also address a lean mixture by advancing the timing to allow more time for the mixture to burn. But it's better to just richen it up.
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So black smoke when reved is from being too lean? Ok I will try to richen it up. I have my timing set as high as I can without being hard to start. I think the total is around 34
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Also my new plugs look like this. I am running 89 octane gas too(https://live.staticflickr.com/65535/50977052493_e0816efd3c.jpg) (https://flic.kr/p/2kEEHGa)IMG_3699 (https://flic.kr/p/2kEEHGa) by Daniel Crymes (https://www.flickr.com/photos/169098912@N02/), on Flickr
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Maybe check fuel pressure and float level.
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Get a 600 Holley and a Duraspark, ditch the AFB and UGLY and crude HEI
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It's rich. It needs to be leaned out in one way or the other. Following the other guys, check your fuel pressure.
I ran into this with a Quick Fuel Slayer 600 on a 390. I just think that a 600 is too small of a carb for a 390. I don't even use a 600 on a 289.
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X2 with MeanGene
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try some better fuel too.
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What jet and metering rod do you have in there ? Are you sure it's not flooding over ?
Not my pick for max performance but the Ebock 600 tuned is a good carb , I've put around 10 on late 78-9 F250's out here back in the 90's with 351M400 and performer intake for some farm trucks and it's a whole new truck when your done
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When I was using a 600 Edelbrock carb, I used to have to adjust the floats every couple years. They’d relax overtime and let the carb flood itself.
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My experiance with them is they are sensitive to high fuelpressure
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x3 with MeanGene
Let the Chebbie guys play with their ugly Quadrajets and HEI's.
I ran a 600 Holley and DuraSpark II on my 390 powered '75 F-250 for years with great success. It was not happy out of the box, and required quite a bit of adjustment to get it set up correctly, but once it was dialed in, she ran like a champ. A wide band O2 sensor made dialing it in much easier then guessing and reading plugs.
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I ran a Holley 3310 on my 390 in a 4x4. Very mild flat top motor. That carb worked excellent towing, off-roading and driving to work. I’ve never been a fan of afbs. I ran an MSD billet distributor, with a 6a box. Also worked great.
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I have to agree with Brent, 600 is too small for a 390.
There are features of the AFB design that is advantageous when compared to the Holley. I've ran them with success, but I think the Holley is overall better for performance tunability.
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A 600 cfm carb will run fine on a really mild 390. Not my personal favorite but it will work. Ford ran 600 cfm carbs - and smaller (2 bbl) all the time.
It's a tuning - or maintenance - or fuel pressure issue
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According to everything I have read the 600 is not too big. This engine has around 300 horse or a little less. the fuel pressure is around 6 pounds. The float is correct. It runs perfect with plenty of pulling power also. The funny thing is that my plugs did not look like this until I started using 89 or higher octane gas. When I used the cheap stuff it was hard to start when hot but the plugs were always clean. It has a little over 10000 miles on a complete rebuild.
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Ok on a dura spark What do I need and where do I get what I need. The hei unit in the 390 was less than 100 dollars but I have had 0 trouble from it. I do have a stock dist but I was having trouble with coils, brains, and pick ups. Every time I bought one of these pieces they did not last long so I got sick of buying these parts and went with the one wire unit. I take the bronco everywhere including out of state so I dont want to get stranded because of some china junk.
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I have dual AFB’s on my 426 Mopar, they are very sensitive to fuel pressure. My was running rich and leaking with the fuel pressure at 6psi. I dropped the pressure down to just under 5psi, runs good now with no leaks.
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There's nothing wrong with the HEI. If you don't cheap out with a module made of Chineseium, the HEI module is better than the Ford Duraspark since it can vary dwell and offer better performance. In fact, it's pretty easy to wire up an HEI module in place of any other module, Duraspark, MSD or whatever.
Some folks get very provincial when you start crossbreeding your parts, like using an HEI on a Ford. But you have to go with what works. There's nothing wrong with AFBs. They don't have the nearly infinite tunability that some Holleys do, but most folks screw those things up once you get past jet and power valve changes. In many ways, an AFB is easier to work on than a Holley since you can affect your tune up just in the rod and spring selection and never spill a drop of fuel.
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I take the bronco everywhere including out of state so I dont want to get stranded because of some china junk.
A Bronco? That sounds interesting. Can't say I've ever seen that combo before.
I understand the negativity towards the HEI GM design, but if you have something that is trouble free, unless looks are super important, keep it that way. You don't fix something that ain't broke 8)
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The reason I went with hei is the easy one wire and I can get a new pick up coil at any parts store. Like I said I have had zero problems. I will check the fuel pressure to double check it is ok(https://live.staticflickr.com/65535/49898899738_4f23c2b639.jpg) (https://flic.kr/p/2j2oUry)IMG_2906 (https://flic.kr/p/2j2oUry) by Daniel Crymes (https://www.flickr.com/photos/169098912@N02/), on Flickr
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The fuel pressure that counts, is under WOT. If it doesn't go under 3 lb @ WOT, your fine. No matter what the line pressure is. Fuel pressure, should only fill the bowl. To much pressure can push the seat open and flood.
You want to increase the needle and seat size, to increase volume, rather than increase pressure.
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Edelbrock carbs ( and their sisters) only like around 5 PSI fuel pressure. Not the 6~7 you'd most likely use with a Holley. IMHO for most street applications, the Ed/Carter design carbs are superior to Holley. Better choke operation, better low speed/light throttle operation and response and once set they work. As for "too small" - I used by go-to 650 DP on my 393 CID / 575 HP dragster engine as a test, it was only off about .2 in the 1/8 and maybe a couple MPH from running a billet "750". A 600 is good from a 302 to a 400 IMHO.
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According to everything I have read the 600 is not too big. This engine has around 300 horse or a little less. the fuel pressure is around 6 pounds. The float is correct. It runs perfect with plenty of pulling power also. The funny thing is that my plugs did not look like this until I started using 89 or higher octane gas. When I used the cheap stuff it was hard to start when hot but the plugs were always clean. It has a little over 10000 miles on a complete rebuild.
Not sure about the gas wherever you are but if the hi test you're running now is non-ethanol and the carb was jetted for typical ethanol blend you may have to rejet. I've found when going through carbs that have been sitting for a long time (like "field find" cars) I've had to jet up a couple sizes if running regular pump gas. There are a few stations around here that have non-ethanol gas and if I put a full tank in anything I normally run normal pump gas it's a little fat.
This will depend on the blend of gas, but something on street stuff I've found gets overlooked a lot around here.
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Edelbrock carbs ( and their sisters) only like around 5 PSI fuel pressure. Not the 6~7 you'd most likely use with a Holley. IMHO for most street applications, the Ed/Carter design carbs are superior to Holley. Better choke operation, better low speed/light throttle operation and response and once set they work. As for "too small" - I used by go-to 650 DP on my 393 CID / 575 HP dragster engine as a test, it was only off about .2 in the 1/8 and maybe a couple MPH from running a billet "750". A 600 is good from a 302 to a 400 IMHO.
A .2 loss is actually quite a bit in regards to horsepower. That's a good 30-40 hp.
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There's nothing wrong with the HEI. If you don't cheap out with a module made of Chineseium, the HEI module is better than the Ford Duraspark since it can vary dwell and offer better performance. In fact, it's pretty easy to wire up an HEI module in place of any other module, Duraspark, MSD or whatever.
Some folks get very provincial when you start crossbreeding your parts, like using an HEI on a Ford. But you have to go with what works. There's nothing wrong with AFBs. They don't have the nearly infinite tunability that some Holleys do, but most folks screw those things up once you get past jet and power valve changes. In many ways, an AFB is easier to work on than a Holley since you can affect your tune up just in the rod and spring selection and never spill a drop of fuel.
Not all HEI modules have the dwell stretch circuitry,the only ones that I'm certain have it are specific part numbered GM modules,the 990 numbered module seemingly being the preferred one.The Ford Duraspark I red grommet box has equally sophisticated features but it is pretty hard to find anymore,the Duraspark II blue grommet box is the more common and basic version with some wiring differences.HEI module failures may be a result of a lack of the correct heat sink compound HEI modules require a specific heat sink compound that has a white chalky appearance,I've commonly seen dielectic grease substituted of the correct heat sink compound sometimes leading to failure due to overheating of the module.That may be a cause of the failure of the offshore stuff,maybe something was lost in the translation to chinese.Also the OEM modules are the only ones that will have the features attributed to them, aftermarket modules may or may not have them.
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There's nothing wrong with the HEI. If you don't cheap out with a module made of Chineseium, the HEI module is better than the Ford Duraspark since it can vary dwell and offer better performance. In fact, it's pretty easy to wire up an HEI module in place of any other module, Duraspark, MSD or whatever.
Some folks get very provincial when you start crossbreeding your parts, like using an HEI on a Ford. But you have to go with what works. There's nothing wrong with AFBs. They don't have the nearly infinite tunability that some Holleys do, but most folks screw those things up once you get past jet and power valve changes. In many ways, an AFB is easier to work on than a Holley since you can affect your tune up just in the rod and spring selection and never spill a drop of fuel.
Not all HEI modules have the dwell stretch circuitry,the only ones that I'm certain have it are specific part numbered GM modules,the 990 numbered module seemingly being the preferred one.The Ford Duraspark I red grommet box has equally sophisticated features but it is pretty hard to find anymore,the Duraspark II blue grommet box is the more common and basic version with some wiring differences.HEI module failures may be a result of a lack of the correct heat sink compound HEI modules require a specific heat sink compound that has a white chalky appearance,I've commonly seen dielectic grease substituted of the correct heat sink compound sometimes leading to failure due to overheating of the module.That may be a cause of the failure of the offshore stuff,maybe something was lost in the translation to chinese.Also the OEM modules are the only ones that will have the features attributed to them, aftermarket modules may or may not have them.
I have a pretty savvy electronics friend (some of his workmanship is likely in orbit over your head as we speak...). He is quite fond of some of the OEM HEI modules. He had us using one as part of his own design ignition system which was tested and run in a couple EMC competitions on my entry.
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>A .2 loss is actually quite a bit in regards to horsepower. That's a good 30-40 hp.
Agree - but here, bracket racing, we can lose that much between Saturday and Sunday depending on the weather. Easy from Friday night testing to Saturday afternoon. 2500 DA on Friday to 5500+ DA on Saturday is not an odd thing LOL. One reason I want to run methanol out here. I like using the 650 for a test carb because that one just works on everything. No jet changes, just bolt it on whatever and go test. Only sorting is the pump shooters, if that. It's on the 351C right now. It's my carb version of a Timex watch.
Most of the Ed 600s - model 1406 - that I've used for regular pump gas driving ended up +1 calibration change on both ends. But that all depends on the engine, climate, fuel, etc. The tuning book and kit make it easy. I've run two of those 600s on my 302 and had them work well.
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back in the early 80s i bought a new 650 dp holley.i loved that little carb on my mild 390,cam,headers,etc.it got good mileage if i stayed out of it,but when you kicked it in it ran great.good 390 carb.i later bought a new 850dp,put it on and it ran even better but didn't get the mileage of the 650.my buddy tried my 850dp on his 350 chevy and it boiled smoke out the back.way too big and rich for the mild sb.
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A lot ways to do this check some of this out.
http://www.gofastforless.com/ignition/tfi.htm
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600 should be enough for a standard 390. There is a formula on the net to work out you carb size.
CFM = Cubic Inches x RPM x Volumetric Efficiency ÷ 3456. Any ordinary stock engine will have a volumetric efficiency of about 80%
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Back about a zillion years ago I did a rework on the 302 2-barrel engine in my '72 E-150. I put on an Ebock Sp-2P manifold, a Holley 6708 carb, a mild cam, and a set of headers. Basic feel, I doubled the usable horsepressure and increased highway MPG from about 12 to 18 or a bit better.
I have a friend who also had an E-150. We swapped in a 351 Windsor with a couple of changes. My van would easily outrun his.
The Holley 6708 has smaller primaries and larger secondaries than the usual list 650 DP. And it uses a choke cable. Unfortunately, they're no longer made, but you can find remans on the 'net. It's a great carb for the sort of use I made of it. (But likely not as good as EFI.)
KS
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Keith, there is another carb, similar to your 6708 but, with much larger venturi. It has the 600 primary and 850 secondary's. It cam on the 383 Mopar engines. It's list is 4218. I think it would be perfect for a 390 if, you could find one.
It's one of the carbs that I will try on my 419.
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I think this is a tuning or setup problem that may or may not be fixed with parts replacement.
A 600 Edelbrock will be happy as a clam on a 390, even a healthy-ish street one. It won't make the same power as a equal Holley, but by no means should it be choking the engine and going pig rich on the plugs and blowing black smoke. In fact, they tend to do very little wrong other than being down a little bit on power
First - Make sure the air cleaner lid isn't slammed against the top, filter isn't plugged, make sure no linkage is binding the choke, and the choke is working properly. It needs to be open when hot and not too tight when cold, plenty of videos on You tube. Even if adjusted correctly, it needs to be working too, wide open warm, and not able to close under acceleration. Choke thermostats do go bad, and wiring can be incorrect letting it close on you
Second - I'd put the carb back to stock with a full rebuild, carefully make sure all adjustments are right and linkage doesn't bind on intake etc. Don't assume anything, and be gentle with the parts, check all the numbers of parts, make sure it hasn't been modified
My hunch tells me those two things will do it, however, next make sure the engine has heat, run a thermostat. Then look at the ignition, what it is means less than if it's working right. You should have a mean blue spark from an HEI, if it is anyhting less than that, look closely at coil, module, grounds etc. The ignition could be bad as a small change in a/f generally does not bring you from pig rich to surge FWIW, HEIs can generally handle it, but I tend to not go big on gaps, although some claim wild benefits, typically, .035 is easier on ignition parts and will fight you less with misfire on a marginal ignition. Likely NOT your problem, but my technique is .035 for most builds
I could see you buying a 40 dollar carb kit, or a coil/module, but I really don't see this being a brand/parts mismatch, requiring a new carb and ignition, you are simply having a tuning or malfunction problem with the parts you have
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I just cleaned the air filter (k and n). Nothing is binding. The choke is tied open. I am going to double check all that you mentioned and look at the fuel pressure too Thanks for all the replies
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Fuel pressure is a good call, I agree with that if i didn't have it in there
Some other thoughts, looking back, what have you fixed from past problems?
I see you had:
1 - Oil use from the PCV (which shouldn't be an issue if low blow by on a fresh engine and a correctly configured PCV) Eliminating it is sort of a band aid
2 - High but unsteady vacuum reading
3 - Timing issues, to include being very sluggish and not running your vacuum advance
I read a few times that 20 years ago the shop built you a good one, but this one seems like it isn't as good as the last one. Have you picked away and found the cause of the earlier issues?
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If you want to run a spreadbore carburetor you can do it with Quadrajets, Thermoquads, Autolite 4300/4350, many of the AFBs, and Holley as Q-jet replacements in both vacuum and double pumpers in 650-800 CFM. They work great. The downside is you have to use an adapter to use them on non spreadbore intakes.
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A comment not likely related to the original issue: I personally wouldn't run the plug gap that wide even with HEI. Just my opinion, but I have not ever seen any measurable gain by doing that and I have seen issues caused by it. I like 0.035". I even even do that on my "modern" 2000 Saturn. I could see going to 0.040", but not more.
I also don't think a 600 cfm Edelbrock is too small for a mild 390. It may not be optimal for the last couple of horsepower, but it will work fine. If I was the slightest bit concerned in that respect, I would just put a 1/2" open spacer under it. It will effectively increase the carb size, and insulate from heat, to boot.
So I am guessing the guys advocating making sure the fuel pressure is right on, are right on.
JMO,
paul
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like was said above , check the breather lid , maybe already said , make sure the bowl vent is open and far enough from the breather lid and or the vacuum lines are hooked up in the correct locations .
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This new 390 is now running as good as the first one I had built years ago. I have the vacuum advanced hooked up now.I also have a spacer under my carb. It is a carbon fiber one.
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This new 390 is now running as good as the first one I had built years ago. I have the vacuum advanced hooked up now.I also have a spacer under my carb. It is a carbon fiber one.
Was there anything in particular you think fixed it?
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Running higher octane gas, played with the timing.
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i knew the better gas would help.my dad had a 63 1/2 galaxie 390 and he was so cheap he ran the cheapest gas he could find in it.it still ran ok but it pinged on hills and you could tell it needed better fuel.he later gave it to me and i always ran premium in it and it would fly.