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I had plugs in my engine with a heat range of 44 initially and the edelbrock metered as it came in the box. The plugs looked lean as hell so I went to cooler plugs and went 3 stages richer in power mode and 2 stages richer in cruise mode.
I looked at 2 plugs last night after a 60 mile drive this weekend and I wouldn't even know the plugs have been used.
Shouldn't these things be slightly brown?
what gives.
without lead in gas it is sometimes hard to read them by looking at them
I used some lead substitue actually, but I don't know how similar to lead it really is.
But still, the first time with the leaner jetting and hotter plugs they looked real bad. They were all chalky.
Now they just look like they weren't even used. If it wasn't for a slight change in texture on the ground strap I could put them in a box and say they were new. The porcelin was SPARKLING.
What ignition system are you running?
msd 6AL
I'm running the 6A, so same one really. Have you messed with the spark plug gap like MSD recommends? I was way rich, or so I thought. I opened up the gap as MSD recommends and they got better. However, you may have your gap too large.
Quote:
Originally posted by DennyW
Show us a picture of them, or one. Sounds like you are right in the zone. Do change anything yet. :)
sounds like its right to me.
what cid are you running & what size carb? Cam? Intake?
I set the gap to .050.
It is a 402.
226 @ .050 single patter hyd.
650 edelbrock thunder carb
dual plane intake
I put about 80 miles on it again yesterday so I'll pull a plug again this afternoon and post a pic then.
in order to check plugs don't you have to go out and run for awhile and shut down @ like 2500 rpm and check plug THEN?
pic of plug
I'm not sure where the oil is from.
I'm really surprised that this thing is still lean. I'm using just about the richest metering in the carb as possible.
I can still go a little richer though.
ride around with a vacuum gauge attached for a while
this will give you a good idea where the vacuum goes
under a range of driving conditions
then adjust the metering springs so the power step
comes in sooner or later
I suspect your seconday jets will have to be upped also
Your set-up requires 756.0764 cfm for opitum performance. Take a 750 and step it up one jet size from stock on the primary side.
Your taking a chance on your exhaust valves matching the electrode on that plug by running too lean.
how did you arrive at 756cfm?
I called edelbrock when I was deciding and they told me to use the 650.
This engine is mostly stock and I don't EVER plan on seeing over 5000 rpm's.
Quote:
Originally posted by DennyW
Looks like it's getting to hot (lean). Correct this right away.
cid x max rpm divided by 3456 = CFM
The 402 with a hyd. cam that carries a max rpm without float @ 6500.... doesn't matter that you decide to run it at 5000, or a 650 if you want, as long as you can achive enough cfm to stay away from lean burn.
You posted that you've already reached the next to max with the carb that you've got- that put's you at about 670 now & still too lean- I guess that after you reach the max on the primary side you can - I dunno, hog it out.....or rework the venturi's- good luck with that one, or get a carb with larger primary's.
you'll are talking 5,000 up rpm. the(way i read it)he is just driving it normal and at idle and should be able to run a 2 bbl. without burning the plugs up. am i reading it wrong?
I also agree with LS1.
I thought by using a smaller carb it would HELP the streetability.
I would think that a smaller one would create better pressure drop in the venturis and therefor pull harder on the jets and pull more fuel.
Obviously this isn't working out as planned or I wouldn't be posting this problem.
if all you are doing is normal driving and you are heating your plugs up then you have other problems. I can pee enough gas to ride around on . how hard are you running it ?Quote:
Originally posted by tcodi
I also agree with LS1.
I thought by using a smaller carb it would HELP the streetability.
I would think that a smaller one would create better pressure drop in the venturis and therefor pull harder on the jets and pull more fuel.
Obviously this isn't working out as planned or I wouldn't be posting this problem.
I was having some fun with it, but nothing crazy.
just some hard pulls out of some stop signs and maybe
up a couple hills.
I still haven't even given it full throttle though.
I don't know, but I doubt you are running out of cab.Quote:
Originally posted by tcodi
I was having some fun with it, but nothing crazy.
just some hard pulls out of some stop signs and maybe
up a couple hills.
I still haven't even given it full throttle though.
k
Fatten up the jets on the primary side by 0.003" to 0.005". If the motor isn't surging (changing rpm's up and down on its own) in cruise mode, then it isn't too lean, but try the fatter jets just to see what happens. I know you've been changing metering rods, but try jets.
As far as carb size, you are right on the money with what you intend to do with the truck. You'll get great throttle response and manifold vacuum with smaller primary venturis.
i thought on you had to change the metering rods with the jets at the same time to properly adjust an edlebrock? or could i have always just been able to swap out the metering rods and be done?
No, you can change either or both. I'm just thinkin' that he's probably gettin pretty thin on metering rods and might have some more flexibility if he changes to a fatter jet.
yep, you can change either the rods or jets, and you are correct, I am pretty thin now on rods. I have some new jets that are .003 larger that I'm gonna put in tonight.
It isn't surging or anything in cruise though, nor was it even before I went richer.
if you haven't gone to a bigger jet before, then i believe tech. is right.Quote:
Originally posted by tcodi
yep, you can change either the rods or jets, and you are correct, I am pretty thin now on rods. I have some new jets that are .003 larger that I'm gonna put in tonight.
It isn't surging or anything in cruise though, nor was it even before I went richer.
just for reference this was the plug before I richened it up a few steps.
one thing I wanted to check on is the large tube connection on the front of the carb that I think is for PCV. I had the carb off last night and saw that this tube has a passage that leads below the throttle plates.
I had it hooked to my valve cover breathers, but wouldn't that line suck with full manifold vacuum on the breathers then?
There is a very similar connection on the rear that I have hooked to my brake booster. But both have passages leading under the throttle plates.
thats what that large tube is for. the pcv valve will control the vac. it idles ok, right?Quote:
Originally posted by tcodi
one thing I wanted to check on is the large tube connection on the front of the carb that I think is for PCV. I had the carb off last night and saw that this tube has a passage that leads below the throttle plates.
I had it hooked to my valve cover breathers, but wouldn't that line suck with full manifold vacuum on the breathers then?
There is a very similar connection on the rear that I have hooked to my brake booster. But both have passages leading under the throttle plates.
it idles ok I guess. I still have start up problems though.
Is there supposed to be a VALVE associated with this hook up though?
All I have is breathers that I custom made that lead from the valve covers to this line on the carb. The breathers are essentially just a tube that hooks to it, I have no special valve or anything.
I'm getting the feeling I missed something big here.
if you are running a straight vac. hose straight into your motor then that's why it lean. you have to have a pcv valve in the hose somewhere before it gets to the valve cover. you could just block that hose, just to try it, but you need to get a pcv valve installed.Quote:
Originally posted by tcodi
it idles ok I guess. I still have start up problems though.
Is there supposed to be a VALVE associated with this hook up though?
All I have is breathers that I custom made that lead from the valve covers to this line on the carb. The breathers are essentially just a tube that hooks to it, I have no special valve or anything.
I'm getting the feeling I missed something big here.
http://www.sweethaven02.com/Automotive01/fig0452.gif
OH MAN I am an idiot.
welp, hopefully that is also why I have start up problems.
thanks
should help everthing, you might need to stand on your head more often, to get the blood flowing the other way!!! :LOL: :LOL:Quote:
Originally posted by tcodi
OH MAN I am an idiot.
welp, hopefully that is also why I have start up problems.
thanks
well, I plugged the pcv line on the carb and then just vented the breathers to the air.
This weekend I tried running it and I couldn't even get it started. The most I ever got was a weak cough every once in a while like one cylinder barely lighting.
I don't know if fixing that pcv screw up would make my idle settings far enough out of wack to prevent it from starting since I before I must have had it tuned to compensate for a major vacuum leak.
Quote:
Originally posted by tcodi
well, I plugged the pcv line on the carb and then just vented the breathers to the air.
This weekend I tried running it and I couldn't even get it started. The most I ever got was a weak cough every once in a while like one cylinder barely lighting.
I don't know if fixing that pcv screw up would make my idle settings far enough out of wack to prevent it from starting since I before I must have had it tuned to compensate for a major vacuum leak.
that's not the reason it want start up. you don't start off of the idle circuit. you've got some other problems. screw your idle screws all the way in, and then back them out 2 1/2 turns for the time being.
I just don't understand what the problem is.
Before it wasn't perfect, but I could always get it started EVENTUALLY.
This time I had nothing.