mopar 3 B
Well-Known Member
Sounds like the float seats are not closing causing carb flooding. May have pickup up something. You need to check float levels and jetting anyway. Even with 2.94 gears there is no excuse for engine bogging.
'69 383 Setup Headache
- Thread starter Addabob
- Start date
dieseldazzle
Well-Known Member
Do you have known good tune up items in this engine? Cap, rotor, fuel filters, plug wires, the CORRECT spark plugs? Gapped accordingly etc etc?
Addabob
Active Member
Yes, I think so... New Pertronix Distributor, new Pertronix coil, new Pertronix 8mm wires, new Champion RJ12YC plugs gapped at 0.040 (Stock is 0.035, but Pertronix Ignitor III recommends 0.005 over with the new coil), new fuel filter, fresh oil and filter, new PCV, new hoses throughout... Was running pretty well but for the bog... Now won't stay running so need to do as Mopar 3B outlined and see if I have picked up some junk in the carb causing it to flood out. Also need to do the timing chain slop check recommended earlier.
Thank goodness I am enjoying this self-imposed torture and don't need the car for a daily driver...!!!
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yes, I will look into the Edelbrock book and see what to do to check the floats. Not sure about jetting and what that means... More homework for me...!
Thanks!
Merry Christmas all!! If Santa asks me, you all get on the nice list, maybe with a naughty twist if you prefer...!
miller
Well-Known Member
Man...and I thought my thinking was dangerous! Just to clear things in your head, think of a four barrel as two carbs built side by side. Though each side has a primary bore, and a secondary bore, each 'side' basicly separate from the other.
The 2 mixture screws set the air/fuel mix...one for each side...each screw adjusting that 'side's' fuel to air.
That's why together, they should be 'balanced', or adjusted the same.
Once you get a good adjustment on mixture screws, a good idea to...gently turn the screw in, counting turns exactly, only seating the screw lightly when it bottoms. Write down the number of turns, and keep that number for reference. With that info, if things go wrong, you'll know where to re-set the mixture screws.
Why are you trying to go lean on the mix? You can hurt the motor with a too lean mix. There's a short range of 'peak' on mixture, one side lean, other rich. Should find the middle of that range, then slightly rich, not past peak.
But, you could be running into other issues on the motor, such as worn timing chain, that don't help. You had it running fair at one point, and possible to get back to it, but, motors like things right, before their gonna act right.
dieseldazzle
Well-Known Member
I'm pretty sure you have some garbage floating around in your fuel system wit your latest post and issue. Hammer that out first. I agree on the needle and seat probably got some doo doo in them.
miller
Well-Known Member
Cobwebs!:evil7:
Addabob
Active Member
Miller -
Yes, when this person was telling me about how the carb adjustments worked, I just had to shake my head. And the bad part was that he works at an auto parts store, and was giving me this "advise" on how to setup the carb when I was getting the pressure gauge to check my fuel pressure. All I said was that I thought he was mistaken, and should re-read the Edelbrock manual. He, like many it seems, was not an Edelbrock fan, and maybe if that is how he tried adjusting one it explains why it would not run right.
Thanks for the description of the carbs. That does make it easier to envision what is going on with the carb. Can't say that it is all jiving yet in my "understanding and comprehension" department, but I am getting there. I have to get beyond the "what if I "F" something up" mode and just do it... That has always been my concern, especially with daily drivers. This one has no such requirement thanks goodness!! But, I do like to research up and go in with a plan, and thanks to everyone here and the awesome guidance, you point me towards the bird and then it is up to me to flush it out of the weeds...!! I have a good friend that has a lot of experience building race motors, but he does not understand that I am trying to do this as much for my education as it is to get a well running car on the back end of the process. I had to stop working with him on my car as he would just dive in and do things and was not very good at the letting me learn the foundation from him and twist the wrenches and do the work. Reading is one thing, but doing and truly understanding why you are doing it is what is important. His heart is in the right place for sure...
And again, I do appreciate everyone's time and patience with my questions and all your great knowledge.
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Well, the cobwebs are between my ears I think!! Trying to get them cleaned out...
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Yes, I am going to take the top of the carb off and check for debris and verify the adjustment of the floats. The docs say to set it for 7/16" using a drill bit. Dumb question, but I assume that it is OK to do this procedure with the carb on the car, or do I need to remove it...?
Also, my fuel pressure was right at 7psi. I assume that does not require a regulator, even though Edelbrock says it should not be over 6.5psi... Is that a correct assumption...?
Thanks
Addabob
Active Member
Yes, I am going to take the top of the carb off and check for debris and verify the adjustment of the floats. The docs say to set it for 7/16" using a drill bit. Dumb question, but I assume that it is OK to do this procedure with the carb on the car, or do I need to remove it...?
Also, my fuel pressure was right at 7psi. I assume that does not require a regulator, even though Edelbrock says it should not be over 6.5psi... Is that a correct assumption...?
Thanks
miller
Well-Known Member
Now that I'm done laughing on the cobweb bit...
I'd have to look in the book, but pretty sure 4-5psi is about right on fuel pressure. Yes, it does matter.
Other thing is, at least your willing to learn! I'll toss in, that even knowing things, doesn't matter. It takes a knack to 'teach' someone how to understand, and do things on a motor. For many, it's much easier just to do it, than explain 'how' to do it. Just second nature. Main thing is...there are plenty of folks HERE, that are glad to help.
The carb...pay full attention to what's involved in pulling the top. Some parts need to be pulled, some will come out as you pull the top. To set the floats, you need to be able (for one setting) to hold it up-side-down.
That carb was new? Assuming you have a fuel filter...check, or change it. Far as the carb float settings, if you feel easy doing it, pull the top. Make SURE no trash is in the bowls, in the carb base. With the top in your hand, use a carb cleaner spray to flush the needle/seat of each float. Look at the type of floats in the carb...the good ones are brass, other kind are black. If it has the black type, they can get fuel soaked, making them heavier and won't float right, not letting the seats to close. If brass, check to see if any fuel is inside the float...that does the same thing as the black ones.
If the floats are good, then check BOTH up and down adjustments for the floats, adjust as needed, and slap it back together.
I'd have to look in the book, but pretty sure 4-5psi is about right on fuel pressure. Yes, it does matter.
Other thing is, at least your willing to learn! I'll toss in, that even knowing things, doesn't matter. It takes a knack to 'teach' someone how to understand, and do things on a motor. For many, it's much easier just to do it, than explain 'how' to do it. Just second nature. Main thing is...there are plenty of folks HERE, that are glad to help.
The carb...pay full attention to what's involved in pulling the top. Some parts need to be pulled, some will come out as you pull the top. To set the floats, you need to be able (for one setting) to hold it up-side-down.
That carb was new? Assuming you have a fuel filter...check, or change it. Far as the carb float settings, if you feel easy doing it, pull the top. Make SURE no trash is in the bowls, in the carb base. With the top in your hand, use a carb cleaner spray to flush the needle/seat of each float. Look at the type of floats in the carb...the good ones are brass, other kind are black. If it has the black type, they can get fuel soaked, making them heavier and won't float right, not letting the seats to close. If brass, check to see if any fuel is inside the float...that does the same thing as the black ones.
If the floats are good, then check BOTH up and down adjustments for the floats, adjust as needed, and slap it back together.
Addabob
Active Member
Yes, this was a new carb and a new fuel filter. I will try to yank it off this evening and see what I got going on inside. I think that the adjustments in the Edelbrock book says 7/16 down and 15/16 up... Hopefully those are still the right targets.
My fuel pressure is just under 7psi, so is that too high, and such should I get a pressure regulator? Book says anything over 6.5psi, but Edelbrock videos say 7 or even up to 8psi... Everything seems to be all over the place on the recommendation for this...
Thanks Miller!! Have a great day!!
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One more question around this carb. On the back side of the carb, there is an open vac port that they say can be used for brake boost or transmission, or should be plugged. Because of the location of my PCV line, I used this port for it, and capped the front port listed for PCV use. I assume that that is not going to cause any issues, but as I was thinking through things, I thought I would at least ask and make sure. Nothing in the docs says it can or can't be used for this, and it looks like it comes from the same plane as that PCV port...
Thanks
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lewtot184
Well-Known Member
fuel pressure issues may be directly related to the size of the needle and seat. the edelbrocks use a small float and i don't think they always have ideal control. if the needle and seat assemblies are .093" i don't think i'd worry about; .110" needle and seat "may" have an issue.
Addabob
Active Member
Update for the evening. I tore down the carb and verified floats were 7/16" & 15/16". There were the brass floats and didn't seem to have any gas inside. There was some junk in the bowl, so cleaned it out really well and cleaned the jets with some good sprays of carb cleaner. According to the Edelbrock literature, the stock jets are 0.095 and the metering rods are 0.068x0.047 (verified the number stamped on it was 6347), with the orange (5" Hg) metering rod springs (not sure what the 5" means...yet...). Cleaned everything up really well, reassembled and it started right up. I put the accelerator pump rod in the top hole, as that did seem to help things on the last drive till the dirt came into play. Does this change effect fuel flow through out acceleration, or just for that initial demand when hitting the throttle?
Idle was pretty good. A little rough till it warmed up, but was still running at roughly 700rpm. It does jump a bit, maybe 50-75rpm and usually down from the smooth idle. Same thing at 1000 rpm.
Decided to check timing, and was surprised to see it was reading ~34*(vac advance was disconnected, and manifold vac back to steady 19"). I had it set to ~11* initial before the flooding issue yesterday. Mech advance is 24* total with the Pertronix light springs to set the curve to 1k-2500 all in, so at idle of 700, it should not be in yet. Seems like maybe the distributor mech advance could be stuck. I might not have gotten everything back together well when I was hoping to check the timing chain slop yesterday and removed the cap, but I did give it a good wiggle when putting the cap back on. Have to check that again tomorrow.
So, some good progress, but also some loss of ground with the timing... Hopefully (and most likey) just something stupid I have done. Still have to get to town to get some big sockets. If any of you have an idea as to the crank bolt size on the 383, it might save me having to buy the whole set... Those big ones can be a bit pricey.
As far as the timing chain goes, if t is found t be sloppy and needing replacement, and knowing that I am new to motor work, is that something I should even attempt in my garage? If not, what should one expect to pay a reputable mechanic to do the job? I see that the chain and sprocket sets are not overly expensive, but it will probably be the labor to remove all the stuff from the front of the motor. And if I already have the stuff off, given that it has 104k miles, should I just go ahead and replace the water pump, fuel pump, thermostat and gaskets and belts?
Thanks again gents for all the great guidance.
Idle was pretty good. A little rough till it warmed up, but was still running at roughly 700rpm. It does jump a bit, maybe 50-75rpm and usually down from the smooth idle. Same thing at 1000 rpm.
Decided to check timing, and was surprised to see it was reading ~34*(vac advance was disconnected, and manifold vac back to steady 19"). I had it set to ~11* initial before the flooding issue yesterday. Mech advance is 24* total with the Pertronix light springs to set the curve to 1k-2500 all in, so at idle of 700, it should not be in yet. Seems like maybe the distributor mech advance could be stuck. I might not have gotten everything back together well when I was hoping to check the timing chain slop yesterday and removed the cap, but I did give it a good wiggle when putting the cap back on. Have to check that again tomorrow.
So, some good progress, but also some loss of ground with the timing... Hopefully (and most likey) just something stupid I have done. Still have to get to town to get some big sockets. If any of you have an idea as to the crank bolt size on the 383, it might save me having to buy the whole set... Those big ones can be a bit pricey.
As far as the timing chain goes, if t is found t be sloppy and needing replacement, and knowing that I am new to motor work, is that something I should even attempt in my garage? If not, what should one expect to pay a reputable mechanic to do the job? I see that the chain and sprocket sets are not overly expensive, but it will probably be the labor to remove all the stuff from the front of the motor. And if I already have the stuff off, given that it has 104k miles, should I just go ahead and replace the water pump, fuel pump, thermostat and gaskets and belts?
Thanks again gents for all the great guidance.
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SlinktRR
Well-Known Member
Acc pump just for first shot of gas when throttle opens so engine doesnt go lean. Crank bolt should be 1 1/4", maybe 1 1/8". If it is not flooding or running rich, you dont need a regulator.
Probably be best to do the timing chain yourself as it's not difficult, all detailed in the manual. Just remove the radiator for space and start removing accessories. Ask a friend for help if you get stuck.
Addabob
Active Member
Awesome! Thanks for the info! I think I understand the acc pump better now with everyone's great info. As for the timing chain, I figure I will give it a go. Not like I have to be in a rush...
what at about the metering rod springs...? Right now, the stock orange springs are in there, which is 5" Hg. I read that you can calculate the needed size by halving your idle vac. I have 18", so would the silver 8" spring provide better overall performance? Have not yet found what it really does, so more research.
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miller
Well-Known Member
Probably don't want to hear this, even if you already know. 104K miles is bumping toward the high side. Timing chain is a fairly easy fix. One real simple way to check it is...if you have a timing light. Hook the light up, and check the timing. If at idle, the timing mark 'floats', or moves around, instead of staying steady, needs a chain.
Though with that mileage, probably looking at valve guide seals, the guides themselves, valves, piston rings...should I go on? Hard to say how many more miles you might get on it. Depends on condition of the motor, such as compression, and such. But, that's your call. Easier to learn on a motor with time on it, since you can't hurt things that much, over a fresh one. That's my take on it.
On the 5" Hg thing, I 'think' it means it takes 5" Hg to over-ride those springs, to pull on the rods.
Though with that mileage, probably looking at valve guide seals, the guides themselves, valves, piston rings...should I go on? Hard to say how many more miles you might get on it. Depends on condition of the motor, such as compression, and such. But, that's your call. Easier to learn on a motor with time on it, since you can't hurt things that much, over a fresh one. That's my take on it.
On the 5" Hg thing, I 'think' it means it takes 5" Hg to over-ride those springs, to pull on the rods.
lewtot184
Well-Known Member
the 5" refers to the spring compressing at 5"hg manifold vacuum or higher and pulling the metering rod down into the jet for lean cruise. anything under 5"hg will let the rod raise up for power enrichment. with high manifold vacuum you can try a 7"hg spring but make sure idling in gear is around 10"hg or more.
changing the chain isn't too difficult. you just have make sure everything is realigned correctly and you get a good seal at the timing cover/pan area. if the engine has a "silent" chain it's probably long overdue for change.
changing the chain isn't too difficult. you just have make sure everything is realigned correctly and you get a good seal at the timing cover/pan area. if the engine has a "silent" chain it's probably long overdue for change.
Addabob
Active Member
Yes, that is not surprising. I knew with +100K miles, there were going to be many things that might be needed... ;-) I know I do not have the ability to rebuild the motor myself, so I have to assess whether it makes sense to do some of these things myself in a onesey-twosey fashion with the potential of it all having to be done again later, or just bite the bullet now and do a full rebuild... I will probably go with the first option and cross the rebuild bridge when it becomes inevitable.
I know that my timing is definitely "wandering". It does not stay steady at all, so when you pointed that out the other day, I knew that is probably going to be the case. Was going to get the big socket to do the slop test as was outlined just as a final confirmation, but I am confident that it will be a sloppy mess. I will probably go ahead and try to replace it myself, as all it is gonna cost is the money for the timing chain and gear set (~$60 for a Cloyes street roller set)... If I foul it all up, I can always haul it to a real mechanic and "pay the price" to get them to fix it right.
I still have to reset the timing again, as it changed somehow during the flooding issue (11* to 34*, hopefully just a stuck mechanical advance maybe...?)We did check compression when I first got it. All of the cylinders were easily in spec at the lower end (roughly 125-134psi, spec in manual states 125-155).
As for the metering rod springs, I was just in doing the research on other things and came across that, and some saying that changing to a stiffer spring when the motor had good vacuum helped its responsiveness. Just gonna read up on it and maybe try a stiffer one out and see how it impacts things.
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If I recall correctly, I think my vac at idle in gear was about 15-16" (down from about 19" in park). I will check it out again, and maybe play with the stiffer metering rod springs just to experiment... Now that I know where they are and how to get to them, no telling what may happen....
As for chain, really not sure how long it has been in there. I am the 3rd owner and there were no service records to indicate that it was changed. As for the rest of the car and motor, it was bone stock with little done to it.
lewtot184
Well-Known Member
with as much vacuum as you have i'd try heavier step-up springs.
aeon280
Well-Known Member
I noticed you upgraded from a 2 barrel setup to a 4 barrel set up and no one else asked how you setup your kickdown since the geometry from your 2 barrel KD and 4 barrel KD are not compatible. Granted this wont affect your bogging issues but can make the car feel more sluggish and make it difficult to get a proper carb tune that works througout the power band.
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Addabob
Active Member
Aeon -
Not exactly sure what you mean by this. This is my first tinkering car, so don't know all the lingo and stuff. If you mean that the throttle cable and tranny kick down linkage with the 4bbl needs to move outboard further as compared to the 2bbl, then I understand that. I bought a 4bbl linkage w/kick down rod that shifts both outboard and forward a bit, and now both the throttle cable and kick down linkage line up perfect.
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Based on what I have read, I would say that was my assessment too. Have you done this before? If so, can you say is the "feel" or response noticeably different...? Or is this one of the more subtle things? Where will I notice it most? Just trying to understand what to look/feel for.
Thanks!
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