drivability issue

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moparboy340

moparboy340

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hi there again everyone,
i got another problem i just thought i would throw it out there and see if anyone had any suggestions. i am driving a 318 dart, just shy of 10:1 compression, its got a descent little cam 484 lift 284 adv duration, linked to a manual trans in an a body. its a fun car for a daily driver, but thats besides the point. my problem is either with ignition or carburation. it was running fine one day then it just died. weak msd box :-(, i then replaced the msd with a crane ignition, and took the carb off and took it appart to clean it up a bit and change the jet size, 2 sizes richer. its a road demon jr. carb by the way. jet change really helped the cars throttle response and power, but im not sure if i messed something up cuz now the only problem i experience is a backfire and pop at around 2800-3300 rpm only under light throttle, like a cruze condition. under a hard accel though it runs fine through the rpm range. i dunno if i maybe i didn't do something right w/ the carb, or if its something like timing or ignition. if anyone could shed some light on this it would be greatly appreciated, i wanna get back to cruizin around in my muscle mopar! :) thanx
 
Timing would be my guess, how is it set now ? Give us a description of the distributor, recurved, using vacuum adv etc.
 
For the sound of it, I agreee with timing. As a test, disconnect the vacuum advance cannister on the distributor and plug the line.Then drive it again. If the studder is gone, you need to take a small allen wrench (one that just fits into the hose nipple on the vacuum can) and adjust the vacuum can. The wrench will seat in the adjuster when you insert it. Turn counter clockwise two turns from where it is right now, connect the vacuum hose back, and test drive again.
 
you guys hit the nail on the head. the timing was way advanced. my initial was good around 12degrees, but after full advance wow, it was deep into the 40s. i removed the vacuum advance hose and thats how i am running for now, but i got some more questions for u guys. i would like to continue to run my vacuum advance as this is a pure street car, but i would like to recurve the distributer. my question is does anyone know of a good read on how to do this. i know how to adjust the spring load on the vacuum daphram but thats really all. i would like to change the centrifigul advance of the distributer so that i can run like 12 initial 34 total, maybe 36-38 w/ vacuum. any help would be appreciated. thanx
 
You know how to adjust the vacuum can. It's posted. As far as mechanical advance, ther easiest way is the Mr Gasket advance weight spring kit, and soem modification of the distributor. I'm assuming its a factory part? So, pull the unit from the car, and stick it in a vise (lightly, dont crush it). Use a set of needle nose pliers or two screwdrivers and pry off the reluctor (the 8 pointed star looking thing). Then, unscrew and remove the vacuum can, and the ignition pickup. IN the center of the dist shaft is a little brown cloth tab. Pull/remove it with the pliers. Under it is a small spring slip. It has two fingers that point straight up. That clip retains the advance plate the weights ride in. Carefully pull that clip. Sometimes they come right out. Sometimes, they argue. In any case, dont trash it. You need it to put things back. when the clip is out, you can pull the advance plate. There should be a number on the plate stamped in. That "should" be the total amount of centrifical advance the slots will allow. Most I've seen are in the 16-28° range. If you want around 35° total, the vacuum can has a number stamped ont he arm too. (or should). That's the total it can add. So, you take the 35, subtract the vacuum can: we'll say...11, then subtract what you want for initial (I like to use 15°), so what you have left over is what you need in the slots. 35-11-15= 9. So not much. If your advance plate is marked 18, you need to close off 1/2 of the slot to get 9°. So, take the advance plate to a muffler shop, and have him (carefully...) weld up the slots until only 1/2 the length is open. Take a file, flatten out the welds on top and bottom of the plate, and then take a rat tail file (small one) and round out the weld where the peg on the weight will hit. A tight spot there can cause binding, and an idle that doesnt like to come down when you slow down. Then, swap the springs per the instructions..basically, take out the heavy elongated factory spring from the weight and reatiner, and replace it with a light one from the kit. Then reassemble it all. When you're done, stick it back in, and reset initial for 15° as a place to start. When you get the curve right, then it's time to dial in the carb. All done by you, I'd expect total cash outlay to be about $25. You will now own the biggest part of an FBO/MP/Summit performance ignition conversion package.
 
:thumbrig:thanx moper, and yes its a stock mopar performance dist. thats just the info i needed to help me on this project. im gonna go tackle this now and ill let you guys know the outcome.:thumrigh:
 
"You will now own the biggest part of an FBO/MP/Summit performance ignition conversion package."

Please do not include FBO in the same sentence as "MP/Summit" it makes my skin crawl.

Your got the right idea, but if you don't know what your final goal should be how do you accomplish it?

There is no substitution for a professionally setup, curved and phased distributor. It may be better but it won't be as good as it could be.

Your describing what several of our competitors do, which is good because we get to do them over......correctly.
 
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