Why does my car die?

[blue72swinger]

I just did a performer RPM heads cam intake swap on my 1972 Dodge Dart 318. I have been messing with the carb and timing annd i currently have it set at 14 degrees advance at idle. My question is even though it sounds like its running right but when i put it in drive, the car dies with no back fire or anything. What do i need to adjust ????
Thanks

[pishta]

Holley or Carter/Edelbrock? I would aim toward an intake leak since you just changed that. Easy way to do a vacuum check is loosen the rocker shafts until all valves are relaxed (closed), remove carb and put a solid plate, like an engine hoist plate over the carb pad. Use your mighty-vac (everyone should have one of these cool tools) and see if itll hold a vacuum. Well, I guess it is not too easy, but itll sure show if you have an intake/valve leak. Or you can just spray water around the intake gaskets until the idle RPM rises. If that is all good, open up the idle screws, not the fast idle screw, to richen the mix a little...

[blue72swinger]

i dont think that there is a leak because i can idle it down to 500 roms w/o it dieing, only when i put it in gear, and it only happend when i messed with the idle mixture and timing

[pishta]

reset them back to 1.5 out and time it to about 16 BTDC. That is close to stock on a E-57 360. Good luck. Make sure your transition slots are not uncovered in your primary bores.

[dwc43]

My guess is the cam is too big for the converter and that is why it stalls in gear. We ran a dirt track car with an auto one year and you need a real tight converter and it would stall in going into gear cause of the big cam and the converter. Let the car roll as it went into gear and it would go then. What size cam did you install ?

[pishta]

even an RV cam will stall higher than 500 where he says he can idle. I think it a LEAN condition, or maybe a transmission problem (that is a reach)

[ramcharger_440]

Originally Posted by dwc43

My guess is the cam is too big for the converter and that is why it stalls in gear.

I have a tendency to agree. Performer RPM cam specs are 234/244 duration @.050 with .488/.510 lift with 1.5 rockers. This is a pretty big grind in a 318.

[dwc43]

Originally Posted by ramcharger_440

I have a tendency to agree. Performer RPM cam specs are 234/244 duration @.050 with .488/.510 lift with 1.5 rockers. This is a pretty big grind in a 318.

Looks like we found the problem. That 318 wont have much of a bottom end with that cam either. I'd replace it with a 268, 272 or a 272,276 dual pattern and that will work with the stock converter and make a lot more usable power too.

[fastmopars .inc]

maybe i missed a key part somewhere but why on earth would he change the cam to match the engine?
basically the combination of parts you already own would make a 360 sing to the tune of 425 plus hp, more if properly setup. all the cam swaps in the world wont bring a 318 to within 50 hp of that, and the 318 would still idle rougher and make less low end power than the 360 with the same parts.
obviously if you spend several thousand dollars on engine upgrades you plan to have a fast car, and basically the only thing working against you is the 318 block. spend another grand, build a stout 360 shortblock spend a weekend swapping motors and parts and go hack away at the 12.0 et bracket.
the problem was already pinpointed by dwc43 i think, as your motor is very small for the cam, but this was the same problem i had with my 360 with different causes; there was a slight vacuum leak and a power valve was leaking. as soon as the motor was placed under load while idling it would die, even though it idled relatively smooth in neutral.
also ensure your timing is dead on, i always put on a properly degreed mp timing tape when i have to tune a smallblock.

[blue72swinger]

Ok, i think the converter is definitely to small, but here is my pan, i bought a good top end, and i am going to buy a 360 short block to put all of it on in a few months. What cam should i go with in the short block with rpm heads/intake. Also the MOPAR short block comes with cam, should i replace it?

[one bad dakota]

I think it's simply too lean. A bigger cam will need a richer mixture at idle. I had the same problem when installing a larger cam. Try adjusting your idle mixture screw(s) out to fatten it up and, of course, check for any vacuum leaks.
Tom

[mopar_nocar]

1) vacuum leak
2) carb problem -- stuck/blown power valve
3) timing issue

earlier posts gave some suggestions about timing did ya' try 'em?

sb

[rellik eeb]

i wouldnt change the egine just becuase its not a 360, I know the 318'd arent known for stump pulling torque and is giving up over 40 cubes, but you can still have a good running combo once its sorted out. If you have the money go ahead, start a new short block build, but for those who say "go 360" I one could say hey go with a 4 incj stroker. But fact is you can make some good numbers with what you got, Id say 250-300 rear wheel hp can be had with what you got, if you have any compression. Simply invest some money in a good converter like a Dynamic 9.6 inch or so, there more "loose" you can stand the better, id like to see a 3000 flash converter in there, dont buy a cheapo converter too, get a good custom converter which the combo could grow and into also. maybe a 4 inch stroker may be in the future hu? I would have made some "better choices" on a few things, like carb size, cam type etc. A 318 would be very cam sensitive, and easliy over carbed. Id keep the duration short seat to seat, on a wide LSA like a 112-114, and opted for a 1.6 rocker ratio for that combo.

[blue72swinger]

Originally Posted by rellik eeb

i wouldnt change the egine just becuase its not a 360, I know the 318'd arent known for stump pulling torque and is giving up over 40 cubes, but you can still have a good running combo once its sorted out. If you have the money go ahead, start a new short block build, but for those who say "go 360" I one could say hey go with a 4 incj stroker. But fact is you can make some good numbers with what you got, Id say 250-300 rear wheel hp can be had with what you got, if you have any compression. Simply invest some money in a good converter like a Dynamic 9.6 inch or so, there more "loose" you can stand the better, id like to see a 3000 flash converter in there, dont buy a cheapo converter too, get a good custom converter which the combo could grow and into also. maybe a 4 inch stroker may be in the future hu? I would have made some "better choices" on a few things, like carb size, cam type etc. A 318 would be very cam sensitive, and easliy over carbed. Id keep the duration short seat to seat, on a wide LSA like a 112-114, and opted for a 1.6 rocker ratio for that combo.

Yea thanks for the awsome advice, converter will be going in when i go through the tranny later.

[Badarse mopar]

I had this same problem just last week with my 318 too,just turned out to be the mixture screws were set to lean.(Carter AFB)Three and a half turns out on each screw from fully closed put me close with my combination.Then it was a matter of fine tuning to get it right.