Hi folks, it's been awhile but I have a lingering problem w/ my '68 Dodge Dart 270 6cyl 225. It's low idle is very bad. When I'm in Park/Nuetral the motor just shakes and bounces when in low "curb" idle. However, the bouncing and shaking is much, much worse when I'm in Drive and sitting at a stop light or sign. And when I let off the brake and give it gas coming from a stop, it hesitates and doesn't want to seem to go forward very much, then suddenly it "kicks" in and surges ahead ..almost like it wasn't getting the fuel for a few seconds, and as the pressure built ( from my pressing the accelerator) all at once it gets a rush of fuel and surges ..?.

The car runs great other than this low idle shaking and taking off from a stop. I did switch my normal electronic ignition to the recommended HEI set-up last year and a friend who has worked on mopars for 40+years thinks that may be part of the problem. Just for a test he hooked back up the original distributor/points etc.. to my car to see if it would steady out and it did. I never read andything about the HEI causing rough idling but maybe? Would love some thoughts about this issue I have, maybe I need to scrap the HEI ??? THANKS

The more likely issue is a mismatched timing curve in the electronic distributor. HEI should be providing a much stronger ignition.

There are a bunch of threads covering timing curve modification, and articles outlining the full how to. It is also possible there is an issue mechanically with the reluctor, spring perch setup or vacuum advance mechanism. The distributor is most likely not going to "plug & play."

What electronic distributor did you install? Is the reluctor gap correct and uniform for all the reluctor triggers. Is the shaft of the distributor straight? Which governor is in it?

Have you mapped the timing curve? This can be accomplished with a timing light, or on a distributor machine. If you don't have access to a machine, a dial back gun can do the job.

CJ

_________________
Part of Tyrde-Browne Racing

Did you try switching the leads that go to the ickup in the electronic ignition distributor? HEI is picky about the polarity of the pickup leads and will run badly if they are not conected properly.

_________________
Casually looking for a Clifford hyperpak intake for cheap.

What Reed said.
Also , I recently had similar problems on my latest HEI install.
I checked that I actually had TDC (which I thought I did ) and noticed the rotor button was a bit off #1 position on the dizzy cap.
I slid the dizzy out a bit and rotated the rotor 1 tooth clockwise and away she went , purrs like a kitten now .

_________________

DRIVE IT,DON'T HIDE IT

I kinda had the same problem as well and I couldn't figure it out. I know it was wired right, I had swapped out springs, everything! I figured it had to be something in the distributor but what? It got to the point where I said screw it, bought a Pertronix and hooked the leads to the coil and have been happy since. Sorry I'm not more help, but you have this avenue if need be. Good Luck

thanks for all the replies, I'll check out some of the things mentioned. I forgot to add that my car will also stop running as I slow to a stop at a light or stop for any reason. It doesn't always happen but it does always feels like it's going to quit if I keep it in Drive while stopping, and I usually need to put it in neutral ..at least then it will stay running.

That's exactly what mine was doing .

_________________

DRIVE IT,DON'T HIDE IT

A proper diagnose may be a difficult process at times, the problems you describe was caused by the carburetor in my car!
Do you have a timing light? What are the readings at idle and each 500 revs up to a point where the advance does not change anymore? Have you double checked the wires from dizzy to the HEI module? Have you tried to switch them? Is the module properly fitted to a heat sink with paste to transfer heat? (they are sensitive to heat) Do you use a solution with a relay to feed the module from tha battery, to ensure a steady, high voltage?

Olaf

_________________
Aspenized

I was wondering when someone would bring up the fact that timing and carb tuning are a see-saw back and forth until you get the settings right where they both work together...with too much timing/too fast of an advance you can lean things out and have the engine die due to lack of fuel.

Also EI is a bit more tight than points so a slightly sloppy timing chain can drive the person mad looking at all the "usual" issues and still not getting it to run right...

DI rules!

Olaf

_________________
Aspenized

OK I'll do my best to relay this as it was told to me. We checked the wires that come from the distributor, and swapped them around. The car would not even start up when we did this, so we switched them back and it started right up ..so those are correctly connected to the module. Also we have a brand new timing chain and it was checked to see if it was on right ..and it is. The engine/motor is in excellent condition and tight. The distributor seems to be fine nothing bent or anything. All these were checked by a man who's worked on these all his life, and he knows his stuff.
Now about the timing, and this is where I hope I can explain it intelligently. My friend said that with a timing light he has it set right on, but that it's still mechanically off ..I think that's how he put it. He said that at the distributor he can't quite get it where he wants it, like what BUCKET 636 mentions about sliding/moving the dizzy out a bit. So the way it was told to me is that on the dizzy you have the ability to slide/rotate it along a given path ..but you can only move it so far. Well in my case mine is not allowing me to move it far enough. My friend said that he needs to be able move the dizzy to get everything right in line for me, but that he has it as far as it lets him go ( in the direction he needs to go ) but that he can't go as far as he needs to go ..he runs up against the wall of the notched-out patch or space given. We aren't sure what the brand or model is of the distributor is ( it was installed by a prior owner, but my friend and I feel it's a Dodge part because the prior owner worked for them for yrs and was a Mopar guy ). I hope this is making some sense. So without being able to move the dizzy more than we're able to now, we know that the timing there is close ..but not right. Should we get a new one? BUCKET what dizzy do you have, can I get one from ebay, should I? This brings me to the test my friend did when he replaced my electronic dizzy with the original points dizzy. He said that when he put that in he was able to get EVERYTHING in time with the timing light and at the dizzy ..unlike w/ my electronic dizzy. But and although the car smoothed out even better at low idle it still did not smooth out the way he said it should have. It was better but still not right. This makes him suspect that there is some issue with the carb playing a part in this too. My friend can set a carb and fine tune it, but he isn't a pro on the inner workings in terms of opening it up going in and replacing/repairing parts. My carb is a 1945 model Holley it was not a re-manu carb but and original carb from the 70's that was never used and I got it from SLANT SIX DAN ( he has many posts on this forum ). My original holley 1920 carb had broke some 3yrs ago and I had to replace it. So basically we have 2 problems, something isn't quite right inside about the carb and what that may be and how to fix it I don't know. The other problem lies in the fact that we are unable to get the dizzy or mechanical side of the timing in time for said reasons. So here we are, and I would love to hear more thoughts from all our learned gentlemen, not so much about the carb but about the distributor side of the timing and how we can get it in time ..I would like to tackle and solve this issue first. Thanks and sorry if I over-explained or did so poorly

BTW if anyone here knows of somebody or someplace here in GA or nearby that could take care my car issues then please let me know. I'm always open for that and with my '68 Dart being my sole means of transportation, I can't afford to mess around and not be able to drive. My friends who have and do help me have other jobs, and can't always work on my car when I need them. Anyway, just thought I'd throw that out there.

If the guy can't set the timing right, then I wouldn't let him work on the engine.

Here are my two cents:

(1) You say you have installed a new timing set. Did you degree the cam when you installed it? The manufacturing tolerances on parts these days are horrendous and very often replacement timing sets are not indexed correctly. This means that the cam and the crank are not in the correct or optimal relation to each other. I have personally used a timing set that was 8 degrees off out of the box. If you have the time and patience, I highly recommend going back and verifying that the cam and crank were indexed properly with the new timing set.

(2) Have you verified that the timing mark on the vibration damper is correct? The outer ring on the damper can slip over time and give an incorect indication of TDC. I have personally seen these get as far as four degrees out of true. You will need a piston stop tool and some white out to check the timing mark on the vibration dampener.

(3) When you set the timing are you aware that there are two adjustment points on the distributor? The slotted hold down that bolts tot he bottom of the distributor has an adjustment point where the holddown is bolted to the block but also on the bottom of the distributor where the holddown is bolted to the distributor. Your mechanic says he can't get the engine timed right. Is he aware of and using the adjstment point on the bottom of the distributor?

It sounds like you need to find a mechanic who really knows what they are doing and isn't relying on incorrect shade tree "knowledge." At least get a factory service manual for your car.

_________________
Casually looking for a Clifford hyperpak intake for cheap.

Even if he wasn't aware of the second adjustment bolt/slot, why didn't he just take it out and move it a tooth?

What Pierre said .
This isn't hard to do.
My dizzy is a Chrysler electronic dizzy from Old Car Parts Northwest.
I mean actually pulling the dizzy out of the hole and turning the rotor one tooth before sliding it back in .
Not just trying to turn it left or right while it is still installed .

_________________

DRIVE IT,DON'T HIDE IT