Years ago, I had a 318 in the car. Before my 1st 440 swap, I converted the wiring to the famous Mopar Performance electronic ignition. Since then, the system has performed well for the most part but occasionally, I'll get a "no spark" condition where it cranks and cranks but won't start. During this time when it won't fire up, I've changed ballast resistors, colis, ECUs, distributors and even voltage regulators. As odd as it sounds, sometimes it suddenly starts and runs normally after any one of those changes. To me, this indicates that I may have just had a loose connection somewhere or that some sadistic person has a voodoo doll of my car and screws with me just for fun.
The previous generation Mopar Performance distributor is supposed to be a modified Accel or Mallory unit that was scaled down to fit a Mopar. Our B/RB distributors have a small space to work in so the size of the distributor is limited. That scaled down aftermarket distributor has light advance weights that supposedly cause fluctuating timing and spark scatter. Rick Ehrenberg claims that you can see the timing light/timing mark bounce around and move back and forth with the engine at any rpm.
I still have mine but have considered a switch to something better. I want vacuum advance though. It does help with fuel economy. Yeah, these are not economy cars but 2 mpg spread out over a 19 gallon tank could mean driving to the next gas station or filling up early when you still have 3/4 tank.
About the timing bouncing around - I came across this distributor shaft collar that supposedly addresses one potential cause of this issue. The purpose of adding this collar is to prevent the intermediate shaft oil pump drive gear from climbing up the vertical slop on the distributor shaft, which affects ignition timing due to the slant of the gear teeth. The lock essentially eliminates/reduces the amount of slop that the gear can climb.
Has anyone tried installing one of these shaft collars? Reviews I've ready seem positive.
I've seen some photos where the collar is installed on the end of the distributor shaft and some install it on the end of the oil pump drive shaft. I'm not sure which is better or appropriate.
I don't want to derail the thread onto a new topic, but had to ask....
Rick E-booger's ebay site sells one:
for Mopar Distributor Collar Timing Stabilizer 340 440 383 Hemi Dodge Plymouth | eBay
"If you've had trouble with unstable idle, detonation, spark scatter etc., this hardened steel collar can sometimes resolve the issue. Slips on distributor shaft to keep oil pump / distributor drive shaft / gear firmly "planted" in the block. This takes out "bounce" between the distributor shaft and drive gear (in block) , preventing gear from moving upwards as oil pump torque varies as each gerotor lobe builds pressure.
Fits all big block (383-400-440), LA and Poly small blocks, and 426 Hemis. Not needed on 318 / 360 Magnums (i.e., '92-93 up) - they are crank-triggered ignition.
Detailed instructions included."
From an E-bodies site:
"The old racers trick was to just put a length of rubber hose on the end of the distributor shaft. It does the same thing. It keeps the oil pump drive from bouncing.
If the end of the distributor shaft doesn't bottom out in the oil pump drive, it could bounce. Since the teeth are cut at an angle, any up/down movement changes the timing. The problem with the hose is that it eventually breaks down from being in constant contact with the oil"
For the collar - "To set the depth correctly, install the collar on the shaft, just tight enough that it will stay where it is, but can still move. Install the distributor and make sure it is fully seated. The collar will slide up to the correct depth. Pull it out, tighten it down and you should be good to go."
, sorry for any confusion
