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455 motor, eldabrock 750, w-31 cam. Car Stumbles some while driving. As driving at 30+- it seems to miss. Car shakes at stoplights. Tried to set timing with vac adv unplugged to 16. Idle was 650 erratic at time. After timing plugged in vac adv and motor speeds up. While testing vac adv when first increasing the throttle the timing retards about a half inch on the timing indicator (on motor) then advances. Was not able to figure out all in vac #. Has to idle at 1100 or when put in gear it barely runs. Ground strap is from intake bolt to windshield wiper motor bolt that screws int firewall . Vac gauge shows low vac ( 10) if I remember correctly but brakes work good gauge is very old. Thanks in advance for any advice.
Dist #1111982 with nv5 on the module Weight closest to vac adv canister flops loosely. Vac adv # is (502 14). Receipt for vac adv came with car says adjustable. Not sure why the three black dots? #3 plug. Threads smell like gas but car has not run in days #4 plug. Same as 3. Gap is 33
We need some real timing numbers. What is your total timing, at what RPM does it stop advancing with and without vacuum advance? What is you initial timing with and without vacuum advance, at what RPM? What ignition setup are you running? Is it wired as per manufacturers recommendations?
You might have tried a google search, but that distributor number lists for a 70 442 and others.
The module as Pertronix.
The vacuum advance as Accel. Note the blue dot, probably sold by many parts outlets, if you've ever seen those colored dots. Like I said, just the internet who knows how true.
From looking at your photos I don't like the looks of the rotor. The weights and springs are suspect at this point they don't look like GM, and from your observations seem iffy. Plugs look OK...
I'd consider a basic tune up at this point at least replace the rotor and maybe cap. But first, make sure this distributor has the required voltage in the (key) run position.
The weights ; should I shop for stock or w-31? The cam is w-31.
Question I have is should one of the weights move loosely and not move the other adv parts as if the spring is not even pulling on it but the other one when moved by hand seems to move with the other adv parts?
I have an unused dist that both weights operate the same but It is an HEI huge red cap dist in my basement.
So is it normal for one distributor adv weight to move freely and independent of the rest of the mechanical adv system? Will check timing again when rain stops. Wish I knew how to post video.
Anyone know a weight and spring vendor? Looked on some of the usual vendors sites and saw some for HEI and Morroso but they don't mention for stock GM. The HEI is huge , needs different wires and I was told my air cleaner will not fit so I have not tried it.
I tried to reverse my weights but they would not fit the other way. I did notice a (stop) sticking up holding the weight farthest from the vacuum canister ( in my original picture above) from closing inward. I switched the two springs and still ended up with the weight closest the vac canister being loose. One spring is weaker than the other and switching them did not change the loose weight position.
The picture below is of an unused HEI dist I own that looks same as yours. It's weights are just like yours. I may have incorrect weights on my car and don't know if that stop is supposed to be there either.
This is the HEI I have. It matches your configuration. I don't want to use this.
Well, this got me interested so I went and dug my original points distributor out of a box in the garage. I have been the caretaker of this distributor since 1977 so I know its history. Below are some pictures.
First off, apparently the points distributor weights are set up opposite of the HEI weights. I have no idea why this is, but my distributor matches yours so that is a good thing and no issue with your weights. Sorry for leading you down the wrong path with that.
Second, my distributor does not have those two posts that yours has. No idea what those are for but I don't think they have anything to do with your issue. IMG_2860_zpsrny9wqes.jpg
As for that "stop" that's interfering with your weight, I think that is your whole problem. My distributor has a flat circular bushing for the weights ride on. Whatever that is on yours, it is preventing the weights from moving properly and needs to be corrected.
The advance stop is actually below the advance plate and is a bushing on a pin that rides in a slot in the plate. This means you do not need a "stop" on the top to affect the weight travel.
Lastly, (not related to your issue but just for information) I had forgotten that on the points distributor the center bar is welded to the shaft and therefore not interchangeable like the HEI distributor. I then remembered that the HEI uses the contact between the weights and center bar to limit the advance whereas the points distributor uses the pin/bushing in a slot.
Thanks, I appreciate the info. I was out of town and didn't get to mess with it this weekend.Gonna try removing the stop,replacing the wires,cap and maybe the vac canister and springs soon as I get some time.
Yeah, the Olds distributor counter clockwise rotation what made me think your weights were installed incorrectly. I was surprised to see my points distributor was opposite of the HEI distributor. No idea why that is.
May 3rd, 2017, 06:49 PM
