Discussion Forum - Northstar Chevelle Club

jim larson · 2K+ Club

Pertronix or MSD points replacement unit.

jim larson · 2K+ Club

Check this out. www.msdignition.com/Products/New_Products/8019_-_EZ-1_Digital_Points_Replacement_Kit_Chevy_V8.aspx

-- Edited by jim larson on Tuesday 19th of April 2011 07:02:14 PM

-- Edited by jim larson on Tuesday 19th of April 2011 07:54:28 PM

Chris R · 2K+ Club

Looks like another nice replacement for what is long outdated technology.

Lost in the 60s · President

Looks like a nice upgrade. I think you should get one and be the first to have real world experience.

John D · 2K+ Club

It must use some kind of "Hall Effect" pickup to trigger off the original lobes on the distributor shaft. I'm guessing it has to be adjusted dead-nuts on the money, with a distributor that has GOOD lobes - there's not a lot of "bump" on those bumps...

Lost in the 60s · President

John D wrote:
It must use some kind of "Hall Effect" pickup to trigger off the original lobes on the distributor shaft. I'm guessing it has to be adjusted dead-nuts on the money, with a distributor that has GOOD lobes - there's not a lot of "bump" on those bumps...
I don't know what "hall effect" is but it is listed as that type on Summit. It appears to be the same as the Pertronix III I have. That triggers off the original lobes too and no adjustment was necessary. Just make sure the shaft can rotate without touching and tighten the mounting screws. The only difference I see between them is that the Pertronix requires a power wire from the plus side of the coil for power along with the trigger signal to the negative side.
Jim, if you decide to add an electronic conversion and have the dizzy curved on a machine, either disassemble it completely yourself to remove the old, dried grease and install new, or make sure the rebuilder/recurver will do that for you. When I took my '67 dizzy apart for cleaning, the old grease was hard as a rock and doing nothing to lubricate the shaft bushings. The greae is under the plastic cover which is right under the points plate. I would be happy to help with this, but there is the distance involved ...

jim larson · 2K+ Club

Mitch, I took the distributor apart a couple of years ago and installed new grease and a new plastic washer. It thought it was suppose to be a special kind of gease; but forgot what it was suppose to be. Also can't remember what I used to lube the weights. I acquired another 66 BB distributor for a spare that I think I will take apart and recondition. Maybe if I am in the area I will call and stop by. The MDS unit sounds interesting. I wonder if they recommend a specifical coil or I could stay with the original 204 delco coil. I read a little about the electronic kits on TC and some of the guys carry a spare set of points; because sometimes they just quite. I think I would like to try the MDS kit as its about time to change points which I did about 4 yrs ago.

I just got the new digital timing light the other day. So when it warms up I can check how much advance my distributor is adding and when along with checking the vacumm guage function. Currently base timing is at 8 degrees and it runs good. Maybe 10 or 12 would be better and then I would have to change the curve to reduce the mechanical that the distributor adds. You said something about modifying the weight a while back.

jim larson · 2K+ Club

John D wrote:
It must use some kind of "Hall Effect" pickup to trigger off the original lobes on the distributor shaft. I'm guessing it has to be adjusted dead-nuts on the money, with a distributor that has GOOD lobes - there's not a lot of "bump" on those bumps...

I also see the pertronix I listed as Hall-effect unit with no explaination of what Hall-Effect means. This is not mentioned in their pertronix II or III kit. I think all three of their kits read somehow of the lobes and also true for the MDS kit.

John D · 2K+ Club

In layman's terms "Hall Effect" is a magnetically induced pulse...

Wikepedia: Its use as an ignition timing device in various distributor types is as follows. A stationary permanent magnet and semiconductor Hall effect chip are mounted next to each other separated by an air gap, forming the Hall effect sensor. A metal rotor consisting of windows and tabs is mounted to a shaft and arranged so that during shaft rotation, the windows and tabs pass through the air gap between the permanent magnet and semiconductor Hall chip. This effectively shields and exposes the Hall chip to the permanent magnet's field respective to whether a tab or window is passing though the Hall sensor. For ignition timing purposes, the metal rotor will have a number of equal-sized tabs and windows matching the number of engine cylinders. This produces a uniform square wave output since the on/off (shielding and exposure) time is equal. This signal is used by the engine computer or ECU to control ignition timing.

My guess is that the peaks, then flats, of the distributor lobes create the windows & tabs described above, and the sensor is arranged to "see" when the peak of the lobe is closest to the sensor.

Chris R · 2K+ Club

A lot of todays aftermarket ignition systems use the hall effect for timing.

jim larson · 2K+ Club

Much clearer now. MDS rep said it wouldn't be available until this summer and that they are tweaking it now. However, both Jegs and Summit have it for sale. Jegs for immediate deliver. Jegs and Summit probably have the 1st ones of the production line. Maybe by waiting until later in the summer you will get a better unit. Pretty easy to hook up, 2 screws to mount it to the plate and then attach to wire from the coil.

Just got through a partial disassembly of my spare distributor. Found a broken spring clip that holds that plate (the plate that t the points are mounted to) to the upper bushing. Haven't taken the plastic washer out where the grease is suppose to be to provide lubricant to the upper bushing yet. Upper bushing looks good and the upper part of the shaft that rides inside the bushing looks good. The lower bushing has some rings in it and the corresponding shaft has those same rings. I have heard this is normal or is it something to be replaced? Also seems like two much play between the lower gear and the housing. There is one washer in there; but I think it is to much of a gap. I think there is a specification for the amount of play, like .020; will have to look that up.

67ss · 1K+ Club

The only problem with it being a digital hall effect sensor is they need power and ground to make it work. This only has one wire from the negative side of the coil. To me it would seem to have to be more of a a/c generator like a transmission speed sensor and based off the sin wave peaks and valleys it somehow triggers the coil.

jim larson · 2K+ Club

maybe it would be more reliable than the pertronix sysyem if that is the case.

Bowtieman427 · Active Member

Got a Pertronix in '59 Imapla and it works fine. Been working finr for years. Not saying they are grea or anything have nothing to compare it too. I got it when they were still realitivly new and the only ones havine a solution that would get rid of points and fit under a stock cap.