Packard Forum Index » V-8 (1955-56)

...(in this case), the distributor contact point spring gives up?

On the morning of 12/21/2012 (note the date), my usually reliable 55 Pat refused to start, even with the kick of starter fluid.

The timing light confirmed that there was no spark.

After inspecting the points and condenser in the distributor, I determined that the points were "shot" and the condenser wire was loose.

A trip to NAPA with Xref numbers (thanks to this site), got me a new condenser and point set.

So, I installed the new parts and it fired right up.

BUT, what I didn't tell you was that I have an MSD-5 capacitive discharge multi-spark ignition on my Pat. Up until there was complete failure of the points and a disconnected condensor, the ignition performed flawlessly.

Oh yeah, the point failure was due to the contact spring losing enough tension that the points would not open/close despite there being no real problem with the points other than they were not opening and closing. The service manual describes in excruciating detail how to measure the point spring tension and assure that it is within spec. This one obviously was not.

The points and condenser have been in the my Pat since I bought it. I installed the MSD-5 shortly thereafter and the ignition has been solid. After the point/condenser fix, the MSD-5 is still working perfectly.

This post is an FYI, rather than a rant.

Craig

I am a huge fan of the MSD-5 also and have used them very happily on quite a number of Studes and Packs; easy starting and a consistent strong spark right through the rpm range.

Yeah, I guess the point of my FYI was that the MSD will keep the ignition system working until it 100% fails, which was the case with my 55 Pat. $20 at NAPA got me new points and condenser which got it running again. The only real tuning I had to do was reset the timing to 6BTDC at idle.

Craig

MSD?

Microsoft Distributor?

Acronyms are unfortunately confusing.

MSD == Multi Spark Discharge.

msdignition.com/

IMO, the best capacitive discharge ignition ever made, period.

Craig

Appears the MSD-5 is now obsolete and the 6A might be the closest replacement for those with 12v cars interested in adding something.

Please correct me if wrong, but if I'm reading the instructions correctly it would appear the unit could be the best of both worlds. Work with stock dist with points and by use of a different wire, could also be used instead of points with a suitable pickup for the distributor being available. The anti theft feature is nice as well. All in all, maybe even better than the Pertronix.

Also looks like it might be easily revertible on the road should the need arise. If the points are used for the trigger and a couple of the old wires were disconnected & taped but kept available, looks like a simple job of exchanging wires would bring back stock ignition.

Apparently the closest replacement for the old MSD-5 would be the "Street Fire". Here's one for $135 at Summit Racing:

summitracing.com/parts/msd-5520

The old MSD-6AL is replaced with Digital 6A, $40 more than the above:

summitracing.com/parts/msd-6201

The Street Fire now has a rev limiter, something the MSD-5 did not have, otherwise it seems about the same.

My MSD-5 came with a jumper wire that I keep in the glove box. I've used it twice to take the MSD-5 out of the circuit so I can use my old points-capabile dwell/tach to set the points gap and idle speed. Despite the multiple spark, the timing light works perfectly.

IIRC, the MSD-5 was limited to 5000RPM, but I don't see that in the Street Fire's description. Anyway, 5000RPM is surely enough for a stock Packard V-8.

Craig

FWIW, the could the point spring losing tension possibly be a result of carrying more current and getting too hot?

I've seen it happen with several different aftermarket ignitions which don't use the resistor in the point circuit.

The OEM system is designed to carry 12 volts for starting and then switch in a resistor to deliver only 6-8 volts for running.

jack vines

Jack Vines Quote:

Jack,

With the MSD, exactly the opposite is true. Only a tiny current goes through the points as that is simply a trigger signal. The main current goes though a completely separate circuit connected to the battery.

As a matter of fact on the old points, the electrical contact looked fine, not "burnt" at all.

Quote:

With MSD, you can leave the resistor in place or not as you please as it makes no difference in MSD output voltage.

Craig