Thread: Distributor installation

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If you can't find one I'll look around and see if I find a rebuildable one in all of my junk in the garage. If I have one you can have it for the shipping.

NTFDAY, Thanks for the offer, I will keep it in mind. I am supposed to pick up one from Advanced tomorrow morning, but this is the second try. The first try produced a "remanufactured" unit which had one ear with the centrifigal weight bent at about a 30 degree angle! When "we" searched the Advanced Auto network, most stores in Virginia had zero units of that type but one store in Roanoke Va had 13 units, so if I just keep reordering one until I get a good one I should be OK but it is interesting that what was once the "Heartbeat of America" is starting to look like a restorers quest now! The Petronix unit is just slightly more expensive than the Accel unit but the Petronix unit is rated to an amazing 15,000 rpm so it must be a pretty good unit worth the extra $10. Just for discussion on this thread a smaller unit for about $185 from Mallory has dual points and has a base of only 3 5/8" diameter and sure to fit my firewall, but other sources have warned that the dual points have weak springs which will allow point float at a relatively low rpm. So the idea of a magnetic points units for a lower total price seems like a good idea and the Petronix unit seems like the best of the several available units, thanks for the tip.

Don Shillady
Retired Scientist/teen rodder

I have a Mallory dual point in the Mustang and I changed it out for a Petronix unit as the continual adjustment of the points became too much of a hassle. I opted for their matching coil and I did the same when I changed to a Petronix unit in the 73 F100. FWIW, the Petronix unit can wreak havoc on certain tachs, but as I recall there is a unit available to cure the problem.

...ahhhhhh one of the JOYS of a FORD engine - with no dist to firewall clearance problems!!! (yeah the pan.....)

Don, another to consider tho a bit expensive(tho consider how many other $$$ you have invested) is the MSD small diameter, ready to run version

http://www.msdignition.com/Products/...stributor.aspx

OR

Small diameter version
http://www.msdignition.com/Products/...stributor.aspx

I was gonna say the same thing IC2 said: aftermarket small housing; all of the majors make them.

IC2 and Rrumbler, I did spend some phone time with a tech guy at Mallory and the Tech guys at both Speedway and Summit. Unfortunately I would have had to invest about $200 more for a small diameter distributor for which I would not know if it fit unless I bought it and if it did not I would then have the return-policy hassle, soooo the best suggestion was from my wiring guru "Rick" who is the patient hand-holding tech guy at "It's a Snap" (1-866-462-7628 toll free) who advised to buy a low priced "Reman" Chevy points distributor and if it fits my firewall I could then upgrade it with something like the Petronix kit NTFDAY advised. Rick has a Petronix type unit on his '71 Corvette and he warned that the Mallory dual point 3 5/8" diameter would suffer from point-float and would still need frequent adjustment. At $47 (including paying the $5 core charge for the unit I did not have and adding a new cap) Advanced Auto was by far the cheapest deal in my area out of five different stores. Others wanted about $65 with an added $15 core charge and I still would not know if it fit until I tried it! Well the Advanced Auto deal was the cheapest because the first unit I got was bent really bad and you could not even put the rotor cap on it so I had to wait two more days for a replacement. This morning I stopped in to Advanced Auto on the way home from church (they are open on Sunday) and it was there. A quick change of clothes and a trip to the garage produced the satisfaction of a "drop-in" for the points distributor once I took off the rotor cap and wiggled the base so that the narrow part of the base passed the ledge in the firewall. Just for the record there is PLENTY of room in the Bebops firewall toward the rear indentation and there is plenty of room above the cap for the plug and coil wires after the unit is in the block BUT (!) the overhanging edge of the firewall is about 1/4" too short in the vertical dimension and the base of the HEI distributor forces the shaft forward and the angle will not let the shaft go down the hole vertically! Since I need to prelube the oiling before starting the engine I need an easy way to prime the oil pump right before starting and then install the distributor shortly thereafter, so the alternative of unbolting the trans mount at the rear of the trans and gaining the 1/4" by dropping the trans down a little seemed to be too much work to be practical at the time of the first startup. Now back to the original topic of this thread, the mysterious 180 out-of-phase condition. I had to take off the rotor cap to get the flat part of the advance weights parallel to the firewall and that means I will have to remove the rotor cap to take the unit in or out and that leaves the possibility to remount the two screws of the rotor cap 180 degrees off relative to the offset oil pump key at the bottom of the shaft. I made a small mark with a blue felt tip pen on the advance weight plate to keep the orientation of the rotor as original relative to the position of the shaft key at the bottom of the unit. Maybe that is a source of occasional need to offset the wires by 180 after reinstallation of the distributor. Anyway, I now look forward to installing a Petronix kit with a coil good to 6500 rpm. It was interesting to me to learn that the ballast resistor with a given coil needs to be matched to the desired rpm maximum which I should have realized from studying (and soldering lab circuits) that there is a L-R time constant in an inductor coil circuit. A slightly larger resistor allows the spark to last longer but limits the maximum rpm. For me 6500 rpm seems like a reasonable maximum for street, noting that the Petronix magnetic switch unit can go up to 10,000 rpm, so it is the combination of the coil inductance and the ballast resistor that determins the maximum rpm. Anyway I can probably resell the HEI unit on the local Trading Post and use the small base (4") distributor with the Petronix unit. Thanks NTFDAY for useful information!

Don Shillady
Retired Scientist/teen rodder

Don FWIW, if your tach is an old style like my Sun there is a possibilty the Pertronix will cause it to read low. A variable capacitor or resistor would allow you to adjust the C-R time constant which is what the Sun tach uses as a triggering device.