Hot Rods School me on this old Mallory distributor

I was on the computer today rereading this thread and realize that when I typed the part number for the distributor cam in Post #20 my fat fingers put in 4's instead of the 3's in the number. It should read 24933, not 24944 and it is the 24933 cam which is correct for p/n 24875-B dual points and also the Magspark Transformer application. Your dist. has the 24178 cam which uses the older 24205 points and the following Mallory info says that the 24933 cam is used with the 24875 points. Maybe Jim can compare the two cams and determine the difference, is it the dwell?

This info is from a Mallory publication-

All “C” model Mallory Distributors with the #24875-B Circuit Breakers MUST HAVE the following Circuit Breaker Plates and Cams.
Cyl. & Rot. Cam Plate Breakers
8cyl. R.H. 24933 24878 24875-B
8cyl. L.H. 24932 24878 24875-B

The Caps are not mine, that is the way the info is presented in the instructions. I typically check out the HAMB on my iPhone and I can see now that I need to proof read my posts before sending them. I apologize for any confusion.

 

Just cut off the end of it?? And run it??? No Merc cover needed... Right?

 

My distributor is a Zb model. Cam is P/N 24178 breaker plate is P/N 24878 and points P/N 24875-B

 

Also my rotor is P/N 24215 and is the one with the spring behind it.

 

Also just to clear the whole timing cover situation up, I already found a merc timing cover and have it in my possession

 

Yes, I admit to bringing some confusion to this thread, but again, the Mallory info states that the 24933 cam is to be used with the 24875-B points and 24878 plate. As I stated previously someone switched your plate and points to the ZC style, but you have a ZB cam.
Although I do not know why, Mallory stated that you..... “MUST HAVE”..... the 24933 cam for the 24875 points.
Hopefully Jim (Bubba) can confirm why the cam needs to be changed, or if it will work as is.

 

@GMC BUBBA

 

Hey 66,
A little late to this thread, but maybe not tooo late.
I think that your setup was made for marine usage. I have same setup and that's what it came from. As you probably know by now, you can ..'can' the transformer and use dist with coil. Dist doesn't know 6v or 12v so can be used for either. Mine came off 6v boat application, was converted to usage on four banger and 12v. I took one set of points out, but can reinstall/recalibrate at any time.
These are 'bullet proof' USA made ! I wouldn't trade the ones that I have. I kind of like the use/looks of the old transformer coil style, as most are not familiar and stare at it...whatsit?...lol
Anyway, if you need it 'fixed' calibrated, I'd contact Jim (Bubba) Lindner..the best !!

 

Ballast resistor usually drops voltage to around 8v.

 

Heres something we send with our delco units explaining the ballast and the importance of using it.

Primary Ignition “ Balance” !!!!!


In most cases you just cant beat the OEM design of a product !

The Delco distributor uses a balanced primary wiring. The voltage comes from the battery, the switch,the primary resistor and a resistor ignition coil, then thru a final (finely wired) distributor lead.

Using a 12 volt battery the ballast resistor is 1.5 ohms and the ignition coil winding is 1.5 ohms.

That’s three ohms divided into 12 volts for a current flow of 4 amps. Energy wise that’s 6 watts. Using the two resistors the wattage is divided to dissapate heat etc. With each resistor dropping approx 6 volts.. Any extra voltage going to the points is dropped by the distributor lead wire.

 

Sooo... I'm late to this thread too, but did you get it ironed out and what was your final setup?

I just picked up one of these distributors also and am ironing out the details. I think I want to get away from the vacuum brake and go full mechanical... any thoughts on this? My main motivation is simplicity and looking at the brake in mine the other day I'm concerned about it's lifespan.

3blap.

 

***uming the lower end (ie weights advance) is good rust free shape. Just clean everything up and leave out the vac piston spring. No problem....

 

Excellent! And, you were the guy I hoped would chime in! Thank you sir!