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08-03-2020, 08:08 PM | #1 |
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Mallory sbc to 8BA 4 lobe cam issues
I have some sbc Mallory's in the shop to convert to 8 BA. These are the
2 piece vintage cap styles. Here's the problem all have 4 lobe cams, all are dual point using the Ford style Mallory points. These points are adjusted with a screw driver in triangular depressions in the breaker plate. My issue is some distributors have the points 180 degrees apart and others about 135 degrees apart. I slipped a 135 distributor into my test motor and got very erratic spark or no spark at all. If the motor fired it was just burp. I removed the 135 breaker plate and installed a 180 breaker plate using the same points that were on the 135 plate. The motor fired right up no sweat. I was extremely careful that in both scenarios .everything was properly insulated. Help me out here....what's the deal with the 135 plate. Thank you, Charlie |
08-03-2020, 08:27 PM | #2 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Charlie,
I am clueless as I've messed with nothing but original dizzy's. Do you have a sun or allen machine? If so what's the arrow seperation from even to odd cylinders when using the 135 degree breaker plate? |
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08-03-2020, 08:41 PM | #3 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Charlie,
I have a flattop Mallory for an Olds Rocket that has a four lobe cam. The points are not wired together, each set having it's own terminal on the side of the distributor housing. This distributor uses a special Mallory coil that has two primary windings and one secondary winding. Each set of points energizes it's primary winding alternately. It's sort of a "poor man's" dual coil setup that doesn't require a special cap or rotor. I also have a couple of SBC flattop Mallorys with 4 lobe cams where the points are wired together and feed one primary on the coil like regular dual point. I believe these are called "Double Life" distributors because they alternatively fire each set of points to energize the primary, resulting in half the wear on the points. I believe this type of distributor needs the 180 degree plate. while the first requires the 135 degree plate. These "poor man's" dual coil setups obviously require two condensers. Denny Last edited by tubman; 08-03-2020 at 08:50 PM. |
08-04-2020, 06:52 PM | #4 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Is this the wasted spark system?? How do you run a V( with a 4 lobe cam?? Must use 2 coils and a 180 plate. Not sure about the cap.
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08-04-2020, 07:23 PM | #5 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Denny …...I guess that common sense would dictate that these early Olds, Caddy and Hemi engines with the extended, cast bells probably shouldn't be 'hung' off of an engine stand by their butt-ends just like the early flattys? And if that is true, and with the exhaust ports being NOT located in the BLOCKS, just how does one cautiously hang one of these on an engine stand? DD PS....CUTE little gold thingies! Last edited by V8COOPMAN; 08-04-2020 at 09:11 PM. |
08-04-2020, 07:41 PM | #6 | |
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Re: Mallory sbc to 8BA 4 lobe cam issues
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Quote:
And, you can run a V8 with a 4 lobe cam and one coil if you have dual points phased properly. That's the Mallory "Double Life" distributor. Each set of points cycles only four times in two revolutions (all 4 cycles) instead of eight times, hence the name. I think this is also quite clever. As a point of reference, with "regular" dual point system, both sets of points work in concert to increase the dwell and therefore coil saturation. Last edited by tubman; 08-04-2020 at 08:09 PM. |
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08-04-2020, 07:49 PM | #7 | |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Quote:
About the "gold thingies"; I get 'em wholesale; that's almost a necessity with these distributors. |
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08-04-2020, 09:21 PM | #8 | |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Quote:
Sorry if I caused any confusion about 'cams'. I understand the theory, but was merely trying to shorten the "quoted" reference. Getting back to the cast bells....just HOW do guys safely mount these on a true engine stand? As many of these that I had seen in the past, I had never really thought about mounting one before your picture above just 'smacked' me up the side of the head. DD |
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08-04-2020, 09:22 PM | #9 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
I went thru my inventory of Mallory parts and found that I had initially used the only
non DOUBLE LIFE plate to build the distributor that started this post. I had eight DOUBLE LIFE breaker plates. That tells me the DOUBLE LIFE was pretty popular and the Mallory on your delicious Olds maybe not so popular...just a guess. I have a bunch of Chevy Mallory's and most have the 4 lobe cam. It is quite obvious when eye balling an 8 lobe Mallory the distinct difference in the location of the points in relation to each other. Denny, I sure thank you for clearing up my flumox. Charlie ny |
08-04-2020, 09:36 PM | #10 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Charlie,
Yeah, the Olds type was "not so popular". The proper coil that I have for it is a 6 volt unit and I have been looking a couple of years for a 12 volt unit with no luck. I really don't want to run that Olds on 6 volts. Denny |
08-04-2020, 10:36 PM | #11 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Just when you've thought you've seen everything. You have to start all over again.
Gramps |
08-05-2020, 06:20 AM | #12 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Denny,
Some years back Skip Haney rebuilt a Mallory 'square' coil for a buddy, perhaps he still does. Ron, Alice and I will always cherish the hours we spent with you almost ten years ago. Charlie ny |
08-05-2020, 07:08 AM | #13 | |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Quote:
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08-05-2020, 08:04 AM | #14 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
My recall is not what it used to be but I do remember my '53 Olds coupe with a LaSalle trans and '57 J2..........Coming off the line at about 6000 the clutch and pp blew up and
grenaded the rear casting. A bit un-nerving, opened up the trans tunnel and killed my radio, back on the road in a week. Charlie ny |
08-05-2020, 11:16 AM | #15 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
That distributor may also be from a "MagSpark" setup. "MagSpark"'s are hard to find and obtuse, so I don't know much about them. I have a "MagSpark" transformer, and it also has three primary terminals, one marked "Ignition" and the other two are obviously for the two leads to the distributor. I'm starting too believe that a "MagSpark" is nothing but and oddly packaged coil with two primary's and one secondary, just like the "FlashFire". Mallory called it a "Transformer", but I see no sign of AC current anywhere.
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08-05-2020, 12:43 PM | #16 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Here you go Tubman.
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08-05-2020, 02:02 PM | #17 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
That's like the "MagSpark" I have. I find it interesting in that it has two ballast resistors that are on the distributor side of the coil. My "FlashFire" (for want of a better name) has only one ballast resistor, on the "Ignition" side of the coil. The red coil is a regular "FlashFire". BTW, 6 volt "FlashFire"'s are black, while 12 volt units are red.
BTW, is that part of a system you have, or just an odd piece, I try to accumulate all of the Mallory stuff I can. Last edited by tubman; 08-06-2020 at 12:03 PM. |
08-05-2020, 03:53 PM | #18 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
This one says 49-53 Ford / Merc 6volt negative grd on the box. But you can wire them positive ground.
I suspect, all the Magsparks like this are the same unit. The part numbers change because of the mounting for each make of auto. It utilizes two condensers one on the dizzy and one on the coil. Different from the Olds Rocket picture above. I'm using a YC, 4 lope with the contacts is series and one Mallory Best coil. Going back to Charlies original question. Looking through the literature I have, the only two contact plates I see are one for 8cyl and one for 6cyl. Last edited by solidaxle; 08-05-2020 at 04:10 PM. Reason: adding attachment |
08-05-2020, 06:01 PM | #19 | |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Quote:
Sal |
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08-05-2020, 08:13 PM | #20 |
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Re: Mallory sbc to 8BA 4 lobe cam issues
Solidaxle...........in my inventory of Mallory breaker plate I have a bunch of the 26017
plates as shown in your post.....the plate that got me in trouble is 24878. I'd sure like to know what application it services. Thanks, Charlie ny |
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