Installing FBO Advance Plate ...help

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70aarcuda

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I started this morning, following the instruction on his web site but got stuck. I can not find how to get the top shaft off. His instructions says there is a clip or screw to remove....can not find either one.

This is a MP electronic advance distributor made by Mallory for MP




Mopar Distributor Tuning J685S

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20200412_105851_resized.jpg
 
I think your distributor has adjustable mechanical advance built in. The 2 button head Screws I believe can be loosened up and the plate adjusted in the slots to limit advance. Not sure if the FBO Advance Plate works or is even needed with your distributor.
 
yes...i see those but you gotta buy the adjuster from Mallory....and I already have the plate...LOL
 
crap they are cheaper then the plate...and I ordered 150 bucks worth of stuff today......
 
Doesn’t moving the screws in the slots eliminate the need for the slotted plate?

but need kit to adjust it.....well...I guess i thought his plate would fit any MP distributor ....i guess not
 
The FBO plate will not work with that distributor.
 
I was looking for one of those adjustable MP distributors when I built mine. Super easy to loosen the screws and adjust the mech advance.
 
@crackedback I think it was had a chart that associated drill bits with how much advance you get by each diameter drill bit. Maybe he will chime in.
 
well..i just ordered the mallory kit which is now a summit kit......lol
 
crap...i should have gotten one of those old MP distributors instead.....live and learn...
 
To answer you original question, the spring wire clip is on inside. It has 2 little wires pointing up, and you need to expand them outward from center shaft. I did that recently and is real b**tch. I took 2 ink pen metal ink tubes to hook the pointy wires. When I put it back together I slipped a small O-ring over groove on shaft instead of clip. I think I see the up-pointed wire tips.
 
Well...the adjuster are ordered...i will just use them.....
Besides I have several of these Distributors....should have bought the kit along time ago...

Thanks everyone....
 
@70aarcuda I have a BFH if you need to use it to get all those pieces apart... not sure they will go back together afterwards though. :poke::p
 
well...probably have the kit on tuesday evening from summit...should be simple to adjust your distributor....
 
Hell...i would probably have to buy him lunch again...lol

When is lunch?

14° = .130” or #30 drill
16° = .149” or #25 drill
18° = .167” or #19 drill
20° = .184” or #13 drill
22° = .202” or #7 drill
24° = .225” or #1 drill
26° = .240” or B drill
28° = .260” or G drill
 
Rob...thanks.......

dont know went i will down that way again...but someday...lol
 
When is lunch?

14° = .130” or #30 drill
16° = .149” or #25 drill
18° = .167” or #19 drill
20° = .184” or #13 drill
22° = .202” or #7 drill
24° = .225” or #1 drill
26° = .240” or B drill
28° = .260” or G drill
In my street car with bigger cam I couldn't get rid of pinging with this type of distributor. Never did adjust the timing limiter screws. But are the light advance springs a part of the problem?
 
They are ussual set with a fast curve. You need a key set or drilll bits to adjust them and a FBO plate will not work. FYI in the middle of the shaft you see that felt oiler? Take it out and under it is a cap screw to remobe if you ever need to remove the advance cam.
 
But are the light advance springs a part of the problem?
A small part. The mopar kits include a heavy secondary spring.
The real problem is the design of the advance mechanism.
a. The spring force is linear and the 'centrifical' force of the weights increase exponential with rpm.
b. Adjustment to reduce the advance degrees allowed (limit the advance) cuts off the top. Bending the spring perches out compensates for that but can't do that alot.

Take a distributor with the orange primary and purple long-loop secondary spring and set at 24* mechanical advance.
Put it in our engine and set timing per MP instructions to 35* at 2800 rpm.
That puts the initial at 13* BTDC with the advance starting around 750 rpm. That would be OK on close to stock engine.
And the advance curve isn't too quick like this. A little fiddling with the vac advance it will probably be OK.

But lets say this engine is not stock and wants around 16 - 18* at idle.
So we limit the advance to 18* instead of 24*.
We think we're simply limiting the advance like this.
upload_2020-4-13_9-25-50.png


But in fact we've simulataneously reduced the spring tension on the primary spring, and increased the distance (degrees) before the secondary spring gets any tension.
So the advance looks more like this.
upload_2020-4-13_9-35-49.png

In this situation, whether timing is set at idle (say 700 rpm) or by the MP instructions its going to be in too quick to use the vacuum advance.

Moving the spring perch (bending the tab) for the orange spring will hold the start of the advance to a higher rpm.
upload_2020-4-13_9-44-33.png


Then bending the second perch (for the purple spring) will engage it sooner. if you can get to slow the advance before 2000 rpm it will then be possible to get the vacuum advance to work without pinging at light throttle accelerations and uphills.

Skim through this one here for more
Distributor springs
or for why its messed up
Modifying YH Advance Weights
 
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