FE autolite distributor dwell questions

[s55mercury66]

Also, the pic 5851a posted shows the issue pretty well.

[s55mercury66]

I have not had time to play with this any more, yet. Should be able to by this weekend though.

[KULTULZ]

Originally Posted by 5851a

The point plate pivots from a point opposite the vacuum advance arm and swing in a slight arc instead of perfect rotation.

Later dual point distributors with vacuum advance used a breaker plate that rotated in a perfect circle but requires a different cam. Most of the Boss motors and some years of CJ 351/429.

Is this the later style breaker plate assembly you are describing?

I see a pin and slot that seems to not allow the plates to move out of egocentricity ... ... (Where did I come across that word?)



You are correct and I am wrong Sir. The rule is that dwell variation with increased RPM should not vary more than three degrees if not the AUTOLITE two piece breaker plate assy, the upper plate swinging in an arc causes resultant dwell variation that can be up to twelve degrees variation with that design.

I found an old tech sheet and will post it when my scanner returns to Earth orbit.

I am truly sorry if I caused any confusion...

EDIT -

While I am sucking up dust, the second adj hole in the points set is for adjusting points breaker arm spring tension, not dwell angle.

I expect oldmics to call me on the carpet and tear off a few patches...


I was once asked to step out of a bread line because I asked for toast...

[5851a]

I'm not right that often and if you don't believe that you just ask my wife! I like all the different views on things. Everything isn't set in stone otherwise we would have no TSB's to look at

[KULTULZ]

Originally Posted by 5851a

I'm not right that often and if you don't believe that you just ask my wife!

I like all the different views on things. Everything isn't set in stone otherwise we would have no TSB's to look at

After reading your post, it got me to consecrating. I have still yet to find correct theory on the plates but my guess is that the variance in dwell on this design distributor is to decrease the dwell angle at RPM to more quickly saturate the coil.

In 1957 when FORD went to both centrifugal and vacuum advance, the plate was one piece and rotated concentrically on roller bearings. The dual plates were introduced in 1959 and I think there two designs of those. And of course the dual point plates you mentioned.

It will give me something to do and keep me occupied for a while ...

Naturally I don't have a dual plate distributor but do have a 58 MERC one plate design which is of no help.

And how many years and point changes and this never crossed my mind... ... (of course very little crosses it other than static electricity).

[s55mercury66]

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Hey KULTULZ, thanks for the info. Sorry I have not had time to play with this, work has gotten in the way. The theory you put forth makes sense, I am going to put some more thought into taking advantage of the situation.

[KULTULZ]

Originally Posted by 5851a

I like all the different views on things. Everything isn't set in stone otherwise we would have no TSB's to look at

Originally Posted by KULTULZ

After reading your post, it got me to consecrating. I have still yet to find correct theory on the plates but my guess is that the variance in dwell on this design distributor is to decrease the dwell angle at RPM to more quickly saturate the coil.

In 1957 when FORD went to both centrifugal and vacuum advance, the plate was one piece and rotated concentrically on roller bearings. The dual plates were introduced in 1959 and I think there two designs of those.

And of course the dual point plates you mentioned.

As I slowly digest all of this (it still has me wondering as does a lit match), when FORD went with the DUAL ADVANCE DIST DESIGN in 1957, the breaker plate was one piece and rotated on ball bearings (advance-retard). This design was used until 1959 when all advance plate designs went to the two pivoting plate(s) design (intro 1958).

The reason I surmise is cost. Even though the dual plates allowed dwell variation, it was incorporated. Now, in the 1968/9 model year, FORD went back to a non-pivoting breaker plates for a more controlled timing events for performance and emissions (HI-PO only) (I would suppose).

Below are photos of thee 57/59 design and the later late sixties HI-PO design-

Any further findings 55mercury66?

[5851a]

Thanks for the picture, had never seen the early type. They do look costly to manufacture and who would ever think to lube the dist. bearings.

[KULTULZ]

Originally Posted by 5851a

...who would ever think to lube the dist. bearings.

They were self lubing with the crankcase evacuation systems of the day or the owner seldom changed oil. The excess crankcase pressure would exhaust itself and motor oil through the distributor assy ...

Look at this photo, just posted on the Y-BLOCK FORUM-

[KULTULZ]

As you can see on the above photo, there is no lube hole in that particular bushing (B8QH 12120-A).

Here are two bushings, one for a LOM (A8A 12120-A) and the other (B7A 12120-A) that have the holes and appear to be OIL-LITE