Are there "early" and "late" distributor caps?

[rockfla]

Okay'
I know there are "early" and "late" distributor plug wire plates but are there the same for the caps to? I have a 37-41 style distributor but on the left side cap, when indexed correctly I cannot get the cap to mount flush as the rubber boot from the cap to the wire conduit hits the vacuum advance portion of the housing and will not allow the wire plate to index correctly or flush. Working on a 1939 Mercury. Ideas???? Prior to now the boot was missing and it was mounting in the housing fine without it.

[KiWinUS]

Yes
Mid 36 with the switch to the flat coil the caps changed also. I learned the hard way while changing distributor on side of road.

[Don Rogers]

The 1928 thru 36 Chassis Parts Book shows only one style of cap for both the dome top and flat top distributor. 18-12105-B fits both style distributors.

[DavidG]

Robert,


Something else is amiss as the 18-12105-B outer cap also is original equipment for '37 distributors and on up through at least 1939 (where my first-hand experience ends). Only the inner caps changed during the '36 model year and the outer cap fits both sides. Could it be that your spark plug wire conduit is bent out shape?

[Mac VP]

Almost certainly, you have the incorrect inner terminal plates for your distributor. That would reorient the outer cap to the odd position you’re seeing. The outer caps are the same from 1932 through 1948. This picture from our website shows the difference between the two inner caps:

http://www.vanpeltsales.com/FH_web/F.../12116caps.jpg

Usually the later version had the Ford part number molded into it, but the old aftermarket parts didn’t always have that. Order the correct version and your problem should be resolved.

[rockfla]

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Originally Posted by Mac VP

Almost certainly, you have the incorrect inner terminal plates for your distributor. That would reorient the outer cap to the odd position you’re seeing. The outer caps are the same from 1932 through 1948. This picture from our website shows the difference between the two inner caps:

http://www.vanpeltsales.com/FH_web/F.../12116caps.jpg

Usually the later version had the Ford part number molded into it, but the old aftermarket parts didn’t always have that. Order the correct version and your problem should be resolved.

ORIGINALLY (when I started working on it, not "originally form the factory)
It had an early wire plate on the right and a late wire plate on the left. The Early wire plate has a part number cast in it like #68-12### (the left plate on MVP's link above). The late wire plate on the left had nothing on it (the "right" plate on MVP's link above). I have pulled the distributor off the car and even when OFF the engine and mounting the left side cap (Using the "early" style wire plate) CLEARLY the rubber boot is smushed against the vacuum advance part of the housing and will not allow the cap to get "clocked" into the tab on the wire plate to "line up" correctly. SO possibly as DAVDG said the wire conduit is somehow "bent"???? I am getting another "early wire plate for the left ASAP but still will not solve the issue of alignment. SO to KIWI Tony's post......are there two "different" caps i.e early and late as he "suggest" and IF so how can you tell the difference????


NOTE: Before I started and the car was runnig and driving, there was NO rubber boot between the cap and conduit and that clearly allowed everything to "line up". SO??????

[DavidG]

Robert,


I am confused by your last posting. A 68-prefix inner plate is not the 'early' 1932-mid '36 version, it is the 'late' mid-'36 and up plate. Both inner plates must match. It does not matter if both have molded-in part numbers, but rather the spacing of the terminals on the inside of the plate must match the one with the 68-prefix part number as that spacing differs from the early to the late inner plates.

No, there are not different outer caps. I believe that KiWinUS is referring to the inner plate, which are different starting with the new distributor released in mid-1936.

[Don Rogers]

Here's an image of the plates for comparison.

[rockfla]

Originally Posted by DavidG

Robert,


I am confused by your last posting. A 68-prefix inner plate is not the 'early' 1932-mid '36 version, it is the 'late' mid-'36 and up plate. Both inner plates must match. It does not matter if both have molded-in part numbers, but rather the spacing of the terminals on the inside of the plate must match the one with the 68-prefix part number as that spacing differs from the early to the late inner plates.

No, there are not different outer caps. I believe that KiWinUS is referring to the inner plate, which are different starting with the new distributor released in mid-1936.

David
As I am learning here on the "Fly".....Yes, then the right side plate was the 68-12116 "stamped" or "cast into" the plate. The left side was the (I guess) #18-12116 as there are NO numbers on it but matches the spacing on the link Van Pelt shared above. I now have the distributor OFF the car as Hoop (here on the barn) set it up on his Sun Machine and wanted to check it since we've run the car a little bit to make sure its all within spec. When I had the distributor off the car the #68-12116 plate matched the rotor, the other plate did not!!! SO I assume that the #68-12116 plate is the correct plate I need based on the rotor. My Dad is carrying it over to him today with the 18-12116 plate and a cap.....and then I think he is coming over to my shop and see for himself.....sounds and looks as IF I may have the plates reversed as to which is early and late!!! More to follow at this point.

[rockfla]

*****UpDATED PHOTOS************


Okay, here are the actual pictures of the conundrum. You can see I have the correct "late" wire plate and that it is installed correctly with the cap indexed to the plate flush and rubber ring installed. As you see by the black dot (Where the notch is in the distributor housing) and where the tab is on the wire plate. Look further up to the right and see the neck of the cap and rubber boot are slam against the vacuum advance housing and will NOT allow the plate to index correctly???? Thoughts from here????

[DavidG]

Robert,


I checked some NOS inner plates of both versions that I have and the one in your photo is indeed the 68-prefix version and the molded-in tab is where it should be on the inside of the plate. The next step would seem to be to confirm that the notches on the outside of your inner plates are located the same on both of your inner plates. If they are the same, then the fault may lie in the location of the molded-in tab in the outer cap that engages the notch on the outside of the inner plate.


That outer cap tab should be located dead center with the opening in the outer cap for the wires to pass through. If it does not, find another outer cap with the correct tab position or file off the tab on your existing cap which will permit you to orient the outer cap to clear the vacuum brake housing on the distributor casting. Doing so (eliminating the tab in the outer cap) will not affect the performance of the distributor nor compromise the sealing of both inner and outer caps from water intrusion.

[rockfla]

Originally Posted by DavidG

Robert,


I checked some NOS inner plates of both versions that I have and the one in your photo is indeed the 68-prefix version and the molded-in tab is where it should be on the inside of the plate. The next step would seem to be to confirm that the notches on the outside of your inner plates are located the same on both of your inner plates. If they are the same, then the fault may lie in the location of the molded-in tab in the outer cap that engages the notch on the outside of the inner plate.


That outer cap tab should be located dead center with the opening in the outer cap for the wires to pass through. If it does not, find another outer cap with the correct tab position or file off the tab on your existing cap which will permit you to orient the outer cap to clear the vacuum brake housing on the distributor casting. Doing so (eliminating the tab in the outer cap) will not affect the performance of the distributor nor compromise the sealing of both inner and outer caps from water intrusion.

David
The later part of your response is what I was thinking and leaning towards doing. AND I still question even why the tab is on the outer cap to begin because as you state, it has NO effect on the function or alignment of the "spark".

[34fordy]

I can't help but wonder how many older, retired guys like myself, have been going through their odd parts trying to figure this conundrum out. One of the reasons belonging to the Ford Barn is so enjoyable!

[DavidG]

Robert,


I think it makes sense from an assembly line point of view (when all of the components are to spec and compatible with one another for the dating of the distributor), but not necessarily for us working on them once in a blue moon.
.
The irony of this saga is that the first versions of the outer caps in early '32 had no tabs like all of the ones that followed. They were added when the inner caps were substantially revised and a post was added into the center of the inside of the outer cap to insert into the revised inner cap to hold the two components together with a small rubber grommet attached in the groove at the end of the post. From an assembly point of view that was a big improvement as the spark plug wires put up a fight in the close confines between the inner plate and outer cap.

Despite the major degree of change to both the inner plate and outer cap, their 18-prefix part numbers weren't changed, which in itself is somewhat unusual.

[Hoop]

34fordy,

You're right, this is a good thread.

Usually if you just use the correct parts, everything is fine. A lot of guys have been confused by the early plates vs the late plates, sometime thinking they have the right ones when they do not.

Then they try to make them fit.

[35fordtn]

Ford had the tabs for the outer cap alignment for a reason. In most all cases ford did things for a reason.
Without the outer tab for the outer cap it allows the outer cap to rotate. If the outer cap is not aligned properly, then the cap bails do not properly set between the "humps" of the outer cap and come loose..... Don't ask me how I know as it follows with a very embarrassing story

[rockfla]

Originally Posted by 35fordtn

Ford had the tabs for the outer cap alignment for a reason. In most all cases ford did things for a reason.
Without the outer tab for the outer cap it allows the outer cap to rotate. If the outer cap is not aligned properly, then the cap bails do not properly set between the "humps" of the outer cap and come loose..... Don't ask me how I know as it follows with a very embarrassing story

OR Mike, it allows the cap to "settle" further back than it needs to be THUS causing this post!!!! It appears that the tab on my cap broke and allowed the cap to "settle" further back than "IF" the tab had been in place THUS not allowing the plate tab to line up correctly. SO as I have found out "YES" there is a reason. Thanks for everyone's input hope you all have a Merry & Blessed Christmas.