1954 Mercury Distributor Puzzle

[JMFL36]

Hi guys. I'm trying to sort out the distributor on my '54 Mercury Monterey. The car was running fine prior to pulling it for a rebuild. The first thing I noticed was a broken tooth on the drive gear. Second, the gear is a 14 tooth gear, where my shop manual calls for an 11 tooth gear?!? When I pulled the gear off, I found that someone had drilled a 2nd hole through the shaft?!? The distributor body has the correct part number FAE-12127-C for the car. Any suggestions as to what is going on? Should I just find another 14 tooth gear and install it in the added shaft hole? I'd like to make it 'right'.

[KULTULZ]

OH BOY!

Do you know if the your engine is original to the car? There were two 256 CI (as there were two 239 CI - one DETROIT and the other CLV), so it can be confusing.

The 256 MERC also had some differences from the FORD DIF 239 CI.

Your shaft is a tang drive particular to the 1954 239 FORD and 256 MERC (both unique oil pumps). It should be a 13T drive gear unless someone has changed the camshaft to a 55/ design which required a 14T gear. That might explain the need to re-drill the shaft for a different driven gear.

Can you see the cam gear to look for any damage?

Let me do some searching and I will post back later.

[JMFL36]

Here's a photo down the dizzy hole. I don't see any damage but I can't see all the way around the cam gear (and don't want to move it till I get the distributor reengaged). The car is an 'early' 54 and the motor is reportedly original to the car but was likely rebuilt before finding its way to me.

[rotorwrench]

The distributor can be timed back to the engine by setting the engine crank to the timing mark on #1 compression and dropping the distributor in with the rotor tip aimed at the corresponding #1 cylinder distributor cap terminal location. Final timing will have to be adjusted while the engine is running per the normal shop manual instructions. If you can count the teeth on the cam gear, that will tell you what distributor gear you need. It should be a 1:1 ratio to the cam. One full turn of the cam will equal one full turn of the distributor. You should be able to use a long screw driver to position the oil pump drive slot.

I checked the cams and they did a change there somewhere in 1954 but later 272 or 292 cam could be in there and it has 14-teeth. You need to find out how many teeth that cam has. If it's 14 then you need a 14 tooth distributor gear. Likely a P/N FAE-12390-A. I don't know what book you got that part number info from but it should read 14-teeth. That's a bad typo. My book says 14-teeth for that part number. It was used in the later 239 engines and the 272 engines. The flathead 239 cid was the last engine to use the 11-tooth distributor gear.

[JMFL36]

I'm assuming the current cam gear must also have 14 teeth, as the car was running fine before I pulled the distributor. I'm just trying to figure out why the difference in teeth from the parts manual (11 vs. 14, see photos in my first post), and why would someone drill a second hole in the shaft for the gear pin?

[darrell]

Sponsored Links (Register now to hide all advertisements)

a 54 merc would have a small cam and 14 teeth.

[KULTULZ]

Originally Posted by darrell

a 54 merc would have a small cam and 14 teeth.

Correct. The EBY 256 was a small cam wheres the EBU 239 was a big cam.

[KULTULZ]

Originally Posted by JMFL36

I'm just trying to figure out why the difference in teeth from the parts manual (11 vs. 14, see photos in my first post), and why would someone drill a second hole in the shaft for the gear pin?

What catalog are you using as a reference? Thar TEXT you showed is incorrect. See below - 1954-1955 MERC CHASSIS CATALOG

[JMFL36]

Here's the catalog I'm using. It an original print. Looks like there was a misprint in the original 1954 MERCURY CHASSIS PARTS CATALOG. Ugh! Thanks for posting the corrected spec in the 54-55 catalog.

[Merc Cruzer]

Did the picture so you know what the catalog looks like.

https://www.ebay.com/itm/VINTAGE-195...cAAOSwAtlcpVsF

[JMFL36]

Thanks for posting those photos of your catalog. What does the S symbol in front of the gear part number mean? Does it happen to mean it is a correction from the previous catalog?

[Merc Cruzer]

Sorry, I should have posted that too.

[JMFL36]

I've also discovered, with the help of a micrometer, that the gear I just took off the shaft is not the right size. Someone must have just used a 14 tooth gear that was close in size to the original. Here's what I found:

Spec: ID=0.469, OD=0.890, L=0.969
Actual: ID=0.465, OD=0.745, L=0.991

I was wondering why the gear was so hard to get off. Now I know. The ID is a bit under spec. I'll bet that when they pressed the new gear onto the shaft it did not line up with the original hole and they could not spin it because of the tight fit, so they just drilled a new hole.

Now on the hunt for the correct sized gear.

[JMFL36]

Originally Posted by Merc Cruzer

Sorry, I should have posted that too.

So the S symbol next to the gear part number means I need to replace the shaft too? Wonder why?

[darrell]

i usually have to press the gear off.

[KULTULZ]

Originally Posted by JMFL36

So the S symbol next to the gear part number means I need to replace the shaft too? Wonder why?

There must have been some design flaw. When you go to the shaft PN, it is NS (not serviced) and no replacement number is given. It may be the gear was not the original assembly gear but possibly a later design meant to fit only the replacement shaft.

This was most likely covered in a TSB of the era.

Go to 12127 and see the DIST that were available for service.

[KULTULZ]

the gear is a 14 tooth gear, where my shop manual calls for an 11 tooth gear

Do you have both a shop manual and parts book?

Do you see a PUBLICATION DATE on your copy of the CHASSIS CATALOG? They were usually printed in quarters each quarter edition having updated material.

[Merc Cruzer]

I don't have a 54' service manual. My car is a a 53' Merc. I have a few 54' parts manuals, since the many of the parts cross over.

[JMFL36]

My shop manual says April 1954, chassis parts catalog says November 1953, and body parts catalog says March 1955.

[JMFL36]

My catalog, dated November 1953, lists only 1 distributor part number FAE 12127-C. I guess I need to get a later catalog.