1954 Lincoln Shop Manual

JMFL36

JMFL36

Senior Member
Hi. Does anyone have a 1954 Lincoln repair manual? Sometime before my ownership, my '54 Mercury's Holley R804 teapot carb was replaced with a '54 Lincoln Holley R891 carb. They are very similar, but I'd like to compare the shop diagrams before I rebuild the R891. I've attached the diagram from my 1954 Mercury shop manual below. Thanks
 

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The '54 Lincoln 891 carburetor has all the same external hook ups as the '54 Mercury 804 carburetor as far as fuel line, throttle linkage, choke and vacuum line to the distributor. One difference (that won't hurt anything) is that the Lincoln carb has a slightly larger primary venturi diameter (1 1/8"), and the Mercury carb is 1 1/32"). Should work fine. I doubt you could tell the difference driving them back to back.

Sal
 
Thanks Sal. One point of clarification. The 891 and 804 do not have a vacuum line to the distributor. Vacuum is obtained from an opening at the right primary venturi to actuate the diaphragm and operate the secondary throttle plates.
 
JMFL36 said:
Thanks Sal. One point of clarification. The 891 and 804 do not have a vacuum line to the distributor. Vacuum is obtained from an opening at the right primary venturi to actuate the diaphragm and operate the secondary throttle plates.
Click to expand...

There is supposed to be a vacuum line that comes from the front of the carb about halfway up that gets suction (slight vacuum) from the right primary venturi and goes to the distributor diaphragm. It is internally tied to ported manifold vacuum when the throttle is opened slightly. So the max signal to the distributor diaphragm is slightly more than 4" hg.
There is a separate set of siphon holes in the primary and secondary venturi's that control the opening of the secondary diaphragm/throttle plates.

Sal
 
I know that the earlier flathead 337 Lincolns had gone to a mechanical advance in the distributor with load control on the vacuum side. I don't know about the 317 Lincoln Y-block but they may have also had a similar set up. The Mercury should have the Load-O-Matic set up which has no mechanical advance that I'm aware of. I'm not real well versed in the 54 Mercury cars with the 256 Y-block or the 54 Lincolns with the big Lincoln 317 Y-block though. Maybe someone else can be more helpful.

The Holley Load-O-Matic is a different sort of ignition system since it is totally dependent on vacuum for load control so I'd want to make sure the ignition system functions well with the carburetor. If it has an aftermarket ignition system or a later system then it may not matter anyway.
 
The Loadomatic distributors were used from '49 through '56 on Ford, Merury, Lincoln and T-Bird. Six and eight cylinder engines. It was also used on six cylinder engines well into the 60's. I just did a '66 Mustang 200 six carburetor and it was for the Loadomatic system with no centrifugal advance.

Sal
 
In my setup, done by a previous owner, the distributor get its vacuum from the union in the intake manifold that also proving vacuum for the power brakes unit (see photo). The vacuum port in the Holley 891 carb is plugged.

Do you think I should reroute the vacuum line from the distributor's vacuum advance to the carb as originally intended and plug the intake port?
 

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That all depends if the distributor has been updated with a 1957 or later centrifugal advance one. If you remove the distributor cap, and the rotor is spring loaded in the counter clockwise direction, then you have a '57 or later distributor and should be OK.
Otherwise, with the '54 distributor the timing advance would be too aggressive if hooked to manifold vacuum.
I guess if it runs well, and doesn't have spark knock, I wouldn't worry too much.

Sal
 
I found a photo of a Lincoln distributor from a 317 and it does appear to be a Load-O-Matic but it has a large dual diaphragm vacuum spark control similar to the 1956 Ford design. The Mercury distributor appears to be a single diaphragm control so there is some difference in the way these two designs are controlled.

Load-O-Matics generally all have a venturi vacuum ported carburetor in order to get full advance in normal load conditions with a change in vacuum for load conditions to get the proper amount of retard for the engine design. Manifold pressure decreases under load due to the change in throttle plate position which allows for enough retard. If the two systems use different vacuum signals then it will affect efficiency of the automatic spark control.

A lot of folks abandon the Load-O-Matic systems for 8BA flatheads in favor of modified Chevy/GM distributors so that they can use the vacuum spark control along with the centrifugal mechanical advance. The vacuum source from the intake manifold is tuned by use of an adjustable vacuum diaphragm canister. It takes a while to tune one but it can be done. On the small Y-blocks, the 1957 and up 312 T-bird system works that way. The Load-O-Matic was adequate for lower power requirement applications but became increasingly problematic when larger higher power engines like the FE medium blocks and the MEL big blocks came out in the mid to late 50s. The 1957 Thunderbirds with higher perfomance 312 Y-blocks used this new system to good effect. Sal is correct though. Ford kept the Load-O Matic system around as long as there was still an application where it would work effectively.

Bottom line is how well the OPs engine functions for his use. If it works for you then use it. If it is inefficient, ie, uses a lot of fuel, or has a tendency to run hot or there is noticeable pinging under load then those are indications that the spark control is not as effective as it should be. A carb jetted for a 317 Y-block may run a bit on the rich side for a 256 Merc Y-block but that could be changed if needed.
 
Yes, the '53 Lincoln had a dual diaphragm distributor. It also had a cable going to the carb linkage that would manually retard the timing by rotating the point breaker plate. Starnge system.
Also in '56 Lincoln used the same dual diaphragm as the '56 Ford, Mercury and T-Bird.

Respectfully, the air fuel ratio will be fine when using the 317 Lincoln carb on the 256 Mercury. Carburetors all basically are calibrated for the same air/fuel ratio depending on the amount of air going through the carb. A carb from a larger engine does not run richer on a smaller engine. That's wive's tale territory to me.

Sal
 
While I agree in principle, I don't agree when there is a difference in altitude of operation. Ford Motor Co made carbs set for standard altitudes and higher altitudes. The reason was to make the air fuel ratio more efficient for the environment that the automobile is operating in. Most are likely standard setting carbs but there were Denver type applications.

If a person used an air/fuel meter up the tail pipe, if would confirm if it is OK or not. Any time where a different carb is substituted, there is always a chance that efficiency could change.
 
Well, my setup - original 54 Merc distributor and vacuum advance with vacuum supplied from intake manifold, and 54 Lincoln Holley 891 carburetor with vacuum port plugged, seems to work ok. But this may explain the initial slight stumble I get when accelerating (under load). It evens out after a second or two, which could be from the temporary drop in vacuum when accelerating. Make sense?
 
John, I have the Lincoln/Mercury Service Bulletin No. 192 (10-9-53) for 1954 which covers both carbs. It is a 141 page manual. I do not wish to sell it but it is probably the one you need , if you can find it. Maybe on E-Bay?
 
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