1940 V12 Lincoln acceleration issue

[CincinnatiLee]

I have had a 1940 Lincoln Continental for a couple of years and have had several mechanics work on various issues. At this point, my issue is a flat/ stutter point in the middle of its acceleration. It starts and idles smoothly and once it gets through the middle stutter, it runs well. Does anyone have an idea of what would cause this and is there a specialist that might be able to work through this problem? Thanks!

[Ray500]

Time to send the carb to a specialist. I think they list them in the LCOC website.  Accelerator pump......clogged orifices....too much gas being dumped in the engine at some point, that component needs full verification and the  correct needle valves installed.  The V12 is a low compression engine, and you can't just dump too much fuel into it. Could also be an ignition issue and the timing might be off some.  Seems like an acceleration problem, but if it's not the carb then you need to have the other components like the distributor.   Hope you can find a qualified mechanic for this, there aren't many left these days with the experiences of the V12!   Remember another potential part of the problem, and t's the cutout relay for the overdrive if it has one.  It momentarily shorts the distributor out when the overdrive is engaged.  If that's malfunctioning could be the problem. Just stay out of OD and check it out!   Luckily the old Fords had these issues at times  and they might be able to help!  Let us know what you find as the problem!  

[alsancle]

Does it do it cold or only when hot?

[edinmass]

First off, that era Lincoln has almost no acceleration compared to almost everything else……..not dumping on the car, but they were known for exceptionally poor performance when new. If it’s not dialed in……it will drive like a dog. They are not particularly hard to get right, but everything needs to be perfect to have what I call almost acceptable performance. Do your self a favor……….start with the basics………and go through EVERYTHING……..IE- compression check dry and wet, do the ENTIRE fuel system from tank to carb, including the fuel line, sort the ignition to perfection, and then you can enjoy the car. It seems that 80 percent of the late Lincoln twelves I have driven suffer from significant drivability problems……….

 

Also, when rebuilding that engine, it’s the only car I always recommend “heating up”, compression, cam, distributor, ect………it needs more than stock to be enjoyable as a long distance driver if it’s your only car.

 

 

Edited July 4, 2023 by edinmass (see edit history)

[CincinnatiLee]

Thanks for the help! In responce to 

On 7/4/2023 at 8:14 AM, alsancle said:

Does it do it cold or only when hot?

It does it consistently, cold or hot. I have had the tank cleaned and sealed. The carburetor has been replaced with a rebuilt one. 

[Matt Harwood]

80% of fuel issues are ignition. I'd be replacing condensers, checking point and plug gaps, replacing plug wires, and possibly having the coils rebuilt.

[alsancle]

15 minutes ago, Matt Harwood said:

80% of fuel issues are ignition. I'd be replacing condensers, checking point and plug gaps, replacing plug wires, and possibly having the coils rebuilt.

More like 90%.   If it was only doing it only hot I would say coil with a high probability.  Could still be coil.

[edinmass]

 

 

Start with the basics, and diagnose it the correct way. Compression check all 12. Check fuel pressure. Rebuilt carb is meaningless, as 90 percent of the rebuilders out there have no idea what they are doing. I agree it's likely ignition. Check the primary circuit before you check the secondary. You need an experienced guy familiar with pre war cars.......the local mustang guy probably won't be helpful.  The Lincoln club is active and probably has a handful of members familiar with the application. Guessing at it is a waste of time.    

[carbking]

I have never driven a V-12 Lincoln.

 

The specifications on this engine scream "more carburetor"!

 

The Holley used on the 305 CID Lincoln is only 10 percent larger than the Holley used on the 239 CID Ford V-8 and 30 percent SMALLER than the Carter used on the 249 CID Pontiac 8 cylinder.

 

As to the stumble, the Holley has a vacuum accuated power system. Possible with that small a carburetor that the power system is fluctuating at a certain RPM due to vacuum.

 

And the above sentence is because a few feel it is carburetor related; I personally would vote for ignition until the ignition is proved good.

 

Jon

Edited July 6, 2023 by carbking (see edit history)

[Guest]

I have a '38 Lincoln 4door and it performs fine.  I drove it as a daily in the keys and the only thing preventing that now in TN is that the keys had straight roads and I need new rear rubber so windy roads are more of a concern.  Back to the topic on hand, on mine I ended up replacing the coils (cost options) with a home made plate and a couple cannibalized bug caps so I could use modern 12v coils.  When the carb would sit longer due to a trip out of town etc the problem would involve cleaning which was simple tear down/soak/dry/reassemble.  Nobody has mentioned your fuel pump and it might be something to look into.  If it stutters on acceleration when loaded I would look into fuel delivery, stuttering on simple no load acceleration I would look into the ignition.

[19tom40]

The problem sounds like a carburetor problem to me. I would say that your power valve is probably malfunctioning or is incorrect for your carburetor, The power valve system in the Holley 94 carb needs good vacuum in order to work properly and the correct power valve needs to be installed. I suggest that you send your carburetor to Charley Schwendler and have him rebuild it with quality parts.  Many of the carb castings have been damaged by installing an incorrect power valve, Charley machines the seating surface and installs the correct power valve.

 

You can contact him at cas5845@yahoo.com

 

The Lincoln Zephyr distributor does not have a vacuum advance which could cause that type of problem. A weak coil, bad condenser or incorrect point gap would tend to give poor performance at all rpms or any rpm above 800rpm. The mechanical advance in the distributor could be binding, but that is an unlikely situation.

 

[Ray500]

I've had problems with the accelerator pumps in carbs that have  been rebuilt.  Just make sure who ever rebuilds one that they replace the diaphragm on it, some look like little cup washers.   4 barrel carbs are the worst problem with it.  But they get spongy over time and use in the gas and they don't function.  Good acceleration requires the carb working uninterrupted when you need to without hesitation!

[CincinnatiLee]

Thanks for everyone's help and suggestion! I have very little mechanical aptitude, so if someone can suggest a mechanic in the Cincinnati area that could help chase this issue down, I would appreciate it!

[West Peterson]

On 7/4/2023 at 8:34 AM, edinmass said:

First off, that era Lincoln has almost no acceleration compared to almost everything else……..not dumping on the car, but they were known for exceptionally poor performance when new. If it’s not dialed in……it will drive like a dog.

 

You need to stop ragging on the V-12 Lincoln, Ed. Come and drive mine. You will not rag on them anymore. If they're running right, they have really good performance. Not like a straight-eight Packard, but it's a lot better than what you are describing.

[West Peterson]

On 7/3/2023 at 2:19 PM, CincinnatiLee said:

I have had a 1940 Lincoln Continental for a couple of years and have had several mechanics work on various issues. At this point, my issue is a flat/ stutter point in the middle of its acceleration. It starts and idles smoothly and once it gets through the middle stutter, it runs well. Does anyone have an idea of what would cause this and is there a specialist that might be able to work through this problem? Thanks!

I live just north of you. I found good help via AACA friends in the Centerville area, who helped me perform the advice given from great Forum members. I sort of had the same problem, but it felt more like it was only running on six cylinders. We rebuilt the carburetor carefully. That didn't help. I installed new distributor plates... that didn't help. We checked resister/condenser, and found that there was only a single wire from the resistor, forking to attach to both condensers. Once I ran dedicated wire from each resistor, that helped somewhat. 

 

I think the most important thing to do is remove your coil from your distributor and send it to guru Skip Haney in Florida. Also, you might want to read through my thread that discussed how I found "happiness":