Lincoln Continental v12 missing when hot

[billboos]

I know it's hard to diagnose without listening but I'd like to describe the symptoms to see if anyone has any ideas. As soon as engine heats up the car begins to stumble or miss and loses power at about 40 mph in third gear and somewhat less in second. Plug wires, spark plugs, carb mixture, coil ??? Seems to be related to rpms. Car has been sitting for about 3 months but started right up -- it's been on a battery tender. Any thoughts? 

[Matt Harwood]

That sounds almost exactly like the textbook description of a failing coil. Runs great when cold and under low loads, but when it's hot or resistance goes up under high loads, it starts to fail. I'd start there, coils are cheap and easy.

 

Also, this is as good a time as any to double-check grounds, which can be critical to ignition system performance in a 6-volt system.

 

Hope this is it. Please report back and let us know!

[billboos]

Can a technician easily test a v12 coil for strength. If it were an average $30 or $40 coil i would just swap it out but at $250 rebuilt with exchange I would rather be more certain

[19tom40]

I use my SnapOn coil tester to test coils off of the car. When the coils are on the the car, I just pull a plug wire and hold it close to a head nut or other suitable ground. With the engine at operating temperature, you should see 1/2" long blue spark that makes a sharp cracking sound. 

 

Skip Haney in FL rebuilds the Lincoln dual coils for $150 + $8 shipping. He has a very good reputation in the Early Ford V-8 Club, with hundreds of satisfied customers.

 

http://www.fordcollector.com/coils.htm

 

With Jake Fletcher having health problems, Skip is probably your best bet. He has a very short turnaround time.

[billboos]

Can a technician easily test a v12 coil for strength. If it were an average $30 or $40 coil i would just swap it out but at $250 rebuilt with exchange I would rather be more certain

 

Matt, 19tom40, thanks for replies and advice. I am sending the coil to Skip for a rebuild after talking to him. At $150, it's agood way to rule it in or out. I also talked to Jake who is in an assisted living location after fracturing his hip and needs a walker or cane to get around. He expects to be back home in a month or two so obviously not rebuilding any coils right now. He sounds good and seems to be getting along well and we had a long chat about the Lincoln symptoms which he also thought pointed to the coil. He gave me advice on removal and re-install

[38ShortopConv.]

I would replace the condensers first, they are cheaper too.

[19tom40]

It is possible that you may have a fuel delivery problem point dwell problem or bad condensers and your coils are OK. Perform the spark test as described in my previous post. If it is OK at idle, have someone increase the RPM while you watch the spark. If it breaks down, check the dwell and substitute known good condensers and repeat the test.

 

If you have a manual choke, you can also try choking the engine to see if the condition improves. If it does, you might very well have a fuel delivery problem. The flex hoses can look good on the outside, but be bad inside.

 

When you remove your coils, check the underside for engraved information. Both Jake and Skip engrave information to let them know when they rebuilt the coils.

[billboos]

Thanks to all. Ended up not sending the coil to Skip, Took 38Shortstop's advice and had the driver's side condenser replaced  with a tested original part after finding no spark on that side. Also replaced the year old import fuel pump with a rebuilt original equipment pump just to be more confidant. In addition, had the carburetor rebuilt and found that the middle body part was from a Ford truck and had the jets drilled out to enlarge them and not to spec. Replaced carb body part with original equipment part. Condenser fixed the missing and power problem as I may have been running on only six cylinders since I bought the car a year ago. I assumed lack of power was due to the weak v12 engine I had heard so much about. Engine is not weak now and runs like a dream. Starts in about 2 or 3 seconds now whether cold or hot.  I thought hard starting was due to a weak battery which was on my list to replace -- now I don't have to.

Now I have a couple of simple questions I could not find with a search.

1. What grade of gasoline is best to use -- 87, 89, 91. Don't care about cost as car is driven so little

2. What kind and weight of oil is best. Rebuilt engine has only a few thousand miles on it and I live in the San Francisco Bay area where temps rarely fall below 50F or over 80F.

3. Car has overdrive and I only drive it around town. What are pros and cons of driving with it on or off? 

Thanks for any thoughts

[19tom40]

Your engine is a low compression engine and should be happy on 87 octane. I would add a fuel stabilizer at every fill up. Use the amount that is correct for the amount of gas that you added. Doing this will help keep the fuel from separating into water, ethanol and gas.

 

I like 10W30 oil for the warm weather. It is closest to the 30 oil recommended by Ford.

 

I would drive around town with the overdrive off. The V-12 engine is the happiest when the RPMs are higher.

[billboos]

19tom40, thanks for current reply and prior response re bad condenser. Car is now tip/top -- only remaining issue is to perhaps have the gas tank flushed. I am getting some particles in the bottom of the fuel pump glass bulb that must be getting by the screen that I believe exists on top of the pump. I'm concerned junk may get to the carb or clog up the screen filter. I can't tell how to access the screen filter for cleaning.

[19tom40]

You are welcome.

 

I am not sure if you have easy access to the fuel sending unit on the Continental, like I have on my cars, but if you do, you might want to remove it and see if the inside of your tank is rusty. If it is, you should check with other car people for a radiator shop that can clean and seal the tank. CA has so many regulations about this, that it may be hard to find someone to do this. I have heard some bad stories about the Tank Renu service, but they seem to be related to specific shops, so I would do as much research as I could about any shop that you are considering. They don't make quality replacement tanks for your car.

 

To access the screen, you just loosen the thumb screw at the bottom of the glass bowl and remove the bowl. The screen will come out when the gasket comes out.

 

You will need a new gasket and when installing it, do not over tighten the thumb screw. Over tightening can warp the fuel pump and the gasket will not seal.

[DSpringer]

Oil: There's been a lot of discussion on the forum about the importance of using oil that contains ZDP (zinc additive), which is supposed to help preserve the cam from wear. I've been using Valvoline VR1 racing oil, which contains ZDP (it fouls catalytic condensers in newer cars). I've been running 20W-50 because I'm in the hot central CA valley and have had low oil pressure, even with a Melling M-15 pump. If you don't like that advice, Castrol has an article on what oil to use:

 

http://www.castrol.com/en_gb/united-kingdom/products/cars/classic-oils/classic-engine-oils.html

 

Gas Tank: I used the POR-15 three step kit to clean and seal my tank, which was pretty rusty but had no leaks. It's worked very well. The filter has stayed clean.

 

 

[billboos]

On 6/10/2016 at 10:59 AM, 19tom40 said:

You are welcome.

 

I am not sure if you have easy access to the fuel sending unit on the Continental, like I have on my cars, but if you do, you might want to remove it and see if the inside of your tank is rusty. If it is, you should check with other car people for a radiator shop that can clean and seal the tank. CA has so many regulations about this, that it may be hard to find someone to do this. I have heard some bad stories about the Tank Renu service, but they seem to be related to specific shops, so I would do as much research as I could about any shop that you are considering. They don't make quality replacement tanks for your car.

 

To access the screen, you just loosen the thumb screw at the bottom of the glass bowl and remove the bowl. The screen will come out when the gasket comes out.

 

You will need a new gasket and when installing it, do not over tighten the thumb screw. Over tightening can warp the fuel pump and the gasket will not seal.

 

On 6/10/2016 at 10:59 AM, 19tom40 said:

You are welcome.

 

I am not sure if you have easy access to the fuel sending unit on the Continental, like I have on my cars, but if you do, you might want to remove it and see if the inside of your tank is rusty. If it is, you should check with other car people for a radiator shop that can clean and seal the tank. CA has so many regulations about this, that it may be hard to find someone to do this. I have heard some bad stories about the Tank Renu service, but they seem to be related to specific shops, so I would do as much research as I could about any shop that you are considering. They don't make quality replacement tanks for your car.

 

To access the screen, you just loosen the thumb screw at the bottom of the glass bowl and remove the bowl. The screen will come out when the gasket comes out.

 

You will need a new gasket and when installing it, do not over tighten the thumb screw. Over tightening can warp the fuel pump and the gasket will not seal.

Still have a missing problem when engine heats up after driving for 15 or 20 minutes. Starts right up and runs smooth and then misses or  "stumbles' intermittently at about 40 mph.. Trying to determine if it is fuel or spark issue. Could it be a vapor lock? Replaced condenser on drivers side so spark is now good at idle. Rebuilt carburetor and installed rebuilt fuel pump. New rubber feeder line to pump did not seat to line from tank so I put the old one back on. Is there a way to check for air leaks? 

[billboos]

Still have a missing problem when engine heats up after driving for 15 or 20 minutes. Starts right up and runs smooth and then misses or  "stumbles' intermittently at about 40 mph.. Trying to determine if it is fuel or spark issue. Could it be a vapor lock? Replaced condenser on drivers side so spark is now good at idle. Rebuilt carburetor and installed rebuilt fuel pump. New rubber feeder line to pump did not seat to line from tank so I put the old one back on. Is there a way to check for air leaks?  Could worn pushrod affect gas feed when hot?

[19tom40]

What year Continental do you have?

 

You said it was running fine on June 8, did you try checking the spark as the engine speed is increased?

 

Did you try a cylinder balance test (short out the plugs one at a time to see if they all have the same effect on the rpm. The engine rpm should be around 1,000 or more)?

 

Do you have fresh gas in the tank? Try adding some Seafoam or Heet to the tank and see if it improves the operation. These products will allow the water in the tank to be burned. Ethanol can attract water and the separate out, so it will not burn.

[billboos]

Tom, thanks. My Continental is a 1947.I am going to try checking the spark when engine is hot and at increased rpms.

I do have fresh gas in the tank -- ran it down to 1/8th and added 10 gallons. I'll try the additive. Do you think a hot engine would worsen a water in the tank problem vs running colder at lower rpms.

 

When I said it was running fine, I spoke too soon. I had only taken it around the block at about 30 mph on a colld engine.

[Matt Harwood]

As my mechanic likes to say, "90% of all fuel system problems are ignition-related."

 

Still sounds like a failing coil. Might be worth the $150 to get it rebuilt and at least rule that out and never have to worry about it again. Coils are tough to test properly, because you need to get them hot to really stress them, but they won't get that hot on the bench. The heat and vibration of an operating engine cause the problems and after decades, it's not really a surprise that those little tiny wires inside get a little frayed and come out of position.

Do these Lincolns use a resistor to drop voltage to the points? I have a '46 Ford that uses one and it had an odd combination of issues that caused it to stutter and fail after it got hot. Typical flathead fever with vapor lock, right? Wrong. What was happening was that this resistor was getting too hot and dropping voltage to the ignition system to less than 1 volt, causing the misfires, then killing the engine. A few minutes later, it would cool off and it would drive just like nothing ever happened... until it got hot again.

So we replaced the coil, we replaced two fuel pumps (electric and mechanical), but it persisted until we found this oddball issue. So also check the resistor (if equipped), but if that's not it, I'll still put $20 on the coil being bad.

 

Hope this helps!

Edited July 6, 2016 by Matt Harwood (see edit history)

[19tom40]

Matt, you replaced the coil and fuel pumps and still had the problem. If you had spent the time to check out the spark, you would have found it weak and would not have had to replace 2 fuel pumps.

 

I am trying to get Bill to determine the area that is failing, ignition or fuel. Once he determines which of them is causing a problem, he can do further tests to isolate the problem.

 

The quality of the new parts,makes me hesitant to just replace parts to find the trouble.

 

Weak spark can be caused by a coil, condenser, ignition switch, ballast resister, corrosion on the rotor or the inner caps, pitted points and incorrect point dwell.

 

My coil tester has never failed to find a bad coil. Bad condensers can be found by substitution of a known good condenser. The ignition switch and ballast resister both affect the voltage going to the coil, they can be checked with a volt meter. Incorrect dwell is checked on a distributor machine or with a dwell meter.

[billboos]

I am posting the following here as well as starting a new topic:

I am confused by multiple opinions about carburetor setup. One opinion is to use jets based on original specs. Another says larger diameter jets are required because of today's gas. My 1947 Continental; bought last year had the carb rebuilt before I bought it -- the shop said they had to drill out the jets to a larger diameter to get more gas to the engine. The car was still missing when hot and a well recognized expert on Lincolns rebuilt the carb again and installed original spec jets saying it is best to keep everything original. The car is still missing when hot so there may be some other issue. I am replacing the fuel pump flex hose from the gas line to fuel pump next week just because it looks old and brittle. My question is "what jets are best -- original or larger and if so how much larger." Anyone have any experience with carb setup. I am ready to replace everything fuel and ignition related just to get a reliable driver . Thanks

 

[Matt Harwood]

On 7/7/2016 at 11:37 AM, 19tom40 said:

Matt, you replaced the coil and fuel pumps and still had the problem. If you had spent the time to check out the spark, you would have found it weak and would not have had to replace 2 fuel pumps.

 

I am trying to get Bill to determine the area that is failing, ignition or fuel. Once he determines which of them is causing a problem, he can do further tests to isolate the problem.

 

The quality of the new parts,makes me hesitant to just replace parts to find the trouble.

 

Weak spark can be caused by a coil, condenser, ignition switch, ballast resister, corrosion on the rotor or the inner caps, pitted points and incorrect point dwell.

 

My coil tester has never failed to find a bad coil. Bad condensers can be found by substitution of a known good condenser. The ignition switch and ballast resister both affect the voltage going to the coil, they can be checked with a volt meter. Incorrect dwell is checked on a distributor machine or with a dwell meter.

 

Well, there was more to it, but I didn't think it was really relevant to the problem with the Lincoln so I glossed over it. The car would idle forever, even at a fast idle, and no problems. But my first drive was about 1/4 mile before it died and would not restart. Quick failure like that says fuel system to me. Mechanic found that the brand new electric pump installed by the previous owner had failed and the mechanical pump wasn't strong enough to pull through it. So both pumps replaced and it ran great... for a while. I drove it home from the shop, about 25 miles, made it 21 of them, and the same thing happened. Do a quick spark check by the side of the road and sure enough, now no spark. What the...? By the time the flatbed arrives, car is running again.

Car goes back to mechanic who believes the coil is failing. Replace coil, car runs great, as it did before. Dies after another long-ish drive with him. OK, what else could it be? Spark is failing and it's apparently related to heat because it takes a lot of driving to induce it. Ultimately, we discovered that the car had no thermostats in it. The gauge showed normal and an infrared check of the input and output spouts on the radiator showed normal temperatures. But the coolant was moving through the engine so fast, it wasn't picking up any heat from the block. The car was overheating but the coolant wasn't showing it so it wasn't obvious. Those massive temperatures in the cast iron block were cooking the ballast resistor, which is bolted to the block on a bracket. It took a while for it to get hot enough to fail, but fail it did. Installed correct thermostats and all is good now. Car runs perfectly, has new fuel system and ignition system components, and stays at a nice, cool 160 degrees on the road. It's a terrific car that I'd happily drive on any long-distance tour today. But the solution took three tries after eliminating the obvious stuff.

 

If you're the kind of guy who never goes very far in his old cars, you might have never even noticed a problem with this car. It ran great while it was slowly cooking itself, and you'd probably eventually lose your bearings because your oil was cooked, but you'd never see steam and it would run just fine until you drove it more than 45 minutes or so. But I'm the kind of guy who needs to be sure that it'll work no matter what you do, so I make sure. A long drive was the only time the problem revealed itself.

 

Now I don't think this Lincoln has problems like all that, but the ballast resistor is something to check (if the car has one), because it can definitely cause the symptoms he's experiencing.

[19tom40]

Bill the jet size should be stock or very close to stock. The ethanol gas does not require larger jets. Both of my cars run fine and I have driven my 40 Merc with a carburetor similar to your Continental over 30,000 miles since 2005 with the stock jets.

 

Did you check your spark when the engine is at normal operating temperature or when it starts missing? Unless you do this you will not eliminate the coils from the problem source.

[38ShortopConv.]

Ballast resistors on a Lincoln Zephyr are mounted behind the dash on the bulkhead on a heat resistant insulator, there are two of them, one for each coil, this  position avoids  them  overheating from the block temperature build up. The hotter the resistor the higher the resistance to current flow resulting in   lower voltage at the coil.   ' Ohms Law. ' Here endith the lesson.

[billboos]

Thanks, Shortop.I would like to "extendith" the lesson if you wouldn't mind.  Would it be a good idea to replace the resistors just because the car is 70 years old? Are they easy or difficult to get to and replace. Would a weak resistor cause a miss when engine heats to normal operating temps?

[38ShortopConv.]

Bill,    short answer to 3 questions,  # 1, no. only if the resistor is faulty.  # 2. my L/Z is a 38, very difficult to get at,  don't know about 47  Continentals but bound to be, you would need to have a look. # 3. could do,  resistors drop the voltage down from 6 to 4" 1/2 volts at the coils, you could  check for loose connections at the resistors, can cause overheating and higher resistance and too  low voltage at the coils.  Original L/Z COILS ARE RATED AT 4 1/2 VOLTS.  

[billboos]

FOLLOW UP QUESTION RE WHAT KIND OF OIL TO USE:

My shop only has synthetic oil and suggested I bring my own oil if I want non-synthetic. Can I use synthetic in my Lincoln '47 v12? Is it preferable or a no-no? He also recommended 20/50 in lieu of 30 w in original manual when they may have had no multiple weight oils. Any suggestions?

[Matt Harwood]

Synthetic oil won't hurt anything and does, in fact, work better. However, it's a different kind of oil and the smaller molecules and the shape of those molecules make synthetic oil able to work its way through openings that regular oil cannot. In short, you may have leaks where you didn't before. That's not because the gaskets are damaged, just that the synthetic oil is better at getting through smaller openings. Porosity in castings, old gaskets, etc were good enough to hold regular oil but synthetic works its way through. No harm, no damage, but be aware. This is where the old wives' tale about synthetic oil ruining gaskets comes from. It's not true and it'll work just fine in your Lincoln.  I think 20/50 is a good weight for summer driving in an older car with larger clearances. 10/40 is also OK, but I am personally not a fan of thinner oils in older cars. There will be debate, but it is only my opinion that 20/50 is fine for your car.

[billboos]

Matt, thanks. I was afraid of the myths about synthetics being bad for older engines. I guess my guy was not off by suggesting synthetic 20/50. I will try it and worse thing would be leakage and then I would revert to non-synthetic. Good answer, thanks again. I've learned a lot on this forum.

[38ShortopConv.]

Bill , I  use  30/40 or 40/50, non synthetic,  the thicker the better  with  zinc,  in my 38 L/Z.  I find  radial tyres are better for a  L/Z that's driven, steers straighter, lighter and has less rolling resistance.  Cheers.

[billboos]

I'm going with 20/50 Valvoline VR1 Racing Oil because it has the zinc additive and was recommended by several owners in and outside of this forum. Still have an open question about capacity. Some say 5 quarts when changing filter and some say 6 quarts. I'm wondering if there i s a difference between earlier models and 46/47/48 engines. Mine is a 1947 Continental. The original operating manual is not clear to me either.. It says: 5 Quarts (Less Filter Absorption). I don't know how to interpret that.

The v12 does not have a dipstick, only the float gauge which sometimes shows above full and sometimes below. Without any new input, I think I will use 5 quarts with the filter change , see what the gauge reads after sitting and letting oil drain into case and add accordingly.

 Thanks for any references or information.

[19tom40]

Bill, keep as much oil as you can in the pan. The oil helps cool the engine. Fill the pan with 5 quarts and run the engine to fill the filter and then recheck the oil level indicator. If it shows full, you are good to go, otherwise add 1/2 quart and check the level.

 

If the Lincoln filter is the same as the Ford filter, it keeps about 1/2 quart in it.

[billboos]

19tom40, thanks. You pretty much confirm what I plan on doing -- seems like a logical approach. I suspect the difference in the oil gauge float reading is just a function of how long the car was sitting after running and oil settling back in the pan. I'll check it out cold and immediately after running. 

[billboos]

Had a chance to look under my Lincoln when I had the oil changed.-- nice and clean, no rust or visible damage. One disturbing fault --- the muffler has been patched with sheet metal (actually a disassembled tin can like I used on my early Fords when I was a kid) screws and baling wire totally incongruous with the rest of the car's high quality restoration. I assume it was done as an expedient when car was getting in running condition after sitting for 7 or 8 years before I bought it. Anyway, my question is whether replacement mufflers are available for a 1947 Lincoln Continental Cabriolet. Car runs very quietly but now knowing it is patched with a Campbell's soup can is concerning..Are there reliable parts vendors who advertise on this site who sell NOS mufflers and exhaust pipes? Or any other Lincoln parts sources. Thanks for any suggestions. . 

[ezdusit]

There have been discussions in this and other forums regarding the elimination or reduction of zinc compounds in lubricating oil.  This additive greatly reduces lubrication in extremely high pressure friction points, particularly the friction where the cam lobe contacts the flat-surfaced tappet (lifter).  I have completely transitioned to the lubricating oil marketed by one of the chapters of the Classic Car Club of America.  (http://www.classiccarmotoroil.com/)  Before I would change over to synthetic oil, I'd want to get an expert opinion about this issue.  Also suggest you check out 

Best of luck.  Hope this helped.

Edited October 11, 2016 by ezdusit
clarification (see edit history)

[Mssr. Bwatoe]

i have used 15-50 or 20-50 full syn  for years, fresh hydraulic lifter V-12,  Mobil  1 or Napa--change about once  a year

runs nice, I really run it so far so good, I also use full syn for gear boxes--rear axle loves 140 full syn. I have drained the rear axle a couple times to look for

metal, non seen after same 4000 miles on 2 speed with lots of use..I am sold on it--I wont spend the money for my old 96 Cherokee daily driver, but the L-Z loves it.

Edited October 15, 2016 by Mssr. Bwatoe (see edit history)

[billboos]

On 7/6/2016 at 11:54 AM, Matt Harwood said:

As my mechanic likes to say, "90% of all fuel system problems are ignition-related."

 

Still sounds like a failing coil. Might be worth the $150 to get it rebuilt and at least rule that out and never have to worry about it again. Coils are tough to test properly, because you need to get them hot to really stress them, but they won't get that hot on the bench. The heat and vibration of an operating engine cause the problems and after decades, it's not really a surprise that those little tiny wires inside get a little frayed and come out of position.

Do these Lincolns use a resistor to drop voltage to the points? I have a '46 Ford that uses one and it had an odd combination of issues that caused it to stutter and fail after it got hot. Typical flathead fever with vapor lock, right? Wrong. What was happening was that this resistor was getting too hot and dropping voltage to the ignition system to less than 1 volt, causing the misfires, then killing the engine. A few minutes later, it would cool off and it would drive just like nothing ever happened... until it got hot again.

So we replaced the coil, we replaced two fuel pumps (electric and mechanical), but it persisted until we found this oddball issue. So also check the resistor (if equipped), but if that's not it, I'll still put $20 on the coil being bad.

 

Hope this helps!

Reply to an old post. I continued to have a no start problem on very hot days and hot engine and then missing when finally started. Otherwise SEEMINGLY running fine. Finally got around to sending coil to Skip Haney. I understand he replaces original coils with two more modern coils and insulation. After re-installing, coil,  car now starts in about 2 seconds and the SEEMINGLY fine running car now has noticeably more power especially in third gear from lower speeds like 30 mph. Have not had a hot day to test hot/no start problem. Would a functioning but weak coil cause loss of power and also high gas consumption? Never checked mileage but gas gauge seemed to drop like a rock. Thanks for any comments.