Matt Harwood

1935 Lincoln K V12 Club Sedan

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I didn't intend to make a new thread for every car with projects to be done, but the other night while searching for information on something to do with old cars and finding nothing, I realized that some of the projects we do can be documented to help others. And putting it here rather than on my website means others can find it and hopefully benefit from it. Anyway, that's my reasoning.

 

The car is a 1935 Lincoln Model K club sedan that I bought from another member of this message board. I saw the car when he first posted it and found it appealing and after some soul searching I went ahead and bought it. It's mid-way between my '29 Cadillac and '41 Buick and I've long said that 1932-1935 is the sweet spot for collector cars--a spot where the cars are reliable and capable, but still feel like old cars. Mechanical brakes, solid axles, and all. So I bought this handsome club sedan and we'll see what happens from here. There are extensive details on the car elsewhere on the forum, but the short version is this is a car with a known history, lots of documentation, and nice preservation. It has never been fully restored, and the interior is mostly original. It was apparently repainted in the 1960s, and maybe the engine was rebuilt not too long ago, but that's about it. And I have to say that it presents extremely well and drives beautifully.

 

Lincoln1.thumb.jpg.81792945f8b087fe87507c22ce9174e6.jpg Lincoln2.thumb.jpg.7ebcb79391ed485f06e71e5a25094700.jpg

 

In fact, my first experience in the car was being stopped for speeding. It came off the trailer and I immediately jumped in and took it up the road. The speedometer doesn't work, of course, but I guessed that I was going maybe 38 MPH. But as a police officer passed me going the other direction, he made a hasty U-turn and hit the lights. Crap. Actual speed? 54 MPH. Double crap.

 

Worse, I was driving a car without plates and zoomed out of the driveway so fast that I didn't even have my wallet or phone. Ooops. 

 

Anyway, I told him that I couldn't shut it off (I had been warned that it was tough to start when hot) and that I didn't know if it would overheat if we sat there, and would he please follow me back to the shop so I could give him my driver's license and show him the dealer plates. Surprisingly, he agreed. Ten minutes later he's browsing through the cars in the showroom and all is cool. No ticket and I made a new friend. Thanks, Officer Alex!

 

But the big thing is that no-start-hot problem. It's real. About 45 minutes after the officer left, I went out to start the car and bring it back in and it acted just like it had a dead battery. VERY slow cranking and no fire. I rolled it backwards in reverse and bumped the clutch and it fired instantly, and I took it inside. First project: get this sucker to start when it's hot. And that'll be the next post.

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Getting this big car to start when it's hot is important. I started looking around at the electrical system and found that the primary power cable was old and crumbly and maybe a little undersized. That could be it. I also figured I'd improve the grounds and maybe add a ground wire from the frame to the starter itself to make sure it's getting full juice. And finally, more battery couldn't hurt. There's a medium-sized battery in there, but hell, there are 414 cubic inches of ancient V12 trying to crank over. This sucker needs some POWER.

 

cutoff1.thumb.jpg.aa09cdef270674e622fe8985ab3f45c2.jpg OldBatteryCable1.thumb.jpg.9e678de56c4c15b46430fc61e2838298.jpg

 

I bought two Optima 6V red top batteries, which, conveniently are about half the size of a regular battery. I decided to install both of them in parallel to deliver 6 volts of juice and 1600 cold cranking amps. Oh yeah, that's more like it. That's actually more power than the starter can draw, so it will have as much power as it needs. 

 

I also have a really good electrical shop nearby and had them make me some heavy-duty battery cables. They have this awesome wire that's incredibly flexible with silicone insulation, so that it bends easily and remains pliable under all conditions. It's pretty cool. I had them make me a primary cable, two cables to join the two batteries, and a new ground cable, all in 1/0 size. Price? A very reasonable $45. 

 

Battery1.thumb.jpg.65a89832758eaa0289a185cc9a392efa.jpg NewCable1.thumb.jpg.5491d2f0931adbd0364b8e22f788bdbe.jpg

 

The battery is under the passenger's feet and there's a rather large tray down there obviously designed to hold a giant battery. It's not a box, which means there's a lot of flexibility in terms of size and shape and position. I pulled out the old battery and did a quick wire wheel clean-up of the battery tray, which was in good shape but scaly and dirty. Then I gave it a quick coat of black paint to seal it up. This is not a restoration, just mechanical improvements anywhere I can.

 

BatteryTray1.thumb.jpg.24f522e9ffd9a8e887a1a06c9e0658c2.jpg

 

Then I dropped in the Optimas and connected the battery cables. The photos are self-explanatory so you can see how to connect batteries in parallel. I also added a Battery Tender pigtail so that it's easy to connect a battery charger without pulling up the floor. 

 

Battery3.thumb.jpg.381589c91a25094d3606f59e8005f99c.jpg

 

I also made a battery hold-down. The old battery was just kind of sitting there, but two Optimas needed to be secure. I looked around and found a length of 1/4-inch bar stock about two inches wide, cut it to length, and drilled some holes for the J-bolts (which are original and still in place on the tray). To prevent any electrical mishaps, I took a chunk of old inner tube and wrapped it around the bar stock, then bolted it in place. The batteries aren't going anywhere now.

 

Then I put the car up in the air and removed the old woven ground cable and secured the new one to the same spot. The ground on the frame was remarkably clean, so I hit it with a Scotch-Brite pad, a little dielectric grease, and secured it in place. 

 

Ground1.thumb.jpg.faf5bd192eff30875472a35e03a3d134.jpg Ground2.thumb.jpg.0ed1f2b57ec4941d2dbb7bd24dedb7e9.jpg

 

I put it back on the ground, turned on the main power switch, and climbed behind the wheel. It apparently always starts easily when it's cold, but holy cow! This sucker started in like half a turn. BRR-VROOOM! Wow this thing starts fast now! I let it run for about 15 minutes and used my infrared thermometer to check temperatures--the top radiator inlet is about 185, which I can live with. And that's at idle without any air running through the radiator. I was a little concerned that the driver's bank was about 30 degrees warmer than the passenger's bank, so we'll do some checking, but it runs smoothly and I don't expect to find anything. Probably gunk in the block or maybe the fact that the water pump is on the passenger's side has something to do with it. Once I have more time out on the road, I'll have a better idea of what it can and can't do. 


Anyway, I shut it off and let it sit for about 10 minutes to do a heat soak. Climb in, hit the button and BRR-VROOOOM! Another quick, easy start. Granted, that's not definitive proof since I didn't drive it, but it's certainly promising. I ran out of time tonight, but I'm still going to add a ground strap between the starter and the frame and maybe another one between the frame and the engine block. As long as I'm at it, right? I'll report back once I've had a chance to put some miles on it.

 

 

Edited by Matt Harwood (see edit history)
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Matt, I've had superb results from a pair of Optimas in parallel in my three 8-cylinder Pierces over the past 16 years.  I use 00 (double ought) welding cable which is very flexible.  Where batteries are underseat or under floor, Optimas are terrific because they never need water, are only minimally subject to corrosion on the terminals (both of which mean you almost never have to remove the seat or floorboard), retain a lot of charge over periods of disuse, and are long-lived (a pair is good for 10-12 years at least in my experience).

 

My primary reason for a pair in parallel is doubling of the reserve capacity, helpful for long night drives when the generator is running at a slight deficit.  Optimas have 100 AH (amp-hrs) reserve capacity, whereas Pierce 8s were originally equipped with Group 3 batteries at 140 AH, and Pierce 12s had Group 4 batteries with 165 AH.  A pair of Optimas has 200 AH.  Until late in 1934, Pierces had 25-amp 3-brush generators which dropped to 17 when  the temperature compensator kicked in, and that creates a deficit especially when one has upgraded #63 taillight bulbs (3 cp) and #81 stoplight bulbs (15 cp) to #1129 (21 cp) or #1133 spotlight bulbs (32 cp), which of course have a greater amperage draw.  Unlike you, I have not yet jumped to LED lamps. 

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And, because you will DRIVE the car, which may have not seen much usage in recent years, I recommend the world's cheapest--and arguably best--coolant filter, to prevent engine block scale loosened by repeated heating and cooling cycles from clogging your radiator.  I use cheap, comparatively coarse, ladies' stockings from the drug store, the short ones that women wear with slacks.  Ten pair for $6.  Drain off a gallon or so of coolant, remove the upper end of the radiator hose(s) from the neck(s), use a blunt instrument (screwdriver handle or ratchet handle) to stuff the stocking toe into the top tank of the radiator. fold the  selvage (open end) over the exterior of the neck, reattach the upper end of each hose, and refill.  After 300 miles, drain off a suitable amount of coolant, detach the upper hose ends, remove the stocking, examine the captured debris that would otherwise now be in your radiator, wash the stocking out under a faucet, and reinstall.  The amount of debris will inform you as to the next cleaning interval.  My experience was that about four such inspections over time caught anything that could possibly work loose, and the interval has now become 4-5 years when I change coolant (I don't have to run antifreeze in my climate, but I do add makeup doses of anti-corrosion additive.)

 

It's especially important to have the stockings in place before running any chemical flushes (be careful of aluminum heads if you have them), and be sure to replace  the stockings after a chemical flush is completed.

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Matt, I was sorely tempted by this car, I'm glad to see you bought it as a keeper and happy that you are sharing it's preservation. All good calls on the battery and cables, I assume you are leaving - and using - the shutoff switch?

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Finished the battery upgrade today by installing a ground strap between the starter and the frame. Cleaned all the mounting surfaces to bare metal and added some dielectric grease, then tightened it all into place. I just used a standard auto parts store ground cable--since it's not carrying big current, it doesn't need to be massive. Just a good, clean connection is what really matters. 

 

StarterMount1.thumb.jpg.8249b37e3462a6ede592e48ce15bb7aa.jpg Ground3.thumb.jpg.aa64a0806043ad7d8a62780736a18b78.jpg Ground4.thumb.jpg.7a3f87778a789ff3f6f5effb6699fd26.jpg

 

Oh, and last night I had a dream about a shorted ground wire and big sparks, so I went back and looked at how I had the batteries arranged. I don't like it. So I moved them around and rearranged the wires to get them out of harm's way. I thought I took a photo, but I guess not. Anyway, I repositioned the wires tying the two batteries together to the inside of the batteries rather than outside. No risk of touching the frame or transmission or other moving parts now.

 

Put it on the ground and hit the button and it fired up instantly. Nice! But cold starts are the easy ones, so I decided to give it a bit of a stress test. It's 96 degrees here today, so that's stressful. I drove it about a two miles up the road to put some fresh gas in it and while I was there, of course, two or three guys wanted to have a conversation. Since I didn't yet trust its hot starting capabilities, I left it idling. 15 minutes of idling and the gauge was about 3/4, maybe 4/5, to the top of the scale--it was hot, but not boiling or steaming. I headed back up the road and drove gently-ish to give it a chance to cool off, but it didn't, which troubled me. It didn't overheat, but it didn't recover once there was good airflow. Hmmm...

 

As I pull back into the shop, Melanie points that there's rather significant stream of coolant coming out of the bottom of the car--more specifically, from the water pump shaft. Tom warned me about this, too, so it's not unexpected, but it's not a drip, it's a pretty steady stream when the engine is running. I  used my temperature gun to get some readings and the water outlets on the heads, the upper radiator hose, and the top of the radiator were all 220-225 degrees. HOT. Still no steam, though, so maybe not quite as hot as it seems? I don't know. But that's too hot for comfort. At that point, the engine started to stumble as well, which meant that the carburetor and/or fuel lines were hot enough to start percolating the fuel inside. I should add an electric fuel pump, that's an easy job. 

 

Lincoln3.thumb.jpg.a7c23b30fd17202de662d15c61ad5fb7.jpg
Water pump is leaking pretty well (you can see it streaming out
from under the front fender--that's about a minute after I pulled in)

 

But the water pump is my priority. To my eye, it looks like the nut where it is leaking is the packing nut. My gut says that I can back that off, put some packing in there, and tighten it back into place, and it should staunch the leak. Can anyone confirm or deny this? I don't have a manual yet so I'm not sure. There's also a grease zerk at the back that I'll hit with a few shots of waterproof grease. 

 

 WaterPump1.thumb.jpg.e7788bbe4195b0855dc3a28f4e6f92be.jpg

 

Once that's sealed back up, I'll be taking Grimy's advice to put in some stocking filters in the upper hoses and run some cleaner through the block. I've had good results with Evapo-Rust, which is harmless to all the internals and different metals but does an awesome job of cleaning stuff out. They just came out with a substance that is specifically for cooling systems, but I haven't tried it. Maybe I will. But like the battery, getting the basics right is the first step to sorting a car so we'll make sure the water pump is healthy and the gunk in the cooling system is gone, and then evaluate. I think cleaning it out will make a world of difference, just as it did on my '41 Buick.

 

Oh, and the batteries--I almost forgot. After pulling in and letting it heat soak while we looked at the cooling system and measured temperatures, I jumped back in, hit the switch, and VROOM! That starter spun with vigor and the engine started without too much difficulty other than the hot fuel. It was VERY hot and I don't think it particularly wanted to start, but with all that electricity pushing it, it really had no choice. It was going to run. Happy to have won that battle on the first try, a very rare thing in the Harwood Compound garage. What a relief that is. 

 

Next up today, finishing the rear shock absorber installation on the '41 Buick Limited (you'll have to find my other thread for that one, sorry!)...

 

 

 

Edited by Matt Harwood (see edit history)
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This is for the next year models (36) and up but it does say the there's packing in there with a gland nut for adjusting...

lincoln water pump.png

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Sorting an old car is one of the most difficult jobs there is, but its also very rewarding when completed. Some cars are easier than others, and the big multi cylinder cars can be a real pain in the ass. I think ALL pre war cars now need some type of electric boost or full time fuel pump. The E10 fuel just boils away so fast after shut down its just not worth you time playing around with the early pumps. I'm a 100 percent purist, but recently have converted over to optima batteries and double them up similar in the way Matt has done. If I were restoring another car for myself, I would redesign the fuel system and run a return line to the tank. It's well over 100 degrees in Florida this week, and the 30 V-16 is running great on the vacuum tanks, pulling through the two electric fuel pumps.........but we don't run pump gas.........thats the trick if you don't want to vapor lock.....NO E10!

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The most difficult part of sorting for the individual collector is that the car is almost always a new toy that s/he wants to DRIVE -- NOW.  That is, patience or lack of it is the main problem.  I find sorting an interesting intellectual exercise that keeps my geezer synapses firing, and is greater fun outside the normal touring season when I'm not fighting my impatience.

 

Ed, if you're using E0 exclusively, you must be doing only day trips.  How many miles do you get out of that 32-gallon V-16 tank?  Or have a tanker following you on multi-day tours? 

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28 minutes ago, Grimy said:

The most difficult part of sorting for the individual collector is that the car is almost always a new toy that s/he wants to DRIVE -- NOW.  That is, patience or lack of it is the main problem.  I find sorting an interesting intellectual exercise that keeps my geezer synapses firing, and is greater fun outside the normal touring season when I'm not fighting my impatience.

 

Ed, if you're using E0 exclusively, you must be doing only day trips.  How many miles do you get out of that 32-gallon V-16 tank?  Or have a tanker following you on multi-day tours? 

 

Mostly two or three day trips, and I can carry enough fuel to get by, sometimes we end up blending 50/50 except on the week long tours. I jet all out cars for NON E10, but when we do a week long tour, I will jet them for it, back off the timing, and keep an eye on things as we go down the road. Most of the stuff in the garage are the exotic power plant cars from before the war, so we don't drive them to and from the meets. Trailering for safety, comfort, wear and tear, exposure to modern traffic, ect........ also, I have a 15 gallon pump station that can be put in the trailer that filters out the ethanol, so I still end up with lousy modern fuel, but no ethanol which helps things out 70%. 

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1 hour ago, Grimy said:

The most difficult part of sorting for the individual collector is that the car is almost always a new toy that s/he wants to DRIVE -- NOW.  That is, patience or lack of it is the main problem.  I find sorting an interesting intellectual exercise that keeps my geezer synapses firing, and is greater fun outside the normal touring season when I'm not fighting my impatience.

 

Ed, if you're using E0 exclusively, you must be doing only day trips.  How many miles do you get out of that 32-gallon V-16 tank?  Or have a tanker following you on multi-day tours? 

 

Indeed, this is a VERY big problem for me. I always want to play with my new toys the minute I get them home. But I always remember that patience now will eliminate headaches later, so we always go through the cars I buy for myself pretty carefully. No matter where I get them, all the fluids get changed, the carburetors get checked, the cooling system is at least back-flushed, etc. When I first got my '41 Limited and just started driving it as soon as it came off the trailer, it was a massive exercise in frustration. It overheated, it wouldn't idle, it sounded like crap, the braking was lousy. So we started going through it and every one of those things was wrong. The cooling system was full of gunk (now it runs at about 160 under all conditions), the rear brake shoes were soaked in axle grease (fixed those two issues), the transmission would grind going into 1st at a stop (correct gear oil cured that), and I spent a LOT of time dialing-in the dual carb setup. Now it is fast, reliable, and totally bulletproof. I'd drive it California this afternoon without hesitation. Of course, I'm going to have to re-tune it when the headers go on and I switch to two front carbs working in parallel, but that's a different situation.

 

I intend for the Lincoln to be the same way. It probably won't be until this weekend that I have all the parts and supplies that I ordered, but it's on the lift now. We're doing fluid changes (12 quarts of oil--yikes!) we're adjusting the brakes, and we're finishing the draining of the cooling system, although it lost more than half the coolant over the weekend and filled the 5-gallon pan I had under it. No problem, that'll be cured, too. New gear oil in the transmission and rear end (I decided to use the SAE 140 GL4 I'm using in the other cars)I ordered new plug wires to fit inside the plug conduits I found on eBay, we're refinishing the manifolds in black, and since the headlights were pretty beat up from people being careless with the hood and hitting them over the years, the headlights are going to the paint shop. 

 

I looked into a set of Diamondback radials for it, which are always my #1 choice. They have Michelins that will look right, but--gasp--they're $525. Each. So probably no radials for the Lincoln, at least for now. We'll see if these Denmans round themselves back into shape with 40 PSI in them and some extended driving on hot roads. They're a little flat-spotted.

 

Get it right before you start to drive and the drive becomes that much more enjoyable. But like Grimy, I have a tough time not getting behind the wheel and having fun. We're aiming for a CCCA Grand Classic on July 14, so I have some time to get it all done...

 

Thank you for all the advice, guys. Keep it coming, hopefully it's helpful to others.

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2 hours ago, alsancle said:

This is the battery setup I used on my Royale.

image.png.861a2105404425112c9ee5ba70d040b1.png

 

It would be interesting to know if the current from the two batteries is about the same with the tap on the side of the braided cable like that.

Edited by Spinneyhill (see edit history)

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All great stuff Matt!  As to the battery ground, I've started running a separate ground directly from battery to starter mounting bolt.  That way there's no chance of not getting a good ground, I have it on two cars now that positively spin twice as fast as grounding just to frame.

 

Ed, I recently read about a gas return line being added to a car, but problem was that it was heating up the gas in the tank with the returned, hotter, gas.  I know my ex-'67 Lincoln Continental had a three port fuel pump, with one port going back to tank, so it should work, but....

 

As to the water pump, the best results I ever had (on a 1935 Pierce eight coupe) was to take out the packing and install two spring load lip shaft seals, each oriented in opposite directions.  One kept the water from leaking out, one kept the pump from sucking air in.  Worked like a charm, and no packing to worry about......

 

I'm not a fan of electric fuel pumps, after almost losing two cars to fire when the pumps didn't shut off.  There are safeguards of course that can be put in place.  Get a low pressure pump, of course, if you must use one, most pressure regulators you buy now are crap.

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1 hour ago, trimacar said:

I'm not a fan of electric fuel pumps, after almost losing two cars to fire when the pumps didn't shut off.  There are safeguards of course that can be put in place.  Get a low pressure pump, of course, if you must use one, most pressure regulators you buy now are crap.


The best setup I have seen is one that Chris Charlton uses on every car he restores for Pebble Beach.  I need to get a picture from him, but basically the electric pump is plumbed next to the gas tank with a loop return line and a pressure regulator.  If the carb is not drawing gas the pump is just circulating the gas back to the tank.    Ed has seen the setup and can probably describe it better than I can.

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Yes, I know White Post Restorations used to do that, a plumbing issue with check valves and so forth.

 

I had my carb and mechanical fuel pump rebuilt by J.C., on my '31 Pierce phaeton, and am very pleased with the way it works.  I've driven hundreds of miles with no fuel starvation nor vapor lock.

 

I understand that people like electric fuel pumps, but the original systems work too, if they're set up correctly. Usually adding electric fuel pumps is just covering up another problem, as are many of the "improvements" made on early cars. For example, people are so quick to want to go to 12 volt, when the 6 volt system works great if you understand it's function.

 

Just my opinion, I respect everyone else's opinion, and understand all the discussion about poor fuel and such.

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I hope I am not digressing too much from this thread  but I am curious.  The loop return system conversion with an electric pump can obviously be made to work because it has been done many times.  Ignoring for a moment the issues with electric pumps, how is set up to ensure that there is sufficient flow to the carburetor under all load conditions?   Unless there is a restriction in the return line to the tank the fuel can bypass the carburetor.    Is that restriction a valve or a fixed orifice.  If its an orifice the size will depend on the the pump output flow and pressure, the maximum fuel demand etc.    If its a valve is it adjustable while driving?   Sounds like a lot of trial and error to get it right or am I missing something.

 

 

 

 

Edited by DavidMc (see edit history)

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Most fuel-injected cars used to run return lines that are one size smaller than the supply line. Today they have variable-output fuel pumps and no return line, but on my 5.0 Mustang, for instance, there's a 5/16-inch feed line and 1/4-inch return. There's a regulator on the system, but it merely manages the pressure at the injectors. I think the electric pump can supply far more than the system requires, so naturally bleeding some off not only helps keep it cool, but also keeps the pump from dead-heading against a sealed system. As long as the pump can move more than the line can supply, it should be fine with the carburetor/fuel injectors taking what they need from the system as it's needed.

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Matt, I understand your comments, having a pump with a flow rate well in excess of the maximum the car can consume is a solution and with modern cars, pressure and flow can be designed accordingly. 

The 6V low pressure Airtex pump commonly used on our old cars has a claimed flow rate of 30 GPH .  The pressure at which this occurs is not stated .    A large engined 1920's car climbing an extremely steep mountain in second or even low gear could be consuming fuel  at maybe 10-15 GPH .   So with a 30 GPH  pump that sound fine except that a 1/4" return line will offer negligible resistance to say 30 GPH  if there is any restriction at the carburetor this could result in not enough flow to the carburetor.     Such a problem, (if in fact it is a problem)  may never occur until such adverse conditions are experienced.   I am thinking of converting one of my cars to this set up to reduce vapor lock issues and I am considering an orifice of maybe 1/16" may be necessary in the return line.  30 GPH is not a big flow rate, think of a 30 gallon drum  leaking fuel.  If it takes 1 hour to empty the flow rate will be only a trickle so a  1/16" restriction may  not be small enough.    

Maybe I should start a new thread on this topic .

 

 

 

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On a carb system you will need an orifice in the return line. There are inline fuel filters available that have an orifice in the third port. Three common applications (IIRC) are 70s chryslers (big ones, 440 w/ac and so on), some 60s Buicks, and the Chrysler 2.2 carbureted K-car.

 

The K-car filter is generally the most desirable because it is physically the smallest, and the third port tucks along the side. It is also the most recent, and probably the easiest to find.

 

I have tried all sorts of electrical/mechanical combination schemes over the years. They were all lousy. If you want to keep the pump running whenever the car is, remember to come up with some scheme to automatically shut it off in a crash. It will shock you how fast the cheapest, tiniest thumper pump can empty a fuel tank with no restriction. Vane and roller pumps are much faster.

 

The best (and sanest) electric pump scheme I have ever heard of is the one described by many other members on this forum. A little thumper pump is used, on a switch, in the back, and only run when needed to prime the carb, or to mitigate vapor lock when it begins. The rest of the time the mechanical pump just sucks through the thumper, and the restriction is minimal.

 

This solves a whole bunch of problems, like:

1) how to shut the pump off (usually it is not on),

2) noise from the thumper pump (usually not on and also thumpers are cheap and you can suck fuel through them, a "better" pump would require a bypass and check valves, more points for failure,

3) pressure from the back of the car will force fuel through even if the line is hot and the carb is boiling.

4) It can be done with or without a return line (return line has to originate after the mechanical pump). The only thing is you would need to make sure the fuel pump diaphragm is fresh, so the engine doesnt get filled with gas, but even this is less of a big deal than on most pusher schemes, because the pump is normally off.

 

On the other hand, you may not need any of that. If I were doing it I would do the following things:

1) Add a fuel sock in the tank if there isnt one. Modify the sock to fit if necessary.

2) REALLY nitpick the fuel pump. Make sure both check valves can pull and hold vacuum individually. This is a big deal and is rarely checked. Of course it needs an ethanol resistant diaphragm. Verify that the diaphragm moves enough when the pump body is mounted on the car. Worn-out fuel pump lobes are not unheard of. Also check the pressure. Slightly out of range is no big deal, but it should be close.

3) If there is a thermostatic heat riser make sure it opens all the way. Do whatever it takes to fix it.

4) Use completely stock fuel line routing. Get rid the mangled mess of fuel lines, hoses, screw clamps, non-original fuel filters and sediment bowls, etc. that most old cars have by now. There can be no tiny holes or leaks in the lines. You might not notice it leaking on the suction side, but it will prevent the fuel pump from doing it's job properly

 

If it STILL has a problem, I would look at rerouting the fuel line to a more advantageous spot, or the pump-on-a-switch idea. I'll bet you don't need either.

 

Edited by Bloo (see edit history)

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Bloo, I agree with all that you have said  but my cars have vacuum tanks not fuel pumps. An electric pump for priming is not necessary and not the reason for contemplating a change   The sole reason  is vapor lock and yes all of the other possible issues have been eliminated. The vacuum tank sits over the exhaust manifold and gets very hot and the fuel  in the tank boils, which when combined with hot weather,  will cause vapor lock especially in traffic with stop start driving.  Under all other conditions the cars start and run well but once the fuel in the vacuum tanks starts boiling it is at risk of vapor lock.  A system that bypasses the vacuum tank and keeps the fuel in circulation is theoretically a good solution providing the re circulation line does not starve the supply line.  

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David, I have designed a system to integrate an electric pump into my 1929 Cadillac's system without disabling the vacuum tank or causing it to overflow. I haven't actually installed it simply because the expensive restored vacuum tank I was going to use was stolen so I'm still running the car exclusively on the electric pump. But I designed a system and bought the parts. It's simple, I just had a T-fitting in the line from the vacuum tank to the carburetor and connected the line from the fuel pump there. However, to keep the electric pump from backing up into the vacuum tank, I found a very light-duty check valve that would open with something like 1/2 PSI, which I figured was about right for the gravity feed. My idea was to run it on the vacuum tank at all times, but if it failed for some reason or ended up with vapor lock, I could turn on the electric pump to take up the slack.

 

I don't really think a vacuum tank could be subject to vapor lock, though. In my Cadillac's case, it's about 1/3 gallon of gas, which is a LOT of fluid to heat up, especially if it's constantly being replenished. So any heating would take place in the line prior to the carburetor. In fact, I've been running it on the electric pump for about 8 years now, and the only place I've had vapor lock is in the fuel bowl of the carburetor. I've driven the car and had it start stuttering and when I parked it, I could hear the fuel boiling inside the carburetor. Nothing to do with the lines or the pump, but even an electric fuel pump couldn't keep the fuel from boiling in the carb. Of course, that was a 104 degree day and after a 3-hour drive, so that's about as stressful as it could get for the fuel system.

 

Anyway, I had the idea but never got around to implementing it simply because I no longer have a vacuum tank, so I don't know if it would work (the check valve was the crucial part). Someday maybe I'll find a replacement tank and spend the few hundred bucks to restore it, but as it is, the car runs so well, I don't want to mess with it.

 

 

Edited by Matt Harwood (see edit history)
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Matt,  I don't think the vapor lock is in the vacuum tank but the key to avoiding vapor lock is keeping the fuel as cool as possible, pre heating it in vacuum tanks is not good and I have tried various designs of heat shields  with varying success but that's a whole new topic.

 

The system you describe for your Cadillac is exactly how I plan on doing mine and apart from concern about excess recirculation flow finding a suitable check valve to prevent back flow to the vacuum tank is the other critical part of the system.  It has to open or close on negligible pressure differential.  Racing cars use a roll over valve to  shut off the fuel in the event of a roll over.  It functions only when the engine and fuel pump has stopped.  That is a simple ball and light spring which might work.  The concern is that when running normally on vacuum tank it may fail to open.  Another thought is to make a check valve using one from a mechanical fuel pump.  Would you mind letting me know some details of the valve you have found? 

 

Another solution is a shut off valve but that means stopping and getting out to isolate that vacuum tank.  Apart from the inconvenience that will work

 

Thanks for letting me air this topic on your thread, its now a work in progress and BTW that Lincoln is gorgeous

 

 

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3 hours ago, DavidMc said:

Bloo, I agree with all that you have said  but my cars have vacuum tanks not fuel pumps. An electric pump for priming is not necessary and not the reason for contemplating a change   The sole reason  is vapor lock and yes all of the other possible issues have been eliminated. The vacuum tank sits over the exhaust manifold and gets very hot and the fuel  in the tank boils, which when combined with hot weather,  will cause vapor lock especially in traffic with stop start driving.  Under all other conditions the cars start and run well but once the fuel in the vacuum tanks starts boiling it is at risk of vapor lock.  A system that bypasses the vacuum tank and keeps the fuel in circulation is theoretically a good solution providing the re circulation line does not starve the supply line.  

 

OOPS I really missed the mark didnt I? :lol:

 

To my credit I thought we were talking about the 1935 Lincoln.... Does it have a vacuum tank too?

 

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No, the Lincoln actually has a rather sophisticated two-stage fuel pump with built-in vacuum pump. And much to my benefit, it's brand new!

 

1935-Lincoln-K-Sedan-39-1-762x456.jpg.5c83ff7ff536d298701637dac4a46473.jpg

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