philipj Posted July 18, 2018 Share Posted July 18, 2018 (edited) After my last post dealing with some driveability hiccups, I started to drive the car more and more... Now that I have passed the 40-minute mark or so, I have a worse kind of problem... Instead of the occasional blip, now I have the occasional pop from the carburetor and loss of power equal to losing 2 or 4 cylinders at times. The latter is drastic, but It is intermittent as I stop and continue driving... The engine seems to be at normal temp (180° to 185°) with good oil pressure and a charging system in order... As I pulled into my garage (slight incline) it seemed to smooth out... The problem started last weekend and now has gotten worse. Is it the float sticking in the carburetor? Still, I have not ruled the carburetor out. I need to have it professionally re-done. In the meantime, what to do? I checked and adjusted the timing, changed the plugs (R46 Acniter), removed my NOS coil (Delco 1115328) and replaced it with a brand new NAPA IC7 coil... I took my meter to the store to see what the readings would be... The guy at the counter said that all 6V coils are the same and should not be a problem.. Measuring the primary (set @200 scale) I got "0" instead of the 1.5 Ohms required...As for the secondary (set @ the 20K scale), I got just under 10K. With the coil hot, I just measured and obtained 10.5 as a number...Is anything over 10K with the secondary a fail? The primary still at "0" Should I try to purchase a different brand of the coil where I can actually get a 1.5-ohm reading, or all 6-volt coils are the same? I am just about out of options here... Edited July 18, 2018 by philipj (see edit history) Link to comment Share on other sites More sharing options...
philipj Posted July 18, 2018 Author Share Posted July 18, 2018 I need to make a correction regarding the primary coil readings... I was using the wrong scale. I was using the 200K scale (which gave me 0) With the correct 200 scale I get 1.2 Ohms on the warm coil for the primary and 10K on the secondary... Link to comment Share on other sites More sharing options...
TerryB Posted July 18, 2018 Share Posted July 18, 2018 Sounds more like fuel delivery is intermittent, especially that it runs better on an incline. Link to comment Share on other sites More sharing options...
MCHinson Posted July 18, 2018 Share Posted July 18, 2018 Difficult to diagnose without seeing it. I don't remember, do you have an auxiliary electric fuel pump? If so, when it gives you a problem, try switching on the electric fuel pump. It could be fuel delivery issues due to vapor lock, or it could be a carburetor problem, or it could be trash in the fuel tank. It could also be electrical in nature, but I would suspect a fuel related issue first. It could also be some water in the fuel system. That can cause some interesting failures as well. Lots of possibilities... Link to comment Share on other sites More sharing options...
philipj Posted July 18, 2018 Author Share Posted July 18, 2018 My tank is brand new as well as the pump... I do not have an electric fuel pump, but I did Insulate and rerouted the line from the pump to the carburetor. I am also using rec90 fuel since yesterday hoping that it would help... Short of sending the carburetor to my carburetordoctor.com (Do they test on running engines?) I don't know what to do, except try a box of matches! Link to comment Share on other sites More sharing options...
MCHinson Posted July 18, 2018 Share Posted July 18, 2018 I have no idea what "rec90" fuel is. Regular non-ethanol fuel is the best available fuel for these cars today. If non-ethanol fuel is not available, regular with 10% ethanol is the next best thing. You don't need premium or midgrade. You don't need any higher octane. I would encourage you to add an electric fuel pump near the fuel tank. I use it to prime the carburetor after my car has been sitting over a day or so because modern fuels will evaporate out of the carburetor when sitting. I also use it as needed in high heat conditions when vapor lock would otherwise be a problem. With fuels of the 30s and 40s, it was not needed. With modern fuels the electric fuel pump is a necessary addition to to the car for those of us who live in hot environments. 1 Link to comment Share on other sites More sharing options...
philipj Posted July 18, 2018 Author Share Posted July 18, 2018 Around here they call it recreational fuel, 90 octanes without ethanol... The car starts right up even after a day or two of sitting. What I am going to do in terms of heat is to remove the two lower pans on either side of the engine to see if that will help with cooling... Wonder if all the other guys in hot climates (Texas, Arizona. New Mexico) have them out of the car as well... On the other hand, I have to have the carburetor rebuilt by a professional or buy one already done... Whichever is cheaper. I will have to see who is offering carburetors already done other than Kanter's... Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted July 18, 2018 Share Posted July 18, 2018 What are you using for filters and where are they? Ben Link to comment Share on other sites More sharing options...
philipj Posted July 19, 2018 Author Share Posted July 19, 2018 There is only one small metal inline filter 3" long x 2" in diameter very close to the fuel tank, nothing else... Link to comment Share on other sites More sharing options...
MCHinson Posted July 19, 2018 Share Posted July 19, 2018 I don't expect that removing the engine side pans will help with cooling. I trust that the engineers knew what they were doing when the designed the air flow pattern to cool the engine. I would think that you are more likely to find that having the carburetor rebuilt by a professional would be more likely to solve your problem than removing the engine side pans. If you have not changed the fuel filter recently, you might want to do that. Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 19, 2018 Share Posted July 19, 2018 I'd try the electric fuel pump just to be certain that it's not fuel vaporizing in the lines and/or carburetor. I had a '41 Cadillac that would stutter when it got hot, say, after sitting at a long red light. For about 20 seconds after that, it would run so poorly that I was afraid it would stall, and there was popping and backfiring. Adding the electric fuel pump cured it. Hitting it before coming to a stop where I knew there would be a problem would eliminate the problem. If I forgot, it would start to stutter, but hitting the pump would end it in about 5 seconds once cool fuel got pushed into the carb. Since your tank is clean, I don't think it's starving for fuel like my '35 Lincoln was with a clogged pick-up, but it had the same symptoms. I blamed it on the car being too hot, but when the electric pump didn't cure it, I knew there was another issue. The electric pump is cheap and easy to do in an afternoon and will be useful for other purposes even if it doesn't cure this issue. But it's one more variable that you're eliminating. Check out my 1935 Lincoln thread to see how I installed the pump. It can't hurt! 1 Link to comment Share on other sites More sharing options...
philipj Posted July 19, 2018 Author Share Posted July 19, 2018 (edited) I agree with you Matthew, I don't pretend to know more than the engineers, it is just so hot here, but I guess I will leave that alone until I can send the carburetor or find another option such as this one... The fuel filter is brand new also. https://www.ebay.com/itm/173380639999?ul_noapp=true Has anyone used their services? Feedback is 100%... The surging or bogging down happens after taking off or sometimes while going down the road about 30mph in 2nd gear, less noticeable in 3rd... I guess I have to consider the pump, but again it should work the way it was intended when it was designed since almost everything has been replaced... Another question is why is it happening now? Is it all because the temperatures have been over 90F°? Edited July 19, 2018 by philipj (see edit history) Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted July 19, 2018 Share Posted July 19, 2018 philip, the gas formulation was much different in yesteryear. The last carbureted engine , I believe, was 1984. A lot has changed since then. I don't know if '38 had it or not, but some years had a small screen inside the carb fitting the gas line connects to the carb through. Might check if you have not. I realize it is not for everyone. This problem is the reason I went to fuel injection. NO ONE has this problem with FI. The gas is under pressure from the pump to the injector that is squirting it into the throttle body. Can't vaporise. Put the pump in. Can't hurt . Probably help. Ben Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 19, 2018 Share Posted July 19, 2018 It "should" work the way it did in 1938, except it probably won't. You'll note that your intake manifold is bolted directly to the exhaust manifolds and there's a box under the carb itself that circulates exhaust gasses under the carb. In 1938, they had trouble vaporizing the fuel properly, no matter what carburetor they were using. Adding heat helped and vapor lock was probably still not a problem. They needed the heat to make the car run right. Today, our modern fuels vaporize at room temperature. Try putting a few drops on your workbench and come back a few minutes later--they'll be gone. If you park your car for more than 4 or 5 days, the fuel bowl will be empty--not because it drained back to the tank as many people believe, but because it evaporated. The extra heat in the carburetor turns the gas into vapor before it even reaches the venturis, sometimes in the fuel pump and lines. Yes, it's that significant a difference. As Ben points out, using an electric pump at the back of the car lightly pressurizes the fuel to the point where it will flow, pushing the liquid fuel into the carb. The diaphragm-style mechanical pump can't pull any liquid if it's trying to pull it using vapor. That's what causes the problem we call "vapor lock." It's also why it is usually temporary and fleeting--it happens during peak heat periods (like sitting at a long red light or in traffic) but abates once the engine speed goes up and pumps cool liquid fuel into the carburetor again. At low speeds, the gas is moving slowly so it has time to vaporize. At high speeds, it's moving through the system more quickly and has less time to vaporize, which is why it doesn't usually happen while you're cruising, only at low speeds and usually after sitting still for a while. Most people blame their cooling system, but that's only part of it. Your car will run without an electric pump, yes, and it ill eventually overcome the vapor lock once you can get the engine going faster, but an electric pump will solve the problem faster or even eliminate it entirely if you act pro-actively to turn it on before you need it. 2 1 Link to comment Share on other sites More sharing options...
cahartley Posted July 19, 2018 Share Posted July 19, 2018 When the engine starts acting stupid have you ever felt the carburetor to feel how warm/hot it is? It could as simple as putting in an insulator carburetor spacer. Link to comment Share on other sites More sharing options...
philipj Posted July 19, 2018 Author Share Posted July 19, 2018 (edited) Hello Matt, I found your write up on the 6v E8902 Airtex fuel pump installed on your 1935 Lincoln, very nice job installing it... I am pretty close to being sold on the idea except for two things... Can I install something that will work in conjunction with the existing mechanical pump that can be switched on when I start the vehicle and just leave on instead of fiddling with a switch as I drive? Now, thinking about a different solution, would elastomeric insulating tape (1/8' or 1/4" thick) rated @-40F° to 220F° work around the entire length of the fuel line to prevent vapor lock? Edited July 19, 2018 by philipj (see edit history) Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 19, 2018 Share Posted July 19, 2018 You can leave the electric pump on all the time if you like. But if your mechanical pump is healthy, it will pull through the electric pump without any problems so it's not necessary. I like the switch so I can turn it off when it's not needed because it really is a part-time thing. The switch isn't any more difficult to add than just powering it off the ignition (which, if you read farther in my thread, I was advised not to do and I now pull power directly from the battery circuit). I will be adding a relay so that it shuts off with the ignition, however. It's so quiet, it's easy to forget that it's running and if it's not linked to the ignition, it's easy to leave it on and flood the engine compartment should the float be overwhelmed. Put the switch somewhere easy to reach but unobtrusive. On my '41 Buick, I have the switch mounted on a little panel with the starter button under the dash just to the left of the steering column. Reach down and flip it up when I need it, flip it down when it's off. The one in the Lincoln is a bit more of a reach under the dash, but still not inconvenient and it's out of sight. I wouldn't sweat that part. Insulation can only help, but it looks hokey. I have some insulation I bought for the Lincoln's fuel lines, but I just can't bring myself to install it because it looks so wrong. I drive my cars, but I don't like them looking odd, either. Still, I don't know if the insulation will be as effective as the electric pump at curing the problem as you drive. The insulation will only delay the inevitable, not necessarily eliminate it, particularly on longer, hotter drives. Once it's saturated, that's it and you have no other recourse. With the pump standing by, you have a solution when you need it. Insulation AND a pump should eliminate 85-90% of your fuel problems relating to heat. Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted July 19, 2018 Share Posted July 19, 2018 philip, you asked Matt a question ending with " to prevent vapor lock". Can't be done in my opinion. Slow it down. Yes. Prevent. No. As far as wiring an electric pump, mine is wired through a relay. The relay is " triggered" from the ign switch. Very little amp. Relay power directly from the battery. If I wanted capability to run part time, I would run the "trigger" wire from the ign switch to a toggle switch then to the relay. Ben 1 Link to comment Share on other sites More sharing options...
Grimy Posted July 19, 2018 Share Posted July 19, 2018 7 minutes ago, Ben Bruce aka First Born said: As far as wiring an electric pump, mine is wired through a relay. The relay is " triggered" from the ign switch. Very little amp. Relay power directly from the battery. If I wanted capability to run part time, I would run the "trigger" wire from the ign switch to a toggle switch then to the relay. YES! Well said, Ben! On my 8-cyl Pierces I use a Bosch electronic relay (12V, about 1" cubed--it's said that only Bosch *12V* relays will work reliably on 6V) because I installed higher-draw rotor pumps 12 or more years ago and don't want to risk 8 amps additional draw going thru my original ignition switch. Even if you use a lower-draw switch like the E-8902 (and you should), I advise using a relay and a toggle switch as Matt advised in Post #17. Link to comment Share on other sites More sharing options...
TerryB Posted July 19, 2018 Share Posted July 19, 2018 Remember when clip type clothespins on the fuel line to the carburetor were the in thing to prevent vapor lock? No one who used them could explain how they worked. Link to comment Share on other sites More sharing options...
Spinneyhill Posted July 19, 2018 Share Posted July 19, 2018 They performed as heat sinks, perhaps. Link to comment Share on other sites More sharing options...
philipj Posted July 19, 2018 Author Share Posted July 19, 2018 You guys really lost me with the wooden clothespins... Link to comment Share on other sites More sharing options...
TerryB Posted July 19, 2018 Share Posted July 19, 2018 24 minutes ago, Spinneyhill said: They performed as heat sinks, perhaps. They were made of wood. Not the best heat sink material but maybe enough? Link to comment Share on other sites More sharing options...
Spinneyhill Posted July 19, 2018 Share Posted July 19, 2018 Wood is a good heat insulator. If you put enough on, maybe the pipe couldn't heat up coz it wasn't exposed to the heat? Link to comment Share on other sites More sharing options...
philipj Posted July 19, 2018 Author Share Posted July 19, 2018 Very interesting indeed! Link to comment Share on other sites More sharing options...
philipj Posted July 20, 2018 Author Share Posted July 20, 2018 (edited) Back on topic here, I decided for the heat/sun to go down and figured I fire it up and go for a short spin... I let the car run for 3 minutes and took it out... Rough from the get-go and bogging down in second. Did not sit in traffic or anything... So much for extreme heat an so forth... How can this be happening? Back in the garage, I put the timing light on the car again, advanced and retarded the distributor, a little gas and still a stumble, gargle, and cough!... Then I thought of disconnecting the vacuum tube on the distributor side and give it some gas after I set the timing mark dead center again... At this time the car decided to run smoothly with the vacuum line disconnected... To me, it makes no sense at all! What is going on?? Tomorrow I will make sure the line is not obstructed and hook it back on... Or maybe I should go down the road with it disconnected and see how she runs. I don't know anymore, but I am pulling away from the thought that an electric fuel pump will be the magic cure to this nonsense! I have never dealt with anything so temperamental!... Edited July 20, 2018 by philipj (see edit history) Link to comment Share on other sites More sharing options...
philipj Posted July 20, 2018 Author Share Posted July 20, 2018 All and all, I still don't know if a brand new 6-volt coil with a reading of less than 1.5 Ohms on the primary, and 10.5K on the secondary (hot) is any good... Link to comment Share on other sites More sharing options...
Johan Boltendal Posted July 20, 2018 Share Posted July 20, 2018 Hi came upon this one just now. I think it's electrical, coil, condenser, points or some thing in that direction. Make sure all your ground contacts are as they should. Isolation within the distributor is alo to be Ok. Install a ground cable, welding cable thickness, directly between the engine and the battery. Doesn't sound like a fuel problem to me, have some ride with you and check the sparks at failing. How hot is the coil, should not exceed 45 degree celsius when hot. Never measured a coil so I can't help there. Have exp. the same with my '32 Cadillac was on the fuel route as well , turned to be a grounding problem, mind you all original fitted cables new and fitted as tehy should, my problem was solved after the said extra cable. good luck. Link to comment Share on other sites More sharing options...
TerryB Posted July 20, 2018 Share Posted July 20, 2018 48 minutes ago, philipj said: All and all, I still don't know if a brand new 6-volt coil with a reading of less than 1.5 Ohms on the primary, and 10.5K on the secondary (hot) is any good... Your readings for the coil are in specifications from what I found searching on the internet. This coil is very often recommended for many 6v applications. You said the engine ran better with the vacuum line disconnected. Was the vacuum line plugged during your test? The vacuum line causes the timing of the engine to change when vacuum is applied to it. If the vacuum line was open or unplugged during your test you could have been making the engine run more lean as extra air would have been introduced to the gas / air mixture. That could be a clue. If the vacuum line was plugged during your test then it’s possible the distributor vacuum advance is erratic and randomly changing the engine timing as you are driving. I would try plugging the vacuum line at the distributor end and driving the car with no vacuum advance and see how it runs. Link to comment Share on other sites More sharing options...
philipj Posted July 20, 2018 Author Share Posted July 20, 2018 Hello Johan, Every single component in the distributor is new, including plugs and wires... I have a regular flat braided cable between the battery and engine. I will check tomorrow and make sure it is tight... As for the vacuum line, I will try to blow through it tomorrow and make sure it is clear also... If it is, I will still run the car without it and see what happens... If it runs smoothly, can I just plug both ends and call it a day? I would be surprised if it did since the distributor needs to advance after a certain rpm for the engine to run right... Link to comment Share on other sites More sharing options...
Curti Posted July 20, 2018 Share Posted July 20, 2018 Coils have been sold in the USA for many years sans a 6V or 12V designation. According to a 50 year auto-electric friend they will interchange as long as there isn't a internal resistor. Link to comment Share on other sites More sharing options...
TerryB Posted July 20, 2018 Share Posted July 20, 2018 (edited) The distributor will advance as the engine rpms increase using its internal centrifugal mechanical advance mechanisms. The vacuum advance is more of an on demand advance based on gas pedal action. You may notice a delay or small stumble when the gas pedal is depressed when the vacuum line is disconnected. Edited July 20, 2018 by TerryB (see edit history) Link to comment Share on other sites More sharing options...
TerryB Posted July 20, 2018 Share Posted July 20, 2018 Also, are you sure coil terminals (+ -) are properly connected? Link to comment Share on other sites More sharing options...
philipj Posted July 20, 2018 Author Share Posted July 20, 2018 Very interesting things happening here... Started the car and plugged the vacuum port in the carburetor and went for a ride 10 minures or so, Its pretty hot outside and the engine is plenty warm... About 185F° The car runs fine. Does not surge or bog down. There may be a very slight hesitation to the gas pedal but it is almost imperceptible. I can actually go through the gears without a shudder... It also starts right up when hot at the first crank... I really don't understand why all of the sudden it runs as it should this way. The minute I connected the vacuum line to the carburetor, the car did not want to go anywhere! all the old symptoms came back. Is there any logic to this? Scratching my head... 1 Link to comment Share on other sites More sharing options...
JACK M Posted July 20, 2018 Share Posted July 20, 2018 I might suggest that when you hook up the vacuum the advance is pulling the plate inside of the distributor to a place where something is grounding. 1 Link to comment Share on other sites More sharing options...
PFitz Posted July 20, 2018 Share Posted July 20, 2018 (edited) 46 minutes ago, philipj said: Very interesting things happening here... Started the car and plugged the vacuum port in the carburetor and went for a ride 10 minures or so, Its pretty hot outside and the engine is plenty warm... About 185F° The car runs fine. Does not surge or bog down. There may be a very slight hesitation to the gas pedal but it is almost imperceptible. I can actually go through the gears without a shudder... It also starts right up when hot at the first crank... I really don't understand why all of the sudden it runs as it should this way. The minute I connected the vacuum line to the carburetor, the car did not want to go anywhere! all the old symptoms came back. Is there any logic to this? Scratching my head... Possibly a rupture in the vac advance diaphragm causing an air leak and carburetor to run too-lean. Use a hand vacuum pump connected directly to the diaphragm and see if it will hold a vacuum. Paul Edited July 20, 2018 by PFitz (see edit history) Link to comment Share on other sites More sharing options...
philipj Posted July 20, 2018 Author Share Posted July 20, 2018 (edited) Hello Paul, You may be on to something here, it makes sense... The challenge will be to find a replacement diaphragm since when I had the distributor out you could not see any model number or visible information on the tag... I will start the search 37-52 GM vacuum advance... Edited July 20, 2018 by philipj (see edit history) Link to comment Share on other sites More sharing options...
MCHinson Posted July 20, 2018 Share Posted July 20, 2018 While the distributors are probably the same, your engine number is a 1948 engine number not a 1947. Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 20, 2018 Share Posted July 20, 2018 A vacuum leak was my next guess. Maybe the vacuum advance itself is leaking? Link to comment Share on other sites More sharing options...
philipj Posted July 20, 2018 Author Share Posted July 20, 2018 Does anyone know the original Delco # for the vacuum advance on a 1948 Roadmaster? Unless all the smaller engines have the same distributor and components, but I don't know that... Link to comment Share on other sites More sharing options...
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