Mechanical plus electric fuel pump

WINST10

Recently bought a 51 Pacemaker and I am sorting out some stuff to make it a good driver.  The previous owner had some issues with the fuel system and it currently has a mechanical fuel pump with a pressure regulator between the pump and the carb. 
  The previous owner installed a switch and wiring for an electric fuel pump to be installed near the gas tank.  His intention was to run the electric pump a second or two before starting to get gas in the line, then after starting use the mechanical pump only.   
  I read something on Ken Cates' Hudson page that led me to believe this setup is not a good idea.  My understanding is that the two pumps would fight each other...the electric pump would make it harder for the mechanical pump to draw fuel and the mechanical pump would make it harder for the electric pump to send fuel.
  Does anyone have any experience or opinion about a setup like this?  I am wondering if it would be better just to scrap the mechanical pump and go with electric only...

KustomKreeps

I wouldn't run both. just adding stress on the system. The electric will be pushing fuel at the old mechanical at a rate it just cant handle. Even rebuilt the old mechanical pumps seals will start to leak and you run the risk of fuel getting into the engines oil.

Me personally I would rebuild the mechanical. I find the old fuel pumps of the time very reliable. Saying this the only experience I have of the Hudson one is from the motor I ripped out of my 49. It had been in storage since 1969 but it still sucked petrol fine.

Or if you decide to keep electric then you may need a regulator to cut back the pressure to the carb. modern fuel pumps often shove out way more fuel than the old carbs can handle.
Also dont remove the old mechanical fuel pump. leave it attached to the engine with its hose barbs still on it but blocked off. Just run a bit of rubber hose around it by-passing it.  keep some hose in the cars spares tool box you carry. This way if the electric pump dies you can quickly just hookup the old mechanical to the fuel lines and be on your way again.
That trick has saved me before.  My 52 Buicks electric pump died out on adventures. Was a hill no flat ground. Being able to just raise the hood and slip a few bits of hose on to the old pump was a 10 min job. Much easier and safer than jacking up the car and feking about on your back for hours.

Kdancy

I have a friend that runs both on his Studebakers. Flips the "on switch" for a few seconds to prime the carb, then back off. Cars start right up. His electric are 6psi pumps.

50C8DAN

That is what I finally did on my '54H, prime with electric then run with mechanical.  Surprisingly my C8 never has had any issues with starting after a long slumber.

kamzack

I recently installed an electric pump and having some challenges. I installed electric cause I was hoping it would help with vapor lock. It didn't. Carb would squirt gas but not fire. Even highway speeds would start chugging and quit, but let it set for 30 minutes or a bit more would kick off and sometimes jump with 12 volts would fire. I'd also been carrying a jug a water to pour over the carb base and fuel pump. didn't really help. I've never really had a vapor lock problem until this year.  After trying to find the trouble, I decided maybe coil and or condenser were getting too warm. So new coil, points condenser rotor and cap, and gap set at .020 its starts quicker. Points were due. Now problem has intensified, Temp get up to a bit past mid way and if I accelerate it chugs. With the above information gonna bypass electric pump and see what happens. Any suggestions will be appreciated.

    Kim

Glowplug

Shot in the dark... have you vacuum checked? 
Vapor lock is between fuel pump and carb...if the electric did not change anything there are other gremlins in the mix.  One thing I found in the past was the fuel line at the rear was being overheated by an exhaust leak.  Fixed leak and put header wrap on pipe as added insurance.  Fuel filter at or near tank leaking or dirty . Fuel tank crud sloshing to and fro will create intermittent fuel blockage. Good luck

KustomKreeps

@kamzack
Had a similar issue on my 52 Buick with an inline 8.
was fine for short drives around the town but get it at highway speeds it would really cough, splutter & pull back.

My first thoughts was electrics. so i swapped to a pertronix unit, new plugs, leads & coil. Did the old spray water at night trick and no shorts/flashes. Did tappets, timing and compression. When that didnt help I put in an electric pump and filters. when that didnt help I rebuilt carb. Checked intake manifold & exhaust manifolds along with new gaskets. My fuel lines already where newish and wrapped to prevent vapor lock so I next dropped the tank and flushed it - was clean already. Flushed the fuel lines at the same time. When all that didnt work I checked the ignition wiring... was the old 52 wiring and had perished slightly where it left the loom and went along the side of the engine to coil. Did another spray misting and didn't flash  unless you wiggled the wire a little to simulate driving pumps. Once the car starts jerking it just  made the issue worse.
Replaced the wire and car works like a champ.

Long expensive and frustrating process. Aint fun when you dont trust your wheels to go cruising.

I would be hesitant to poor water on hot cast iron.. might crack it.

onerare39

WINST10,

Thanks for joining the Hudson Essex Terraplane Club!  There are a great group of folks around the St. Louis area.  The Gateway Chapter of the Hudson Essex Terraplane Club are a great group of folks, many willing to come over and help sort your problems out.

John Forkner

Val

Check your messages 

kamzack

Thanks everyone. Have in mind to check vac advance. I use a sediment bowl to detect any trash and no accumulation and it has correct filter. Wire harness was new when installed 2012. Tank was cut open, blasted and welded back together 2012. More and more I'm leaning to pump conflict. But I will reexamine everything.

  Thanks again,

     Kim

50C8DAN

Are you using both pumps while driving?

ken1962

"Aint fun when you dont trust your wheels to go cruising." is probably the truest quote I've ever read. When I had my v12 jaguar I'd be on edge the whole trip just waiting for the bloody car to fail. It always did at the most inconvenient point of the trip. One day on the side of the road yet again I just gave up and got rid of the stupid thing later that week.... In 1995.... Years later I've had my 1936 hudson since 2013 and I'm just getting now getting comfortable knowing it hasn't let me down and probabky will not in the future.... Just like a modern car... I know its stupid but once you have had a shit of a bloody car it's hard to let your mind rest if you know what I mean. I really love my hudson terraplane and its only failed me once because I didn't realise the gas tank was empty below the first mark. The mind is a powerful thing and self doubting your car can really spoil the whole car experience. Every now and then it has a stutter when I drive but like a human burping and is nothing in the long run and I just need to roll with it which I'm slowly getting familiar with along with vapor lock cheers ken 

kamzack

   Thanks Ken. Haven't driven it much this summer as I have past summers. Cause it would always be a problem restarting. I love driving it and never had much of a fear of being in it, til this summer. I'm bout to bypass electric pump and go for a drive. My amateur's observation tells me manual is having a struggle pulling fuel through da electric pump when it's off. Other mystery, why does it do ok til temp gets up just barely past middle mark on da gauge? So for first few miles doesn't seem to chug even when pedal is pushed to da floor. So dats why I decided ignition components were getting too warm. Also, problem got worse after tune up. Starts quicker and restarts better, still takes a more revs. Sometimes I've jumped with 12 volts and starts instantly.                    Dan I've done that and mostly not paying attention. So when I discover it, I turn electric off. Don't mean to write a book bout it but my Hudson is half of my transportation fleet. Other is 61 Studebaker pickup. recently put electric pump on it and solve 2 problems, getting fuel to carb to prim at first in da day and vapor lock while in traffic in high temps, pushes fuel through and chug goes away. That prompted me to do da same on me Hudson. I do appreciate da feedback.

   Kim

onerare39

Here was a previous discussion on vapor lock and what worked for me.  

https://openforum.hetclub.org/discussion/171366/vapor-lock/p1

kamzack

By passed E. pump and went for ride. Same problem. First 10 to 12 miles, no problems. then slowly problem came back. About 30 mile round trip. Got within couple mile of home and was like switch turned off, let off gas and had to nurse it home, couldn't get it much past 30mph. In the shop even idling is shakey. try to gently run rpm's up, stumbles and dies. Took some grinding to get it to fire and while running, sediment bowl fuel level up and down. carb base not hot, pump not hot, fuel line not hot. Gonna look at needle and seat, clean sediment bowl tomorrow. Possibly float sticking? I can usually solve problems on old engines, since that's all I have. This one has me stumped.

 Help,

     Kim

   

Glowplug

Kim:  Long distance troubleshooting is like trying to find something that rolled under the bed during the night. That aside, your descriptions continue to point to something that is related to the engine warming up or being moved.   If it is heat related, I would be looking with an extremely strong light for cracks in your intake... blown manifold gaskets, failed or loose intake and carb mountings.  OR OR OR  the tank has stuff in it that is moving around and intermittently or partially blocking the fuel delivery.   My vehicle is equipped with a bypass that allows the mechanical fuel pump to pull fuel from the tank.  The bypass is a check valve that does not allow the fuel to flow back to the tank once past the valve. Trash in the tank is a common problem and if the pickup tube loose from the bottom of the tank... it no longer has the original screen across the end and will pick up what ever is in the tank.  Another thought is the pick up tube has a hole in it near the area place it penetrates the tank. If a rust hole exists inside the tank... the pickup is pulling air everytime the fuel sloshes away.   Pulling the tube is what I would do before anything else is tried... examine it with a very strong light.   GOOD LUCK

kamzack

Thank you.

kamzack

Problem resolved. Always seems when a problem arrives I go for something big, This fix was bout 30 minutes to resolve. Removed pickup tube and found gasket had failed, so air being drawn in was 95 per cent of the issue. Made a new gasket, a dab of sealer and I'm happily on da road again. Wasted 3 or 4 gallons of gas today just driving n smiling.

   Kim.

KustomKreeps

this forum really needs a like button.

Glowplug

Good to know that your car is back running correctly!

Per

Kamzack,
     You may need to loosen the adjustments on your exhaust valves.  The fact that it runs fine for a few minutes and then runs less well may mean that there is very little valve clearance: When your exhaust valve lengths expand with heat, the valves don't quite close anymore on some of the cylinders, and the engine runs poorly.

     I had to do this at the conclusion of a trip from Boston the California and back to Boston.  The car was running very poorly the last thousand miles.  I adjusted the clearances, found some clearances far below specs.  Now the car runs fine.  I did no other maintenance, so this was the reason for the poor running when warmed up.

     Another person near me then solved the same problem doing this on his Hudson. 

Per

kamzack

Thanks everyone.

   Kim