'31 Fuel Issues - Need Help

[Peter Cornwell]

I agree with Johan advising against fitting an electric fuel pump. I bought a 1930 353 which had already been converted to electric pump and inherited a world of problems and consequential problems it caused, pressure regulators reduce the flow as well as the pressure so didn't provide enough fuel in certain situations of high demand.
Kind Regards
Peter
England

[CalCadGuy]

Thanks Peter

[Chris Cummings]

Marc,

The vacuum (and fuel) piping is pretty accurately rendered in Figure 2 on page 85 of the Shop Manual.  I don't have access to my office scanner (due to the Chicom Virus chaos) or I'd post a pic.

Best regards,

CHris

[CalCadGuy]

Thanks, i have the manual and will refer to the diagram. this is how mine is currently set up, although likely incorrect. Marc

[CalCadGuy]

Chris, or anyone in this feed: What type of tubing is correct for the lines? I have seen copper, stainless steel and chrome plated used. Please advise. Marc

[Chris Cummings]

I think they are steel or whatever they make brake lines with.  Some people like to chrome plate them, but I don't believe that is authentic.  Here are some shots from the Internet of '31 V-8 vacuum plumbing.  Some have a fancy fixture that connects to both the wipers and the fuel and vacuum pump (with, I assume, another kind of check valve).  That was how my 1931 V-8 convertible coupe was equipped when I owned one in the 1970s.

[houseboats1]

I'll send you some I'm in Australia hence the delay

[CalCadGuy]

Thanks Chris, this is very helpful. Marc

[CalCadGuy]

Chris and Mark, or any others on this feed. I am still having issues with keeping the car running. Here is what I have done so far:

1) Had carb rebuilt
2) Had Vacuum tank overhauled
3) Located and installed the vacuum pump (Thanks Wayne)
4) Connected everything as described in the shop manual for 1931 Cad where the manifold line only feeds the wipers and the Vacuum Pump has a line directly to the vacuum tank. I filled the vacuum tank with fuel and the car fired right up. Within minutes it ran out of gas. Should I consider now trying to get the lines assembled like the 353 in 1930 and early 1931 355s Where both the vacuum pump and manifold were used? Not sure what to do next, but any thoughts would be greatly appreciated. Also, if any of you are willing to have a short phone conversation, my number is 415-902-5579. Thanks, Marc

[Johan Boltendal #158]

Problem is the information you provide is legit , but says nothing on the functioning correctly on parts in that info.
You should measure what is fact, is there enough vacuum , from engine and or pump, is there suction in the gas line towards the fuel tank, is the vacuum tank operation like it should all the way, can be checked easily, with a seperate electrical vacuum pump and find out if it fills or not. Either way '30 or ;31 connecting pipes should work. If not there must be
something wrong. Testing is the only way to find this, you will no doubt find it.  Johan

[CalCadGuy]

Thanks, not sure how to test the vacuum pump if I can't keep the car running? I'm new to this so any advise on testing each of the components would be extremely helpful.

[Johan Boltendal #158]

At first you buy an electrical vacuum pump, please let me know by a pm is there is one , I will help you from there  Johan

[CalCadGuy]

I bought a vacuum gauge and tested the vacuum coming from the manifold and the vacuum pump, both pulled around 20. I then hooked up each one to the vacuum tank separately to see if it would pull fuel. Primed the vacuum pump, got the car started and quickly ran out of gas.

[Johan Boltendal #158]

that leaves you with two, non working stewart, or no gas from the tank due to ....... Johan

[CalCadGuy]

There is (was) an inline fuel pump with a regulator. I disconnected it, but did not bypass it, Do you think that could be the issue?

[Johan Boltendal #158]

It could be a good point to start and you need to get rid of this setup any how, with an electrical vacuum pump you can test this fuel supply, as well as test the functioning of your Stewart, that's why I recommended to buy one.

[CalCadGuy]

I pulled the fuel pump and put in a new fuel line with a filter. Can anyone tell me what to look for in the vacuum tank that may be preventing it from functioning?

[houseboats1]

Hello Marc
When you are connecting or disconnecting lines or pipes or fittings are you using sealant? Don't rely on bsp fittings to seal or any of the piping to seal, every joint must have sealant. Also you said the vac tank has been rebuilt is it sealing properly? Also there is a small Bakelite flap inside the unit its on the bottom of the inner unit, the tank has two parts to it it has an inner and outer, if the flap is stuck it will run out of fuel, my car did this when I got it. You can pull the top off the vac tank by taking out the small screws around the top and pulling the lid off it should come out easily, check that the little flap is free and you have a good seal on top of the tank. I wish I lived closer to you but I'm 6k miles away. I'm sending some pictures.
Cheers

[CalCadGuy]

Ok, I'll look for the flap. Not exactly sure where that is, but I'll give it a try. I have all the vacuum lines installed as described in the shop manual and am pulling 20 on a vacuum meter. What type of sealant would you recommend? Also, do you have any pictures of the flap I'm looking for. Thanks Mark, Marc

[houseboats1]

Hello Marc
Sealant,  if you have an Auto parts store buy https://www.henkel-adhesives.com/au/en/product/thread-sealants/loctite_567.html this is all you need.  Make sure all your threads are sealed, Take all the pipes off the fittings and take the fitting out of the tank then clean them and replace them with sealant on them also pipes on the manifold try again now.I have loaded some pictures, see the Stuart Vacuum tank on the fire wall take the pipes off and all the screws out and lift the top off. Pull the tank out the flap is on the bottom of that tank.  You also mentioned you put a filter in the line, I assume that is the fuel suction line from the fuel tank. I'm not sure if you will have enough suction to pull through a filter, the system relies on a gauze filter in the fuel bowl on the bottom of the suction tank, so that may cause a problem it may not. You can email me at peakav@bigpond.com if you like