• Welcome to the new SAOCA website. Already a member? Simply click Log In/Sign Up up and to the right and use your same username and password from the old site. If you've forgotten your password, please send an email to membership@sunbeamalpine.org for assistance.

    If you're new here, click Log In/Sign Up and enter your information. We'll approve your account as quickly as possible, typically in about 24 hours. If it takes longer, you were probably caught in our spam/scam filter.

    Enjoy.

Stock mechanical fuel pump adequate pressure for Weber 32/36 DVG 5A?

M

Mbgardner

Bronze Level Sponsor
I have the DGV 5A Weber 32/36 part no. 22680.005. don't know from where i bought it a while ago.
am having and have always had the flat spot on acceleration, not off idle but at cruising and wanting to accelerate therefrom.
have rebuilt it twice. set the floats at least 3 times. Take an hour or more to get the carb and back on because of the nuts/stud accessibility.

The last result: car started, ran fine and idled fairly well after warm up. Looking down the bowls at idle, could see fuel droplets landing on the throttle plates roughly in equal proportions

After fully warming up the car and depressing the accelerator linkage a few times I shut off the car and observed fuel vapor arising in the primary barrel and gasoline almost pouring into the secondary at a steady rate for some time. I note the car would often take longer to start after driving it warm. This is all being done in my garage as we have 10” of snow on the ground.

Talked to someone at Redline and pierce Manifolds leading me to believe fuel pressure may be the problem and needs to be addressed first. Hence my question posed in the title of this thread.

I have read and heard from others (RootesRacer) that the stock pressure is about 1.5 - 2 psi, leaving me to scratch my head while i ponder how to post links to my videos of the above described observation and how to fix my problem

Weber at idle

Weber afterglow
 
Mbgardner said:
I have the DGV 5A Weber 32/36 part no. 22680.005. don't know from where i bought it a while ago.
am having and have always had the flat spot on acceleration, not off idle but at cruising and wanting to accelerate therefrom.
have rebuilt it twice. set the floats at least 3 times. Take an hour or more to get the carb and back on because of the nuts/stud accessibility.

The last result: car started, ran fine and idled fairly well after warm up. Looking down the bowls at idle, could see fuel droplets landing on the throttle plates roughly in equal proportions

After fully warming up the car and depressing the accelerator linkage a few times I shut off the car and observed fuel vapor arising in the primary barrel and gasoline almost pouring into the secondary at a steady rate for some time. I note the car would often take longer to start after driving it warm. This is all being done in my garage as we have 10” of snow on the ground.

Talked to someone at Redline and pierce Manifolds leading me to believe fuel pressure may be the problem and needs to be addressed first. Hence my question posed in the title of this thread.

I have read and heard from others (RootesRacer) that the stock pressure is about 1.5 - 2 psi, leaving me to scratch my head while i ponder how to post links to my videos of the above described observation and how to fix my problem

Weber at idle

Weber afterglow
Click to expand...
Afterglow: worn float needle, bad float level ?
 
I'm running stock zeniths so not familiar with that carb .. and temporally running a electric fuel pump while I wait for a rebuild kit for my stock mechanical one. It's a Edelbrock with 2.5-3 psi and I have no problem so it might not be psi. How old is the carb you have? .. maybe some crud is blocking one of the passages, jets or as Thor pointed out worn parts ... just a thought ... Someone with more knowledge/running that carb setup might of had the same issue and will chime in.

......... David
 
I've used many stock fuel pumps with 32/36 Webers with no issues what so ever. Never had a fuel
starvation or flooding issue. Had flooding issues when I used electric pumps. For those I needed
a regulator.
 
Mbgardner said:
have rebuilt it twice. set the floats at least 3 times
Click to expand...

Mbgardner,

The parameters the carb is designed to operate under seems to indicate you have about about three unrelated issues; calibration, heat, maybe pressure.

The transitional flat spot is generally considered to be a lean idle jet unable to supply enough fuel to cover the transition between the idle circuit into the main discharge circuit. Stepping up the size of the primary idle jet two or three sizes usually improves that issue.

The following presumes you have the float correctly adjusted.

By design, there should NOT be any fuel coming from the main discharge outlets at idle. To have fuel discharging from the main outlets at idle indicates a very high fuel level in the bowl. Now, determining why the level is high is the challenge. If you were to measure your pump's pressure - and you should, I'm almost certain you'll find the pressure is too high because of your two videos. Your fuel appears to be boiling some where in the system - probably the float bowl. That's about the only way to have fuel move through the system while the engine is NOT RUNNING. If you don't have the heat insulator gasket between the carb and manifold, you certainly need one. If you do have that insulator in place, you should start thinking about adding a second insulator and heat shield between the carb and exhaust. That will almost certainly require new, longer studs but will go a long way helping to keep the carb body cooler.

Another possible issue is if your float has absorbed fuel and doesn't float with the correct buoyancy to close the needle valve with authority - replace the float. I think Weber has different size needle valves for the DGV series carbs. If so, You might consider using a size smaller needle valve. That would allow the float to more positively close the needle valve. This is a "band-aid" and might restrict the upper rev ranges by not allowing enough fuel flow and leaning out the engine at high RPM's - bad JuJu.

Just a few thoughts,
 
Thanks Don: Points well taken.
I spent the last half hour or so running down heat insulator manifold gaskets. I see Redline suggests they have one made of soapstone but not for the DGV. I see 7mm and 14mm plastic ones. Redline describes a 20MM but the part no. relates back to the 14MM. Pierce Manifolds describes the same one as 12mm. I see some stud kits. . Looks like I have at least 3/8" inch of thread left on my studs, so 7mm should work. Nothing other than the base gasket in place.
  1. Is there a source for the heat insulation gasket to which you refer?
  2. How thick is it?
  3. Will the 7 or 14mm gaskets cause clearance issues with the bonnet?
  4. Are you suggesting if I had a 7mm gasket in place, i should add a second or just go with the 14mm?
  5. Is there a heat shield between the intake and exhaust manifold? Was always bothered about having the carbs sit over the exhaust, especially with the strombergs.
Will check the fuel pressure.
Floats are brass and not leaking the last time we had it apart.
Have rebuilt the carb with a kit. So needle valve (and seat?) have been replaced. Don't need more bad juju.

Seriously, thinking about buying a new one for a Toyota Pickup on ebay and putting my manual choke on it. Any reason that wouldn't work?

Thanks for now.
 
Mbgardner said:
  1. Is there a source for the heat insulation gasket to which you refer?
  2. How thick is it?
Click to expand...
Just what the usual suppliers have to sell.

I would recommend the thickest you can install.

Mbgardner said:
Will the 7 or 14mm gaskets cause clearance issues with the bonnet?
Click to expand...
I'm fairly certain no clearance issues at those sizes, but to be certain, you could check with a cone of modeling clay on the air filter.

Mbgardner said:
  1. Are you suggesting if I had a 7mm gasket in place, i should add a second or just go with the 14mm?
  2. Is there a heat shield between the intake and exhaust manifold? Was always bothered about having the carbs sit over the exhaust, especially with the strombergs.
Click to expand...
TTBOMK, Rootes never made or offered a heat shield for an Alpine engine. Why would they think a heat shield was needed if the manifold is heated by the cooling system?

If you feel the need for a heat shield, then you will need to fabricate one to your liking. Since there isn't a convenient way to mount a shield, my thought was to use an extension of the shield to mount on the carb mounting studs, between two insulators and needed gaskets. The insulators require a gasket on both sides to effectively seal.

As far as your thoughts about replacing your carb with the one linked, you're free to do so if you wish, but comments in some reviews I saw when those first became available were certainly not inspiring. Things may have changed, but I doubt it. In a nutshell, those carbs DO NOT have the name WEBER on them anywhere. They are an offshore, reverse engineered unit of a Weber design with no parts interchange ability, no tuning or repair parts seem to be available. If an issue is found, then you end up with a replacement unit - they are effectively disposable.

Hope this helps,
 
Thank you. love the idea about modeling clay. Just have to find some. May have some old plumber's putty around.
 
So I have about 1.5" above the air cleaner to the underside of the hood above my weber 32/36 DGV 5A.
It's a 37 degree F heat wave here before the polar vortex, so I decided to test out my new 1-15 PSI fuel pressure gauge, before doing anything else to the carb in regards to installing a 1/4" spacer w/gaskets I found or heat shield etc.
Started fine idled under choke until operating temp achieved. Fuel pressure steady in the +3 -4 psi range. Occasional slight drift over 4, never 4.5, under varying degrees of acceleration or coasting in the garage. Never accelerated enough to open the secondary throttle plate.

VIdeos posted before tell the same story. Much more fuel seems to be flowing into the secondary while idling, especially so after shutting the car off.
With attention paid to the temperature/feel of the intake manifold and float bowl, by hand, the manifold barely got warm by the time I shut the car off and the float bowl was always notably cool to the touch.

Hoping nobody will tell that the fuel pressure is too high and that's my problem and get a regulator and/or electric fuel pump.

Without further feedback, i intend to remove the carb and revisit the float settings (open/closed) and the needle valve and seat. And depending on what we find, if nothing is out of whack, serioussly cut backon teh float level when open and increase the pressure/weight of the float on close. Try again and refit the spacer.

Looking forward to any replies.
 
From my own experience 1.5 - 2 psi is more than adequate for the 32DGV (normal road use).

You're looking at almost twice this pressure. If you have the standard mechanical fuel pump, the way to adjust fuel pressure is by adding or subtracting spacer gaskets at the pump mounting flange, as per the WSM.

FWIW, living down under its common to have daily temps in the 30 - 40 degree C range (37 at the moment) ; I've never had the need to fit insulated carb base gaskets.
 
Thanks BeamDream. So I didn't bother checking the shop manual until just now. The manual says to check the pressure at the pump disconnected from the carb with a gauge and rotate the engine on the starterto compare with the Tech Data spec of 1.5-2 psi. I just hooked my gauge up in line at the carb and ran the motor, .monitoring it through idle, warm up and acceleration by hand on the throttle rod.
I guess that's what I ought to do before adding packings to reduce the pressure. Thoughts? Do packings equal paper base gasket in the queen's english?
 
Mbgardner said:
I guess that's what I ought to do before adding packings to reduce the pressure. Thoughts? Do packings equal paper base gasket in the queen's english?
Click to expand...

Yes, the paper gaskets.

WSM 124 also includes a comment about the pump diaphragm hardening due to age and causing higher pressure.

If you are removing the pump, it might be a good idea to replace the diaphragm before adding more gaskets, unless you have a good idea on the history of the pump.

By the way, online information seems to be the WEBER should have a MAXIMUM fuel pressure of 3 PSI.

Just a thought,
 
Good to note. Do you think I need to measure the fuel pressure at the pump on just the starter? Do you think I can do that just by plugging the outlet of the gauge I have fitted to the carb in place now? Or do you think I need to move it down to the level of the fuel pump so its not pumping up hill (i.e., lowering the head on the pump). At such low pressures it seems to me that these slight refinements might matter.
My configuration is this: long fuel line from pump to about 4" from carb inlet. Tee'd into gauge and short line to carb.
So, query, should i just cap it at the carb end? Or move the whole hose down to the pump level? Or just remove the T from current position, plug the end and connect short hose at the pump?
Again, your input is welcome and appreciate.
Cheers!
 
You're overthinking measuring fuel pressure, it can be done on the bench using the priming lever if needs be; read the WSM again.

If the pump's still on the engine put the pressure guage on the outlet, use a catch can, motor it over. (disable ignition)

If you have it removed, its always good to fit a new diaphragm kit.
 
Mbgardner said:
should I just buy the repair kit from SS
Click to expand...
beamdream said:
You're overthinking measuring fuel pressure
Click to expand...

For right now, just think of pulling the pump as a next, but probable step.

For testing fuel pressure, where you've got the test rig currently, is workable.

The current program is the supply correct pressure to the carb, not if the pump is blueprinted to factory specs. The installed Weber isn't a factory carb selection, so the spec for the Weber probably doesn't exactly match the carb(s) which were originally installed.

Okay, intuitive deduction time - also known as time for guessing games. LOL

You stated the manifold and carb didn't become hot enough to boil fuel to your touch. Yet, you continued to have fuel delivery and overflow from the secondary main circuit delivery orifice after shutdown. (There should NOT be any fuel delivery from that orifice unless enough vacuum is induced in the secondary's auxiliary venturi to actually pull fuel upwards from the correct float bowl fuel level below the level of the gasket between top cover and body.) If fuel isn't boiling and causing pressure in the carb or fuel pump, then it's possible the pump lobe on the camshaft stopped with the pump spring partially compressed which would need to release the spring pressure before all flow would halt if the needle valve doesn't seal.

Wild guess question > IF your garage started at 37*F, did you heat the space before you started testing your Alpine? Or heat the car some other way before your test session? IF SO, then check the tank cap to see if the vent is operational. This is just a possibility and doesn't cover all bases.

Now, we have deduced a supply issue causing bowl fuel level too high or, the needle valve doesn't seal ALL fuel flow.

IIRC, the needle seat should have one or two gaskets between the seat and the carb cover - supplied in kit and help with float adjustment.

When adjusting the float level, make sure the float doesn't hit the cover before rising enough to seal the needle, and the needle tang should not hit the seat base before sealing the needle.

Check for trash in the cover's passage to the needle seat.

Just a few thoughts,
 
So it seems like removing the fuel pump and rebuilding with kit is the way to go first. And then test the pressure (optionally). then go trhough the Carb again as suggested by husky driver.
If the rebuilt fuel pump doesn't take care of this, I'm very tempted to offer it up for parts and get a new one for ~300 USD. That hardly covers all of the fun i've had over the years futzing with this used carb I bought so long ago from some where i long ago forgot. This is getting as old as I am.
Note the uninsulated garage was heated just to the take the chill off. Maybe got to 50 degrees F Fitted the gauge and then opened the garage door 1/2 way to vent exhaust.
Is there a test procedure for the gas cap?. Never impressed me as anything i could put faith in as providing a pressure seal I thought it at most might prevent spillage if filled to high going around a corner.
Thanks
 
The cap test is VERY complicated.
Start car and warm up.
Shut down car and observe fuel leaking out of the jets into the manifold.
Remove gas cap.
Observe carburetor.
Fuel flow stops. Tank was pressurized and not venting.
Fuel continues to drip. Tank venting is NOT the issue. Keep looking.
 
Put enough gaskets on the fuel pump to get the pressure down to around 2 psi.

I read you changed the needle but did you also replace the seat? Your video looks like this is the culprit due to too much fuel pressure that has toasted your previous needle and probably now the new one too. I would replace the new needle and seat with quality ones just because I'm paranoid and test the float separately in a cup of gas to make sure it does float too.

If rebuilding the fuel pump brings no joy, get a new 'modern' mechanical fuel pump from Classic Sunbeam. I rebuilt one and it started leaking and getting goofy, so I swapped it in. $45 plus tax and shipping. Nothing but joy so far.

For all things Weber, order from Pegasus.

I'm running the thickest Phenolic spacer they make and with gaskets and the 1-7/8 air cleaner and ZERO issues after YEARS of wrestling with it due to issues that weren't from it or that caused issues with it. Car runs GREAT now and I'm nothing but happy. Once you got it running right, you'll never look back.

I also run a psi gauge on the line from the pump to carb as well.
 
You must log in or register to reply here.
Back
Top