The Stovebolt Site Forums The Shop Area Engine Shop Dual Fuel Pump Plumbing Schematic???

Ok, I’m throwin’ in the towel, I give up. Been looking for a few days and again for the last couple of hours for anything that shows the vacuum line connections and routing for the dual fuel pumps. I’d swear that Timothy at the Stovebolt had directed me to that info a while back but I just can’t seem to find it. Might have been Gene over at the VCCA chatter but I never was very good at organizing my references. Heck, talk about disorganized, I worked with all my tools in a pile at the end of the work bench my whole adult life. My wife heard me cussin’ bout not being able to fine anything and she made me go out and buy a toolbox this summer.
Well anyway, my buddy wants to get his 1950, 216 running before the snow sets in so he can move things around in the garage. He decided to put a dual fuel pump on instead of the old single and I told him I’d help him.
I’ve looked thru every GM manual, document, bulletin, paper, etc., that I have for a schematic and nota. Anybody want ta help the old man out here, please????
Denny Graham
Sandwich, IL

Also, What could you do if you didn't want to hook up the vacuum section at this time? Thought about a couple of 1/8"-npt x 1/4" hose barbs and a hose connecting the outlet into the inlet or visy versy.

there should be a hose running from the wiper motor to the upper diaphragm, rear side, then another from the front of the upper diaphragm around to the intake manifold behind the carb. All the pump does is boost the vacuum from the manifold, so plugging the in and out temporarily should be ok. Make sure the vacuum created by the pump is flowing in the right direction, I learned from rebuilding my Buick pump that you can put it together backwards and it will not work.

I do not have the schematic but I can describe the layout in my 1952, which I think is stock. One line runs from the manifold vacuum port down to the fuel pump. My truck does not run but it would make sense that this would be the fuel pump port not producing vacuum. The second line goes from the fuel pump up to the wiper motor. These lines follow along the same course as the fuel line and distributor vacuum line. They are all tied together with a clamp at the thermostat outlet.

Chuck

Denny,

A hose from the side of intake manifold to In/Input side of pump; a hose from the Out/Output side of the pump to the vacuum motor.

Different pumps have different labels/words/markings on the ports, and I have dual-action pumps that have no labels/words/markings

Someone recently posted the logical way to determine how to hook up the hoses:

- Just do it; and, if necessary, re-do it (you have a 50-50 chance of getting it right the first time).

- leave both pipes/hoses at the pump disconnected and run the engine (plug the manifold port). With the engine running, see which port on the fuel-pump sucks (nothing personal). Connect the hose/line to the wiper motor to the sucking port on the fuel pump; the other port gets connected to the fitting on the intake manifold.

Did you rebuild your pump (if yes, tell us the story)?

Thanks guys, no Tim, I didn't rebuild mine, I've got a new one on the shelf that I will probably install when I finish the engine rebuild. Haven't started on that yet either, that painting thing has drawn everything to a hault for the last couple of months. Don't know what it will take to get me back on track. The pump in question is just a new one my bud is installing. He got PO because he was getting rust in the W-1 that I just rebuilt for him and he bought a new tank, fuel pump and glass filter and I'm running all new lines for him.
Well I guess I can finger it out without a picture.
Thanks again,
Denny Graham
Sandwich, IL

Denny, I have a GMC with factory duel pump for the wipers. Its cold, dark and rainy at the moment. If it's not covered with ice in the morning I will go look how the factory did it. If I can't get a decent picture, I will draw a schematic and email it to you.

Hey thanks a bunch Ken, I was asking over at the VCCA also but not geting a lot of responce yet. I think I worded something wrong and it was taken the wrong way and now I probably won't get any responces.
Should be relativly simple. I've seen a couple of instalations that simply ran hose barbs from the pump and then plumbed it in with vacuum hose the rest of the way. I'm sure the factory didn't send them out that way. Some where you have to make a transition to a rubber hose but the steel line has to be fastened down to the carb or manifold some way at the end.

Thanks and I really do appreciate it.
Denny Graham
Sandwich, IL

It turns out to look like a plumber's dream where they pass the thermostat housing. You end up with four lines including the fuel line and advance line.

Denny,

Here are three pages from the 47-55 Factory Assembly Manual - diagrams of the dual-action fuel pumps on various sizes of trucks:

Sheet 18.00 RPO 340

Sheet 18.00 RPO 340

Sheet 18.00 RPO 340

Here is my 54 233 with home-made plumbing of a dual-action fuel pump. I could not make out the the routing of the tubes on the 3000 series trucks, so I put one between the water pomp and water outlet .

That's the one I was thinking about Tim, thanks.
How in the world did you find that drawing? I thumbed thru the engine sections several times yesterday, never thought to look in the first section. The instruction index at the front is orful sketchy and not very reliable. With no real index every time I need to find something in that FAM I have better luck thumbing through every page till I run across what I'm looking for. I thought you had some pitures of you engine before you put the front clip on but spent literally a couple of days at your site and never ran across it.
In the end the illustration leaves a lot to question as to the routing and it looks like the vacuum line to the wiper is just left hanging in the breeze once it makes the bend and heads back behind the carb. I think I'm gonna fab some kind of bracket or clip to tie it to the vacuum advance line. At least then it won't be just laying there loose.
DG

The FAM takes some getting used to.

RPOs are listed near the front.

Someday, I'll take the time to make a table of contents (TOC). The organization of the FAM is logical but there is no TOC or index.

Originally flexible metal clips or "ties" (part number 3690306 - shown in the diagrams) were used to hold the various tubes that were routed between the valve cover and the thermostat housing. Over the years, I have collected those clips (I think I have seen them for sale, but I cannot remember where).

Yep that along with the Shop manuual was in the first order the week I brought the old gal home. I just never could figure out the logic behind it and I've alway felt there was something missing from the reprint.

We've got a few of the clips, I think he ordered them from Chevy Duty along with the new fuel pump. Thats what I was thinging of doing, running the line that goes back to the wiper motor parrelell to the vacuum adbance line and clipping them together at a couple of places.

Think we got it figured out thanks for the help.

Denny Graham
Sandwich, IL

Here they are, Chevs of the 40's, Can't believer the price they get fot them, $8.75 a pair. http://www.chevsofthe40s.com/detail..._VACUUM_LINES_TOGETHER_FUEL_PUMP_TO.html

Looks like something else I'll have to make up a little die for to form some of them up for my inventory.

Denny, curious how a person would make up these clips with enough tension to keep lines together but not so tight as to rub the lines together or so loose that they slide around? Thanks Don

Did you take a look at the link Don? the clips were a stock item on all the GM fuel/vacuum lines, the replacements are very close to the originals for once, but way way over priced in my opinion. With a couple of the clips installed on parralell lines the tubes won't slide around so I don't thing wear is a concern, never has been with any fuel/vacuum line I've seen.

I have a selection of blue-spring sheet that I stock for reproducing spring clips for my vintage radio/record player work. I'm going to try and make some of these up, hopefully I won't have to heat treat them. I've done that in the past but it's a hit or miss proposition. You can anneal the material for forming but re-hardening them often leaves them to hard, and they break. I've tried a number of ways of tempering them but I've yet to figure out a consistant way of drawing them back. Might help if I had a heat treat oven.

And yes, the easy way out would simply be to tie-wrap them, which accomplishes the same purpose, but that wouldn't look very original now, would it!
Denny Graham
Sandwich, IL

Don, the original ones did allow the lines to rub. However pickups were usually not driven enough to rub all the way through. On our gasoline delivery trucks that were driven a half a million miles with several engine replacements, we wrapped friction tape around them ever so often. We didn't want gas squirting around under the hood with 2000 gallons of gas behind the cab.