Avanti R1 fuel pump leaking out the top-revisited

[sbca96]

EDIT : 7/27/09 - to update picture locations.

EDIT : 7/20/07 see new post

EDIT: Was "63 Avanti fuel leak ... returned ... HELP!!!!!!"

Looks like my Avanti has a hobby of leaking fuel. I solved the leaks
at the input and output of the fuel pump, the leak from the return
line, and the leak from the tank. Now its leaking fuel out the top of
the fuel pump itself. There is an odd brass fitting that goes into
the upper half of the housing, and has threads to hook up "something".
Any ideas what is supposed to go here, and why it didnt leak before?
I think I will just remove it, and plug it, but I thought I was see if
it is there for a reason (usually things are).

Tom

[sbca96]

I went to Home Depot and bought a 1/8 square head pipe plug, slapped
some teflon tape on it, and plugged the stupid hole.

Here is what the fitting looks liek that was in the hole, with a thru
hole in it :





Tom

[gordr]

Tom, is your Avanti an R2?

Supercharged cars have a line that runs from the supercharger output port to the pressure dome on top of the fuel pump. What that does is adds supercharger pressure to the atmospheric pressure on the "air" side of the pump diaphragm. That ensures that fuel pump pressure always exceeds the ambient pressure within the carburetor fuel bowl.

Lacking that feature, fuel delivery to the carb could fall to zero under prolonged high-boost conditions. Can you say "melted pistons"?

If you have an R1 engine, plugging the fitting is OK. On an R2 or R3, it is critically important. (Whether the carb is in a pressure box, or pressurized via a bonnet doesn't matter; the supercharger pressure signal is present inside the float bowl, and the fuel pump HAS TO overcome that pressure in order to be able push fuel into the carb.)

Oops! Almost forgot to mention: if there is fuel leaking out of that fitting, which is on the "dry" side of the diaphragm, it tells me that your fuel pump diaphragm is shot, and you should be getting a new fuel pump sooner rather than later. Denied an escape path via the fitting, the fuel that seeps through the diaphragm is going to wind up the crankcase.

Hope this helps.

Gord Richmond, within Weasel range of the Alberta Badlands

[sbca96]

No, its an R1, so I guess its not needed then.

Thanks for the input! This is ALL I needed to give me the reason to
dump this mechanical nightmare, & put on a trouble free electric one.
I wasnt planning on doing it this soon, but I dont see another choice.
I already have the pump (from my 60 Hawk), so I just have to figure
out where to install it. I put the Hawk's pump in the front, & never
had a problem. The fuel was leaking out WHILE it was sitting. I had
nothing but trouble with the Hawk, until I put on the electric pump.

UNLESS, there is a rebuild kit available for these? I notice that it
DOES come apart, whats the success percentage for rebuild, if possible?

Tom

[sbca96]

Just checked Studebaker International :

1558925

1963-64 Lark, Hawk, & Avanti with Jet Thrust R-1 or R-2 engine ... 39.95 ea.

Since I JUST fixed the other fittings, I am tempted to keep the stock
pump, but what can I expect in rebuilding it?

Tom

[Mike]

If the diaphragm is leaking, gas can leak into the crankcase, or out into your garage. Either is pretty dangerous. Remember it's gravity flow to the pump from the tank.
That looks like a fitting from a hardware store. It sounds like you have an R2 pump. It's the same as an R1, except the housing is tapped to connect the back side of the diaphragm to the supercharger volute, instead of having a vent hole to the atmosphere. If you plug the tapped hole you should open up the other one.
I think the pump rebuild kits that the suppliers, (at least T-Bolt & SI), sell come from "The Old Car Parts Cellar". The kits contain a diaphragm made of modern materials that will resist the fuel additives now in use. Some parts are of different design than the original; but should work well. My first kit came from "SI" without instructions, and I thought I had the wrong one! You should use the heavier spring, from the original diaphragm, rather than the light one in the kit; if you want stock fuel pressure.
I don't use Teflon tape on cars. It always seems to find its way into oil or gas lines, and makes it too easy to over tighten tapered fittings and crack housings. Teflon tape is for plumbers, like that fitting!
The stock "R" pumps are a little hard to find, and not hard to rebuild.
Mike M.

[N8N]

The pumps are easy to rebuild, but I believe that you will need to find an R1 pump (or at least the top half of one) rather than just plug the hole in the R2 pump. The R1 pump has a different vent hole to allow the diaphragm to reference atmospheric pressure, which is not there on the R2 because of the supercharger. Alternately you could plug the hole *and* drill the vent but that sounds like a lot of work.

I wish I had a box full of fuel pumps and a digicam here so you could see what I'm talking about... the above probably doesn't make much sense without visual aids...

nate

--
55 Commander Starlight

http://home.comcast.net/~njnagel

[sbca96]

Wow ... and I was all set to order the rebuild kit. Now I think its
less trouble to just add the electric fuel pump and forget about it.
Its no wonder they dumped this crap later.[xx(]

I dont know what to do. Wife gave me the OK to order the rebuild kit.

Tom

[Roscomacaw]

Does she "OK" all your purchases?

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

[CHAMP]

Over one year and 6,000 miles with no fuel pump problems with electric pump on my 48 Champion. That might be the way to go for you Tom? Just my two cents worth of advise BTW I still love those seats! They even look more comfortable[8D]

GARY H 2DR.SEDAN 48 STUDEBAKER CHAMPION NORTHEAST MD.

[ROADRACELARK]

Tom,
If you're gona' "go electric", make sure you put the pump at the tank...they like to "push" rather than suck the fuel. Also, wire in an oil pressure cut-off switch for the obvious safety reasons.
Dan

[img=left]http://static.flickr.com/57/228744729_7aff5f0118_m.jpg[/img=left]
Road Racers turn left AND right.

[Karl]

Tom . If you got gas comming out of that fitting. You got gas in the Oil!It will need to be changed also!

[sbca96]

I JUST changed the freakin oil! Dammit, the bad news just keeps on
coming. I am swaying back and forth on electric vs mech pump. I JUST
got the fittings right, so I am tempted to fix the pump. How would I
have gotten an R2 fuel pump? It worked fine before, maybe I can just
put that fitting back in, with a line to it, that vents it down, that
way water can not get into it (probably what helped its demise). I'm
considering going for the kit, since I need headlight gaskets anyway.
I am waiting for word back from S.I. on the headlight gaskets. I am
not sure I want the can of worms of figuring out the return line deal
and how it will work with the electric pump. I have read that they
like to blow, and not suck, but the Avanti IS gravity fed pretty well.

Yes Biggs, it helps in a marriage if you run stuff past your wife.

Tom

[N8N]

Actually the R2 pump should be fine - so long as you do NOT plug the hole in it, and the stem seal is in good shape. If the stem seal fails, you will blow oil all over your exhaust manifold with smoky results (or at least that's the experience I had with my '55 when I tried a '57 Golden Hawk pump "in a pinch") The vent passage in the R1 pump is a little more convoluted - y'see that little hole drilled crosswise through the casting at the very top of it, near the "stem" part of the pump? On an R1 pump, there's a vertical hole drilled up through the casting parallel to the stem to vent the diaphragm. That vertical hole is not present on an R2 pump. So to turn an R1 pump into an R2 pump, you should really put a small pipe plug in the bottom of that vent hole to make sure you get full boost referenced fuel pressure. Likewise, to turn an R2 pump into an R1 pump you should drill that vent passage, if you are going to plug the R2 boost reference line fitting hole. Of course, if you did either of these mods, you would have a "universal" R-series fuel pump, that could be used on either a supercharged or nonsupercharged engine just by judicious adding or removal of pipe plugs. I *think* the diaphragm spring is supposed to be different between the two, but when it comes to rebuild kits, you get what you get- I think they're all the same now.

...and here I am sounding like an authority on fuel pumps, when I'm the guys whose car sounds like it's about to blow a rod because the @%#$%^ fuel pump is so loud. Well, I know SOME stuff, anyway.

nate

--
55 Commander Starlight

http://home.comcast.net/~njnagel

[N8N]

Oh, yeah, if you do go with an electric pump, you could either go to the later style inline filter with a return fitting on it and duplicate the later style return deal, or try to find a brass tee that would allow you to just keep it the way it is. The fuel pump goes near the tank, obviously.

nate

--
55 Commander Starlight

http://home.comcast.net/~njnagel