[xk] Fuel Pumps

After my fuel pump giving up the ghost a number of times ( always at the
worst possible time and at the worst possible place ) I have replaced it
with an electronic S U fuel pump conversion kit . It fits inside the
existing cap and is easy to fit. It can be obtained from Autoflux in the UK
( Phone 01579 320459 ) at 45 Pounds.

Roger Herrick

Thanks for the tips re the fuel pumps. I had a friend who was
transistorising his pumps (3.8 150 S) here recently and sent him a print
out of the web site article, so I hope he makes it work and translates the
article into Aus for me (i.e. local suppliers of the necessary parts etc).
In the meantime, I will keep thumping as required - the 120 has jammed
brakes too - damn! Regards, John Elmgreen

1 Like

The necessary electronic parts for the fuel pump are available at Dick
Smith Electronics in Australia and New Zealand.

The transistor and diode are as specidied in the Website article and the
transistors are catalogue number MJE2955T (PNP) for negative earth and
MJE3055T (NPN) for positivr earth. Total cost about $5.00.
Regards, Michael Standley

Michael S: Thanks for the tips re the transistor / fuel pump parts in
Sydney. I will pass the details on to Ian Hutchinson (XK150 S DHC 3.8).
Regards, John Elmgreen

Dave,
The points gap is not critical like a distributor, but they should click
open and click closed, actually it is a throw-over lever action. If they
don’t throw over, your diaphragm is screwed in too far or not far
enough. Years ago I wrote a spiel about how to rebuild these things,
which should be in the old jag-lovers archives somewhere, and I know
others have also written things about it. The subject seems to come up
every few months.

There is a scheme for converting them to transistorized electronic
operation in the library of the xk list, which I have done on about 12
pumps and am very happy with. New pumps from our favorite vendors I
believe have some variation on this same idea, though perhaps more
professionally done.

Most of you probably already know there is a filter inside the pump. You
get to it by taking off the bottom cover.

PS for Dick, I’ve had a valve in my fuel line for 12 years, and I
suspect the reason I’ve never needed it is because it’s there. :wink:

Rob Reilly

R,J,G&KReilly - I have searched the archives, but am unable to find any
info on
fuel pump rebuilds. I know the “throw over” action you speak of, but to
achieve
this the diaphram is barely screwed in, and yes, it is the correct
length as compared
to the original. What is different, however, is the thickness of the
steel parts that
actually hold the diaphram…the new one is thicker, and I am led to
believe that
there are only two models of this diaphram. The only way I can get the
points to open
is if I screw the diaphram in completely, and even in that state, they
only open when
the diaphram is pushed into the “solenoid” - and there is no “throw
over” action.
Dave Goard
S811784

Rob - and others interested in this thread.

I have found with SU Fuel Pumps it is important to note the DATE-CODE of the
actual pump before being confident pump is in fact original to car it is now
fitted to, as over the past 50+ years many a fuel pump is easily/often
replaced. With Carburetters this is not often the case, but even so I
still check their date-code stamping.

LCS fuel-pumps as used on all XKs, as well as Mark 1, 7, 8 and 9 and Mark 2
saloons up to May 1964 all have a common die-cast aluminium BODY which is
readily identified with the number 4644/1 cast onto the top-left corner of
the coil-housing face. 4644/1 is the SU part number for just the body
casting, not the complete pump, thus some confusion in the Jaguar Spare
Parts Catalogues - its always more accurate to reference the SU Catalogues
than the simplistic Jaguar ones.

Initially the bodies were fitted with two 3/8" high aluminium die-cast LIDS
AUA4645, but from 1962 onwards these were superseded by shaped pressed-steel
LIDS made from 0.048" thick mild-steel. An LCS fuel-pump with pressed-steel
lids is invariably ex a 1962-64 Mark 2 saloon, but date-code will be exact.

When fitted with the cast-aluminium lids, one lid only received a YM
date-code stamp on a short-side. When the pressed steel lids were fitted
the date-code was now stamped directly onto the 4644/1 body casting.

It is possible to mix and match Lids to Bodies, just need the correct length
Cheese-Head Setscrews to suit aluminium or steel LID, so be interesting to
look for a date-code on your ex-Mark 1 Pump. Maybe it’s the original Pump
that for some reason has had replacement Steel LIDS fitted, or more probably
it’s a Pump originally fitted to a 1962-4 Mark 2. If no date-code on body,
tells you it originally had aluminium LIDS, but if date-code is on the body,
what date-code is it?

Roger Payne - XK140MC OTS; E-Type 4.2 S.1 OTS; DSV8.
Canberra.-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
Rob Reilly
Sent: Wednesday, 9 July 2014 10:06 AM
To: xk@jag-lovers.org
Subject: RE: [xk] XK120 Assembly coming along

In reply to a message from Rob Reilly sent Tue 8 Jul 2014:

I think it is more accurate to measure the body of the coil
from the flange base where it meets the valve body to the
step where it meets the Bakelite cap.
The pumps from my 1950 Mark V and 51 XK120 and a spare
removed from a derelict Mark 1 all measure 2-7/8’’ (73mm)
flange to step.
The pumps in my 74 XJ12 measure 2-1/4’’ (57mm) flange to step.
I have not seen any other coil sizes than these two.

The Mark V and 120 pumps have cast aluminum covers.
The Mark 1 pump has stamped steel covers.
The XJ12 pumps are double pumpers on round valve bodies.


The original message included these comments:

I am away from my garage, but when I get back I can measure
the long and short versions of the fuel pump coil body.


XK120 FHC, Mark V saloon, XJ12L Series II, S-Type 3.0
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Rob,

Thanks for reference to Clausager report of the Earls Court XK120 prototype

  • I knew I had seen such a reference.

Other research I had done implied/said that the LCS fuel pump was
specifically developed by SU for Jaguar for the XK120, as during development
the previously best available SU fuel-pump options were not up to the
pressure/volume requirements of the XK engines 160 hp.

Post war SU offered their basic LP (Low Pressure) pump (with a short-coil
housing on a Round-body) and a HP (High Pressure) pump (with a long-coil
housing actually with a cast HP on its flange, using the same Round-Body).
They also offered a dual-HP pump with a single Round-body but now having two
HP coils attached one either side of body. Now this is what I presumed was
fitted to the prototype XK120 rather than two individual HP pumps plumbed in
parallel - although maybe Jaguar experimented with both. Any known pics -
again I am sure I have seen somewhere!

Whatever, nothing was suitable, thus SU developed their LCS
(Large-capacity-Single) pump which used the identical HP coil, but mounted
on a newly designed square-body that gave increased fuel volume at the same
HP coil pressure - clearly now suitable for the XK120, thus adopted across
the Jaguar range.

So that must fit in with timing of Mark V build - do you have a date of
first and 121st Mark V build? (Alan Crouch’s new book may touch on subject

  • havnt checked)

But one other loose end I would like to chase up is that all LCS pump bodies
I have seen have part number 4644/1 cast on face. Presumably there was a
4644 body prior, but I wonder whether a prototype that never saw a
production XK120 or Mark V, or maybe a few early build cars. Haven’t had
chance to look that closely at any 1948/9 build XK120/Mark V.

Roger Payne - XK140MC OTS; E-Type 4.2 S.1 OTS; DSV8.
Canberra.-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
Rob Reilly
Sent: Wednesday, 9 July 2014 10:25 AM
To: xk@jag-lovers.org
Subject: RE: [xk] XK120 Assembly coming along

In reply to a message from Roger Payne sent Tue 8 Jul 2014:

Hi Roger,
PP31 was specified for Mark V after 121 saloons had been
built, so presumably late '48 or early '49. I’ve never seen
monthly production figures for these.
So depending on whether the Earl’s Court 120 was a running
car or just a shell, not forgetting that Clausager reports
this one as having 2 pumps on the scuttle, you’re probably
right.

The original message included these comments:

Single) fuel pump was first introduced (as far as I can establish its
first
application was for the first aluminium XK120 with the then range of LP,
HP
and Dual-HP SU pumps not suitable) the SU part number was actually PP.31
(Petrol Pump No.31) which is why PP.31 is shown in the XK120 Spare Parts


XK120 FHC, Mark V saloon, XJ12L Series II, S-Type 3.0
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In reply to a message from Roger Payne sent Tue 8 Jul 2014:

Roger,

What is the YM code explanation for K 6 stamped on the
short side of the top aluminium lid on one of these pumps.

Pump is a 4644/1 L

Paul Gavaza–
The original message included these comments:

Rob - and others interested in this thread.
When fitted with the cast-aluminium lids, one lid only received a YM
date-code stamp on a short-side. When the pressed steel lids were fitted


S674106
Cohasset, MA, United States
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G’day Paul,

From what you have just advised, I can identify your Fuel Pump as being an
S.U model LCS as identified by the 4644/1 SU part number that is cast onto
the main body of an LCS model pump. The 4644/1 is the part number of just
the aluminium body and not the total fuel-pump ( I don’t know significance
of the “L” underneath the 4644/1 but its always there)

The K6 is the date-code for when the fuel pump assembly was completed by SU,
thus before delivery to Jaguar to use. In this case K = 1953 and 6 = June,
so your LCS fuel pump was made in June 1953.

In June 1953 SU was only making LCS model fuel pumps to their specification
AUA31 (under their new terminology or specification PP31 under the older S.U
terminology - PP = Petrol Pump).

Your car S674106 has a build-date of early July 1953 (don’t know day, but
10th LHD OTS built in July), so that is totally consistent with your June
1953 dated fuel-pump being your XKs factory original.

What I cannot confirm is whether your fuel-pump remains it its original
condition or not, as these pumps are fully rebuildable with use of either
original parts or later upgraded/revised parts.

An LCS model fuel pump to AUA31 specification was originally fitted with
SINGLE-CONTACT-POINTS however these were discontinued in about 1955 and
updated with 100% interchangeable DOUBLE-CONTACT-POINTS, thus the otherwise
exactly the same LCS fuel-pump assembly was now considered to be to AUA57
specification (this format now well established, so never to the older PP
format).

If your fuel pump has had new points fitted at some time in its life (common
maintenance job) then it will probably now have DOUBLE-CONTACT-POINTS
fitted, but you never know - you do still see AUA31 specification fuel-pumps
still with their original Single-Contact-Points. (Personally, as points
are hidden under the Black Cap and cannot be seen and in operation SOUND the
same, I would prefer having better functioning Double Contact points fitted,
a product improvement made by SU in 1955.)

Otherwise the AUA31 or AUA57 SU model LCS fuel-pump continued unchanged for
the rest of XK120, XK140 and first few 1957 XK150s, with the only
identifiable variable being the YM date-code stamped on the short-side of
one cast-aluminium end-LID.

But as noted previously, the original ‘long’ COIL BODY can be replaced with
a post 1960 ‘short’ COIL BODY, the two cast-aluminium LIDS can be replaced
with the post 1962 pressed-steel LIDS, and the FLAT-BLACK CAP can be
replaced with the STEPPED-BLACK CAP from a post 1957 AUA52 specification
fuel pump as fitted to XK150 1957-60. There were 6-volt versions of these
LCS fuel-pumps identifiable externally by having a BROWN CAP instead of
BLACK.

Sorry to be long-winded to your simple question, but there is some general
interest in this subject.

Roger Payne - XK140MC OTS; E-Type 4.2 S.1 OTS; DSV8.
Canberra.-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
etype38
Sent: Thursday, 10 July 2014 7:09 AM
To: xk@jag-lovers.org
Subject: Re: [xk] Fuel Pumps

In reply to a message from Roger Payne sent Tue 8 Jul 2014:

Roger,

What is the YM code explanation for K 6 stamped on the
short side of the top aluminium lid on one of these pumps.

Pump is a 4644/1 L

Paul Gavaza

The original message included these comments:

Rob - and others interested in this thread.
When fitted with the cast-aluminium lids, one lid only received a YM
date-code stamp on a short-side. When the pressed steel lids were fitted


S674106
Cohasset, MA, United States
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In reply to a message from Roger Payne sent Wed 9 Jul 2014:

Thanks very much, Roger. Excellent information.

It appears, based on your info that it is the original pump,
although with replacement double contacts.

I have been recording all possible dates of fitted equipment
and so far it is all dated within a few months prior to July
53, except brake drums which were cast in Oct 52.

The Heritage Certificate indicates 2 July as the build date
and 15 July as the dispatch date. From there I loose track
until my friend traded in her TC for it in July 55, in Boston.–
S674106
Cohasset, MA, United States
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In reply to a message from etype38 sent Thu 10 Jul 2014:

The pump that was on my Mark V when it came to me in 1969 is
stamped with a number 2 on one of the aluminum end covers
but no letter. The body has 4644/1 and L below that. The car
dispatch date is 18 April 1950.

( I don’t know significance of the ‘‘L’’ underneath the
4644/1 but its always there)

The derelict car my spare pump came from could very well
have been a Mark 2, as that was 30 years ago and it was
stripped out, not much left. There is nothing on the body
except 4644/1 and a very faint L. Nothing on the steel end
covers.

The pump currently installed on my XK120 has what may be N6
or Z9 or G2, attempting to read it with a flashlight and
mirror. I may have to take the floor out to read the thing.–
XK120 FHC, Mark V saloon, XJ12L Series II, S-Type 3.0
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It gets difficult with Fuel Pumps, especially if installed.

The nature of the two END-LIDS means they can be interchanged and rotated,
but the best I can establish is that when you look at the main-body with the
COIL-CAP in front, and the TOP on the pump body on top, the BOTTOM LID has
no stampings anywhere and the TOP LID has the date code stamping on the
short-side positioned to the RIGHT side.

This way around - on an XK140 (at least) near impossible to see mounted on
the chassis bracket, and sounds no easier, maybe harder with an XK120 being
inboard of frame.

But as above, very easy now with a used pump to swap LIDS around during
maintenance/restoration, albeit originally the pump was assembled with both
LIDS unstamped, and the date-code then stamped onto that right-short-side on
the top-lid as a matter of easy and consistent process.

Rob - just a ‘2’ - my guess is for some reason the letter ‘F’ stamp was
lost/mislaid - with F2 or sometimes 2F denoting Feb 1950 being totally
consistent.

Not saying my theory on number codes is yet 100%, with still mystery over
significance of letter ‘Q’, and I also have a pump with 2MD stamped on it,
so no idea what MD means either.

Still have not located any definitive/explaining SU documentation on this -
more an idea I fell onto, worked out a code significance, and now several
years of sightings/reinforcement. I did find eventually find one later SU
reference to X = 1961 in a 1961 SU publication, so at least that is one
confirmation of their being a date-code.

Roger

Roger Payne - XK140MC OTS; E-Type 4.2 S.1 OTS; DSV8.
Canberra.-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
Rob Reilly
Sent: Monday, 14 July 2014 11:47 PM
To: xk@jag-lovers.org
Subject: RE: [xk] Fuel Pumps

In reply to a message from etype38 sent Thu 10 Jul 2014:

The pump that was on my Mark V when it came to me in 1969 is
stamped with a number 2 on one of the aluminum end covers
but no letter. The body has 4644/1 and L below that. The car
dispatch date is 18 April 1950.

( I don’t know significance of the ‘‘L’’ underneath the
4644/1 but its always there)

The derelict car my spare pump came from could very well
have been a Mark 2, as that was 30 years ago and it was
stripped out, not much left. There is nothing on the body
except 4644/1 and a very faint L. Nothing on the steel end
covers.

The pump currently installed on my XK120 has what may be N6
or Z9 or G2, attempting to read it with a flashlight and
mirror. I may have to take the floor out to read the thing.

XK120 FHC, Mark V saloon, XJ12L Series II, S-Type 3.0
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Greetings. What is this from? It came in my XK120 box of parts? Thanks.

john


Small capacity, too small for a Jaguar or any 6 cylinder car, I think it is a model AUF 300 or 400 or 500, probably for 4 cylinder cars such as MG etc.
If you find an AUF number on it we can probably figure out what it came from.

It is an AUF300 series pump. Zooming in it looks like tag reads AUF301, but it has later smoothing mechanism found on AUF303 and on.

These 300 series pumps replaced the LCS pumps during mid 60s Jag production. Also used on many other british makes.

Regards,
Clive.

Thanks Clive, I learned something new.

Thanks Clive. Th e tag does say AUF301.
How does the diaphragm come out? I would like to take it apart and rebuild it and utilize it on the XK120. Thanks for any help.

john

Hi John,

Take a look here: Fuel Pumps. It has all the original SU docs for each pump type. Lots of other original docs on that site, such as from Lucas.

I have used https://su-rebuilders.com/ to buy parts and rebuild kits several times.

They are easy to rebuild, and not as complicated as they look.

Regards,
Clive.

Also, if you are patient, you can get rebuildable square body fuel pumps on popular auction site for under $100.

Oh, and yes, the AUF300s are a drop in replacement, they have the same mounting geometry as the square bodied pumps. (Well I know of one exception to this in the XK range!?)

Regards,
Clive.