Fuel Sender for 1994 K-series Caterham 7
Discussion
Hello
I need to replace the fuel sender from a 1994 K-series Caterham 7, but it's proving frustratingly difficult tracking down the source of this part - given the age of the car and the fact that it has a K-series engine, I suspect the sender may be from an MG-Rover vehicle, but if so, I've been unable to identify which.
Some details of the old unit as removed from the tank, as follows.
Critical Dimensions (nominal and approximate):
Mounting flange bolt pattern: 6 off Ø5mm holes on a 60mm PCD (maybe 2.375” PCD)
Float arm length: 120mm
Vertical distance of float arm pivot below mounting flange: 115mm
Markings on Rheostat Housing:
7 30 33
824 / 10 / 4
11 93 38 / 5 26
Can anyone identify this part? If not, is there a good, compatible alternative?
I need to replace the fuel sender from a 1994 K-series Caterham 7, but it's proving frustratingly difficult tracking down the source of this part - given the age of the car and the fact that it has a K-series engine, I suspect the sender may be from an MG-Rover vehicle, but if so, I've been unable to identify which.
Some details of the old unit as removed from the tank, as follows.
Critical Dimensions (nominal and approximate):
Mounting flange bolt pattern: 6 off Ø5mm holes on a 60mm PCD (maybe 2.375” PCD)
Float arm length: 120mm
Vertical distance of float arm pivot below mounting flange: 115mm
Markings on Rheostat Housing:
7 30 33
824 / 10 / 4
11 93 38 / 5 26
Can anyone identify this part? If not, is there a good, compatible alternative?
Thanks for the swift response, but I'm okay for a pump (I managed to track down a complete "New-Old-Stock" pump assembly from Rob at Boss Racing).
It's the fuel sender unit I need - It sits in the top of the tank and consists of a float-operated lever arm, operating on a rheostat, such that resistance measured is proportional to fuel level. As I mentioned in my original post, its probably a standard part from an MG-Rover, but I can't trace which.
It's the fuel sender unit I need - It sits in the top of the tank and consists of a float-operated lever arm, operating on a rheostat, such that resistance measured is proportional to fuel level. As I mentioned in my original post, its probably a standard part from an MG-Rover, but I can't trace which.
Hello Bert!
Yes, I plead guilty to being “Laurence of Clubsport fame”, though I think “fame” might be overstretching it a bit!
It was my involvement first in Formula Ford and then in 750MC Bikesports with the Radical Clubsport that led to my little Caterham falling into neglect. It’s been stored under a car cover in a dry garage unloved for the best part of two decades, but has now become the subject of efforts to bring it back to life, get it through an MOT and then back on track (just for track days - not racing).
Despite the passing years, it’s mostly faired pretty well in hibernation – with the exception of the inside of the fuel tank, the pump and sender unit being caked in corruption and corrosion! I’ve given the tank a good soapy high-pressure jet washing and have managed to source a new pump assembly, but am stuck for a fuel sender unit – hence my cry for help.
Regarding the fuel sender unit and to clarify my description of “Vertical distance of float arm pivot below mounting flange: 115mm”, the float arm pivots at a point low down on what I’ve called the “rheostat housing”, which is basically a sheet-metal box (housing the rheostat), spot welded to the strut that projects down from the mounting flange. This point, about which the arm pivots, is about 115mm below the bottom face of the mounting flange. The float arm will then sit at a fairly shallow angle (about 20deg), with the float sitting on the floor of the tank when empty.
Hopefully this will make a bit more sense (perhaps?), but if not, I’ll try to upload some pictures.
Yes, I plead guilty to being “Laurence of Clubsport fame”, though I think “fame” might be overstretching it a bit!
It was my involvement first in Formula Ford and then in 750MC Bikesports with the Radical Clubsport that led to my little Caterham falling into neglect. It’s been stored under a car cover in a dry garage unloved for the best part of two decades, but has now become the subject of efforts to bring it back to life, get it through an MOT and then back on track (just for track days - not racing).
Despite the passing years, it’s mostly faired pretty well in hibernation – with the exception of the inside of the fuel tank, the pump and sender unit being caked in corruption and corrosion! I’ve given the tank a good soapy high-pressure jet washing and have managed to source a new pump assembly, but am stuck for a fuel sender unit – hence my cry for help.
Regarding the fuel sender unit and to clarify my description of “Vertical distance of float arm pivot below mounting flange: 115mm”, the float arm pivots at a point low down on what I’ve called the “rheostat housing”, which is basically a sheet-metal box (housing the rheostat), spot welded to the strut that projects down from the mounting flange. This point, about which the arm pivots, is about 115mm below the bottom face of the mounting flange. The float arm will then sit at a fairly shallow angle (about 20deg), with the float sitting on the floor of the tank when empty.
Hopefully this will make a bit more sense (perhaps?), but if not, I’ll try to upload some pictures.
So, I've just registered as a PostImage user (for free uploads), and if (big if!), I've successfully uploaded some pictures of the fuel sender unit, you should see them here
https://i.postimg.cc/Kjb4TM0d/IMG-5448-Fuel-Sender...
https://i.postimg.cc/GhcHhv8D/IMG-5451-Fuel-Sender...
https://i.postimg.cc/Kjb4TM0d/IMG-5448-Fuel-Sender...
https://i.postimg.cc/GhcHhv8D/IMG-5451-Fuel-Sender...
Thanks for further inputs Bert. I tried Chris at Redline today without success - I’ll try again in the new year (the interlude between Christmas and New Year is never a good time to be in too much of a rush to get parts).
In the meantime, the plot thickens (this is becoming one of those learning exercises where the more you learn, the less you seem to know).
Merlin Motorsport market a Racetech Fuel Level Sender https://www.merlinmotorsport.co.uk/p/racetech-fuel...
It has the correct mounting plate bolt pattern and has both a very long float arm and very long vertical ‘stalk’: I assume that both (arm and stalk) can be cut to length to suit – important for the Caterham tank since it is relatively shallow, short from front to back, and, in the case of the S3 Rover/Vauxhall tank, narrow between the baffles, so sender dimensions and orientation within the available space are important.
The Merlin advert blurb states “Sender reads Zero Ohms at empty and 183 Ohms at full”, but (and here’s where the plot thickens), I’ve noticed that some gauges and senders are designed to show EMPTY at minimum resistance, while others to show FULL at minimum resistance.
So, the question arises, does the Caterham fuel gauge register EMPTY or FULL with the sender at minimum resistance?
Another option might be to source a VDO 'dip tube' type sender, but I haven't been able to track one down short enough (it would need to be about 180mm tall), with the right attachment flange bolt pattern.
In the meantime, the plot thickens (this is becoming one of those learning exercises where the more you learn, the less you seem to know).
Merlin Motorsport market a Racetech Fuel Level Sender https://www.merlinmotorsport.co.uk/p/racetech-fuel...
It has the correct mounting plate bolt pattern and has both a very long float arm and very long vertical ‘stalk’: I assume that both (arm and stalk) can be cut to length to suit – important for the Caterham tank since it is relatively shallow, short from front to back, and, in the case of the S3 Rover/Vauxhall tank, narrow between the baffles, so sender dimensions and orientation within the available space are important.
The Merlin advert blurb states “Sender reads Zero Ohms at empty and 183 Ohms at full”, but (and here’s where the plot thickens), I’ve noticed that some gauges and senders are designed to show EMPTY at minimum resistance, while others to show FULL at minimum resistance.
So, the question arises, does the Caterham fuel gauge register EMPTY or FULL with the sender at minimum resistance?
Another option might be to source a VDO 'dip tube' type sender, but I haven't been able to track one down short enough (it would need to be about 180mm tall), with the right attachment flange bolt pattern.
Thanks Jeremy - As you say, an easy test, so why didn’t I think of it ?!
So if, when grounded, the feed wire produces an EMPTY signal at the gauge, does that mean (and forgive my ignorance of electrickery here), that when the feed wire is disconnected and therefore open circuit, resulting in infinite resistance, the gauge will show FULL?
So if, when grounded, the feed wire produces an EMPTY signal at the gauge, does that mean (and forgive my ignorance of electrickery here), that when the feed wire is disconnected and therefore open circuit, resulting in infinite resistance, the gauge will show FULL?
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