My 77 XJC has come out of storage with a weeping fuel tank. So far, I haven’t found anyone in the area to reseal it, so I’m looking at replacement. The car was V8 converted when I bought it and changed to external pump. The tank is the older style with a front pickup and the float mount behind the taillights. Do I have to replace it with an original series 2 immersion pump type or can I use an external model?
I am doing this on a friend’s lift and need to have the tank when I get it in the air.
‘Thanks
‘RichardinMaine

 

I see no reason why an external pump tank would not fit just fine. I have removed, cleaned and re-installed with a new internal pump on my 77xjc (jag engine). Im sure the suppliers know, or best call Spectra the manufacturer in Canada. Or check their website.

good luck geneo

 

I bought two new ones from Rockauto, made by Spectra. They have both the old and new styles. Around 275 bucks ea. if memory serves.

 

I I used the Spectra's for a Series 3 in my '77 XJ12L. A bit of additional plumbing was required. Be sure to use Series 3 sending units with series 3 tanks. Series 2 sending units in a series 3 tank only register about 5/8 of a tank when full.

 

Clyde, This is interesting because when I picked up my 85 S3, the seller told me that both sender units had just been replaced. After the passing of money, I topped up both tanks for the 200 mile drive home and each tank, full to overflowing, reads 3/4 full on the gauge. The PO had explained that they needed to be "Calibrated" by removing each one and bending the float rod so it read correctly. Made no sense to me then and still no sense now.

Perhaps he installed the S2 senders in my S3? What are the different part numbers if you have them?
Ian

 

Over the years I've replace a number of sending units on old Jags and none of them were very accurate. In all cases they either would never give an "F" reading or would barely touch the "F" if the tank was filled to overflowing....so the problem seems to be at that end of the scale. Additionally, after fill-up, burning just a couple gallons gives an exaggerated drop of the needle.

However, they've always been quite accurate at the lower end of the scale. Once I'm down to a 1/2 tank or so, all's well.

<shrug>

Cheers
DD

 

I would rather know where Empty is than Full anyway.

When my needles get to about 1/4 I still have at least 50 miles on that tank. Of course I've got used to that now and it doesn't bother me like it did in the beginning.

I begin to think it's just another charming quirk of a 40+ year old car.
(';')

 

“The PO had explained that they needed to be "Calibrated" by removing each one and bending the float rod so it read correctly.”

This is correct. The sender is a potentiometer (variable resistor) where the resistance changes according to the position of the arm, which is connected to the float. When fitting a new sender unit, the angle of the rod to the float needs to be adjusted so that the contract on the potentiometer winding is in the right place to correspond with empty and full positions of the float.

With a little trial and error you can get an accurate display on the fuel gauge

 

Iramfhal,
Sorry, I can't help with part numbers. I "cheap charlied" myself. I knew going forward that the 1977 senders were not going to register correctly if I put them in a Series 3 tank.
I have to reset my trip odometer and watch the gage. If I watch carefully, I switch tanks when the first one hits "E". It will still have about 4 gallons left. Depending on my driving style, I usually fill up both tanks at 150 miles. Fuel economy is 5-13 MPG depending on how hard I I keep my foot in it.

 

LOL I speak that Fluently!
(';')

 

I cant imagine the "calibrating" task on an XJ. The mounting is not that access friendly for multiple fitments till you get it right , plus the usual concern of working with open fuel tanks and fuel vapor. The risk / reward just doesnt seem to be there vs just getting used to what the car is saying.