Rusty gas tanks: yes, common on old cars that have sat unused.

The *best* path, IMO, is to remove the tanks for cleaning. I've found that the local radiator repair shops will 'boil out' gas tanks with nice results. One, in fact, actually does gas tank restoration.

However, removing the tanks is no 15 minute thing. Rather big job.

One fellow I know simply flushed out his tanks, in situ, with a garden hose....which removed the loose rust. He then added a fuel filter between each tank and the selector valve to catch any remaining debris. He had to change the filters 3-4 times as they collected additional debris but eventually....smooth sailing.

(Adding the additional filters, by the way, is rather common on 'general principles' to protect the selector valve and fuel pump. The fuel pumps in particular just won't tolerate rusty gasoline)

Some others recommend simply installing new tanks (about $350 each as I recall) and being done with it.

Cheers
DD

 

The metal alloy Jag used in the 70's is rust prone. No way to prevent it without replacing the tanks. You can flush and coat all you want but, unless you heat cycle the car daily and run a constant supply of fuel through both tanks they will re-rust quickly. Then over time the particles will clog your filters and wear out / jam the pump. Then eventually the tank will leak when it's sure to be a most in opportune time.

New spectra tanks with more resistant alloy is the only long term solution. Get them while you can.

 

Yes, new tanks are the way to go...have used (6) Spectra tanks in Jags now and they fit fine... change all the rubber hoses!!!! The hardest part is getting the filler necks out.. (soak them with rust remover for days before).

 

my solution for the complete fuel system ,from new tank to new injectors, and any thing else in between.

including SS pump, aluminum lines ,Aeroquip lines and fittings etc.

i just wouldnt like being 500+miles from home and have something silly happening.

 

Probably not at all what you have in mind, but we elected to replace both troubled tanks with a spare tire boot custom single aluminum tank. This application has in-tank high pressure pump for EFI, fuel level sender, etc. but carb set up could work the same way. Now only need one fill cap; the other one was repurposed as a battery cutoff switch.

See full writeup at EFI fuel system - XJ6 Restomod

 

Nice

Cheers
DD

 

where do you put the spare tire? No spare? Or is it just like flopping around the trunk loose? Or exposed?

A better idea is to fabricate and xjs style tank that fits behind the seats and can hold about 18 gallons

 

 

NOPE no suggestions.

 

No spare. This aluminum tank holds 22 gallons and weighs about 8 lbs less than the steel twin tanks. Also, from a center-of-gravity viewpoint, it is much improved since it is lower and completely centered on the chassis. A cover over the tank makes the trunk space fully useable. Four vibration isolation mounts on the right and left sides with a drain plug on the bottom placed directly over the old spare tire screw-in holder (this was drilled out and a rubber cap fitted).
Again, this is for an EFI setup that requires a high pressure in-tank pump.




Aluminum custom designed 22 gallon tank with filler, EFI pump, fuel level sensor, fuel return, vent, and clean outs.

 

Alan,

I just did this job a few months ago. The cap assembly is a close fit with a big o-ring to seal it. As stated before, soak the thing with PB Blaster or other penetrating oil overnight before commencing the festivities. It helps to rotate the cap assembly back and forth as you pull it up (a large pair of channel lock pliers helps). I ended up using a 3 lb. slide hammer to get my RH cap out.
Not complicated, but tedious. Grit your teeth and get at it.

 

Again...I think this is a very bad idea even though many people have done it. The myopia on this one is astonishing... there is no real word benefit to having no spare and a much less usable trunk space. The use of photo effects seems to indicate that more and more cars are being built to simply look good on the interweb and not for actual and safe usage on the road. If it was a light weight stripped and trailer-ed track car then maybe it makes sense.

As a driver.... No spare?...what do you in case of a flat tire?
This makes the trunk much less usable with all the plumbing and wiring sticking up above the floor surface. no?

So you save 8 LBS. Meaningless when you're walking along the side of a highway or waiting for a tow. What good is a resto-mod if driving it can put you and your passengers in a bad situation? Fuel isnt as heavy as other liquids like water so the amount of "center of gravity" change for this type of mod is insignificant and arguably slightly worse if you consider you moved the CoG forward albeit, slightly.

Case in point... I went to a Jaguar car show on the grounds of a large estate in Montclare NJ. It was a great setting and with a bridged OE tank setup, I had enough space in the trunk for 3 lawn chairs, a cooler and few cleaning supplies. On the way back, at 6pm on Saturday or Sunday... I hit something on the highway at speed and it sliced the tire. There was no shoulder on this parkway so I rode it to the next approaching exit... Martin Luther King Jr Boulevard in the crime ridden city of Newark NJ. Just off the short exit ramp, I found a side street out of view to evaluate the situation, the tire was shredded. I was dressed better than usual so I called AAA and told them my location, they said it could be up to a 2 hour wait as there were a few calls head of me. I changed that tire myself as quickly as I could. If I didn't have a spare, I'd be helpless and I dont like being helpless.

Another idea... if one is compelled to be different for the sake of being different.
https://www.summitracing.com/parts/sum-293255/overview/
This 19 gallon tank would fit...nicely behind the seat back like the XJS. A modern engine should be able to return over 20mpg so range would be about 380 miles. That's plenty good for a rest-o-mod. Use a 15 gallon tank (300 miles) and there's room for the battery back there too.

...but bridging two new OE tanks with the much loved OE bosch pump with a filter in the corner of the spare tire well just like the series 3 OE design is my go to solution as it's easy to service and super quiet. It's also the safest, as any leaks drain harmlessly out the spare tire well vents. This is, by far, the more practical solution for a street driven car, especially since you can fill up on either side. No waiting for a pump spot because of fill side issues. Also the OE tank arrangement offers the most range at 24 gallons.

 

I came real close to using that Summitt tank, but opted for just replacing the tanks with Spectra replacements (again). I use the Pollak 6 port valve to switch between tanks and return the fuel (fuel injected) to the same tank I am driving on. The whole upper trunk area would not be useful if I had gone that route. The system is totally reliable and has been in there for thousands of miles now.

Still have a full size spare under the new floor material as it will help with a tire problem. I did use the compact spare tire insert to hold the needed tools for changing a tire plus lug nuts for the stock wheel since the XJ 40 wheels are too wide to fit under the floor cover. Plus I have full fuel capacity the car came with for fuel..I switch tanks at 175 miles if on the highway or 150 if mostly city driving... want a little reserve in each tank!

 

A few thoughts:


1. Using the space in the rear wings made boot space for cargo larger. Compared to other cars of the era particularly USA cars the "tail end" of the S cars is taut. A design thing. But, useable boot space a marketing issue. "mine is larger than yours".


2. The twin deco filler caps are more unique than a mere flap.


3. My car has four XJS sourced Lattice wheels. Too "fat" for the spare well. Even the Kent original when shod with a 215 is a tad fat. but, close, so, that is what I in there.


4. I do have enough tools aboard to swap in the spare if needed. But, at this stage in life, I'd prefer my cell and road service !!!! So far, no need for either .


5. I think the dancesque moves at the pumps is kinda fun. I've never been much at dancing!!! Although holding a gorgeous gal in my arms ain't that bad !!!


6. Decades ago, I worked in CA's Imperial Valley. Summer temp's about 120 F not uncommon. One such day, I was coming back to my officer on a back road in my company furnished 59 Ford Galaxie. AC full on. Business attire, slacks and short sleeve shirt. Oh, (@#@$^$##y), flat tire. Pulled off toa welcome shoulder. Plan made as I did. Pop the deck lid. Pull out the spare, bumper jack and lug wrench. Pop the wheel cover. Crack the 5 nuts. jack up the rear. Fast. Remove the lug nuts. remove the wheel with the flat tire. Ouch, the durn thing is hot!!! Pop on the spare. Still moving fast. snug the nuts. Lower the car. Tighten the nuts. Still moving right along. Toss everything in the trunk, loose. Close the lid. Get in the car. Fire it up, enjoy the AC.


No cells or road service then!!!! Be prepared, essential !!!


Oh, clothes a bit sweaty, but still clean.


Carl

 

I had a radiator shop chemically clean out both tanks and then line them, as there was some serious rust in the bottoms. My father and I also have several antique John Deere tractors which I have done the same to, and those tanks have been good for the last 30 years with no internal peeling of the liner. It was about $260 US to have this done. Just another option if your tanks aren't perforated.

 

Many decades ago, I up graded my 23 T Ford to 27 spec. A fuel tank in the cowl. Better gravity feed over the under the seat tank in 23 spec.


Rust in the cow tank plaqued me for a bit !!! Teen fix !!! Used a small tank on the "A" post. Small nails and tacks in the cowl tank and some kerosene . The latter cheaper than gas. Drove it and flushed the cowl tank a few times til it ran clear. Natural agitation at work.
Was fine afterwards !!


Carl

 

And less than half the cost of new tanks so for some it's worth considering.

There's more than one way to skin a cat

Cheers
DD

 

In a week or so I will be having my tanks cleaned out by a professional radiator shop with lots of experience and they don't put in the liner. My little neighbor hood one man shop (who just finished a radiator re-core for me) wants to clean them out and use the liner. He's been doing it for lots of years.


To liner or not; that is the question. What comments do you all have?


My tanks are not very rusty.


geneo

 

Opinions vary by experience. I've never had to have the tanks cleaned on any of my oldie Jags so I can't speak directly to that.

On various other cars I've simply had them cleaned and all was well afterward; no treatments or liners.

I'm in the process of taking an old 240z out of long term storage. Had the tank cleaned and decided to have it lined just to give it a try. Far too soon to analyze; the car isn't even back on the road yet.

If a car sits unused for any period I always try to do so with full tanks....which is age-old practice/advice.

Cheers
DD