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Fuel Tank Options for Lucas Injection on A TR250

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Trident750 Jeff D.
Livermore, CA, USA   USA
I’m getting ready to fit a Lucas PI set-up on my TR250. Have a fresh 2.5PI head, NOS 150hp cam, a 41219 distributor I rebuilt and an early PI system from a ‘69 TR6PI. I’ve had the MU gone through with viton seals and bench tested. I also replaced the injector o-rings w/viton as well as the PRV. All the lines are ready. I’LK most likely go with the Bosch fuel pump.
My question is: what are options on the fuel tank? Buy a new Al version, rework my stock TR250 tank? I’ve heard a late TR6 tank has the fittings and a swirl pot on the pick-up. A fallacy?
Any advise appreciated.

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YankeeTR5 Dan M
Seattle, WA, USA   USA
I have never heard about the later tanks having the fittings, but a maybe on the internal baffles, so can't help you out there.

I guess the answer to your question is whats the biggest driver for you? If cost is a primary driver, I'd use the 250 tank and add the return line fitting on the top of the tank AND also a second outlet to fuel pump fitting on the opposite side (passenger side) of the tank and connect the two into a single line before the fuel pump and forego the internal baffling. The second outlet should help with fuel starvation at low fuel levels in corners (recommended even w/the internal swirl pots). Also, I'd recommend a slightly larger outlet line (lines) to the fuel pump. This comes lately recommended from the TR-Registry folks (who deal mostly w/PI and are a great resource for PI folks) and it seems to help the fuel pump work easier. Maybe more relevant if you go with Lucas.

Alternatively, you can always buy a PI tank out of the UK. TR shop has them starting at 225 gbp in either aluminum or steel. Given where the tank sits and how its mounted, I'd be inclined to stay away from aluminum. There's lots of vibrations and flexing that it absorbs and aluminum can be brittle vs steel. If you go aluminum make sure the mounts are beefy and way over engineered as there are stories of them cracking.

Cool project - look forward to hearing more about it.

TuRtle5 Avatar
TuRtle5 Kevin Kelly
Absecon, NJ, USA   USA
1949 Triumph 2000 Roadster "Coral Mistress"
1959 Triumph TR3A "Drandulet"
1962 Triumph Vitesse "Ohtoseethelightofday"
1968 Triumph TR250    & more
As Dan says- a second fuel pick-up helps considerably and the bung is already there! Simple to route the line right into the filter which also has an extra port.

Also- Do you guys have a source for anti return valves on the fuel distributer? anything in the US?

Thanks- Kevin (Absecon, NJ)

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tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
Do you have a copy of the official Lucas Pi training manual?
It's online at or available from:
The Wheatsheaf Press
The Printworks
Lacey Green, Wilmslow
Cheshire UK

That includes diagrams of the various layouts of swirl pots, reservoirs and return pipes used.

Those are required because unlike carburettors, fuel injection cannot tolerate air in the lines, and will suddenly fail if surge leads to air aspiration by the pickup in the tank.
I've found that for spiritred driving, a lifter pump, a small facet or other pump, and a separate swirl pot is the only way to guarantee this will not happen.

It does make the boot a bit of a distillery!

fuel pump house 001.jpg    58.1 KB
fuel pump house 001.jpg

RGB Roger Bolick
Adding PI to a 1973 TR6. Sounds like we are at the same "state".

From memory, the stock TR6 tanks are worthless for PI.

1. Tap bottom front left for carb fuel out... No outlet into the trunk per PI tanks.
2. Tube on top for the vent.
3. Filler pipe and sender hole.
Do not recall seeing ANY baffles and the later tanks have the filler tube extended deeper, thus reducing capacity in the name of reducing production costs. See early TR6 tank vent/overflow vs. later.

Friend ordered the BPNW steel tank for a TR6 and it had PI fittings. I ordered the aluminum version and it has a baffle at each side, two upper taps and two taps on the bottom, one in stock location and one rear into the spare tire well, both left side.
(suggested this was Bastuck brand, earlier photo shows insignia, but NO markings on this tank, so suspect cheap clone??)

DOES have a swirl pot welded over the lower rear outlet. Appears the left top inlet (return line) is piped into the swirl pot, EXCELLENT!
Will get it outside for better light next visit. All fittings appear the same size, likely 1/2" thread for 5/16" compression.
Thinking the PI return was 1/4" line with associated 1/4" compression tank fitting, meaning the tank fitting is wrong by PI standards

Will look closer and reply. To answer your concern... THIS tank WILL work for PI and should bolt into the TR250.
(NOTE: EU mention of Bastuck tank rear bottom excluding larger spare tire (165-15 ONLY), US tank allows 185-15, unverified.)


PS will post info when I get the tank out in the light. Not certain steel is the same, hence my purchase of the Aluminum version.
(above based on a 2 minute exam upon un-boxing...) Will also verify the steel version's "taps" as its $200 cheaper...

PSS someone mentioned adding a 2nd right side tap to the bottom of the US tank... Early tanks had two bottom taps, but the right side
was deleted later... BUT NEITHER is in the trunk area like the PI tank which facilitates the Y connection into the filter.
Early systems show a separate swirl pot, later this seems incorporated into the tank... BUT if you examine carefully, the filter actually
serves as a mini-swirl pot, Same filter assembly is available in a "dual" design... each side connected to its own filter with a single outlet?
(add the early style purge line from the filter(s) to the tank top to make certain both filters stay purged of air during radical driving)

PSSS also researching nylon fuel lines... as I have a complete 2.5PI system here (all nylon)... many modern cars run nylon, more later.

Edited 1 time(s). Last edit at 2017-12-07 12:24 PM by RGB.

Trident750 Jeff D.
Livermore, CA, USA   USA
Hi Dan,
Thank you for the inputs. I have an early TR6 tank I could modify with a return fitting and lower right feed fitting as well but concerned on the lack of baffling or swirl pot. Maybe with dual feeds, the problem when hard cornering and low fuel level won’t present a problem. Looking at the aftermarket Aluminum and steel versions as well.

Trident750 Jeff D.
Livermore, CA, USA   USA
Hi Kevin,
Thanks for your thoughts. When you mention non-return valves, can you clarify? I don’t think there is a non-return valve on the stock PI set-up.

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Trident750 Jeff D.
Livermore, CA, USA   USA
Thank you for the link to the training manual. Very useful! That’s a pretty elaborate set-up in your boot! Where do you put your spare tire?

RGB Roger Bolick
Reporting details of NEW TR6 Aluminum Tank obtained Dec 2017.
Also a Steel tank of similar design, have yet to examine it, but suspect its functionally the same.

CF516 = Compression Female 5/16" line (1/2-20 UNF thread) w/brass sleeve.
(meant for "hose tail" or "hose end", stub of tubing bent 90 degrees with Male thread nut and brass sleeve)

Careful observation shows 5 taps (3 Top, 2 Bottom):

1. Top Left - CF516, Return Line for PRV (Pressure Relief Valve) to tank, NOTE it feeds into the Swirl Pot.
2. Top Left near filler - CF416, 1/4" Return Line from the MU (Metering Unit) i.e. Overflow (NOT a return line...
NOTE: uses a 5/16" Female Compression style with 1/4" Line (unobtainium?), a Step fitting (two sized).
Meant for Male "hose tail" OR "tube end", i.e. 1/4" internals, but external fit to 5/16" (same as mech pump outet on carb cars).
3. Top Right - CF516, PI cap is vented... Better to use US TR6 cap (sealed) and connect this vent to the carbon canister/air cleaner.
(lessen the fumes in the garage from today's stinking fuel)
NOTE: seems this would be MUCH better centered forward of filler LIKE US cars and thus hook up US vent line easily?
4. Bottom Left Front - CF516, hard to see, front of swirl pot, standard US location for fuel outlet AND drain on right side (early tanks).
5. Bottom Left Rear - CF516, front inside swirl pot, PI location outlet to Filter.
Outlet INTO THE TRUNK to facilitate Filter, Pump, PRV.hookup.

NOTE: Swirl Pot is about 4.5" OD x 2.75" tall and fed by a 3/8" OD tube from upper left tap. Tube welded to bottom of tap and tacked into Pot.

NOTE: Lower Rear of tank is made like TR4A tanks with no ANGLE cut for the spare tire. Normal TR6 will fit a 185-15, but not 205/70-15.
This tank WILL NOT FIT EITHER, plenty of room for a can of "Fix-A-Flat" or some small spare or might 165-15 fit?
I run no spare anyway, but it IS important! VERY NEGATIVE aspect worth noting.

NOTE: Seems this tank would be AWESOME on a US Carb car, EXCEPT the Swirl Pot is NOT over the carb tap, OUCH.
Guess the pump would pull from the trunk area, just need good components to eliminate the fumes into your clothes bag issue!

Edited 2 time(s). Last edit at 2017-12-20 01:52 PM by RGB.

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A - TR6 Gas Tank Aluminum - NEW Dec 2017.JPG    23.3 KB
A - TR6 Gas Tank Aluminum - NEW Dec 2017.JPG

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