Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 More worries - cracked gas tank.

I'm not sure about gluing reinforcing parts to an already cracked tank but it seems like that is a reasonable preventative strategy before cracks appear. I'd wonder how the gas vs. glue will hold
The cracks are in the brackets not the tank itself, so no glue in contact with petrol. so hopefully will last for a good time! we have to watch and see............

DocNik
Chris99
MarkH
RedThree
Dolph
RicHardy
ArchieWetLeg
Bunny..................................2012 build, Cracks in both front brackets spotted 2018, Approx 9000 miles. Also, crack between filler swan neck & top of tank.
Brooklands Pete..................2014 build, Cracks in both front brackets spotted 2018, Approx 9000 miles [Straps were loose]
Planenut..............................2013 build, Cracks in both upper and lower brackets found at 20,500 miles. Straps were loose.
KankeL
PaulV ................................. 2015, <6000 miles, possibly 2017 tank crack (strong fuel smell in garage), identified 2019
Nippymog........................... 2013 build, crack spotted 2018 at 12k miles
Chocadoodledoo ................2012 model, both brackets 12,000 mls in 2019
Skullmog ..... cracks in both left and right upper brackets
3Gs ..................................2013 with ~2.5k miles.
Laurens ............................(only 1 of 2 M3W!)

Wondering if there is a long-term solution to the bad design of fuel tank mounting / location.

1. The 2- and 3-speed M3Ws (if I recall) have a fuel (or combined fuel+oil!) tank in the front scuttle / under the "bonnet". I suspect a bit of reordering of the oil tank / use of a compact LiPo 12v battery might leave room for a decent tank, passenger side, say courtesy of https://www.conceptracing.co.uk/fuel-tanks-swirl-pots/ ?

2. Probably a good space would be in the passenger footwell, subject to a suitably "safe" construction and bulkhead?

Don't forget balance.

Good point. Changes mass from around the back wheel to between the wheels at the front, although a bit higher. Less pendulum effect! Worked well in the 20s and 30s...

Superb drawing.
Look at the rise to the front on the drivers seat squab!

Hey, with all the discussion about tank cracks and loose straps nobody has mentioned torque settings for the straps. Anybody know what it is?

Not much, otherwise you will shear the bolt. The tensioners are made of crap and those M8 bolts are weakened during the welding (they weld M8 bolts to a bracket to make a tensioner). Mine had cracked and that lead to loose straps, which resulted in the cracked tank.

What has the discussion been about putting in a flexible section between the top of the tank and the filler neck so that long pendulous pipe is not weighing on the tank weld?

Well I was sent a pair of tanks to repair from one of the dealers....

After pressure testing to find the cracks/leaks. both in the mounts and in the tank body itself, the original IMO flimsy mounting brackets were cut off, and the original welds linished flat, large load spreading patches were then welded on to the tank body before fabricating new more substantial mounts from a far higher strength material , which were then welded in place






Simon @ SiFab