Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 2 New fuel tanks for around € 140 in a week time

From the beginning when we had bought our M3W in December 2022 I smelled fuel.
This fantastic TM forum gave me a lot of info about this subject to digest.
Because I had the last 8 month engine and fuel pressure problems I thought the smell should come more seriously from the fuel system it selves.

I had checked the Starboard tank front side an saw that it maybe was a little wet, but not really much to worry about.
When I was in Holland in June I decided to buy some special epoxy for aluminium tank repair. Stuff I had used on ships too with great satisfaction.

It stayed for month in our storage because of all other mechanical trouble I had with the M3W.
I really went technically from the front crank-shaft pinion bolt to a not working rear fog light and I passed again that tank.
When we decided to change the drive belt to Phil Bleazey’s Chain Conversion and taking the NVH kit out, I got enough reasons to have a better look at the starboard tank.
The smell was much more than in the beginning.
I checked with paper to find out where it got wet.
And found - not to my real surprise - it was the front bracket. I am not the first one and - I will try to show - I am for sure not the last one too.
I am sorry to say – I get a little tired from bashing them so often – but it is again amateur work of Morgan. Cheap as possible and welded by not a real aluminium-expert, I dare to say, I know something about it.

We took the tank out and cleaned it carefully and sanded it.
We found that this welding was one of the worst aluminium welding I have ever seen.
On several places it was welded or heated far too hot so you could easily see that the aluminium got that typical aluminium crumbled texture of overheating.
I found too that you easily could see - inside the tank - that welding of the brackets went through the surface of the tank, which should not happen.
And the welding had made extra bulbs of melted aluminium and/or creating holes. So the problem is there in the first place because of MMC.
And not so much because of movements of the brackets which I read often on TM.

The simple aluminium story is :
Most aluminium used for construction is an alloy. There are many types with all different strength and elasticity. Also the welding-method is slightly different for every alloy.
The most used alloy is AL-MG-SI and AL-Mg-Mn in different variations.
AlMg4,5Mn exhibits very high mechanical properties – with a low melting range of around 600oC – and is therefore often used for construction in shipbuilding and ( huge ) vessel-storage, which I designed long ago.
In general - and checked f.i. by Germanische Loydd or Tuff for shipbuilding - aluminium welding is strictly controlled after the work and that is not for nothing. All aluminium welding build under strict specifications was 50 years ago checked by Röntgen and now ultra-sonic before official approval of the product.
When you want to bend aluminium , you have to warm it slightly. And when you want to weld the best way is two sides so you can actually pre-heat.
A little bit over-heated and the aluminium gets bridle and losses it strength nearly totally.
We all now the effect when you bent aluminium when not warmed up, you see that the aluminium surface gets bridle immediately in contrast to steel.
The moment you see that bridle surface the structure is broken and does not have any of the original strength anymore.
Aluminium stands very low in the chemical periodical system, which means you always need an electrical sealant when riveting or bolting with other materials of a chemical higher grade than aluminium.
MMC made a ridiculously big mistake with stainless steel rivets on an aluminium body. How stupid can you be? And to my surprise they still do. They do not learn much from TM.
Isolate and buy and use a lot of Tefgel. It really works.

The MMC made Tank
We found several places - even on the plain surface - were the aluminium was over-heated. And the work seems to be done by people without a clue. We really asked ourselves : “Do they went to school?”
The tank is made from one long plate of aluminium and I am afraid not of the right alloy for this construction.
From the front to the aft the plate is bend slightly half-way and at the aft-side twice and back to the front.
At the front are two little slips bend so the front plate can be welded more easily ( See picture ).
Standard but still well done by MMC is that they made just aft the fuel inlet a little bulkhead to break the movements of the fuel.
But . . . it seems that the welding of that bulkhead is exactly the place where you find overheated aluminium on the outside too.
The top and bottom plates are welded on this long bend plate.

So what to do?
Ordering a new tank from people, who clearly seem not having any clue what they do, does not bring you further.
So we decided to make actually a new epoxy tank and using the original structure as a base. This will probably last till the vehicle and we are gone.
There is special epoxy on the market which can help you.
But aluminium is neither easy to paint nor to glue epoxy to its surface.
Want we did was sanding ( P 80 ) cleaning with ammonia sanding again and cleaning and this several times.

When really clean we immediately painted the surface with a special primer.
You really have to prime directly after your last cleaning is dried.
Because aluminium start oxidising directly again and the aluminium oxide will not accept any paint.
This primer has several advantages. Actually it closes all minor holes and hair cracks.
We primed two times with thin but covering layers till the whole surface was good covered. You can do that second time after 24 hour depending of the humidity and the temperature.

After priming we painted the surface again after 36 hours with a special epoxy, which is quit elastic. Epoxy is a glue and when hard normally not so elastic.
We did this – bringing the ‘Pantsercoat epoxy’ over the primer - also 2 times with the same waiting time of 24 hours.
The second time we glued some very fine and thin woven glass mat around the brackets and pressed it well in every hole, corner, etc. So the glass mat was good glued to the brackets.

After again 36 hours we used a normal standard epoxy to cover the whole tank – especially all the welding and corners – with the same thin well woven glass mat.
After all this work we kept the tank drying for several days.
Finally we painted the tank in the same nice rover-almond-green colour of our vehicle. And let it dry again for some days.

Stone protection
We changed the rotten plywood stone-protection by a simple green nylon kitchen cutting plates of 10mm thick. And glued them with a simple MS Polymer to the new tank. It will never rot again.

Band-spanner
When installing the new tank, we had a lot of problems to get the spanner in place.
There is absolutely one very good thing designed on our M3W and that is the strong made chassis holder of these spanners.
They are so strong build that we decided to cut a sleeve in them so we just could slide the spanner-bolt in it with an extra wide washer, which makes attaching the straps now very easy.
But tightening we were again disappointed by the quality of the stuff MMC is using.
The bolds are not of hard steel and probably that’s the reason many of us have problem to adjust them tightly.
There is a simple solution for it: Give the nut more thread to support.
We used 2,5 cm nuts so the force we use is nicely spread and covered over more thread.
We block that long nut with an extra nyloc nut.
The advantage of using these long nuts is too that you protect the thread better from all the dirt and grease stays in.

Time used in Total : 7 days

Materials used :
Total costs for 2 Tanks around € 140
+ Sandpaper P80 and P180
+ Cleaning Ammonia
+ 2 component Primer – 2 x 200 ml which is less than half a tin of the tin we bought
Poly-Pox Primer set 750 ml - € 29 - Used per tank 2 times 2 times 180 + 45 - ratio 4 : 1
So enough for doing both tanks. You can keep it for 1 year.
After ½ hour a fly could already land on it without a problem.
+ 2 component Epoxy – 2 x 200 ml which is also less than half of the tin we bought.
Poly-Pox Pantsercoat – set of 750 ml - € 36 - - Used per tank 2 times 180 + 45 - ratio 4 : 1
So enough for doing both tanks. You can keep it too for 1 year.
Another fly tried this again after the same ½ an hour and it survived too.
+ Very fine woven glass matt from Amazon.fr - EsportsMJJ 1X2M 0.03mm Fibre De Verre Tissé € 16, you use less than ½ of it. So also good for two tanks.
+ Normal epoxy from Amazon.fr - 1.6kg Resine Epoxy Ultra Transparente Polyvalente à haute performance € 38 ( we used only 60 ml epoxy and 36 ml harder ). So good for a lot of other applications.
Unfortunately the same fly family tried to make jokes with us and even after 2 hours they could not touch.
It costed the family two partners.
Never joke with us they know now.
+ Kitchen cutting plate amazon.fr - Hygiplas Planche à découper standard basse densité Hygiplas verte, préparation de salades et de fruits, taille standard : 12 (H) x 450 (L) x 300 (L) mm € 19,29. One for each tank.

Not a M3W owner but what amazing report.you have gone to a lot of trouble writing it.
My son in law was looking at buying a new 3 wheeler a few years ago.
He has ocd and what stopped him believe or not was the length of the cable tie ends !
And wood srews not even in the wood at rear !

Thanks for the detailed report on your fuel tank mods, that should fix it! Good to see some alternatives to replacing or weld repairs of the tanks. I like the kitchen chopping boards under the tanks. I have one under the tail of my M3W to help prevent damage to the skin if the rear wheel drops off a kerb, they are very useful and cheap.

Most of the tank leaks I have heard of have been from cracks starting in the bend corners of the forward attachment brackets, a smaller number have been from bad welds in the seams on the edges of the tanks. I would say that the cracks in the forward brackets are from fatigue caused by movement of the tank, the crack then propagates through the weld and into the tank. No doubt this crack propagation route is not helped by the less than perfect welding but I don't think the leaks are just down to bad welds, or they would be happening all over the tank rather than a specific point. Leaking tanks (at the forward brackets) seem to be on cars that have done some miles, they don't happen from new, which also suggests movement and fatigue is the main cause I would think?