Mar 212013

The fuel tank has been another area that hasn’t gone as smoothly as I had expected. At first glance the tank appeared to be fine however the problems were only revealed once it had been removed.

Over time the untreated tank had rusted through which is a common problem. It had been repaired by welding several replacement patches but the weld seams weren’t the best and had started to corrode quite badly.

My concern was the thickness of the tank, or lack of it, either side of the weld. I think water that had entered the tank must have been settling in the various troughs in the weld so it was again rusting from within.

As luck would have it, there was an advert in a Jaguar magazine for an unused later S2 fuel tank. The S1 owner had purchased the tank unaware that the design had changed from a single breather pipe to three from chassis number 1R1393, some 28 cars before mine! In fact I wasn’t aware of a difference until I’d read his advert.

The three breather pipes were introduced with the addition of the expansion tank into the fuel system, late in the production run of the S2 cars. I think this is why it’s not referenced in any of the manuals.

A number of owners on the E-Type forum have reported running problems as a result of fuel starvation. Insufficient venting of the fuel tank was enabling a vacuum to build in the tank, acting against the fuel pump. A common remedy is to drill a small hole in the fuel filler cap. I can’t see how the addition of an expansion tank would alleviate this problem. The S1 and early S2 tanks were just vented directly to the outside rather than via an expansion tank. So fuel starvation issues may still be a problem …. but more of that later.

The replacement tank been already been treated with the white PVC type tank sealer. However, during the time it had been kept in dry storage, the sealer had started to crack and come away in sheets. It would all have to be removed otherwise it would quickly start to clog the fuel filters.

I started to research the different types of tank sealers on the market, mainly to find out the best method to remove the sealant used in my tank. The conclusion was that the PVC type sealers have very good coverage but don’t fill holes or seams well and have poor film strength. I’d found that out to my cost!! Most recommended using a paint stripper to remove it.

I had a large tin of Nitromors lying about so I gave it a go and poured it into the tank along with some nuts and bolts. The latter providing a mechanical method of dislodging loose bits of sealant. The problem with modern Nitromors is that they have changed its properties to a more gel like consistency rather than liquid. As a result it wasn’t very good at getting into the baffled areas.

I then switched to Por-Strip which was better but didn’t reach much of the internal baffle surfaces. I needed a new approach.

One of the local powder coating firms offers a burn-off service but they didn’t want to do it as they were concerned the temperature would melt the brazing. Eventually I took it to a furniture restorer who was able to dip the tank. However the borescope revealed that there was still quite of a lot of sealant stubbornly attached.

I think paint stripper just softens the sealant which then becomes a sticky goo. Unless it is successfully removed immediately it simply sticks back to the tank surface as it dries out.

Like most troublesome issues, I put it to one side to have a ponder. I would tackle it at a later stage!

I recently found out that the PVC coatings can also be removed by dissolving in either Acetone or MEK (Methy Ethyl Ketone). Spurred into action once more, I ordered a small quantity of Acetone and added some sealant flakes to confirm it worked. 20 litres of Acetone have now been ordered and the tank is going to receive a thorough soaking at the weekend. Fingers crossed!

It still leaves the dilemma of how to treat the tank to avoid it rusting from the inside out. Not only that but it dawned on me that swilling around sealant inside the tank might cure the rusting problem but would be guaranteed to cause another. I’d realised that the PVC sealant had done its job and sealed the ends of all the internal pipes for the expansion tank connections.

Unless the Acetone can unblock them, I might have to resort to removing the brazed joints and withdrawing the pipes. I’m now wondering whether tank sealants might be the cause for some of the people suffering from fuel starvation problems.

 Posted by at 7:27 am

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