Rusted tank and compatability
 

I recently started to work on my S1 again, hoping to see her on the road soon. I realized it needed some fuel, and so i put some in the LH tank. Well then it started pouring out just above the drain plug. I drained it and am going to drop the tank to see the extent of the damage. I have an 85 VDP which also doesn't run (I have been wanting to build a Salt Flats Racer out of it), that I was thinking of robbing the tanks from. I have seen a few posts about people using S1 and S2 tanks in S3s, but nothing going into an S1. Saw something about using a filler neck from an S1 if using those tanks in an S3, as they're longer. Well if I use a S3 tank will I have to change anything else? We have a pretty good radiator shop in town I may take them to, regardless the route I take, just to have them cleaned up real well. If I clean the S1's originals up really well, what kind of reliability would I see from using that plastic epoxy and coating the inside? Assuming my tanks aren't beyond repair, would this be an easier fix? Thanks for the input!

All three tanks fit and secure identically in the space in the bodyshell, it is the fuel fittings that are different, and you have to adapt them. AFAIK, S1 and S2 tanks are pretty much interchangeable, it is the Series 3 tanks that need adaption to fit the earlier cars. I am not familiar with the detail so wait until somebody comes along who has done the job.

Series 1 and carburated series 2 cars have an large opening on the forward facing surface for the intank fuel lift pump. The opening is about 2 inches large and a small fuel lift pump was fitting through the opening. This opening is absent from the series 3 tanks and instead there is a 1/2 inch tap on the bottom of the tank used as the supply for the fuel injection system. You could adapt anything given enough time and money but to do so you'd need to re plumb most of the fuel system and devise a new pumping method.

You can clearly see the opening here...
http://empirebritishcarparts.com/ima...ducts/8700.jpg

Last time I checked proper series 1 tanks were still available on Rockauto.com

Thanks for the replies. I got the tank dropped and it turns out the thing isn't as bad as I had thought. It appears to be leaking from the sending unit gasket, but inside the tank was bad. I have a bunch of blackish-colored flakes coming out. Some are very tiny, but others are larger than quarters. To me it almost seems like it was lined already and it's now flaking off. Is this a safe assumption? I have no pictures, but it isn't just rust.

I've read most of the older tank sealing formulations were methanol soluble so its likely a filed liner if it was coated many years ago. Seem like the liner is being broken down by the metanol in today fuels. Methanol is hard on any partially filled tank unless its stainless steel or poly.

Would you recommend re-lining it or would simply cleaning it out suffice? I'd hate for water to get in there and start rusting the thing out, but at the same time, it's pretty solid as is, with no signs of actual rust (maybe surface rust on the outside, but it is painted, and the rust could be taken off with 000 steel wool).

Someone lined it for a reason. Are you sure it's leak free? You can fill it with a few gallons of mineral spirits to check. Anything other than a new tank is a gamble. I dont think relining a previously lined tank is a good idea. Years ago there were radiator shops and gas tank repair shops that did their magic to restore old parts but 'round here those places are long gone, I suspect by you its the same. Rockauto still has new tanks, get one while you can.

I have done this in January. The new tank cure (brand name, that is) epoxy can resist todays fuel. The tank I did half a year ago turned out very well, and free of any leaks up till today and I have good confidence it will stay that way.