Removing fuel tank foam without removing fuel tanks

[lotusespritse]

I have done a lot of searches on the fuel tank leaks, and it's clear they will all start to leak eventually, and the cause is almost always the damp carpet foam on the bottom of the tanks.

 

My tanks are original, and I am happy to say that they are definitely not leaking....yet.

 

Instead of waiting for them to leak and having to deal with the massive headache of removing them to repair or replace them, I am looking for ways to prevent the failure in the first place.

 

My question to people that have hands-on experience removing the tanks is whether or not it's possible to lift the tanks up enough to get your hands/tools in there to remove the carpet foam from the bottom of the tanks without having to completely remove the tanks?

 

From reading posts on the removal process, it seems some have lifted the tanks enough stick their hands down into the cavity to cut off the balance pipe on the left side, so I would think it's possible to get a hand or tool in there to pull/scrape off the foam, and then drop some closed cell foam onto the shelf for the tank and remount the tanks.

 

What do you think?  Sound possible?

 

If so, how far do you think you would need to go to get the needed access to the bottom of the tanks on a V8?  The engine compartment sidewalls out?

Edited August 6, 2014 by lotusespritse

[jammy-pop]

Phil,

 

I pulled my fuel tanks out last year and found that the foam was firmly stuck to the underside of the tanks. They also have a lip around the bottom, same as the top, so getting the foam off without removing the tanks would be very awkward.

 

My tanks weren't leaking but were starting to corrode, so you may find that you would need to address this issue also.

 

For me it was a 'no brainer' to take the fuel tanks out as I already had the engine out so access wasn't an issue. I've also heard that some people have said it is possible to remove them with the engine in situ. I think the side panels would be difficult to get off with the engine in place as all of the fixing screws on mine were seized and had to be ground off!

 

Cheers,

 

Steve.

[Alex Carter]

Yup if your going that far take them out and paint them to protect them more

[lotusespritse]

Compared to just lifting the tanks, taking out the tanks completely is a monumental job that could cause other major issues.  The people taking them out are either removing the engine, disassembling the top of the engine, dismounting and wiggling around the engine, cutting the fiberglass, and/or lifting the body from the frame.

 

I don't want to do those things unless I absolutely need to do them, and if I can find ways to extend the life of the tanks without removing them, then I will do those things.

 

I have the advantage that none of the fasteners on my car are rusted.  All of them are like the car just rolled off the showroom.  So I should be able to get the side panels for the engine compartment off without problems.

 

Also, I have some ideas up my sleeve for treating the tanks without removing them for rust and rust prevention.

 

If they are not leaking, they will not need the type of repair that requires removal.

Edited August 6, 2014 by lotusespritse

[mdw]

Then yes you can just lift them.  The foam is stuck to the tank quite well unless rust has got in there.  I think as with others I would just do the whole deal as  lifting them and clearing  the foam will be 1/3rd of he job anyway especially if your side trims come out easily.

[DaveyT]

Phil, where has your car spent its life? Always in Texas? If the fasteners are in that good condition you may well be lucky with the tanks...

I have a S3 (tanks now out and one does need replacing, though this wasn't evident until I'd cleaned off the surfaces) and like you I'd hoped not to have to take them out. Hopefully yours is not too different.

Tops should be no problem, and I was able to get 80% of the bottom foam off with a scraper by going through the various 4" access grommets...then I realised the tanks were still fixed with a single bolt to the engine bay surround. With this off, I reckon it would have been entirely possible to get at all the foam.

Someone also suggested not bothering to replace the foam as it's only there for sound deadening. Not sure how true, but would remove the cause of the problem.

Good luck

Dave

[Alex Carter]

How are you going to ensure that you will be able to protect the tank properly just by lifting and replacing the base foam . If your disconnecting and lifting the tanks your nearly there anyway . You won't do a proper job in the half in half out location this would always niggle me that they weren't done properly bite the bullet and get them out there's pics on my build for you

[lotusespritse]

Thanks, mdw.

 

That other 2/3rds is a real grizzly bear, so I will go with the preventative approach and hope to avoid the need to remove the tanks anytime soon.

 

 

Then yes you can just lift them.  The foam is stuck to the tank quite well unless rust has got in there.  I think as with others I would just do the whole deal as  lifting them and clearing  the foam will be 1/3rd of he job anyway especially if your side trims come out easily.

 

 

Davey,

 

The car spent the first few years in dry southern California, and then the next 10 years in Reno before coming to rust free Houston for the last 2 years.

 

I am friends with the previous owner of 10 years now.  He told me he never took it out in the rain, and always kept it garaged.  I completely believe him based on him being a good guy, and the physical evidence of the condition of the car.  I really feel for the UK guys that drive their car daily and if they were to use a wire brush on their car they would turn the entire chassis into a large plastic garbage bag of dust.

 

I definitely don't plan to put back the original style foam. I may put back some kind of rubber honeycomb that doesn't absorb water and allows any moisture to evaporate quickly.  

 

Phil, where has your car spent its life? Always in Texas? If the fasteners are in that good condition you may well be lucky with the tanks...

I have a S3 (tanks now out and one does need replacing, though this wasn't evident until I'd cleaned off the surfaces) and like you I'd hoped not to have to take them out. Hopefully yours is not too different.

Tops should be no problem, and I was able to get 80% of the bottom foam off with a scraper by going through the various 4" access grommets...then I realised the tanks were still fixed with a single bolt to the engine bay surround. With this off, I reckon it would have been entirely possible to get at all the foam.

Someone also suggested not bothering to replace the foam as it's only there for sound deadening. Not sure how true, but would remove the cause of the problem.

Good luck

Dave

[lotusespritse]

Alex,

 

Once I get the foam off, I will use my camera on a stick to examine the condition.  If the integrity of the tanks is compromised, I will take them out all of the way. 

 

If there is just surface rust, I will have removed the cause of the problem (foam) and effectively stop the rusting process.  Then I will buy a 5 gallon container of this stuff, and bathe the tanks for a couple of days to remove any and all of the existing rust:

http://www.evapo-rust.com/

 

Please watch the videos and read the full FAQ before bashing the product.  I bought a sample, and it's truly odor free, which is also important.  It will safely remove the existing rust after soaking the tanks in place for a couple of days and then draining the product from the holes in the bottom of the car.

 

With the existing rust removed, and the cause of the rusting removed, I will have cheated death.

 

The camera on a stick will show if they are done properly, so I won't have those niggles to cause me to lose sleep.

 

I am still surprised that anyone would suggest that simply lifting the tanks is "nearly" there for removing the tanks.  Everything I have read and seen shows the engine needs to come out, or the entire top of the engine removed and then also cut the fiberglass (!) to make the extra room needed, or cut up the tanks in place to make them smaller and put back in smaller tanks, or remove the body from the frame, or move the engine side to side.

 

How are those things just a little more work than removing the rubbish from the top of the tanks and releasing the engine compartment walls??

 

My timing belt and accessory belts are new, my clutch is new, my compression is like new, the engine runs like new, the alternator is new, the water pump is new, the AC works amazingly well for a super cars...In other words, it doesn't make sense to disturb a perfectly running Esprit's engine just to have a little better access to treat the tanks. 

 

How are you going to ensure that you will be able to protect the tank properly just by lifting and replacing the base foam . If your disconnecting and lifting the tanks your nearly there anyway . You won't do a proper job in the half in half out location this would always niggle me that they weren't done properly bite the bullet and get them out there's pics on my build for you

Edited August 6, 2014 by lotusespritse

[Guest modifiedv8engines]

Sure this has been well documented but the reasons for the rusting of the tanks is mainly due to leaks around the window seals and the type of foam used on the base and top.

 

Lotus used what appears to be sponge rather than foam so any ingress of water from washing or rain tends to soak in to the foam and eventualy rusts the tanks.

 

Replace the foam with the single cell type that doesnt absorb water. Also check the seal around the filler cap on both sides as these have a habit of perishing ( water sits in the lower portion of the seal) until it gives way and water either from washing or rain leaks throught onto the tank top board and the then the lower "sponge" under the tanks.

 

If the fasteners on your car are all "as new" its doubtful whether the tanks on your car have suffered from the type of weather we get in the UK and Europe.

 

After 10 or more years - Esprit V8 engines tend to look like something that was dragged up from the sea bed. The louvres on the rear deck look okay and do the job as far as dissapating heat but a rain shower means water in the engine bay and everywhere else if not sealed up.

 

Paul 

[mdw]

Its not just the 1/4 windows on earlier esprits. On  my 88 stevens there are 2 holes behind mesh  in the r/h ear.  The top one is simply an angled plate that allows any water or air to come in via the ear and drop any water straight on top of the wood tank cover. My windows did leak like a sieve  but even sealed up the tank would still have been drenched.

[Vulcan Grey]

My dry climate car has no rust... except the fuel tanks... Those had rusted! I had to refurbish them many years ago (2004).

 

The water actually gets in there through the holes for the hinges on the gas filler doors.

[lotusespritse]

My quarter windows were definitely leaking, so I sealed them up without removing them, and they are fine now.  Everyone should at some point take out the interior quarter panels and get a mate with a hose to check for leaks on the outside of the car and in wheel well area.  A garden hose works wonders to pinpoint any problem areas.

 

I am hoping my tanks are too bad.  Not only has my car not been driven in rain, and never left outside in the rain, it has been very rarely washed.  I have owned the car for 2 years, and I washed it recently for a big concours car show, and that was wash #3 in the 2 years.

Edited August 6, 2014 by lotusespritse

[iainskea]

I recently removed a tank to fix a leak. The bolt through the inside of the body to tank sheered. It wouldn't easy-out either, so I had to drill another hole. This would be near impossible with the tank in place. Check your fixing bolt comes out first.

Iain

[lotusespritse]

Good info, thanks.  I'll check them first.

 

So far no bolts have been an issue with the work I have done on this car.  Even the exhaust mounting bolts on the turbos were like new.

 

I recently removed a tank to fix a leak. The bolt through the inside of the body to tank sheered. It wouldn't easy-out either, so I had to drill another hole. This would be near impossible with the tank in place. Check your fixing bolt comes out first.

Iain

[Bibs]

Wash your car more! Water isn't the problem, salt water is! 

[lotusespritse]

Wash your car more! Water isn't the problem, salt water is! 

 

Fortunately, they never put salt down on the roads here in Houston, and I live far enough away from the Gulf of Mexico not to have the salt in the air that rots the cars.

 

As a true car guy, I hope I never have to live again in those winter conditions.  I went to college in Massachusetts, and my 11 year old beater was completely rust free when I took it up to school.  Within 2 years, I had holes in the floor boards and bubbling cancer in the door panels.

 

And having to pull out the grinder and torch for every bolt must get old quick.

[Günter]

Styropor *Trademark*  ..is closed-cell type of foam, this orks weel as replacement

 

..there is not only the quarter-windows or the fuel filler flap hinge, it is also the air intake ducting that is not evenly in contact with its several parts attached on the body

 

..oh and there is no cutting off on the body, at least not on the younger S4 (V8) cars  -just undo the seatbelt from the cabin wall and the rrear deck 'opener' with its cable  .. (plywood plates and additional stuff like ECM and parts on top there LH/RH need to come off as well)

 

..if you lucky you could manage to lift up and tilt the tanks by undoing the head-covers (valve covers) both sides