Petrol Tank Internal Corrosion - Petcock Damage - Lead Replacement Additive

[Angusa10]

Two years ago I flushed my petrol tank out while I was fitting new adaptors 3/8” to ¼” BSP  to convert from the cork Ewarts “pull on” petcock to Triumph type twist petcocks. The tank was in good condition. Didn’t need a shrapnel rattle, or chemical intervention just a soapy water shake up , rinse and dry and fill.
I put a couple of gallons in the tank , a dose of Lead Replacement Additive for my first road outing having rebuilt the engine. [An unsuccessful outing  - a cloud of blue smoke followed me].
So took the tank off and set it aside and commenced the forensic examination. The tank sat in the garage for the best part of the intervening time. Meanwhile I identified a couple of issues with my engine – valve springs, rings worn etc. All resolved now (I hope) and time for another outing now the weather is back. (Thanks forum for the previous help)
Went to put the tank back on the bike, looked inside the cap. Found it encrusted and badly corroded.  Distraught, put the cap back on and went back indoors. Two days later, having stopped crying (but still sulking) I’ve ventured back in the garage to look at the extent of the damage. See photographs. The only positive I’ve found is the tank doesn’t appear to leak.
So I’m trying to figure out firstly where I went wrong. This condition is after only say two gallons of petrol left for say 18 months. I guess leaving the fuel in the tank was an error. The new petcocks were sold as ethanol proof (ebay), the plastic fuel filters are dissolved/ disintegrated and of less use than an ashtray on a motorbike.
I’m hypothesising that maybe the lead replacement additive (Redex) is particularly aggressive?.
Anyway this brave (tryer) is looking for advice from the elders of the forum tepee. WTF happened, what did I do wrong?. Should I be even bothering with LRA Redex. 
And the solution I guess is to seal the tank as a precautionary step. Is POR 15 sealant the way to go?. Can alternative methods be used to prepare the tank for the sealant (rather than the expensive propriety ones) before applying the sealant itself to keep costs down.?,
Appreciate any advice or, ideally a pointer to best practice procedure..

[berger]

wow messy, I don't know about lead additive on it's own causing a problem but the petrol sucks moisture in violently . for many years now I have been using the octane booster called tetraboost [ look it up but expensive] I now leave the fuel in the tank with no problems at all. and it makes the bike very happy

[RichardL]

I know that some here use POR15, with which I have no experince. I've been successfully using Caswell's tank sealer. No prep required other than breaking away loose corrosion by shaking the tank with a handful of drywall screws inside. The product is advertised as encapsulating the rust and making it a non-issue. So far, that's been my experience.  I will say that removing it, if you must, is quite a challenge. I had developed a leak in my tank due to external abrasion. The brazing repair dictated removal of the Caswell's. That's too long a story right now.

Richard L

[Swarfcut]

Not so good, and the shape of things to come as the Alcohol content is pushed ever upwards.

 Modern fuels contain ever increasing amounts of ethanol, a short chain alcohol that is hygroscopic and absorbs moisture from the atmosphere.  In  the presence of atmospheric oxygen this moisture produces the corrosion seen on unprotected mild steel. So in an enclosed space, a full tank (no room for air) or an empty tank (no ethanol) would have been better than the half full situation allowing air and moisture (condensation) on the poorly protected steel. Open, dry tank (no cap)  and tank stored in the warm  is perhaps the better way, depending on how much you can get away with.

 If the tank doesn't leak, try it as it is for now after a good wash out with an organic solvent, petrol, kero diesel  etc,  anything but water. Forget those tap filters and fit  in line cheapo transparent filters. That way you can see what's going on and  while not original fitment at least  for now you have a practical  runner.

 There are different schools of thought about tank sealers, and long term are worth a consideration. Older types are said to dissolve in E5 fuels, newer formulae  are still under scrutiny.

 Nodoubt some  more experience with later  sealers will come along, and there are also previous posts debating the use or not of  the various sealers available.

Swarfy.


 

[Greybeard]

My tank came back from the plater with mild internal rusting. I wasn't on this forum then so didn't have a good source of information. I first tried shaking it with screws and paraffin inside. That didn't do very much. I bought the POR15 motorcycle tank sealer kit. I followed the instructions carefully. That was 2012. I've not noticed any problems with the lining yet.

I see that the UK government have ok'd higher percentages of ethanol so who knows if POR15 is going to be safe!

[BigJim]

I've found those types of tap to be a bit rubbish! They break easily in at least 2 places when I've used them, but then i am a bad mechanic. Am very pleased with my BAP type taps so far. As swarthy says some sort of clean and see how it goes, keeping it topped right up. I also have the POR15 lining mine as my Indian tank rusted quite quickly. I use an additive and keep the bike on the road as much as possible and thus far doing ok.
 

[ellis]

I only use Esso synergy 97 octane and contacting Esso they said they only put Ethanol in the fuel in Cornwall-Devon and the north east of England. They also said they have to put a 5% label on the pump because they have to do this by law even if it doesn't contain Ethanol. I have been using this fuel for the last 18 months and do regular tests for Ethanol and I have never found any in the fuel. I live in the north west of England.
Hope this helps.

ELLIS

[Black Sheep]

I chuck in a good splash of 2 stroke oil when I fill the tank. No corrosion problems to date.

[Angusa10]

Well I’m learning a lot.
Berger – Thanks for the tip on Tetraboost. At just over £30+/ litre. Adds  £1/ gallon. Very expensive.  But I think it would be better than the Redex  I’ve been using.  Least its real lead. Maybe I could reduce the dose – I’m interested in valve protection rather than the octane boost…and the protection of my tank.  [The amount of miles I’ve managed to do though – it’s not going to break the bank!.]
RichardL – I did look at Caswell. I guess you save on prep time using this –but must admit I don’t like the idea of the sealant over rust. I think I would rather spend the extra time getting it all out, back to good bare steel and getting the sealer to bond directly to an etched surface. That just feels more permanent. (Not that I have any experience with any of the systems)
Swarfcut – I think you’re right about ethanol . Maybe I have blamed my Redex as the culprit unfairly. (I was over emotional). Whatever, the fuel has obviously been unforgiving and punished me severely. [Note to self :  look at procedure when I lay up the bike to either drain the tank, maintain it full,  or seal the filler properly  (rubber  & clamp) to deny air to vapour space – or, really over-engineer it with an inert gas system,  fit anodes in the tank etc..). But the hygroscopic nature of ethanol you’re right probably was the villain. Think your way forward sensible too. Once all that sh!t is out of the tank maybe ill feel more secure about it and not use a sealant. In line filters rather than tank, yes.  But I still don’t understand how my tap filters, which were new, and plastic (ie inert) disintegrated.
Greybeard – Thanks for the feedback on POR15. I’m not seeing any bad reviews for it . Ive never done it before (lined a tank) and I’ve only got the net to go on). Did you buy the whole kit or just the sealant?. It looks pretty pricey at around £60 for the kit.  I’m thinking if you can do your own solvent wash, own citric acid treatment /wash and rinse very thoroughly for a few quid – is that good enough to use the POR sealant (£15) alone – ie without using all their propriety prep treatments which comprise the other £45. [Note to self :-must look at the MSDS sheets – see exactly what that sh*t  is]. Gonna assess first having given it a good wash out as per Swarfcut’s recommendation.
Big Jim. BAP valve on the Villiers site £9.00 a pop not bad. And another plus for POR15.
Ellis – Thanks for the info on Esso Synergy 97. Geography is against me. Live in Hampshire. Note to self:  Investigate where you can still get leaded fuel locally.
Blacksheep – Two stroke?. Love it. Gonna try it. Got some in the garage for the hedge trimmer. But if it protects that tank. Bit concerned I’m going to be followed by a cloud of blue smoke again though… which is where this whole sorry saga began..
Cheers

[Greybeard]

Re POR15. Yes you might save money procuring the ingredients seperately but will you be worrying that the prep was not as good as the official stuff? I have only done this once. I bought a kit for motorbikes.

During preparation, when I needed to dry inside the tank after flushing with water I wedged the nozzle of our vacuum cleaner into the filler hole using rags. With the vaccy running air came in through the two tap holes. Seemed to work well.

As the POR15 had run into the tap bosses I needed to buy a thread tap to clear them. If you want to borrow it give me a shout, I'll pop it in the post to you.

POR15 is mighty strong stuff; do not allow it to get anywhere it should not be. My tank had been plated and painted so I was very careful!

[bikerbob]

You could have a look at a company called Tank Care Products theyy specialise in motorcycle fuel tanks mods and repairs also they carry a range of products for preparing and sealing petrol tanks. I have used them before and also have used Por 15 both with good results if you follow the instructions carefully.

[Angusa10]

Just for information
Got round to looking at the POR15 MSDS for the preparation treatments - before you apply the tanking sealant.
POR15 Cleaner/ Degreaser is 90.1% deionised water, 2.03% butyl cellosolve, 4.24% Potasium hydroxide, 3.68% alcohol
POR15 Metal Prep is 86.4% deionised water, 8.52% phosphoric acid, 4.55% zinc phosphate.
ie - nothing really out of the ordinary from other treatments.

[oldbeezageezer]

Hi there all
For what it's worth, I did my old Honda tank about 4 years ago with POR15. I think I bought the whole system at the time. A lot of arm aching to shake the old nuts and bolts (count them in and count them out!) about. It was a nice hot day when I did it so after blasting the inside with the hot air gun I left the tank in the sun to thoroughly dry before coating. Jobs a good un.

I have left both the Hondas with full tanks and a dash of stabiliser each winter lay up and apart from getting a bit of rough running with the cbr600 flushing out the carbs, I have had no problems. Tempting fate here as I have yet to start them this year.

A10 tank has been off the bike for a while while I have had work done on the engine/electrics etc and is in quite good nick so I might leave that 'til I get up and running with it.

[Jules]

Interesting point about ethanol in fuels. I used to work in R&D at Ford when we went to ULP way back when they declared leaded fuel to be removed from market, we had all sorts of issues with corrosion through the fuel systems and the rubber seals/pipes and had to upgrade lots of parts to accommodate it ( eg advent of plastic tanks and viton seals etc) because of the fundamental change in the fuel's constituents (organic content comes to mind?). Ethanol came in as I was retiring but I know that it created similar issues again. Personal experience on my home generator when I used 10% ethanol fuel was that the fuel tap locked up due to the seals expanding inside, upon reading the book closely it specifically said to use ULP fuel, but no ethanol. If you extrapolate back from there to our machines its actually surprising that they actually work at all and/or dont leak profusely everywhere!

[muskrat]

G'day Jules.
We are lucky here in being able to get fuel without ethanol.
I work in a lawn mower shop and see daily the results of ethanol fuel damage. Anything that leaves the shop has 98 in it.
Cheers