Tank Sealant in fuel

Hello,

This is my first post, so hello all....
I've lurked around for a while and always found the answer to my questions in the archive, but I thought I'd post this to see if anyone else experienced my problem.

I'd been having carb. issues for a while on my 1976 Interstate. Shes been with me for 18 months now and after the first few months I couldn't get her to idle and the plugs would foul up quickly. I changed recently to a new set of Amal Premiers and she was running better, except for the oil leak that had sprung from the head gasket. So I shored her up for the winter and set about stripping the top end down to see what was going on....

As you can see from the pictures, the pistons were very messy and the barrels marked and scored.





There was a brown/yellow coating on the piston skirts, rings and in the barrels. At first i thought it was oil that had got hot and stuck on. So I carried on with the plan to change the gasket and sort out the barrels, which is where i thought the oil has come up from.

While waiting to get a parts order in I thought I'd drain the tank and seal a small leak it had from one of the mounting studs at the front. When the tank was getting empty I could hear something rattling around in the tank as I sloshed it around. I shook the tank out and this is what came out.



Tank sealant I guess, of some sort, glassy and like amber. Not anything I've put in and the sealant I've used before has dried to a solid pinky colour, as far as I can remember.
The fuel was very cloudy as well. Also, one of the Taps was almost blocked.



So, with that I thought again on the nick of the Pistons and barrels and wondered if this failed tank sealant had dissolved in the fuel and gathered in the head. The black deposits on the crown of the pistons was quite bitty, for want of a better word, like crystals, not like a regular carbon build up and flaked off. I'm thinking that as the contaminated fuel burned it left this in the pistons. Possibly this could have caused the scoring on the barrels. The brown yellow deposits are hard but can be scratched off with a finger nail, to some degree.
All this resin in the fuel and blockages would also account for the carb. problems, fouling plugs and the fact it ran better on a new set of carbs. For the short while they were on.

Has anyone else had this trouble? I'm guessing that the Sealant is old and the new unleaded eth. fuel has done it in. It could be fairly poor quality sealant as I've no idea what it is.

I would love to know what people think and if anyone has any ideas on what to get rid of all this stuff with.

The plan at the mo. is to clean it all off and re-seal the tank with something new. Again any suggestions appreciated...

thanks

Kevin White
London
UK

Hi Kevin,
I've am having similar probs with my glass tank ,was advised hot soapy water and a few screws and keep at it. As for tank treatment you could give Caswells a phone and ask to speak to Jeep,he will give you good advice.I bought dragons blood but my tank still has stuff stuck inside so I haven't used it yet.I hope you do well. Regards jim

Prolly Cream or POR prior to the alcohol era so only had to deal with rust and hole sealing. I can't see how anything in the bores would cause diagonal spiral scoreing as I've had grit inhaled on my Combat that scored almost as deep for smoke clouds but were all strictly vertical. I'd guess DPO put them in there trying to rehone or something and just left it for next sucker to deal with.

If tank fiber glass likely trashed as booze seeped deep into the resin. MIght save it but oven heating many hours then acetone wash with screw and bolts and chain and nuts and washers and nails, for a few minutes or worse than ethanol on old resin, then oven cook off again and try the Novalac 2 part Castwell treatment put on at least 1/8" in one layer or several taking care to get some to remain around filler then leave so front mount studs are low point, after 30+ min turning till sets up mostly. Steel tank no problem lye or acid boil then Caswell it.

The pic down the barrel was mainly to show the deposit that had gathered there. Here's a better pic of the scoring...





Thanks for the replys,

Kev

I am against using tank sealants, because of stories like yours. I bought a nice roadster tank a while back that had been sealed with something. I filled it with MEK and left it to soak for quite a while. I then washed it out, put in fresh MEK and a handful of bolts, wrapped it in a packing blanket and stuffed it into an electric cement mixer and left it to tumble for a number of hours.

I wonder now if I should have used ethyl alcohol! As MEK is nasty stuff.

Russ

I've since worked out that the sealant in my tank was Petseal or something like. I've found some Petseal remover from a Company in the UK, Tank Care Products. He also supplies a Tank Sealer, Sure Seal that is said to be 100% ethanol Proof. I've ordered a pack of products and I'll let you know how it goes....

I had considered getting a new tank, but at £500+ its a bit steep. Chances are it will only rust again anyhow and best just to seal what I have properly.
Barrels are off to Mr Hemmings for rebore and new pistons. Valves I'll be stripping and cleaning. Apparently, thinners will remove the thin coating on the head parts.

kev

The increased content of ethanol in pump fuels attacks the old formula tank sealing products
Which can make a real mess of your fuel system and top end , I have seen carbs blocked and inlet valves almost glued open by failing sealant

There is a product on the market called seal eater which will effectively remove the old sealant you can then re apply one of the new ethanol resistant sealers to a steel tank

if you have a fibre glass tank then I would not recommend using seal eater as it will also attack the resin bond
using original fibre tanks with current fuels Is becoming an issue , can some one design a bag tank to fit inside to give a perfect lining

I now see the horrible vertical score marks in bores, ugh, but don't see how the crap from tank would be hard enough to do that but something sure did. They look similar to Trixie's smoking bore scores after carb boots cracked in the valley so found out the hard way. We lucked out that Norton had hard enough valve seats that no lead change in gasoline didn't need new ones like too many other vintage craft did, finding out the hard way. Buy a C'do for a penny then go down for pounds and pounds before back roadworthy.

I think there may have been other problems... I pulled the cam followers out before packing up the barrels to be re-bored and they too are scored to hell. The tops of the valve springs have a coating of burned on oil and I think there has been a lack of oil and some serious over heating going on. Not sure if the resin in the tank was a red herring or part I the problem. There is a lot of black glassy residue on the crown of the piston but it crunches easily and doesn't seem that hard. Unless that with a lack of oil could make it all worse.
I had on oil seal go on the oil intake before Christmas, thinking that was it.
Wondering how far to pull It down....

I'd keep going until you stop finding problems.

Greg

Maybe a case of multiple diseases at once, definitely the tank gunk could cause gunk in chamber and maybe carbonized-hardened its crud so scored the barrels while DPO ran it low on oil w/o knowing it till too late so you lucked out to get it to enjoy. Lifter bottoms can be milled smooth and cam lobe refinished maybe nitrided and polished while all the time in the world dealing with all the other things we all do a good bit over our oringal guessimate.

Seems like you are rolling the dice when using any of the tank sealers available. A metal tank is a lot cheaper than restoring the engine.

beardyweirdy said:

I think there may have been other problems... I pulled the cam followers out before packing up the barrels to be re-bored and they too are scored to hell. The tops of the valve springs have a coating of burned on oil and I think there has been a lack of oil and some serious over heating going on. Not sure if the resin in the tank was a red herring or part I the problem. There is a lot of black glassy residue on the crown of the piston but it crunches easily and doesn't seem that hard. Unless that with a lack of oil could make it all worse.
I had on oil seal go on the oil intake before Christmas, thinking that was it.
Wondering how far to pull It down....

Click to expand...

If the cam follower bores are scored, that means that iron filings will have mixed with the oil and been gently cascading down onto the cam, so close inspection of that would be advisable. Mine was scored like yours, and the cam looked ok at a glance with the bottom end still in the frame etc, but when I did strip it, and look at the cam closely, it was not good.
If you suspect a PO has run low on oil, the big ends could have suffered too.
All in all, I would suggest stripping the bottom end 'a stitch in time saves nine' etc.
I was in your position a few months ago, I really didn't want to strip the bottom end, but eventually I decided to. I am so glad that I did as I now KNOW everything in there is bang on. I had my crank dynamically balanced and it was way out. All of these things add up to make the thing better when done, and give a nice sense of satisfaction in the doing, and also in the end result.
It also helped me to learn about how the thing works, and I have been pleasantly surprised so far, just how easy it is to strip and rebuild.

Thanks for the replies and sage advice Eddie, I've decided to do the right thing and have it right down. I've just done the same with an LC I have and your right, knowing all the problems is better than shying away. I'll have to invest in a running bike to tide me over spring while I take the time and enjoy it. Sod's law, we get a bit of decent weather and all the bikes are layed up ;-) It's a shame as the thing was only re-built in 2009 and 3000k ago by Norman White at great expense ( previous owner). Still won't hurt to know it's all good when done..... now anyone know of a decent runner to tide me over.... ;-)

I had my interstate tank painted in the 90s, and the guy who did it gave me a can of sealer to use. The sealer was a creamy white color and IIRC came from a small aircraft parts company or was intended for that application.

Any idea what it might be, and whether or not it would work with ethanol + petrol?