I've been out of the RX7 game for a few years now. Been into the working my life away and starting a family game haha.

But I just picked up yet another FC. Not quite sure on my plans yet. But as for my question.

The fuel tank has been sitting with fuel in it for... Who knows how long. I don't have a problem dropping it and cleaning it, but I'd prefer to not drop it. Is there a way to get this gunk out without having to drop the thing? Maybe disconnect my fuel lines and let it soak with some sort of cleaner, siphon, and then blast it out with the pressure washer?

 

honestly, drop it, it will make life MUCH easier, and make it a better job

 

no no no no....

you want to be able to put some rocks in it and shake the hell outta it.
or just drain and fill. if it's just bad gas, no cleaning needed..( unless it's dried chunks)
have you looked inside to see rust or how bad?

 

Inside was bad enough to clog a new fuel pump sock in about... 15 minutes. It's sat in it for quite a long time I'd say. It's turned into gunk basically.

I guess I'll just drop it. I was just hoping I would have to.

 

Dropping the tank is much like pulling the dash...everyone dreads doing it but later admits it really wasn't that bad.

 

Hahahaha heard that clokker. Last time I pulled a dash, it was a nightmare. Dropping a tank isn't a horrible job, but I do dread it.

 

If you can get the sending unit off with the tank ON the car then there really isn't too much of a problem.
Drain the fuel with the 14mm drain nut on the passenger side of the tank,mop out the old fuel..clean up and put back together.
If the Y pipe is already off the car then the tank can be dropped in like 15 minutes with a floor jack.

 

The amount of work it is going to take to clean it out through the little fuel pump flange hole just isn't worth it. You'll have a very hard time getting the whole tank clean unless you use a small pressure washer wand or something. Then draining it becomes a hassle. Honestly removing it isn't really that bad at all. Remove catback, disconnect lines to tank, remove tank straps. Plus then once it's out of the car, you can coat it to avoid this issue in the future.

 

Just dont have it boiled at a radiator shop, they made a f'ing mess of mine

Degreaser and water, flush , flush flush until water is clear.
Repeat. Dawn dish soap and water,flush until clear again.

Then i filled it with white vinegar and let it sit a week
Flushed with water and dawn again.
Dried it out with a towel through the top, then let air blow in it with a cage fan for a day or so.

Depending on what the surface looks like when you are all done you may want to seal it, i used red kote

 

I watched your video Aaron. That's one of the reasons I wondered if there were a way to do it without dropping the tank haha. Looked like a hell of a workout. Hahahaha

 

Than again, Aaron is quite good at Shaking his Tank, and applying a considerable amount of suction with his mouth. Ladies, take note...

Drop the Tank, Give it a Shake and Do the Aaron Cake

 

Hahahahaha that is my new sig

 

I drained the tank and got a good peek inside. It's bad. Really bad. About an inch thick layer of rust/sludge. And the sump area(correct terminology?) appears to have oil sitting in it. But it's the consistency of honey.

 

Some kerosene, or acetone might break that up.
Follow what i suggested the vinegar takes care of any surface rust

Or source another tank and hope its in good shape

 

I poured in a few gallons of vinegar and it's slowly breaking down everything. The tank is actually in good shape under the sludge. Nice clean metal.

 

After a little bit of cleaning the gunk out by hand

 

Amazing what some soaking does. Try Super Clean poured in 100% (buy the big jug) and then let it sit several days. Agitate it often. Then cut it with water about 50% and give it a few more days.

 

Soaking and agitating will work but abrasion will speed the process up considerably.
Toss in a few pounds of pea gravel (or ball bearings) and agitate.

Can't recall where I saw it but one guy did just that and then strapped the tank into a cement mixer and spun it for a few hours...came out sparkling.
If you don't have a cement mixer handy (and why don't you?), it'd be relatively easy to cobble up something similar.

 

Perhaps fabricate some sort of rotisserie with a clamp on handle? Use it specifically for cleaning the tank, and it would also work for coating it too!

 

Be careful with this. Tanks are usually galvanized and too aggressive of an abrasive may do damage to an already weakened surface coating. I like the ball bearing idea, rocks and gravel, not so much. If you're using a petroleum solvent, try rock salt.

The last tank I dealt with I had cleaned and coated by the radiator shop. It worked just fine though others above had a bad experience.

 

I do believe that was the '29 speedster build

 

I would assume that after such a cleaning the tank would need recoating, so the condition of the original galvanizing would be irrelevant.

Yes, thank you.

 

I used very strong acid on parts of my tank to see if it was galvanized and i could see no sign of it

The red kote is good stuff, very easy to use. 2 quarts will do 2 nice coats. Just follow instructions and take your time. If you never had premix in the tank it takes some worry from the job

I think it was cheaper from amazon then from them direct

 

New discoveries. Every single one of the little bolts for the fuel pump lid type deal, have been snapped off by PO. So now I have to attempt to drill these minuscule little things out.

 

They are 4mm IIRC.