Fuel tank coating and what it all means.

[oldroaddog]

So I'm running with a suggestion that my '75 280Z is having engine problems because trash in the fuel tank is clogging the screen. A member of our local Z Club offered this up from his own experience. The symptoms I described were indentical to what was going on with is car - running well for some period of time and then suddenly loss of power, sputtering and finally stops running. Let the car sit a while and start it back up and all is well... sometimes.

Over the weekend I drained the tank and yes there was some particles in the fuel which I strained into a gas can. Didn't really look like rust. So I dropped the tank and got a little surprise. On top of the tank there appears to have been some repair work done. There's a V shaped "scar" of unknown material. Otherwise the tank looks in really good shape. Externally there's no rust or dents. From what I can see internally there appears to be some reddish deposit on the bottom of the tank but that could be the factory coating.

Now I've researched the do-it-yourself cleaner/coating kits and it looks like a really involved process. The POR-15 kit seems to be the most desireable but takes a week to complete. All the information says you've got to remove the screen which I haven't figured out how to do that on this tank. I'm not convinced I'm going to tackle this proceedure at this point.

My other option is to have the tank boiled at a radiator shop but that would mean I'll have to find someone to coat it as the radiator guy is saying he doesn't do that. I've got a call into a local guy that has done coatings before and I'll see what he has to say about it when he returns my call.

So my questions at this point...

How do you get the screen out of the tank?

If there's a patch will it come off when it's boiled?

Does the POR-15 kit work and is it worth saving $50-$100 to do it yourself?

Any input will be appreciated.

[=Resurected280=]

I had a very rusty gas tank when I began restoring my Z (a '78 280Z) and I also had to have the gas tank relined. Most of the people that I talked to about the do-it-yourself kits (older guys that restore american cars for the most part) said that the do it yourself kits are more meant to do motorcyle tanks and tanks off of carbureted cars. The reason for this I was told is that the lining material can clog a pick up line if your not careful and this is a pain to fix if this happens.

What I ended up doing with my tank, which was VERY rusty, was I sent it a radiator shop that was experienced in this kind of thing to have it boiled and relined. They ended up having the tank for about a week, they spent 3 or 4 days just boiling it, and I had to let the lining cure another couple days before I installed the tank but it was well worth it because the car now runs awsome.

So far as the question about the screen and the patch i'm not sure what to do there but some one this site must know.

Good Luck!!!!!!!!!

[=Resurected280=]

Oh and one other thing the shop only charged me $110 for this job last summer.

[Walter Moore]

I took my 240Z's tank to a radiator shop here locally that also specializes in repairing gas tanks. It looked fine, until they "dipped" it in the cleaning solution... then they noticed that the tank was draining from everywhere, not just the drain holes.

On my tank it was closer to $300. I don't recall the exact amount... the mind suppresses pain you know. :surprised

[oldroaddog]

So I found a raditor shop locally that had experience in and would clean/coat the tank. When I showed the tank to the owner of the shop this morning he said that it had already been coated and that cleaning it would cause the coating to melt and really screw things up. I mentioned that I had taken as good as look as possible at the screen and that it did appear to be partially blocked. He said this may be caused by the coating not having been appied properly. So I'm looking at him saying "So what can you do?". His solution is to plug the original fuel service fitting, drill a new hole and install a new fitting and draw pipe. This new pipe won't have a screen but he suggested I put an in-line filter between the tank and fuel pump. It sounds like a good fix to me. If there's still trash in the tank it will clog the filter and be easy to access and change. The only issue I can think off would be a restriction in flow caused by the in-line filter but wouldn't the internal screen have the same effect even if perfectly clean?

[=Resurected280=]

The in line filter would cause a restriction in flow but it should be minimal, I cant imagine it would cause a noticable difference in performance but I have never tried this so I cant say for sure.

One other thing that you could do with your tank is send it to Gas Tank Renu USA http://www.gastankrenu.com/ these guys are a little pricey (they quoted me $400 to do my tank) but they will cut your tank in half and do whatever is necessary to make the tank good again (welding, patching, etc.) and then reassemble and reline the tank.

If you look around there are other threads on this site that get into what they do in more detail.

[oldroaddog]

One other thing that you could do with your tank is send it to Gas Tank Renu USA http://www.gastankrenu.com/ these guys are a little pricey (they quoted me $400 to do my tank) but they will cut your tank in half and do whatever is necessary to make the tank good again (welding, patching, etc.) and then reassemble and reline the tank.

That's the one of the good things about this situation - the radiator shop owner is only going to charge $68 to install the new fitting and plug the original.

[oldroaddog]

The fuel tank has been re-installed and I thought I would post some photos to update interested members. These two show the added service line beside the original which has been filled and capped...

[oldroaddog]

This shows the fuel line with the in-line filter which takes the place of the internal fuel tank screen...

[oldroaddog]

And now the road test. The car started up fine and sputtered a bit for a short while but once the fuel lines were filled everything was good. Feeling confident that the problem was solved I got the car off the stands and out on the road. After adding 4 more gallons of gas to the 4 that I put in from a jerry can I proceeded to the highway. I forgot to mention that while the tank was dropped I put in a new fuel sending unit and it's sure nice to have an accurate fuel level on the gauge!

So I'm cruzin' down the highway 70 mph for a few minutes waiting to see if the sputtering is going to start again. I thought I felt a few tiny misses and after I pulled off down a local road... wham! Ignition just stops as if the key had been turned off and then when I started the engine it came back. I stopped for a moment then pulled back into traffic and then again. The engine just stops but this time it's not restarting. So as I'm sitting in the parking lot waiting for my wife to come by and tow me home I'm thinking this is something electrical and possibly heat related. There may have been some blockage in the fuel flow before but this other issue was happening as well. I'm going to CC this post in the Electrical or Ignition section and I'll continue there. I'll add a link here after I complete that post.

http://www.classiczcars.com/forums/showthread.php?t=18225

[zpizzaman20]

I had the same symptoms a while back on my 78 and it was the distributor. After is stops poor some cold water on teh dizzy. If it starts right up you have it. By the way when mine sis this it got worse and worse, started out doing it about once a month and worked up to several times a day

Fred

[oldroaddog]

Problem finally solved!

After a conversation with a local Z car expert I changed the coolent sensor and the associated wire harness. Apparently with that circuit bad the EFI never gets the message that the engine has reached operating temperture and the fuel/air mixture is screwed. I think my sensor and/or harness was intermittant and that's why sometimes the car ran great and then like the flick of a switch it would run bad.

Lesson learned. Consult an expert when all else has failed or even sooner!