Fuel tank material ?

shlim · 01-19-2003, 11:59 PM

Okay, as I had posted in the past, I've got 3 holes on the fuel tank thanks to the previous owner. Had tried to repair it with epoxy (at least an inch and half beyond each hole). But the repair probably lasted all of a few days. It no longer leaves drip marks down the side of the tank (maybe it's because I no longer fill beyond 3/4) but it still stinks of gasoline.

Had lived with it for a while now and decided it's time to do something about it.

1. Does anyone know what kind of material the 86 944 fuel tank is made of ? Fiberglass of some kind of ABS plastic ? Apparently some people are telling me that if it is ABS plastic, the tank is beyond repair.

2. Has anyone successfully repaired a late version tank ? The 80 litre "plastic" ones ? What did you use ?

Any suggestions will be much appreciated - the tank (and gearbox - again...sigh...) goes down tomorrow. A body-work shop was confident of fixing this but only if it's fiberglass. I'll get them to look at the tank first !

It's probably hazardous (to health + fire risk) to continue to drive this the way it is (was worse before though !))

shlim
86 944

AFJuvat · 01-20-2003, 01:22 AM

It is an ABS type of plastic.

Have never seen one successfully repaired. (success is defined as a repair lasting more than a few weeks)

Would recommend you start checking Junkyards and the like. 20th Street Auto in Phoenix AZ has lots of used, hard to find auto parts for sale.

AFJuvat

1.2gees · 1.2gees's Garage

I may have access to one, but I doubt shipping would be justifiable... Your location is not listed, so I have no way of knowing...
Ahmet

shlim · 01-20-2003, 04:45 PM

THAT's the problem - l'm in Singapore. So far shipping ($$$) has been a problem, though it still works out alot cheaper than a new tank. And there's only a handful of 85.5 (and later) 944 out here and impossible to find one in the scrapyard.

If it is ABS plastic, I think I am out of luck here. Sigh... D**M those hifi installers !

shlim

SoCal Driver · SoCal Driver's Garage

Polyethylene or polypropylene.

Can be common bonded -- dry heated inert gas/air welded. Have to have totally clean surfaces to do this. Usually extra material is fed in as a small diameter rod. Since you are in Singapore you might have contractors that repair the plastic processing tanks that the electronics industry uses to plate and etch with.

As was suggested: A sheet metal screw with a inert plastic washer with a metal flat washer over it. If you can get a bolt through it with plastic washers on each side it's much better. This will still seep gasoline.

shlim · 01-20-2003, 08:47 PM

Yeah, I've tried to self-tapping screw trick so far, with epoxy over it. Reduces the smell by about half and stops the VISIBLE seepage. Probably still putting me in the high cancer risk category - I have resealed the fuel filler neck cover (inside the trunk) and the trunk cover of the fuel sender but still have the drainage holes on the floor of the spare tire space and 2 sides (I have some seepage from the tailgate area still, so need the water to drain. The smell is still getting in, especially anywhere more than a half tank.

I will see what the guys at the shop can do - they are the Lambogini agents (but was one of the best independent Porsche workshop before) and was hoping that they had more experience working with plastic - but I forgot, with those $$$ cars, you just replace never repair !

On a separate note - I just found out that ZF themselves do overhaul 944 steering racks and can order practically every single part in the rack. Their new racks are also significantly cheaper (still $$$) than the OPC and even comes with "Porsche" sign and porsche part number - I guess Stuttgart just buys the rack and sells them without having to re-label anything. My rack looks like its history as well - the knocking noise is worse, steering is loose and after 2 independent mechanical assessments from experts, it looks like it is the rack (I've got 3 new A arms - one side changed twice, luckily the second time under warranty, newish tie rods, shocks, strut bearings etc).

shlim
86 944

Techdraftsman · 01-29-2003, 10:31 AM

can you please tell me how and what you used to seal the top of your gas tank? the tank in my 85 late 944 is leaking and i would really like to seal it up. if anyone else happens to know a good product to use, please let me know. also, how hard is it to remove the fuel tank in order to work on it or replace it?

thanks,

joe

SoCal Driver · SoCal Driver's Garage

Have to remove the axles, transmission and cross support.

Baza · Baza's Garage

Seeing that you are in Singapore have you thought of trying to get a fuel tank from Australia? There are two companies that deal in 944 parts One in Perth which would be alot closer for you, the second in Melbourne.

Swanporsche Perth www.swanporsche.com.au

Aporscheapart Melbourne www.aporscheapart.com

I have found both are good with David in Melbourne being the most knowledgeable. Due to the fact that he race in the 944 cup. But are a little more expencive.

Hope this helps you out a little.

Barry

marksportcts · marksportcts's Garage

I had a hole drilled into the top of mine a few years ago. Just couldn't fill up. Took it out and used a bunch of Fiberglass and resin. Hasn't leaked since, but being at the top, fuel vapours can't do eat away like liquid fuel
will. I am removing the tank this month coming and putting one that I bought on ebay for like $30 plus shipping. I am gonna be running all Aeromotive components and braided fuel lines.

The early cars use a different tank than the late cars. I think early use a steel tank. If you got money, call World Wide Motorsports or Lindsey Racing
for the fuel cells.

shlim · 01-29-2003, 07:31 PM

Ah, finally a success story. I was going to do the same - fibreglass and resin - got a couple of small holes on top and one at the side. But decided not to try patching it after hearing all the unsuccessful attempts. Will probably get a used tank, it's just not worth the trial and error as the labour to take the tank out is substantial.

thanks for the feedback
Rdgs
shlim
86 944

shlim · 01-29-2003, 07:55 PM

Oops, Barry, somehow missed your post. You are right and I have used aporscheapart in Melbourne (suburb somewhere), in fact, I think it was David who picked me up from the station. They have some interesting stuff - managed to get a convex side mirror from him at a good price ! I think they had one or two late model 944 in his yard when I was there (I was looking for a console).

shlim
86 944

ugo968cab · 01-30-2003, 04:22 AM

If the tank is poliethylen/polipropylene (PE/PPP), I think you can TRY a repair, but only using the correct material AND if the holes are small, no large cracks.

You cannot use epoxy, because PE/PPP are impossible to bond with such glue, and everything you do will not last that few hours.

For a "long term" repair, you have two possibilities

1) Search for a PE specific adhesive, not sensible to gasoline (if any)

2) Use hot air (150-250°C) to fuse the same material (PE/PPP) in the hole. Some art if needed here, because you must heat also the tank hole borders if you want a stable bonding ! But you can can do some practice with a normal PE/PPP can, before trying the gasoline tank

Eventually use method 2) to do the main work, and 1) to refine. If you use method 2)

!!! CAUTION !!!

on completely drying and ventilating the tank and keeping it open, to avoid problems with gasoline vapour.

Bye

Ugo