Tibo

iTrader: (15)

I have been working on my 91 Convertible for a good long while now and have finally made it to working on the underbody. The link to which is in my sig. After I removed the fuel tank I found out that the prior owner cut an "access panel" above the fuel tank for replacing the fuel pump. Scariest thing is, it is evident that he used a cutoff wheel that was turning very fast. You can see the discoloration from the heat input and the characteristic metal strands. It's also the same width as a cutoff wheel. It's a sure bet he was throwing sparks.




That is a picture of it from underneath, after I dropped the tank. I immediately thought of just welding it back up but then I thought, well, it's already there perhaps I can do it "right."

If I did it "right" changing fuel pumps would be super fast and ridiculously easy. The tank and interior is now out so welding and grinding is safe and a snap.

So what would be the best way to fix this? I was thinking about welding in some radiused corners so the rectangle hole would be an oval and then EITHER welding in a thicker ring (that would add in strength where strength has been lost) where a plate could mount to OR just using a thicker plate over the hole and use rivets and fuel safe sealant on it.

With rivets what is the recommended spacing?

I'll welcome any input as long as its not along the lines of "you're a lazy idiot, weld it back up and perform an exorcism on the car."

I have already read through these threads:
https://www.thirdgen.org/forums/faq-...tal-above.html
https://www.thirdgen.org/forums/tpi/...es-done-1.html
There is also this post by BigMods and there are many other posts by knowledgeable, experienced members so really, there is no need to start with the hacking comments.
https://www.thirdgen.org/forums/tpi/...ml#post3868614

thtanner

iTrader: (1)

There is no 'right' with an access panel, in my opinion, because you still have to cut the metal fuel lines and splice in some rubber tube. Not a fan of that action. Since that has already been done I'd replace the sending unit assembly.

You already have the tank dropped, that means next time you do it it will be that much easier. Weld her back up right imo

Tibo

iTrader: (15)

I specifically asked not to receive the input you just offered up.

There is nothing wrong with an access panel as many cars from the factory come with them. Here is a thread with pictures about how Pontiac/GM put them in the Grand Prix: http://www.clubgp.com/newforum/tm.as...heck=887120392
BMW used them, Ford made use of them also.
There are untold amounts of cars at the dragstrip that have access panels. You can read through the threads that I posted and find many more examples.

OrangeBird

iTrader: (1)

Hi Tibo ,

Since it's already cut , and you'd have to weld to close it back up correctly anyway , here's my idea ;

You rightly mentioned lots of cars having a hatch , and that sparked a thought , why not peruse your local pink N pull and cut a chunk out of a vehicle that did have that kind of hatch and weld it in , already having all it's hardware and seals pre engineered for you . It wouldn't even have to been a fuel sender hatch in the first place , lots of RVs and trucks have all kinds of little access panels just waiting to be cut out and used as you new hatch .

And of course you can use compression fittings so that no rubber would be needed to join the metal tubing . And best of all , No exorcism required

mmadden55

Hardware stores sell hinges and latches for a variety of purposes. I would cut the fourth side and put a hinge on it, and a latch on the other side. Slit piece of vacuum tube lengthwise and put it over the sheet metal edge for a seal.

Tibo

iTrader: (15)

The thought of using a piece of rubber tubing slit hot dog style had popped into my head. It would save me from cutting myself and help protect from rust. Heading to a hardware store for a door or a piano hinge isn't a bad thought as long as it's sturdy.

Tibo

iTrader: (15)

That is a great idea. I've googled the pictures of stock access doors but not all of them were flat. Still I might head down to a yard and see if I can find any possible donors-- otherwise i think I'll just buy a smaller sheet of 14 gauge (at least) and cut it to just larger by 1/2" per side and cut out a large oval in the middle which would make a flange I could weld in. Then just use another piece to cover the hole. Use tubing on the edge and then maybe weatherstripping for the mating surface. I had heard of a member using some type of sealant that worked too well and it bent up his access panel when he was pulling it off.

TylerSteez

iTrader: (3)

If I was to do it, I would take half inch angle iron and make a square that perfectly surrounds the access hole. Then I would make a sheet metal door to cover the hole and sit inside the angle iron framing nice and snug, I would then drill and tap holes in the angle iron so that I could mount the sheet metal door to the angle iron with flat top machine screws and cover the hole. Then I would get some of that foam that has an adhesive side and put it on the angle iron so it has some form of gasket/sound deadening affect.

I personally like the idea of a fuel pump access door but everyone on this site hates it. In my opinion there is way worse hack jobs you can do to these cars than a very useful fuel pump access door. And in terms of structural integrity, i don't believe a square hole in that place on the car would cause any issues

Tibo

iTrader: (15)

I'm leaning towards that route, But I may differ in that I'm pretty dead set on using riv nuts instead and using just 3/4" wide metal strip instead of angle iron. Sounds like you just finished reading this thread also:
https://www.thirdgen.org/forums/body...-previous.html









That member seemed to do a good job of it like I want to but as I understand it an oval hole would be better structurally. Here is a picture of BigMods panel

Tibo

iTrader: (15)

I found this panel and while it looks like it would fit, look good and work I'm not sure that I like that it doesn't seem to create a perimeter seal.
https://www.summitracing.com/parts/kys-100-89989

TylerSteez

iTrader: (3)

actually never saw the thread but that guy did do a fantastic job

mikeceli

iTrader: (2)

I would reinforce the hole, as the OP suggested and use a Riv-Nut tool,(below) to secure the plate. Plate would be approx. 3/16 steel, for strength.

I'd get some neoprene rubber from Lowes or the like and make a gasket, to prevent fuel leakage into the interior, in the event of a crash.


http://www.harborfreight.com/45-piec...-kit-1210.html

snakeshooter

What about a dry hatch cover from a marine supply house? They come in aluminum too.

Tibo

iTrader: (15)

I actually have a rivet nut tool that I was leaning toward using for this unexpected fuel pump access door mod. Are you suggesting 3/16" for a frame just around the perimeter or 3/6" thickness steel for the access door to be made out of?

Tibo

iTrader: (15)

I may have one in the area I'm in but I won't hold my breath that it would fit my bill. Had you seen them online?

EDIT: What I found on Google looks far too big or small or at least twice what I'm willing to pay.

mikeceli

iTrader: (2)

Yes. I would have to eyeball sample steel. I was thinking 1/8" might be overkill, maybe not.

Tibo

iTrader: (15)

I made these two templates, the larger one is going to be the size of the cover plate and both plates will be 16 gauge steel which is the same thickness that the frame rails are made from. The floor pan measures to be 18 gauge thickness. The smaller template will be the size of the opening or id of the hole, it's also the the shape I'll cut out of wood to bend the flat bar around sideways. The hole id will be 6.75" x 11.5" giving me a 0.75" gasket surface.





The threaded rivets didn't install straight and the piece I welded in distorted and I didn't tack it all over first before I started welding so when I began welding one side it pulled toward that side and made a gap on the opposite side. So it looks sub par. Should've just went with 1/8" plate all around and just threaded that for 8-32.






The fuel pump access door, all done. I did like any welder who has made a less than perfect weld- seam sealer! Then a coat of paint. I think I used 22 bolts for it, one every two inches. 8-32 machine thread.

BrutalGTA

iTrader: (2)

Subd

mikeceli

iTrader: (2)

Well done!

Tibo

iTrader: (15)

Thanks. If this fails or something starts to occur I thought the other way to do it would be to use either 1/8" metal plate drilled and taped for 8-32 bolts OR use 16 gauge with rivets or rivet nuts then cut out the same size and shape oval as I currently have. Right now the sides of the plate are welded to the inside portion of that pressed down channel portion of the trunk floor. The new metal plate plate would be a little bit wider so that it would be welded to the outer edge of that channel on the topside and be welded from the the underside of inside of the channel.

The 16 gauge vs 1/8" is an argument for a car engineer. Do you want something strong (1/8" plate) or something that will crumple (16 gauge) similar to the trunk/floor pan in the occurrence of a crash?

UltRoadWarrior9

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BovineZro

iTrader: (11)

This looks really nice!

I personally haven't done this to my car (and wouldn't, I'm not trying to cut into anything if I can help it) but my donor car had an access panel. The PO cut a slightly larger piece of sheet metal and sealed it with what looked like RTV and pop rivets. I think that sort of hack job is what people get upset about. Your end result looks clean, professional, and you'll be able to get in there easily if you need to work on your fuel pump. And of course nobody will see it under the carpet in any case! Well done.