Diagram to dremel a hole in floor for FGuel Pump Access??

[1987 T/A TPI 305]

Does anyone ahve a diagram of where to cut a hole in the floor to access the fuel pump on my 1987 T/A?

[deadtrend1]

Don't do it. It is faster to take the tank out than it is to properly prep, cut, and metal finish an access door. Lowering the rear is easy and only requires the removal of a few bolts. You just have to let it sag. You don't need any special tools other than a socket set and maybe a few wrenches. It isn't that hard but for some reason everyone thinks it is so much harder.

If you don't have the tools to do it right, i would get them. Or have to towed to a shop to do it. Its a tight fit to get a good cut, so the best and safest way to prevent injury to the tank would be to do it with the tank out. Thats just my opinion.

[//<86TA>\\]

dont cut a hole in the floor to get to the pump, its a total hack way of doing things. Any if you f-up, you could blow yourself up, those lines are real close to the metal
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VAPORIZER EASY VAPE

[String]

DON'T HACK IT!!! Its not just the center hole you have to cut, you would have to cut like a 3 foot section across it as well to actually pull out the pump and fuel lines. and theres a few supports welded to the bottom of the trunk you would have to cut through too.

[JohnG]

oh come on, people have been cutting the trunk on 3rd Gen's for 20+ years now

[ar0ck]

Don't listen to the haters, its fast and easy!



you can't go wrong they are the same on 3rd & 4th gens, just give it some space between the ribs and you'll be fine. I've done it on 2 cars so far and not once have I had a problem. Just lift your rear carpet and its clear to see. Some of us just don't have the skill, knowledge or time to drop the rear and all that crap. When you lift the carpet you'll see these cars were designed to have an access panel, it probably just would have cost to much for GM to actually put on there.

[WildBillyT]

Alex-

From whatI see in the picture, you did it the way I would have. With a set of aircraft snips. Not a dremel, cut off wheel, grinder, or plasma cutter. That greatly reduces the risk of explosion.

Regardless of how safe people may say it is I would never use anything that throws sparks near a gas tank.

[ar0ck]

When Ted & I did his 89 Iroc, we used an electric powered chisel that just sliced through the metal like a hot knife in butter without a single spark.

I did use aircraft snips because thats all I had. I had to cut in a little more though to reach the quick connections (LT1+ has them)

[//<86TA>\\]

Originally Posted by WildBillyT

or plasma cutter. .

that would probably be news worthy
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NEW MEXICO MARIJUANA DISPENSARIES

[Mike]

personally, to remove the stocker and put in an aftermarket the FIRST TIME, i would drop the tank.............while the tank was OUT OF THE CAR i would cut and fab a quality access panel...

that way it was quick and easy if anythign happend to the aftermarket pump

[deadtrend1]

Originally Posted by cbrrmike

personally, to remove the stocker and put in an aftermarket the FIRST TIME, i would drop the tank.............while the tank was OUT OF THE CAR i would cut and fab a quality access panel...

that way it was quick and easy if anythign happend to the aftermarket pump

yea, thats kinda what I was saying above.

[Mike]

if your putting in another oem pump, i would drop the tank for sure since you will probably have many miles before another problem

if going with a racing pump, maybe cut the door while the tanks out so that you can change if it fails, they dont seem to last as long

when i do mine it will have some sort of weatherstrip/gasket seal and a xeus fastener/hinges.......

[WildBillyT]

Originally Posted by cbrrmike

if your putting in another oem pump, i would drop the tank for sure since you will probably have many miles before another problem

if going with a racing pump, maybe cut the door while the tanks out so that you can change if it fails, they dont seem to last as long

when i do mine it will have some sort of weatherstrip/gasket seal and a xeus fastener/hinges.......

dzus fastener?

[Mike]

sure

[IROCdan330]

I agree with those saying not to cut a whole in the floor.

I'm no engineer, but based upon where the rear shocks bolt into the back and the twisting it will see during a launch and or cornering, I wouldn't want it any less structurally sound.

Alex, I understand you haven't seen a problem on the two you've done thus far, but in a long term setting problems could arise. And if like you said, some of you don't have the skill, knowledge, or time to drop the rear and the tank...well think about what you just said. If you don't have the knowledge or the skill to remove a few bolts or set up a lift or jackstands properly, what makes you think you have the skill or knowledge to cut a hole in the trunk of a unibody car? GM didn't put that access panel there for a reason, what the reason is, I do not know, but quite honestly I don't think you do either. If you don't have the skillset and time, the car should go to a qualified shop to be repaired properly.

If replacing with an aftermarket pump, instead of cutting a hole in the car, an external pump is a viable option...

[//<86TA>\\]

the floor back there is a flimsy piece of sheetmetal, not very structural
________
Black Lesbians

[ar0ck]

Originally Posted by IROCdan330

I agree with those saying not to cut a whole in the floor.

I'm no engineer, but based upon where the rear shocks bolt into the back and the twisting it will see during a launch and or cornering, I wouldn't want it any less structurally sound.

Alex, I understand you haven't seen a problem on the two you've done thus far, but in a long term setting problems could arise. And if like you said, some of you don't have the skill, knowledge, or time to drop the rear and the tank...well think about what you just said. If you don't have the knowledge or the skill to remove a few bolts or set up a lift or jackstands properly, what makes you think you have the skill or knowledge to cut a hole in the trunk of a unibody car? GM didn't put that access panel there for a reason, what the reason is, I do not know, but quite honestly I don't think you do either. If you don't have the skillset and time, the car should go to a qualified shop to be repaired properly.

If replacing with an aftermarket pump, instead of cutting a hole in the car, an external pump is a viable option...

It was more of a lack of knowledge on how to drop a welded exhaust, rear & gas tank in a drive way with limited amounts of tools in the middle of March. I had aluminum sheer cutters, and my two hands and thats all I needed to get the job done. To patch it up I used a similar thickness aircraft grade aluminum, sealed it with a sealant gel, then used sheet metal screws to close back up, then I used insulation duct tape to go over it all.

86T/A is right, if it was meant for structure and support between the shock towers they wouldn't have used material thinner then a penny.

[IROCdan330]

Originally Posted by ar0ck

It was more of a lack of knowledge on how to drop a welded exhaust, rear & gas tank in a drive way with limited amounts of tools in the middle of March. I had aluminum sheer cutters, and my two hands and thats all I needed to get the job done. To patch it up I used a similar thickness aircraft grade aluminum, sealed it with a sealant gel, then used sheet metal screws to close back up, then I used insulation duct tape to go over it all.

86T/A is right, if it was meant for structure and support between the shock towers they wouldn't have used material thinner then a penny.

I don't know yours or 86t/a's qualifications with regard to engineering...but I do what I've learned at school. Every piece of a unibody car is a structural piece, be it for absorbing impact or providing strength for the overall frame of the vehicle, as the body is the frame. The fact is, you are cutting a big hole in your car. Last time i checked, a solid piece of penny thin metal is a lot stronger than a piece with a hole in it, regardless of how thin it is...

I recently heard a good argument similar to the subject by one of our fellow members...

"...You can get the trans out of the car from the top a lot easier if you cut a hole in the floor..."

[WildBillyT]

Originally Posted by IROCdan330

I don't know yours or 86t/a's qualifications with regard to engineering...but I do what I've learned at school. Every piece of a unibody car is a structural piece, be it for absorbing impact or providing strength for the overall frame of the vehicle, as the body is the frame. The fact is, you are cutting a big hole in your car. Last time i checked, a solid piece of penny thin metal is a lot stronger than a piece with a hole in it, regardless of how thin it is...

I recently heard a good argument similar to the subject by one of our fellow members...

"...You can get the trans out of the car from the top a lot easier if you cut a hole in the floor..."

Dan,

I'm not trying to discount what you are saying, but if you have suspension mods to improve torsional and beaming stiffness (SFC's, STB's, etc) wouldn't that offset the missing metal?

[IROCdan330]

Oh yea im sure that it would...my argument was mainly that its the wrong way to get the job done...i just needed other reasoning besides that to get my point across...structural integrity being one of them. My personal preference would be to have every bit of strength available in the car...

[JSPERFORMANCE]

I just dont want to cut holes in cars.

These cars arent getting any younger, just cause rust isnt a factor today dosent mean it wont be tomorrow and besides the bodies were all treated at the factory when they were bare metal if you go "breaking the seal" you make that area more succeptable to the invasion of rust.

[98tadriver]

guess it all depends on your personal preferences. if you are going to cut a hole in the floor, fill it up with gas before you do it. an tank with fumes in it is more dangerous than a full one. And most important- take your time with cutting, because you only have about 1/2" or so of room between the floor and tank, the fuel lines are even closer. I think im going to do like cbr mike said, and cut the hole while the tank is out. my exhaust and heatshields are already off, and its up on a lift behind my garage. and my tank is about empty too.

[JohnG]

Originally Posted by IROCdan330

I don't know yours or 86t/a's qualifications with regard to engineering...but I do what I've learned at school.

uhh, what school is that ?

I'm a mechanical engineer, and the first thing I learned is o=F/A

when you have less Area, the "o" (stress) is lessened.

http://en.wikipedia.org/wiki/Stress_(physics)

this is why drilling holes in a wheel will make it more rigid structurally...
this is why a car with a sunroof is more rigid than a hardtop...
etc. etc.

[JSPERFORMANCE]

Originally Posted by JohnG

uhh, what school is that ?

I'm a mechanical engineer, and the first thing I learned is o=F/A

when you have less Area, the "o" (stress) is lessened.

http://en.wikipedia.org/wiki/Stress_(physics)

this is why drilling holes in a wheel will make it more rigid structurally...
this is why a car with a sunroof is more rigid than a hardtop...
etc. etc.

so you are saying that a flat panel that has been swiss cheesed is stronger and more ridgid than one that is solid?? Or a broom stick that has holes drilled in it for the full length is stronger than a solid one??? And I am sorry but there is no way that a car with a sunroof is more ridgid than a hardtop without. I am no engineer but none of that sounds quite right to me.....

[IROCdan330]

Originally Posted by JohnG

uhh, what school is that ?

I'm a mechanical engineer, and the first thing I learned is o=F/A

when you have less Area, the "o" (stress) is lessened.

http://en.wikipedia.org/wiki/Stress_(physics)

this is why drilling holes in a wheel will make it more rigid structurally...
this is why a car with a sunroof is more rigid than a hardtop...
etc. etc.

im sorry for the confusion, i went to a technical school for cars, and learned that in a unibody construction the body is the frame, it is designed to provide strength and absorb impact and not transfer it to the occupants of the vehicle. All I am is a lowly mechanic, what do I know?

But i will keep what you said in mind...

going by the equation you listed, o=f/a...

o being stress, f being force, a being area...

Throwing in some random numbers...lets say force is 200 whatever unit you would use...area being 12, again whatever unit is used...stress = 16.67...lets have less area now, 10 for instance...force remaining the same...stress now = 20...a higher number...I'm not an engineer, and I stated that...but unless my math is wrong or the equation you gave me is wrong, under the same force conditions, less area = higher stress. However i suppose it goes the other way as well, if the force number is less than the area number, the equation works.

I dont know the units or the way to calculate each, I'm not perfect...but by your statement If I took my car, ran it on a skid pad, recorded the g's it pulled, then cut holes in it, and ran it again, I would pull a higher number because its more "structurally rigid." Or, instead of having a forged bottom end in an engine, you could take a stocker and drill some holes to have it be just as strong if not stronger...

I think this is a job for mythbusters.