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It seems most DIYs gain access to the charcoal canister by cutting off the top along the vertical sides as shown. I am concerned this makes it impossible to reseal it with strength, compromising safety during a hard rear end collision. Does this mod turn the car into a Ford Pinto.
Hood Motor vehicle Automotive lighting Automotive design Vehicle

If the top was cut 3/4" in from the edge as shown in yellow, you could easily fabricate a flat steel lid. After applying a little gasket maker, screw it down every 2 inches for a very robust seal. But does such a lip provide enough access to do the job?
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I believe it’s a luck of the draw. On my ‘07 daily driver, I’d always played the game of ‘stop at zero‘ when filling her up... which means I’ve topped her off each and every time I filled up! (Ridiculous is know! Proof I WAS dropped as a baby!! )

We‘re talking 15 years of possible canister abuse here! Luckily, no issues yet (of course Murphy’s Law will now strike me down, and since I’ve mentioned this, I’ll be forced to suffer the canister gods wrath tomorrow! )

What I did on my project car, was similar to what rjgrsmps theorized above. I cut just below the curve of the temples top, because I wanted as much access as possible. I then used a parts cars temple, cut further down, and used that as my new, removable Mayan Temple top. Added a u-nut to each side, and secured it with a flathead screw.

I couldn’t be happier with my setup now. I mean, just the thought of it brings me actual joy!


Where I cut the top (notice the slit where the u-nut will go- the other side already has it installed)


The donor top (if you zoom in just below the u-nut, you’ll see a mold line that goes all the way around the temple. This is the guide line I used to cut the donor top at).


Donor top screwed in place.


Grand finale, which sits exactly where the original did.



Oh! And as I always like to mention, I source ALL my parts through @Hoosier GXP ; If it’s kappa related and I need it, he’s my FIRST contact.
 

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When the pump auto-shuts off, you keep adding gas after that. That’s topping it off. The person typically believes that there’s more space and the shut-off was premature (“I know this puppy can get a little more in there”).

Well, add stupidity to the mix in trying to reach a certain number (let’s say an even $15, as opposed to the $14.62 that it auto-stopped at), and you have the ‘stop at zero‘ game.
 

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Discussion Starter · #26 ·
There has been a great deal of effort to convince me that topping off is the root of all evil. I have taking the system apart even driven to the gas station (without the canister installed)and attempted to re-create the describe the situation. Short of turning the vehicle upside down and filling it, is the only way I can see to make this happen.
 

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Super Serg, Your approach is a whole lot better than seen in the picture I borrowed, but I would add a lot more screws to keep it all together during a serious rear end collision. I imagine GM had the Ford Pinto in-mind when designing the limited access in the first place.
 

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There has been a great deal of effort to convince me that topping off is the root of all evil. I have taking the system apart even driven to the gas station (without the canister installed)and attempted to re-create the describe the situation. Short of turning the vehicle upside down and filling it, is the only way I can see to make this happen.
Have you not read my explanation of the mechanism? Was it not clear? Or do you just not believe it?

The fuel intrusion into the canister does not happen while fueling. It happens after driving the car and getting it hot so that the fuel expands more, then driving around turns, stopping and starting, and having the system run a vacuum purge. It is also incremental over tens of thousands of miles, so you simply are not going to see anything during one stop at a gas station.

All that said, you can certainly believe what you want to believe, since it not really going to affect the rest of us. We are trying to help you by relating what has been observed during the past 15+ years of community experience, and the behavioral changes that seem to make a difference.
 

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...... I imagine GM had the Ford Pinto in-mind when designing the limited access in the first place.
This is doubtful in my mind. The Pinto fuel tank was located low, between the rear axle and the rear bumper, with some ill-placed bolts that seemed designed to puncture the tank in a rear-end collision. The Pinto was built before any rear-impact standards were put in place, and the design of the filler tube was such that if it was pulled loose the fuel tank was left completely open.

The Kappa fuel tank is above the axle and is protected from punctures, rear-impact safety has been significantly improved since the 1970s, and the filler tube has a check valve that prevents emptying of the fule tank if it gets pulled apart.

"Limited access" is normal in vehicles today because they are built to be easy to assemble as economically as possible. Ease of service and repair is not really a consideration, as much as we would like it to be.
 

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why not put an inline fuel filter on the canister? That’ll prevent the charcoal from getting into the tank and lines.
I think that the problem is that when the charcoal gets loose from the canister it blocks the lines and keeps the fuel tank from venting. The filter would keept it out of the rest of the lines, but the one coming out of the canister would still be blocked.
 

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It seems most DIYs gain access to the charcoal canister by cutting off the top along the vertical sides as shown. I am concerned this makes it impossible to reseal it with strength, compromising safety during a hard rear end collision. Does this mod turn the car into a Ford Pinto.
View attachment 121689
If the top was cut 3/4" in from the edge as shown in yellow, you could easily fabricate a flat steel lid. After applying a little gasket maker, screw it down every 2 inches for a very robust seal. But does such a lip provide enough access to do the job?
View attachment 121707
LOLOLOL Good one
The cover is not really structural and while it may make a very small contribution to structural integrity, the forces of a rear end collision are controlled by the structure of the car. The frame, the force absorbing materials and the frame rear cross member. Cutting the top off this area is not changing the structure of the car. Its basically structural plastic material and you can cut it with a nail file if you try hard enough. Using a cut off wheel it offers little to no resistance.

But if you are concerned, I highly recommend you follow the factory guidance. Lift the car, drop the driveshaft, drop the rear suspension then drop the fuel tank out the bottom of the car. then you have a tank partially full of gasoline to manage and you get to do a wheel alignment when you are done because you dropped the rear suspension.
 

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I think that the problem is that when the charcoal gets loose from the canister it blocks the lines and keeps the fuel tank from venting. The filter would keept it out of the rest of the lines, but the one coming out of the canister would still be blocked.
I think you are as usual correct.

I also observe that by repeatedly pumping raw fuel into the canister during over filling, it attacks the structural integrity of the charcoal retention system which starts the process of freeing up random particles of carbon which then travel where they are not supposed to be. If the canister is not subjected to fuel contamination, then the design should be adequate for many years.

In preparation for swapping out the canister, we did some light research. And there are apparently techniques for "refurbishing" the charcoal that involve passing warm air through the canister and even applying significant heat to cook off any volatiles that are trapped in the charcosl. Since we found a ready supply of replacement canisters, we did not attempt to refurbish any canisters but I found this interesting.
 

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LOLOLOL Good one
The cover is not really structural and while it may make a very small contribution to structural integrity, the forces of a rear end collision are controlled by the structure of the car. The frame, the force absorbing materials and the frame rear cross member. Cutting the top off this area is not changing the structure of the car. Its basically structural plastic material and you can cut it with a nail file if you try hard enough. Using a cut off wheel it offers little to no resistance.
I am not concerned about over-all structural integrity, rather the fuel tank getting compressed in a serious rear end collision, rupturing, then shooting the fuel upward, popping off a minimally reattached dome. It seems wise to reattach the dome "robustly" to avoid a lot of fuel from flooding the trunk or worse.

Maybe I am simply paranoid.
 

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If you get rear-ended so hard that you've ruptured the fuel tank, your car has been totalled (and hopefully you're not injured).
Having some fuel spilled into the trunk is not going to be a concern at that point.
 

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Given that many of us have not had problems for the lives of our cars, that would not tell you anything. My Skys have 115 and 95 thousand miles on them with no canister issues.

There have been no reports of replacement canisters being any different than the originals in any case.
Yes my 08 redline sky has 114,000 miles and no issues with canister -although I knew of an 07 with 80,000 miles non turbo sky and it wouldn't fill with gas without the pump handle shutting off over and over again
 
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