Fuel cell cracking

[Darren Brown]

I have been running into a problem with my fuel cell on the Vee. The bladder is splitting or cracking. Maybe an age thing, first cell was 6 years old, the second that replaced the original cell was maybe 5 years old.

I have had many cells degrade and become brittle over the years, but never a nice looking cell just split. Both bladders seem in good shape and very flexible.

The bladder has to get folded and tweaked to get inside the aluminum container. I wonder if this is compromising the cell. I have opened the back of the container as much as possible while still keeping the bolt on rear cover, but the cell is wider at the front than the rear and really has to be flattened and folded.

Anybody have any ideas or experience with this issue? Do you think I am damaging the bladder getting it into the container?

Would like to figure this out before I buy a brand new cell and damage it installing it.

One other note that may have been the reason, but not sure it would do this damage. On the first cell i was pumping out the fuel and forgot I had capped the vent. The bladder collapsed while removing the fuel. The second cell I had the cell removed just sitting on the work bench with the outlet and vent capped. So maybe the temperature change made the cell crack not being able to vent?

Thanks
Darren

[DaveW]

Maybe it's an optical illusion, but even blowing the 1st photo up to 4X size, it looks to me more like a crease than a crack. Look at it closely with a magnifying glass to see if cords are exposed. If there are no cords exposed, that would reinforce my opinion that it's just a crease from being folded. That's not great either, but it would not warrant replacement, IMO.

[Darren Brown]

Unfortunately they are both cracked down to the material (kevlar maybe), I will try to get a better picture. The fuel leaks out of the crack, lost probably a half gallon over night.

My wife got in her car the other morning and told me the garage smelled funny, whoops.

[Darren Brown]

Here is a better picture by pushing on the bladder. Not sure why my pictures keep going sideways

[DaveW]

Since it's leaking, it sure is a crack.

And I am 98% positive that you are correct that deforming it as much as you did squashing it into the enclosure caused it. You need to get a smaller cell or larger enclosure, or it'll happen again.

On a side note, the Eagle rubber cells are less critical in that regard, and you can get exact-fit custom ones made by them to avoid the situation entirely.

[Darren Brown]

Hi Dave thanks for the replies. Would Eagle copy the existing cell or would I need to figure out how to take measurement? I will modify the enclosure some more to make getting the bladder in it less destructive.

I was thinking Eagle or Harmon because the fuel safe has been less than impressive for the price.

Thanks again for the advice

[DaveW]

Hi Dave thanks for the replies. Would Eagle copy the existing cell or would I need to figure out how to take measurement? I will modify the enclosure some more to make getting the bladder in it less destructive.

I was thinking Eagle or Harmon because the fuel safe has been less than impressive for the price.

Thanks again for the advice

Eagle can do either, but since the cell is too big now, it would likely still be too big if they copied it. They work from paper drawings very well, since that's their history. So you could make a dimensioned sketch AND send them your cell for reference.

Most of the cells they make are for aircraft where many of the enclosures the cells go into often have small openings requiring the cell to be folded up to get them in. So I wouldn't worry about that, but I would try to size it so once it's in place it's not buckled.

Jim Baxter was my contact - he was good to work with.

Eagle Fuel Cells
617 Skylane Taxiway
Eagle River, WI 54521
USA

T: 715.479.6149
F: 715.479.6344
E: custom@eaglefuelcells.com

[Rick Kirchner]

To me that is the single biggest issue with fuel safe cells. they just aren't all that flexible.

[veeten]

Darren
I had the same issue with a FuelSafe cell.
Fred Clark at Caracal cars is a PyroTech dealer.
He had me ship my old cell to them and they
reused my old hardware which saved a ton and
ensured a perfect fit,
I know they have built cells for most popular vess
since they went back into cell Manufacturing.

[Darren Brown]

Darren
I had the same issue with a FuelSafe cell.
Fred Clark at Caracal cars is a PyroTech dealer.
He had me ship my old cell to them and they
reused my old hardware which saved a ton and
ensured a perfect fit,
I know they have built cells for most popular vess
since they went back into cell Manufacturing.

Would you suggest contacting PryoTech or fred? What type of material is the Pyrotech cell?

I like the Eagle idea if the cell is more flexible.

I would really like to utilize the existing enclosure, it fits the space perfect. If I modified the container a bit more I think it would make getting the bladder in easier and with less folding and smashing.

Thank you for all suggestions. Lots of good ideas.

The shame in all this is the cells are otherwise in perfect shape, hell the car has only 10 races on it since new in 2011 . Oh well always something.

Thanks all

[veeten]

It Is best to go through Fred, he has the contact info. \
He also gets orders rush through as needed
The PyroTech cell is much more flexible than
the old fuel safe. It looks different also.

[Angus]

I don't have to "deform" my fuel cell to get it into the container, but I've had great life with ATL cells. Expensive but they seem to last a good long time.

[DaveW]

...I like the Eagle idea if the cell is more flexible....

I'm pretty sure rubber cells are more flexible than urethane ones. The rubber layup is usually a bit thinner, and the rubber has (IIRC) a lower modulus.

[S Lathrop]

I would recommend Eagle Fuel cells. They are a FAA approved maker of cells for certified airplanes. The FIA standards for fuel cells are taken from the FAA standards. Airplane cells are expected to last decades, not years as racing cells are.

[Darren Brown]

Awesome information thanks everyone.

Going to start with Eagle. I think if the bladder is a little more flexible I will be able to use my existing container and the final fit in the chassis will not change. I have not ruled out the Pyrotech either, cost is always my biggest obstacle.

All my problems may have been self induced. have been playing with different fuel pickups and pickup mats so I was removing the bladder a few times to change out the pickups. My guess is all that deforming the bladder cause both failures (bummer). I just assumed the bladders could take that.

Thanks all for the suggestions and tips, got to love this community.

[dereklola]

Fuel bladder size.

I've always ordered slightly smaller than the Al or CF container - maybe 1/4" smaller.

Fuel bladders are flexible on the sides but pretty inflexible on the corners.
Going slightly smaller stops the inflexible corners rubbing excessively and the sides
simply flex outwards when full of fuel.

I also try to add 3/8" to 1/2" foam all round inside the container.
Got bitten 35 years ago - been shy ever since!

Eagle are great to work with.

[2BWise]

I'm pretty sure rubber cells are more flexible than urethane ones. The rubber layup is usually a bit thinner, and the rubber has (IIRC) a lower modulus.

I'm curious if Fuel Safe has changed to rubber. My cell just required replacement due to essentially the same issue. Same material and same result although mine started to fully disintegrate. I ordered my replacement thru Fuel Safe (they did the original and had the drawings for the Carbir cell). The returned product appears to be of a different material. It was black in color.

[DaveW]

Fuel bladder size.

I've always ordered slightly smaller than the Al or CF container - maybe 1/4" smaller.

Fuel bladders are flexible on the sides but pretty inflexible on the corners.
Going slightly smaller stops the inflexible corners rubbing excessively and the sides
simply flex outwards when full of fuel.

I also try to add 3/8" to 1/2" foam all round inside the container.
Got bitten 35 years ago - been shy ever since!

Eagle are great to work with.

Absolutely correct - NEVER have the cell too large. That causes wrinkles and buckling which are potential failure sites.

[problemchild]

Based on some recent issues, I have taken to modifying the fuel cell container and firewall so that the pickup mechanism or pump assembly can be accessed in the car without removing the cell from the car. I believe that this increases the long term integrity of all the components involved, but also makes at-the-track repairs possible, rather than going home early. I would certainly modify the container into sections so that crushing the cell is not required for removal.

If I was having to invest in a new cell, I would certainly order the new cell with the access openings in appropriate locations. While it is nice to re-order parts to match the original, you must accept that many compromises may have been made for cost, availability, and production reasons, either during manufacturing, or maintenance since.

[Darren Brown]

Just a update to this thread on the fuel cell. I called a few companies and in the end I went back to Fuel Safe. They were the most helpful and responsive. I dealt with a Ben Rogers and he was very helpful.

Fuel Safe has indeed changed their material. My new bladder is also black, not sure if it is more flexible or not as they assembled everything in house and returned a plug and play cell. They were also very quick with the turn around, less than 3 weeks start to finish.

thanks for all the help on this.

Darren