I serviced the evaporator canister on my 72

[rsgt]

My evaporator canister did not have any carbon chips in it anymore, I could see the carbon chips under the battery tray where they had come out. The canister had a filter at the bottom that was worn out. I took the valve apart on the top,Just pop the top off. I rinsed the canister out with the water hose and blew air through the passages. I put the valve back together and put vacuum on it and it held vacuum. I went to Walmart and bought activated carbon chips in the pet supply dept. Next to it was a filter I got to make my bottom filter. I cut the filter apart and used the plastic screen to help keep the chips in and help hold the filter. I put in all of the nine oz of chips.

[randy.powell]

Very nice work! Thanks for sharing!
Randy

[71CHEVYSHORTBED402]

The reason they lose charcoal is the thin spongy element on the floor inside the canister wears out. There's one on the ceiling as well, but they don't wear out like the bottom, obviously.

Looks like you're going to run without the bottom element. Nice mod, seems it would work, I may try it. Currently the plan is to use my best canister, which has a slow leak. I picked up a Standard (white) filter, and it's stiffer than common, so it will retain spill more better. I'm adding a funnel, which should add to some longevity.

At some point I may rebuild my other can, but "you have" to cut it open...........Shame someone doesn't build replacements. I'd think there would be a market. GM trucks and passenger cars used the same can.

[joel5150]

Does the vehicle even need this filter? I only ask because when I replaced the battery tray on my truck I noticed that the filter has been cut out. There were just 2 hoses stuck in the spot where the filter would sit. Thanks, previous owner. LOL

[Steeveedee]

Originally Posted by joel5150

Does the vehicle even need this filter? I only ask because when I replaced the battery tray on my truck I noticed that the filter has been cut out. There were just 2 hoses stuck in the spot where the filter would sit. Thanks, previous owner. LOL

Yes. The fuel tank is meant to be vented to the vapor canister, where the vapors are collected when the vehicle is not running. Once started, the vapors are drawn off into the engine and combusted. Those canisters are common as dirt and readily available. Here is one source-

https://www.summitracing.com/parts/a...SABEgLqEPD_BwE

[Don Quixote]

I built an evap system out of an old external oil filter system. Both tanks vent into one line which leads to the down tube which goes straight to the bottom of the canister into a bed of steel wool. Using a toilet paper roll in the middle where the tube sits, I filled around it with activated charcoal with another layer of steel wool on the top and put the cap back on. I installed a tee on the outlet and capped it with a small breather element. I ran the other portion of the tee to the breather hole on the valve cover. This system is much like Chryler's early system and I could make it more elaborate to seal it to open at a certain engine temp, &c., but I was mostly concerned about containing some or most of the fumes and using an unvented gas cap that won't spill whenever I turn right.

[joel5150]

Good times. Thanks for the link, Steeveedee.

I only have 2 lines going over in that direction. One from the fuel tank and one to the carb. Nothing better than cleaning up someone else's stupidity. LOL

[71CHEVYSHORTBED402]

Originally Posted by joel5150

Does the vehicle even need this filter? I only ask because when I replaced the battery tray on my truck I noticed that the filter has been cut out. There were just 2 hoses stuck in the spot where the filter would sit. Thanks, previous owner. LOL

There may be variances, but here's a great video for a 1971 Chevy, with three ports. https://www.youtube.com/watch?v=8HmiBp9ibfU

I wonder if the canister per Steevee's link has these ports and fits with the existing bracket?