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914World.com _ 914World Garage _ Charcoal canister
Posted by: FJ1200 Jul 30 2022, 04:46 PM
Howdy everyone,
So I think the next project I need to address is the horrid fuel smell. My car is a 1972 with twin Weber IDF's. Nothing is connected in the frunk. My plan is to order some cloth braid hose from Belmetric and reconnect everything up front, as well as possible a filler gasket. The engine compartment is a different story. Where is the pressure tap off the fan housing? I can't seem to find it. And then, what have people used to cleanly attach to the generic IDF filters? I went on a date today (first date in 23 year, newly divorced) and the woman complained of nausea from the smell. I had planned on doing it soon. Now it is on the front burner. Last question. Is it worth getting a later plastic canister and recharging it? It seems like it is easy to find canisters, but not the corrcect mounting hardware. Will the later one sit correctly on my early tank?
Thanks for any help
Dan
Posted by: Montreal914 Jul 30 2022, 04:55 PM
Don't carbs always tend to smell? 
Switch back to the original FI maybe? 
Posted by: bbrock Jul 30 2022, 05:41 PM
Most carb setups use crappy K&N filters that are even worse for containing fuel vapor than they are as filters. You need a closed air box that will trap and contain the vapor so it can be burned. There are a few on the market but they are not cheap. Or you can make one yourself but expect to spend hours and hours fabricating. They can significantly reduce fuel vapor smells AND noise from the carbs.
For my money, I'd rather put the money toward going back to FI, either stock or aftermarket. In fact, that is what I plan to do even after building my own air box. Here's what mine looks like. BTW, even with an enclosed air box, proper carb jetting is important for containing the smell. When my carbs were running rich, they still sunk up the garage. Now that I have the properly tuned, the vapors are tolerable but I think still more than a properly function FI would leak.
Posted by: mxkinn01 Jul 30 2022, 06:17 PM
If you do decide get a plastic one and recharge/replace the charcoal I have extra charcoal media. Enough to do one more canister. Just pay shipping and it's yours.
Thanks
Mike
Posted by: FJ1200 Jul 30 2022, 06:22 PM
Brent,
I watched your build. I actually really like your setup, I don't think I have the skills to make the pieces over the carbs. Also where your snorkel is, is right where my heater booster fan is. The smell I have when driving is overwhelming, I have no liquid leaks. I think its the temperature swings causing the tank to vent in the frunk. My plan is hopefully this winter build a 2270cc and use either Borla or Jenvey throttle bodies and modern EFI. Without going to a filter housing like yours, I still need to tie the canister line into the crappy K&N filters.
Dan
Posted by: bbrock Jul 30 2022, 07:22 PM
Brent,
I watched your build. I actually really like your setup, I don't think I have the skills to make the pieces over the carbs. Also where your snorkel is, is right where my heater booster fan is. The smell I have when driving is overwhelming, I have no liquid leaks. I think its the temperature swings causing the tank to vent in the frunk. My plan is hopefully this winter build a 2270cc and use either Borla or Jenvey throttle bodies and modern EFI. Without going to a filter housing like yours, I still need to tie the canister line into the crappy K&N filters.
Dan
I do think refurbishing the vapor system to move the vapors from the front to the rear will help, especially while driving. I recently stopped at a full service gas station (I didn't know those existing around here anymore) and the kid forgot to put the gas cap back on. It didn't take many miles down the road for the wall of gas fumes to hit me. So yeah, do set it up. It will help, and you'll want it when you go EFI anyway. To plumb the outlet hose to the carbs, just find a bulkhead hose barb fitting and drill a hole in one of the carb housing to insert it. It will still stink up your garage but should improve the driving experience and hopefully not drive away future dates.
And take Mike up on his offer for the canister. Fresh charcoal is going to help a lot.
As for skills to build that air box. I didn't have them either. It's just a matter of not being afraid to fail. That said, my whole setup will likely go up for sale after i megasqirt the car.
Posted by: wonkipop Jul 30 2022, 07:23 PM
Most carb setups use crappy K&N filters that are even worse for containing fuel vapor than they are as filters. You need a closed air box that will trap and contain the vapor so it can be burned. There are a few on the market but they are not cheap. Or you can make one yourself but expect to spend hours and hours fabricating. They can significantly reduce fuel vapor smells AND noise from the carbs.
For my money, I'd rather put the money toward going back to FI, either stock or aftermarket. In fact, that is what I plan to do even after building my own air box. Here's what mine looks like. BTW, even with an enclosed air box, proper carb jetting is important for containing the smell. When my carbs were running rich, they still sunk up the garage. Now that I have the properly tuned, the vapors are tolerable but I think still more than a properly function FI would leak.
he is right.
Posted by: FJ1200 Jul 30 2022, 07:39 PM
I think going with a modern EFI (mega squirt, Haltech etc) and adding a canister purge solenoid that draws into a central airbag under cruise conditions would ideal. The purge solenoid would "seal" the system when parked. I have to believe we can bring these cars into the modern age while still enjoying the charm and the induction sound of the Webers.
Posted by: FJ1200 Jul 30 2022, 07:40 PM
So where is the pressure port on the fan housing?
Posted by: wonkipop Jul 30 2022, 07:50 PM
So where is the pressure port on the fan housing?
on all original 1.8 engines its on the rhs of the mag fan duct casting.
out towards where the battery is.
a cast nipple comes out sideways.
i think this holds for all 73 1.7s as well and maybe even earlier cars.
it also was used in 75 2.0 L cars so will be used and opened up on all those original engines.
however 73 and 74 2.0s were different. @http://www.914world.com/bbs2/index.php?showuser=104 knows where it is on those.
i wouldn't have a clue.
so it depends on just what engine and fan casting you have in your hot little hands.
look over the fan casting on right hand side and see if its there on yours.
its just a cast in nipple comes out sideways.
Posted by: wonkipop Jul 30 2022, 07:55 PM
@http://www.914world.com/bbs2/index.php?showuser=22751 
Posted by: bbrock Jul 30 2022, 08:11 PM
I think going with a modern EFI (mega squirt, Haltech etc) and adding a canister purge solenoid that draws into a central airbag under cruise conditions would ideal. The purge solenoid would "seal" the system when parked. I have to believe we can bring these cars into the modern age while still enjoying the charm and the induction sound of the Webers.
Totally!So where is the pressure port on the fan housing?
Here's where it is on 2.0Ls. And thank you @http://www.914world.com/bbs2/index.php?showuser=24231 for confirming that the port is in the mag fan housing on 1.7s. I wasn't sure if I was remembering that right. I believe it should be on the housing just above the number stamped on the tin in my pic. It is pushing 40 years since I worked on a 1.7 though so take that for what it is worth.
Posted by: FJ1200 Jul 30 2022, 08:18 PM
Interesting, mine has neither! I guess my engine really is a bastard build. I think when my engine was rebuilt (prior owner) it was actually a put together engine from bus parts. I think all of the 2.0 parts went away. Just another reason to start from scratch
Posted by: wonkipop Jul 30 2022, 08:35 PM
Interesting, mine has neither! I guess my engine really is a bastard build. I think when my engine was rebuilt (prior owner) it was actually a put together engine from bus parts. I think all of the 2.0 parts went away. Just another reason to start from scratch
buses and 411s/412s used the cast nipple on rhs.
must be a 2.0L fan casting or maybe earlier 1.7 cars than 73 were different?
interesting to see photo posted by @http://www.914world.com/bbs2/index.php?showuser=20845 . looks like its part of the special engine tin on the 914 2.0 L motor.
i did think that all fan castings for all engines were the same and they just drilled out ports for the various applications. but that all came with all provisions cast in for everything a type 4 engine was to be used in.
so that little block that the port fits into might be there on right hand side but not drilled out with the tube sleeve pressed in. but i'm guessing because i have never seen a 2.0 up close and personal to know.
Posted by: wonkipop Jul 30 2022, 08:41 PM
here it is on a bus.
you can see its a block off the side of the casting.
i think they drilled it out and pressed in a tube sleeve to take the hose.
so you might have the block on the fan casting but it has not been drilled.
Posted by: bbrock Jul 30 2022, 09:09 PM
Looks like you could either drill the mag fan housing and press fit a tube in, or follow the 2.0L approach and drill the tin in the same spot and add another bulkhead hose fitting.
Posted by: ClayPerrine Jul 31 2022, 06:31 AM
Some later 1.8L engines had a fitting that screwed into the timing port hole to push air to the canister.
Just find one of those. There was a thread on it not too long ago.
Clay
Posted by: Jim C Aug 1 2022, 08:23 AM
Cars with dealer installed A/C had a timing port cover with a nipple which acted as the purge for the charcoal canister. They are hard to find, but they are out there.
Posted by: bbrock Aug 1 2022, 01:49 PM
Some later 1.8L engines had a fitting that screwed into the timing port hole to push air to the canister.
Just find one of those. There was a thread on it not too long ago.
Clay
Cars with dealer installed A/C had a timing port cover with a nipple which acted as the purge for the charcoal canister. They are hard to find, but they are out there.
Shouldn't be too hard to modify a standard timing port cap to do the same. Things like this make me want a 3D printer.
Posted by: nathanxnathan Aug 1 2022, 02:37 PM
Some bus shrouds don't have either the timing hole or the canister port though 
Engine pic of my first 72 — fan shroud is from a later bus
Not hard to drill the side port though. I measured one, OD is 13mm, ID is 11mm, it sticks out by 20mm. maybe some JB weld to hold it in.
Posted by: wonkipop Aug 1 2022, 04:35 PM
Some later 1.8L engines had a fitting that screwed into the timing port hole to push air to the canister.
Just find one of those. There was a thread on it not too long ago.
Clay
fitted as one of the AC installers parts.
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