As I round the final corner, I need to wrap up the crankcase breather and fuel tank vent system. The 912E has a fuel filler vent that runs from the tank to a canister up front, then runs a small vacuum line to the rear that plugs into what looks like a charcoal canister. This canister also has a larger inlet and outlet. I am assuming the outlet can go to the breather can, and also lines from breather can to the inside of the air filter on the carbs.
Looking at the left side of the fan housing on the type 4 motor, I see a nipple. I'm 99% sure that this is to go to the inlet side of the vac canister.
Based on some of my reading and files,, I've been planning a simple breather can.
http://www.hamincgroup.com/type4-test.php
I decided to draw out what I am planning, black lines are confirmed, the blue is what I am thinking. Anyone have recommendations or thoughts on this? I've seen breather cans that run from $80 - $300.
Thanks
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I would be better able to help if I knew more about what you want to accomplish. The original design was for efi, so it cycled between capturing vaor from the tank while parked to blowing the vapors into the intake while running. I also was wondering what you meant by chimney. Makes me think of stove pipe and Santa claus.
Thanks
If you want to retain the charcoal canister run a separate hose to the carb. You don't want fuel in your oil.
I'm not sure if it has any affect on the AF ratio, it's only a slight amount of vapour and bulk of it is suppose to to be blown in and burnt at start-up.
I'd personally just remove it and block it off for a carb app.
The two original systems were independent of each other. I think mark was trying to say you don't want to vent gas vapors into the crankcase. All carb setups I've seen run the head vents into a catch can, then back to the crankcase.
The black/blue line out from the charcoal canister, run that direct to a carb then you config diagram is good to go.
If you want to be anal you can put a "T" in the line and run it to both carbs.
I've only ever run the oil breather line to one carb, above #3 cylinder, I've been doing this for years, including the 2.6L T4 engine that is in my bug.
Just one observation:
The Oil "chimney" that clamps onto the case is already the first stage of an "Air Oil separator" as it allows the circulating crankcase vent products to settle out in liquid and drain back to the case before exiting.
So you dont need a really elaborate external system. Just keep it simple.
I use the stock breather and the exit routes through a 3/4" hose to just a catch can (no drain back to engine) with a vent.
The catch can has a sight-glass so I can see if it ever starts to fill up, but after ~6 track days and ~500 street miles, it hasnt collected anything worth draining.
That's with a fresh motor.
And I do not have head vents.
True, the OEM set up is injected. It's vented into the intake plenum. SO technically it should be "T"ed and ran into the carb intakes. Perhaps adding dual nippes to the top of the cab air cleaner assemblies?
Catch can works nicely too.
Correct. The "E", after all, stands for "Einspritzung", which is German for "fuel injection".
Mind you, that is following a pretty specific definition of "right". You can probably find a way to make it work, but it won't be "right". When you change stuff that the factory originally put on there, you more often than not have to do some re-engineering, or accept someone else's re-engineering. Even if it just means adapting something the factory did in different circumstances.
--DD
Well, if that's the standard for right, my car is all wrong ;-)
Brakes - 1983 master cyl, vented rotors, calipers, pads all around
Suspension - Rebel Racing Bushings all 4 corners
Clutch/Pressure plate - 6 spring
Engine - 96MM P&C, Big cam, type 1 oil pump, 1.7 rockers with 911 swivel adjusters, big valves and ported heads, Pertronix Ign II billet dizzy, Dellorto carbs, Tangerine Exhaust, AFM, CHT added
Dash - added dual gauge out of 911, moved clock and fuel gauge to center of dash (ashtray area) and replaced with aux fan/in place of clock and fuel gauge.
Interior - Center console, door panels and armrests from 88 911SC, Blaupunkt Toronto 420 Head unit with 5 1/4" Infinity Kappa Door speakers. MOMO Steering Wheel, silver shifter arm, aluminum door pulls and window cranks.
Alas, SO much NOT right in my car. I think a better way to say it is 'factory-correct' not right ;-) My goal is to do all this wrong stuff .... well right, lol.
Seriously though, I appreciate everyone's help on my rebuild. I'm an old wrench, but this is my first P car, and the only thing I have to go on is the mess I disassembled over the last couple years and what I read and research in the forums and in manuals.
Its been a fun journey, and know that turning the key is just the beginning of a new phase of the project.
I'm like that, if I had to settle for stock HP I wouldn't be into VW bugs and 914's, 90hp just doesn't cut it for me.
180 hp 2.6 litre in my VW beetle and my 914, if I ever get it done has a 280 hp (on paper) twin plug /6 going into it.
You only need the oil breather going into one carb, it's all I've ever done.
Fuel vapor I'd likely start with one carb and see if it through off my carb balance, if it did then I'd add a Tee and run a hose to both carbs.
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