oil breather connection '74 MFI

[74euroc]

Newbie here. I was following the thermoswitch thread, and I removed my air box/intake (terminology?). underneath is the connection for the oil return flexible tube (top one on the oil filler). the connection to the underside of the air box is a plastic Tee - but one side is not connected to anything. I can't seem to see where it might go.

I wondered why this back section of the engine is fairly greasy....

thanks
lee farrell
1974 euro carrera, MFI

[356RS]

The smaller line in that tee goes to the "oil drain pipe" bolted to the sheet metal near the flywheel. There is also a little rubber boot on the bottom of that metal "oil drain pipe". The part is about 4" long with a 1/2" ID. Has a small tab off one side to bolt it on the sheet metal piece. The top has the small connector for your oil drain hose that comes from the air cleaner box. That's most likely the missing hose and where the oil mess is coming from. I don't have a 74 MFI and it may be different than the earlier ones. Hope this helps.

[74euroc]

suppose I should ask if the small closed-off port is correct, also.

[74euroc]

thanks for the reply. but....try as I may, I can't see anything within about 4 inches (if that's what you meant). I see a metal loop (what I would call a standoff), just behind the thermoswitch, as if a ~~1 inch tube would go through, seemingly then back behind the fuel pump assembly.

[jphillips-998]

I just looked at mine and there is no hose on it. My engine has just been reinstalled by my shop so I'll double check with them tomorrow, but my guess is it's just a breather.

[jphillips-998]

how about some pics of the car....mine was just in the historics diplay at the parade in Keystone.

[356RS]

Thanks for the picture. The small single connector that has the hose clamp and is plugged is the line that goes to the oil drain pipe assembly. The small line at the tee in your photo is called the "flame arrester" and is open, nothing connects to it.

[356RS]

Picture of Oil Drain Tube less the rubber boot on bottom. The only part of the Oil Drain Tube you can see is the small tube connection that is sticking out of the right side engine tin that is next to the flywheel and covering the oil cooler. Just behind the oil thermostat as you are looking from the rear of the car.

[74euroc]

- thanks again for the help
- do people put some type of filter/cloth/gauze to cut down on actual oil coming out of the tube?
- if the T is meant to be a breather, what is the point of the tube connection??

lee farrell
berkeley ca

1 photo here. a few more at: http://picasaweb.google.com/7T2PNTR (ignore the non-Porsche side project....)

[356RS]

Inside that tee is a "Flame protection cartridge" part #901.107.729.00 This must have something to do with the other end being open. Must have to do with backfire issues. Porsche uses the same flame protection cartridge and same part # in the early CIS air filter box.

[74euroc]

Is the reason I don't see the tube a) I'm an idiot (second choice, please) or that b) the tube is supposed to be where the horizontal hole at the back is? (this would be consistent with the port being blocked - they took out the tube.

see photo

[356RS]

That's the hole alright. You have a missing part. If you can't locate the oil drain tube locally Lee, I will give you the extra one I have, N/C free.

[74euroc]

thank you Mark. I will do a little research locally first.
lee farrell

[tharbert]

On my 72 MFI, I believe the smaller end of the tee goes to the charcoal container of the fuel evaporation system.

[356RS]

Tharbert, That could be right. I'm trying to find more documentation on all the hose's connected to the air filter box. The fuel evaporation system lines connected to the 72 -73 MFI air cleaner box are not shown in my factory manuals.

[signature65]

you guys are corect. The Tee has the breather hose and the fuel evaporative line connected to it. The line comming out the bottom is simply a drain that runs to the drain tube on the front of the engine.

[74euroc]

could the "raised ring" in the photo carry the evap line across to the driver side? (picture is a little awkward - camera is tilter. the ring is NS oriented)

lee farrell

[dtw]

No...that ring is for hoisting the engine when it is out of the car.

Beautiful car!

[max964t36]

Hi, I was browsing for the same question but couldn't find any definitive answer for the small end of the "T" shaped connector ... thanks for your help!

Max