OK, what's missing?

Jerome74911S · 07-23-2010, 02:49 PM

Just above my (leaking) crankcase breather, there is this red colored fitting that sure looks as if it should have a hose on it. What's the story?

Scott R · Scott R's Garage

Well on a later car that's the inlet for bypass air from the AAV to assist in cold start-up. The early hand throttle cars iirc don't have this and the hole is just plugged.

Flat6pac · 07-23-2010, 04:23 PM

I sure would want to make sure its plugged...big air leak
Bruce

Jerome74911S · 07-23-2010, 05:10 PM

It will get plugged pronto.

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by Jerome74911S

Just above my (leaking) crankcase breather, there is this red colored fitting that sure looks as if it should have a hose on it. What's the story?

Jerome,

Attached is a picture of a '78 SC 3.0 liter CIS engine. For CIS, it is a by-pass for metered-air to facilitate starting and increase engine speed during cold start. Keep us posted.

Tony

Scott R · Scott R's Garage

It probably is plugged I have a few early CSV plates like that and that connection is sealed right inside the inlet.

Jim Williams · 07-24-2010, 07:16 AM

Scott is right. These were made in two versions, open and cast with a plug. The early CIS (74 and 75) cars did not a throttle bypass arrangement using the AAR and AAV and didn't need this connection.

If this one is open (not already plugged) the engine would not run at all due to the massive air leak.

Jerome74911S · 07-24-2010, 09:20 AM

Scott and Jim are correct. The piece is cast with a "plug" inside, therefore, it is non-functional. So, why is it on a '75 engine at all?

Jim Williams · 07-24-2010, 12:02 PM

My guess is that the one with the plug was possibly made to cut down in manufacturing costs for a period of time. Leave in the plug and use it for the early cars; cut it out and use it on the later ones. I have no hard data on this, just a guess.

Jim Williams · 07-24-2010, 01:05 PM

Here is an original CSV mounted on a '74S airbox. This is the stock configuration.

Jerome74911S · 01:12 PM

Hmmm. Another mystery. It's a '75 S engine and it works the way it is. It's not actually plugged, but moulded so as to have no opening, therefore, I imagine the factory did it

Jim Williams · 07-24-2010, 02:21 PM

i just found these photos in my CIS files which show the internal configuration of the two different mounting pieces for the CSV.