can 911sc be driven w/o oil hose resistor installed??

groovzilla1959 · 04-25-2012, 07:24 AM

i posted a question last week regarding my friend missing the oil hose restrictor in his 911sc and the car not idling when removing the oil cap.

he ordered the resistor from dc automotive and will arrive this week and was told that it is not good to drive the car in its current state because the back pressure can blow up the oil tank?

is this possible? his plans are to install the resistor this week but he has been driving the car and poerhaos he shouldn't?

thx

kerthunk · 04-25-2012, 07:41 AM

The restrictor helps prevent the oil tank from burping liquid into the air box. As long as the hose is still attached, it is creating LESS pressure in the tank. I didn't think that the SC had a restrictor anyway. I know that my car went 189k miles with no restrictor..

Peter Zimmermann · 04-25-2012, 07:44 AM

We used to, once in a great while, get a car into my shop that had a missing restrictor. None of those oil tanks "blew up," and some had been driven many thousands of miles since the crank breather hose was replaced by others. Actually, as long as the oil cap is on, nothing else changes. I just don't know where some of these stories start!

groovzilla1959 · 04-25-2012, 08:00 AM

Quote:

Originally Posted by kerthunk

The restrictor helps prevent the oil tank from burping liquid into the air box. As long as the hose is still attached, it is creating LESS pressure in the tank. I didn't think that the SC had a restrictor anyway. I know that my car went 189k miles with no restrictor..

the 911sc did have a restrictor - i verified this before ordering

just wanted to make sure my friend wouldn't damage his engine if he continued driving it before he installs the restrictor.

thx for the info!

kerthunk · 04-25-2012, 08:07 AM

Ah, according to the PET it is used in '81 and newer. Would explain why I didn't have one in my '79. The restrictor for the pre-81 is built into the elbow that attaches the oil line to the air intake boot.

Jdub · 04-25-2012, 09:23 AM

My '78 also features ONLY the flame arrest item at the backside of the rubber plenum from plate to throttle body. But then again, I am not the PO and so still am not sure if the early SCs features BOTH the flame arrester AND the restrictor.

It appears from this thread that I do not need both? That would put my mind at rest.

groovzilla1959 · 04-25-2012, 09:57 AM

all i know is my friends car would stop running when the oil cap was removed - if i used a clamp on the oil hose leading from the oil tank to the intake, the car would idle fine so it was obvious it was missing the restrictor.

not sure how the pre-81's are setup

kerthunk · 04-25-2012, 10:21 AM

Quote:

Originally Posted by Jdub

My '78 also features ONLY the flame arrest item at the backside of the rubber plenum from plate to throttle body. But then again, I am not the PO and so still am not sure if the early SCs features BOTH the flame arrester AND the restrictor.

It appears from this thread that I do not need both? That would put my mind at rest.

The "rubber plenum" is the air intake boot. It has a restrictor on one side of the elbow and a screen at the other with a brass wool material in between. I always thought that the brass wool is for catching droplets of oil in the air that passes through it. The PET looks like it calls it the "backfire grid" inside the "connecting pipe" and that it is used '81 and earlier. The PET designates the cone shaped restrictor at the oil tank side of the line as being used from '81 and later. Not sure if that means that '81 has both or that they made the change mid-year.

I think that it is safe to say that you need ONE of them in place and that the cone is the newer style.