E Sully, gazzerr, 47silver -

I have neither of those parts on my car = drain cylinder & rubber flap valve, etc
Wonder what happened to them.


thanks for all the info !

Hey TRACKS, sorry I don't know if the 74 is supposed to have the drain cylinder. Do you have the PET?

It is listed in the PET for '74-77. '74 used basically same air box as '73.
To see what it looks like, go to post 3 in this thread.
http://forums.pelicanparts.com/porsche-911-technical-forum/899776-newbie-air-box-oil-leak-no-drain-pipe.html

E Sully -

I saw that picture in the link you gave - I don't have any of that on my car.
hmmm ...
My father in law was the 2nd owner and bought the car in 1979.
I know he had the air box replaced once - ( back in the early 80s I think ).
Maybe the pipe and rubber flap was removed at that time and not put back on?

I do have a smaller hose that lays right above the oil thermostat on top of the engine.
the hose goes into the firewall.
from its placement , it looks like maybe it could connect to the drain tube coming out of the air box ...maybe ?

I will continue to investigate.

thanks everybody for all the help ... I enjoy this process and I am forcing myself to take my time and be thorough. :)

WAIT !!
I just looked at that picture again.
I think the top of that drain tube and rubber flap is actually where that hose is going that I mentioned in my previous post.
I just can't see them because they are up against the firewall... but I think the nozzle that sticks up on the top part of it is what my hose is connected to.
I will check again soon when i am near the car.

Hope so !

Cool - yep the detective work is half the fun for me.

Hi All -

I'm in the final stages on the CIS air box replacement. Yee Haw !
I've been cleaning the heck out of everything and replacing all the hoses, gaskets, etc.

Questions:
As far as the new O-rings for the throttle body and cold start valve are concerned , should i soak them in gas first ? Or just install them ?

I also got a new oil breather cover gasket. Should i use a little gasket sealer on that as well or just use the new paper gasket by itself ?

On the diagram below, does anyone know where to get the hoses # 65 & #66?
Or what size the are ?
Porsche mixture control unit

Lastly, how do i get to the PET for 1974 ?

thanks
Kevin

Cool glad you are making progress!

I did not soak my throttle body or cold start valve in gas. I just installed them. I *did* soak the injector o-rings in gas to make them easier to get onto the injectors.

According to Wayne's engine build book you install the oil breather gasket dry and be careful not to install it backwards.

You can get the PET in PDF form here -

http://www.porsche.com/all/media/pdf/originalparts/usa/911_USA_74_77_KATALOG.pdf

Hopefully that will tell you size of hose you are looking for.

gazzerr -

thanks again for the help, I really appreciate it.
I plan on getting back to the car this weekend. Maybe even get it finished !
Just noticed that you are also in GA - howdy neighbor !
I'm north of Atlanta.

Kevin

Sure no probs! So am I Suwanee/Buford area.

Make sure to seat your injectors well after new o-rings! I had one pop just a bit loose and got a stumble under load. Good thing I had considered that while putting the car back together; it may have taken a long time to diagnose otherwise.

well , life decided to take over and keep me busy for a while. Started looking at a new house / selling our house ... but that has since all gone away.
So i got back on the CIS project today.
Question = I've looked around for the torque spec for the intake runner bolts ( 2 for each runner ) ) ... and it seems that the more i look , the more different answers i find.
The intake runner bolts are 12mm .... is the torque 18ft lbs ? ... I've also found 25 ft lbs.
thanks all ... car should be running again tomorrow !

Kevin

I think I did mine to 18ft lbs which is about 24/25 Nms.

I also had an injector pop out so I replaced the o-ring with another new one and it's been good so far.

thanks Gazzerr ... again ;)

hi all -

Everything is back together and the car is running again.
One note =
After the car is warmed up - When i rev the engine and then let go of the throttle , the throttle mechanism returns to idle position ( within 1/8 on an inch )
BUT, the engine speed is staying up at 2000 RPM.
Before the car is totally warmed up it DOES return to idle, but not immediately. Kind of slowly moves down and takes a couple seconds to go from 2000 RPM to 950 idle speed.
If I manually grab the throttle mechanism at the throttle body and push it down a little bit , the car returns to idle.

I sprayed a bunch of WD on the pivot area of the throttle linkage , but it didn't help.

I didn't have this issue before I replaced the box.
Vacuum issue ?
WUR?
Decel valve ?

Hey TRACKS,

First I would make sure that you don't actually have any vac leaks either existing or introduced on the rebuild. Do the revs drop slightly when you remove the oil cap when the engine is warm? If so that means that you do not have a significant vac leak.

The AAR is supposed to provide bypass air to the engine when the car is cold and warming up and hold the idle high but yours might be higher than normal. As it warms up the 12V applied to the AAR will close the bypass air valve driven by the bimetallic mechanism and the revs will slowly drop over a number of minutes before it rests at 950 rpm. During this time the WUR is also leaning out and the engine with lambda will flip into closed loop mode at idle. You can watch this happen through the diagnostic pin.

The oscillating I think is generally caused by an overly rich mixture (surging), vac leaks or incorrect baselines (leaky cold start injector, CIS plate height, WUR cold control fuel pressure). Do you have the CIS repair guide?

Maybe you just have a sticky throttle that's not returning to the idle position properly. I'd check the throttle mechanism bushings on the gearbox and at the rear of the engine. Perhaps a weak return spring that's hooked onto the number 2 intake runner? The big spring on the throttle body might be binding with something. On mine the throttle push rod from the gearbox was fouling the engine tin on the rear of the engine. I think there's also a procedure for checking the idle setting on the throttle body. My throttle body was full of gunk. I spent a lot of time with carb cleaner cleaning it up.

I'm also chasing an oscillating cold idle on mine. I suspect my cold control pressure might be too low but I need time to do another pressure test.

I'll let the real experts chime in. I really only know enough to be dangerous :).

Thanks Gazzerr -
So i got a new Vacuum Limiter ( part # 91111022000 ) ( its the thing that sits behind the throttle body, near the microswitch. It has a small vacuum hose line on the top, and a larger hose on the side and a hose on the bottom)
Replacing that part solved my engine revving / high idle issue that i was having.
I think the diaphragm in the original one was probably partially shot and not correctly holding the vacuum.
Anyways, now i can rev the motor and it snaps right up , drops quickly to around 1500 and then settles shortly after that to 950.

I'm also going to to replace that spring that is connected to the intake runner. Good idea.

I do have the CIS Manual that was created by Jim's Basement Workshop. Very helpful.
I also need to check my system mixture, among other things. :)

I did put the car in gear the other day and noticed that the idle got down around 400 or less when IN GEAR... so i need to figure out why that idle is dropping so much.

thanks
Kevin

Cool thats awesome! I've got a wandering cold idle i'm chasing too. A pressure test is in my future. I'm going to switch out the plugs and wires too.

Definitely sounds like a timing/mixture thing. You should be able to find that pretty easily.

Good Luck!