vacuum advance for 79 911sc euro

[jerkan]

NOticed that my vacuum advance is plugged off on the distributor. I have a 79 euro 911. I believe that it came from the factory with the vacuum hose hooked up, but I do not know where the point of attachment is. I think it is somewhere on the throttle body, but I did not see any openings to attach it tol. Can anyone provide assistance please?

[Bill Douglas]

Sounds odd, but so is the vacume advance on my '79 euro. LOL, I don't think the factory sent them out that way.

The speedo should arrive any day now via UPS.

[jerkan]

Hi, Bill
got the speedo and it was really cool to know how fast I was actually going. Tried it out and it workded great, unfortunately, the odo was inop which I really wanted, so I shipped it back to you today. My wife also got wind of what I was up to and chewed me out royally. Something about destroying the traditional valvue of the euro sports car. yada, yada...The shipping was quite reasonable at 12 us dollars!
thanx, anyway and sorry for the inconvenience.

[Bill Douglas]

That's strange about the odometer bit not going as it was working fine when I pulled it out of my car Sorry to you for the inconvience.

[jerkan]

No problem
I tried resetting it several times to no avail. I also verified all the wiring. Beats me. Try it back in your car and let me know.

[Bill Douglas]

I'm presently using a mph speedo ( out of my spare parts car) with a smaller line of kilometers marked on the inside of the mph section, and the odometer and trip odometer are in mph. Are you interested in this one (please check with wife first )? I'll check on the way home the milage is ticking over on both.

[cmonref]

Hmmmm. A question about distributors and 5 responses about a speedometer ...

The connection of the vacuum hose to the distributor comes off of the throttle body at one of the ports above the throttle plate. Mine (1980 SC) is on the forward side (forward, as in the direction of travel) in about the 1 o'clock position (12 o'clock is straight forward).

Do NOT put it on the port on corner of the throttle body nearest the distributor. That port is the right size, but is BELOW the throttle plate.

[jerkan]

did you miss a post or something, Brian? Now try and keep up, those Kiwi's down under move fast!
Really appreciate the advice. I have heard from many, including Bill, that many of the sc 911's vacuum advance were capped off. Makes me believe that it does not really make a difference or something goes wrong and they just disconnect it. I will do a test to see shortly and let you know the results. thanx again

[thabaer]

Mine has always been connected.

[cmonref]

jerkan: no, didn't miss a post. Upon rereading the thread, noone answered your question about where the vacuum line connects! So, slow mover that I am ("deliberate" is the term I prefer to use!), I tossed something onto your plate.

As for running with it disconnected, methinks that is not beneficial. Under those conditions, advance is controlled by engine speed -- so engine speed is totaly dependent on the response of the CIS, which is not know for lightning-quick throttle response.

But with the vacuum connected, there is at least SOME increase in engine response as soon as the throttle is cracked and before the CIS comes on line. I think is can only help the response.

And I had mine connected to the port BELOW the throttle plate for a while. When I connected it to a port ABOVE the throttle plate, I think it did, in fact, help with the engine response.

[na2ub]

I checked mine ... 79 US49. The vacuum advance hose for the distributor connects to the 1 o'clock position (looking at the engine compartment) of the left column of the CIS boot. My question is : (posted on another thread, with picture), what is the vacuum line at the 7 o'clock position of the same CIS boot column? Anyone.

Hope this helped.

[GMR911]

Hi, I also have a 78 euro motor with the vacuum line plugged at the distributor. Can't find at all where to connect it to the trottle body or cis boot. If any one has a picture or any more info that would be appreciated. What would be the disadvantages of having it disconected?, thanks jerry

[Bill Douglas]

Heehee, I thought I better make a distributor contribution to this thread. I've just been out and looked at the car and I can't see anywhere where a vacume line could be connected (back to speedos the one I've got in the car now clicks the miles over ok).

[cmonref]

GMR911: Disadvantage to not connecting the distributor vacuum advance is that you will not get the full advance at 5000-6000 rpm and will not develop full power.

The advance has a vacuum portion (6 degrees) and a mechanical portion (about another 13-19 degrees, depending on the engine.

From idle, open the throttle and the following sequence occurs:
The distributor advance increases from the idle setting of 5 BTDC to 11 BTDC because of the vacuum advance. I think that helps the throttle response a little while waiting for the CIS to catch up. Then, as the engine RPM increases, the mechanical advance comes on gradually until the total advance reaches the maximum for the engine (usually 25-30 degrees.

ADVANTAGE to not connecting: less chance of detonation at high power, 'cuz you're limited to less power than the engine is capable of.

[GMR911]

Hi, Thanks for responding. I would like to hook up the vacuum line if I could find a port to hook to. I can't find a plugged port or not aware of the port on the throttle body that is for the distributor. Any info on this or diagrams or pictures would be a great help, Thanks, Jerry

[jerkan]

the problem, I believe, is that all the ports are already taken on the throttle body with other devices. Makes me think that maybe there was a tee connection somewhere that someone conveniently removed. If anyone has the time, I (we) would greatly appreciate an inspection with followup report.
thanx