1974 dizzy and CIS question

[Fidalgo911S]

Relatively new to CIS and my car. Two questions:

1) There is no hose connected to my vaccuum advance drum on the distributor (Bosch). No hose in sight. Was there ever a hose? Is this normal?

2) I also noticed there is no hose connected to the auxillary air device. There is, however, a braided hose right next to it flapping in the breeze that's capped off with a screw. Is this normal?

The workshop manual didn't shed any light on this and neither did a search on this forum. Thanks.

[Rex Walter]

Fidalgo911s,

There should be a vacuum hose hooked up to your distributor, but it will run fine without it. The vacuum advance is for fuel economy during cruising. It should come from behind the CIS unit, and will be hard to see with the engine in the car. It could be capped off.

The vacuum hose should be connected to your warm up regulator. If it is capped off, the PO may have been having problems with it, and did not understand how to fix it.

If you want to see how a 1975 looks, and are close to Bothell, PM me.

Rex

[jtkkz]

Hope this helps, I took pics of my '74 carrera distributor

[Jubbie]

I assume you were talking about the WUR when you said "aux air device"?

My WUR and dizzy were disconected by the PO and when I re-attached them, I noticed that I had no vacuum. It ended up that the throttle body plate stop was adjusted wrong and the vacuum ports were not on the vacuum side of the butterfly. You might check that too.

When you set your timing with the distributor vacuum line disconcected, the idle mark will not be right. You will have to either subtract out the vacuum retard and make a new mark on the pully or set it at max advance (which is always fun)

Reconnecting the WUR vacuum made a big difference.

[Fidalgo911S]

Good info and pictures. My underlying reason for all this is to be able to set the timing correctly.

Rex the car runs just fine without any vaccuum hose at all. It's good to hear It's not a bad thing it's not there.

Jubbie I am talking about the aux air device. I highlighted it the picture jtkkz sent and put a red arrow pointing at it. It has no hose connecting to the top of it.

So that leads me in to my next question: how do I accurately set timing? How do I subtract the vaccuum retard and what do I set the new timing mark at?

Thanks guys

[Jubbie]

Doope, my bad, the decel valve. Forgot the WUR in a 74 has no vacuum lines. I have heard that the decel valve has been removed with no problem. This is what Waren wrote on timing:

Ryan,

Your rotor turns clockwise, so turning dist. body to the right is retarding the setting.

My suggestion is to remove and plug the vac. line to the distributor.

It will be a lot easier if you have an advance-type timing light, but the fixed-type will work, too.

Set the timing to 36� - 38� BTDC at 6000 rpm, then check the advance curve per the spec book at 1000, 1500, 2000, 4000, & 6000 rpm. Your engine should run 'better' without the vacuum retard, on an idle setting of 5� - 10� BTDC ... which is where you should be [without vac. hooked up] if the advance mechanism is working properly!

__________________
Warren Hall
2002 Wife -- Phyllis
1973 911S Targa ... 'Annie'
1968 340S Barracuda ... 'Rolling Thunder

See post at : timing/dwell gurus...help!

[Fidalgo911S]

Sweeeet. Thanks for the help! Gotta love this forum.

[Rex Walter]

Fidalgo,

I think what Warren is trying to tell you, and what the link that he included never got to is this:
With the vacuum disconnected, you should set your static timing (timing at idle) to about 5 degs BTDC (or about 5mm to the right of Z1). With the vacuum connected, it should be about 5 degrees ATDC, or retarded about 10 degrees due to the vacuum. With the vacuum disconnected, you can follow the timing curve vs RPM that has been given here before. Most of the timing charts I have seen start at 5 deg BTDC, which is done with the vacuum disconnected.

Here is another good thread on timing:
http://forums.rennlist.com/rennforums/showthread.php?t=128799

Most people just set the static timing at idle - however, the timing at high RPM is the critical one, and the one that will affect performance the most. If you don't want to play with springs and weights inside your distributor, just set 5000 to 6000 RPM with 36 to 38 deg BTDC.

Rex

[al lkosmal]

Not ot hijack, but how is your motor running Rex. Sounded like you may have had a timing issue. Did you solve it??

P.S. thx for the vino.
Al

[Rex Walter]

Al,

I found that my Pertronix Ignitor, which replaces the points, had broken, and only 4 of the 6 magnets were still in place. My symptoms were two spark plugs that looked like they were not firing at all, the other four were really black -- like too rich, and it sounded like it was only running on 4 cylinders. I have ordered a new Pertronix from our host, but it won't arrive till next week. So stay tuned (no pun intended).

Rex

[RoninLB]

Originally posted by Rex Walter


I found that my Pertronix Ignitor, , had broken, and only 4 of the 6 magnets were still in place.

I have ordered a new Pertronix

Hi Rex..
I don't understand about the dizzy shaft ring magnet ?

fwiw.. I used a connector block to attach the Pertronix wires to instead of soldering.

[Rex Walter]

RoninLB,

Yes, the shaft ring magnets. The top and bottom of the plastic ring came apart, and only 4 magnets were still there. I think it came apart last time I installed it (on the work bench), and I didn't notice until I tried to fire up a fresh rebuild this week.

Rex

[RoninLB]

Originally posted by Rex Walter

The top and bottom of the plastic ring came apart, and only 4 magnets were still there.

wow.. that's new info to me.

thx