Distributor with vacumn advance, what do i do with carb's and k&n's.

cheapporsche · 08-24-2007, 07:16 AM

2.4 CIS, 2.2E pistons, E Spec cams, E spec head. I'm in the process of putting this motor together and noticed that I have a 'vacumn' advance type distributor. Does somebody know of a trick that I can use in order to hook up this vacumn? I don't have the original air cleaners, simply K&N filters with steel lids.

Steve@Rennsport · 08-24-2007, 09:30 AM

Hi:

Can I assume that your engine is NOT equipped with CIS??

cheapporsche · 08-24-2007, 11:52 AM

Yes ,...should have included that. I have 40IDA webers that will be used for this engine. :-)

Henry Schmidt · Henry Schmidt's Garage

Supertec can convert your distributor to full mechanical advance.
Problem solved.

Steve@Rennsport · 08-24-2007, 04:51 PM

Quote:

Originally Posted by cheapporsche

Yes ,...should have included that. I have 40IDA webers that will be used for this engine. :-)

Thats what I would have guessed but I wanted to be sure.

Two options:

1) Install fittings and lines in the intake manifolds to plumb & retain vacuum advance.

2) Disable the vacuum advance mechanism and run centrifugal advance only (strongly recommended).

There are several vendors that can provide this service,...

cheapporsche · 08-25-2007, 07:26 AM

I'm reading on several posts that the vacumn is there solely for retarding and emissions. Is this valid, or just incorrect postings?

911pcars · 08-25-2007, 12:51 PM

I think CIS distributors are set up for timing retard, but only for idle (and emissions). Please verify.

To confirm the vacuum unit either advances or retards, here's how to determine (other than a confirmation from Steve, Henry, Grady or a number of other knowledgeable fellows):

If vacuum is applied to the diaphragm, does the breaker point plate rotate clockwise or counterclockwise? Since the rotor on your engine rotates clockwise, if the plate rotates CW, the timing retards when vacuum is applied. If the plate rotates CCW, the timing advances when vacuum is applied.

As Steve recommends, you can disconnect the vacuum hose (plug intake port), then recurve the distributor, or just find an early E or S-type distributor and set static timing to factory specs.

Sherwood

kucharskimb · 08-28-2007, 02:00 PM

I have just about the same motor, except mine was built on a 2.2E. I also use Webers.

My distributor has been set up to give me about 6 degrees at idle and 36 degrees at 6000rpm. I have been searching for years to see if anyone has a true vacuum advance setup that would allow vacuum advance at cruise conditions. No one seems to have any input.

Why would I want this?... for fuel economy on the highway and better cooling. Sure, I run the snot out of it on the track and AX, but would also like to save some gas going down the road.

There is an aftermarket unilite unit from mallory that fits bugs and 914's. When I contacted them, they said that there was no market for such a distributor with the 911 crowd.

The port location is important when considering the vacuum advance, also. True manifold vacuum, ie a port right below the butterfly, is usually recommended.

For more info, please see this article:
http://www.pro-touring.com/forum/showthread.php?t=217

If you have any luck finding someone that will help you setup a system that will give you a true vacuum advance unit, please let me know.