How to ID CIS year?

[Tom '74 911]

Hi -
Are there differences between the various years CIS intakes? My car is a '74 911 w/a '77 2.7 w/CIS. The numbers on the engine case say it's a '77 at least. Is there a way to positively ID the year of the CIS? I ask because my engine is out of the car and I was looking things over and noticed a few unplugged electrical connections and hoses w/in the CIS jungle. Also, I ordered some new intake manifold rubber sleeves (for a '77) and noticed the existing ones look different than the ones that came from PP - they look like a later version judging by the photos in the catalogue. Are there differences? How can I ID what I have?

Thanks,
Tom

[javadog]

Something in the CIS system changed yearly. Sometimes the changes were small, sometimes they were large.

What you have to do is get familiar with the evolution of the system, by studying parts books, manuals and so forth, and start comparing each piece to what you have. It takes a little work but it can be fun. You do have to be careful, though. Sometimes a part will be superceded to a new one, as stocks of the old part are used up, and what you think may be the wrong replacement part can end up being correct.

There's a really useful series of manuals that was published by Porsche for their dealers each year. They detail the little yearly changes that were made to the car. In the one for 1977, there were quite a few little things in the CIS system that were different from 1976. You can find these for sale on the internet, or on eBay, from time to time. You'd need the one titled "911S, Turbo Service Information, Model 77."

Hope this helps.
JR

[T77911S]

while it is out, pull the injectors and replace the injector sleeve ond O rings, along with any other hose or seal. this will make life a lot easier down the road if you start having problems.

http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_FULcis_pg5.htm#item17

one of the things that changed was the warm up regulators. also i think in 77, they added the thermo time valve. it is a device that further richens the mixture when cold. it has a vacuum line from the WUR to the throtle body along with a 12v connector.
if you do find a list of all the differences, please post.

[SC-targa]

Check your part number against this list...

http://members.rennlist.com/jimwms/CIS/CIShome.html

Regards,

Jerry Kroeger

[Tom '74 911]

Thanks for the replies. Jerry - that rennlist link is great - thanks for that. I will do some parts number comparison and try to narrow it down. My "while I'm in there" list grows by the second.

Tom

[Gunter]

Tom:
Your '77 CIS may have smaller intake runners closer to the US '80-'83 CIS with Lambda.
If the rubber sleeves you ordered are too large, PP may have sent you the sleeves for the US '78-'79 CIS which has the larger runners O.D. 47.5 mm.
Measure the O.D. on your runners in mm and post.
Here are some numbers:

CIS parts for US ’77 S

0 280 140 206 Auxiliary Air Valve
0 280 160 400 Auxiliary Air Valve (Thermo-time Valve?)
0 438 120 004 Air Flow Sensor
0 280 170 402 Cold Start Valve
0 438 170 009 Fuel Accumulator
0 438 100 006 Fuel Distributor - New
0 986 438 006 Fuel Distributor - Exchange
0 280 160 111 Vacuum Limiter (Decel.Valve?)
0 437 502 004 Injection Valve
0 438 140 033 Warm-Up Regulator - New

[Tom '74 911]

Originally Posted by Gunter

Tom:
Your '77 CIS may have smaller intake runners closer to the US '80-'83 CIS with Lambda.
If the rubber sleeves you ordered are too large, PP may have sent you the sleeves for the US '78-'79 CIS which has the larger runners O.D. 47.5 mm.
Measure the O.D. on your runners in mm and post.
Here are some numbers:

CIS parts for US ’77 S

0 280 140 206 Auxiliary Air Valve
0 280 160 400 Auxiliary Air Valve (Thermo-time Valve?)
0 438 120 004 Air Flow Sensor
0 280 170 402 Cold Start Valve
0 438 170 009 Fuel Accumulator
0 438 100 006 Fuel Distributor - New
0 986 438 006 Fuel Distributor - Exchange
0 280 160 111 Vacuum Limiter (Decel.Valve?)
0 437 502 004 Injection Valve
0 438 140 033 Warm-Up Regulator - New

Hi Gunter -
That's very helpful! Some numbers I wrote down last night match what you've written above - namely these two:

0 438 120 004 Air Flow Sensor
0 438 100 006 Fuel Distributor - New

Some of the intake runner numbers I copied down are:

911 110 206 2R - from cyl. #2
911 110 169 2R - from cyl. #4

I guess the reason I asked the question in the first place was because the rubber sleeves I have look (for '74-'77 CIS according to the PP catalogue) look different than the ones that are currently on there. I will measure the OD on the runners tonight and post back.

Thanks a lot for the help.
Tom

[Tom '74 911]

O.K. - My runners measure 39.9mm ± OD where the rubber sleeves slide on. So I'm assuming that I have a complete '77 CIS setup w/the smaller intake runners? Here's a photo of the old (on the right) vs. new (on the left) rubber sleeves. The new ones seem a bit shorter and thinner and don't have ribs on them around where the clamps go. They do fit on the runners though just fine.

Another question - this connection was not hooked up (see second pic.) should it be? There are also a few other hoses that go to nowhere etc... - I may post pics of those later to ask about them too.

Thanks a lot for the help,
Tom

[boyt911sc]

Tom,

There are 2 similar electrical connectors at the back of the motor. The CSV (cold start valve) and air sensor plate switch connectors. The CSV is already connected (as shown in the picture) so most likely that is the air sensor plate switch connector. The wires should be brown for this particular connector (ground wires). HTH.

Tony

[Gunter]

Tom:
If you search the PP catalog under "Rubber Sleeves" you'll see why the '74-'77 have no ribs.
You could return the sleeves for credit and order these:

930-110-885-00-M260 Rubber Sleeve, 911 (1980-83) Brand: OEM [Photo] [Photo] [view in parts diagrams]
$4.00

The connector for the Air Sensor Plate may have lost the tiny wire clip to hold it in place.
The function of the switch is to stop the pump when the engine is not running.
When it is disconnected, you may notice the pump running when you turn the ignition ON.
When connected, the pump will only run when you turn the key to start and the engine turns over provided the wiring is OEM.
Providing more pictures is good to show how the rest looks.

Vacuum lines you could check:
You may not have 17A (Thermal Time Valve)
If not, the vacuum may go straight from 54 (WUR) to the top of 7 (Deceleration Valve)
Either way works; some prefer to have the TTV.

[Tom '74 911]

Originally Posted by Gunter

Tom:
If you search the PP catalog under "Rubber Sleeves" you'll see why the '74-'77 have no ribs.
You could return the sleeves for credit and order these:

930-110-885-00-M260 Rubber Sleeve, 911 (1980-83) Brand: OEM [Photo] [Photo] [view in parts diagrams]
$4.00

The connector for the Air Sensor Plate may have lost the tiny wire clip to hold it in place.
The function of the switch is to stop the pump when the engine is not running.
When it is disconnected, you may notice the pump running when you turn the ignition ON.
When connected, the pump will only run when you turn the key to start and the engine turns over provided the wiring is OEM.
Providing more pictures is good to show how the rest looks.

Vacuum lines you could check:
You may not have 17A (Thermal Time Valve)
If not, the vacuum may go straight from 54 (WUR) to the top of 7 (Deceleration Valve)
Either way works; some prefer to have the TTV.

Gunter -
Thanks for the great info. Is there any reason the rubber sleeves I have as replacements won't work - are the ribbed ones better? I'm replacing the old ones as there is visible cracking on a few of them.

You're absolutely correct about the air sensor plate and my fuel pump - it does run when the ignition is turned on. I can see the benefit of this switch if I was in a accident where the engine shut off, but the pump kept running - possibly a bad situation. I may try to connect it to see if the wiring is there when I put my engine back in.

And once again you're correct - the Thermal Time Valve is not connected. I'm not sure if the WUR is connected directly to the Decel. Valve, but I suspect it's as you say.

I may post back w/more photos and questions about some of the operations and connections etc... once I get further into it.

Thanks a lot for the info and help,
Tom