CIS question

[Patrickprice]

Hi,
Doing an engine swap for my father in law(No pressure) in his 1972 911T Targa. Swapping from a 2-4 T with Webers to a 3.0SC CIS pre Lambda.

The problem is I didn't get the original CIS with the engine and the one I purchased is the later CIS Lambda system. I also purchased a non lambda fuel distributor but it turns out that it is from a 2.7. Can I get away with using a 2.7 fuel distributor or am I in the hunt for the 3.0 unit? I am pretty well versed in CIS so If I need to mod system pressure etc that is within my abilities.

I also may source a Lambda control box and harness but am curious where I would locate the O2 sensor since it has early SSi's with a twin inlet muffler. Hard to get a good sample with this setup.

Please don't tell me to rejet the Webbers and put them on. My father in law has a really tough time getting it running with them.

[James Brown]

man what pressure! put the O2 in somewhere before the cat if using one, one is fine. Now the cis, they run bad enough before you start swapping components. try to keep the 3.0 system complete. Do you need the lambda for pollution control? i doubt it with a 72 and if this is the case just skip it all together, many people disconnect it when it fails without problems. As long as the AAV and WUR are in good order you should be able to tune it close enough. A good A/F meter is required. (i'm sure the webers can be fixed easer than the CIS can be) and look cooler! Yes, the CIS cams work with carbs just fine

[T77911S]

you cant use the O2 with that fuel dist (FD).

whats more critical is that you match the FD to the WUR.

you say you have a 3.0sc that is pre-lambda? that would mean a 78-79. this is an awesome motor! it has the large port heads so you need the CIS for that car to get the most out of it. the reason is, the intake runners you have are not matched to the intake ports of the 3.0.

if you want to make the 2.7 FD work you need a WUR from 76-77 that has the vacuum enrichment at WOT. the one from 78-79 will work too, but without looking up fuel pressures, i am not sure if you will need to adjust the CP to match the FD.

find the 78-79 CIS. the other great thing about this system is there are no electronics to deal with or go bad. that equals incredible reliability and cheaper main. no O2 sensor to replace every 100k.