123 distributor ignition curve, new install in 1.7 djet Options

[jhynesrockmtn]

I just got my 1970's engine back in after procrastinating with finishing up this project. Engine came out to address RMS and trans fluid leaks and a bunch of other stuff. I installed a 123ignition distributor. Stock 1.7 djet. It started right up and seems to run well. Idle settles in at 900 once warm. I need to address the AAR as it does not work. I took it for a 30 mile drive yesterday.

I wanted to ask about the curve on the distributor. I haven't changed it. The distributor is the bluetooth version. Pics of the curve and dashboard during the drive. Any input on what might need changing? Engine runs so much better. It does have new injectors as well. The old ones were not able to be serviced and one was from a 2.0. That cylinder was fouling.

[JamesM]

This pelican article has 3 point curves for various stock 914 distributors
https://www.pelicanparts.com/techarticles/9.../914_timing.htm

As you can see all except the 75-76 cars are 27deg by 3000 RPM

the 75-76 cars retarded the entire curve to run up the EGTs for emissions and addition of a CAT, this is part of why they lost so much power and ran HOTTER.

For a 1.7:
Keep somewhere in the range of 1000-1200 RPM and below set to your idle advance, generally you want this as low as possible that still allows you to return to normal idle, you may be able to pull this off @1000 rpm given the dizzy has no moving parts, but if that causes idle run up then try 1100, then 1200.
then:
1500 RPM 17deg
2000 RPM 20deg
2900 RPM+ 27degrees


That will give you the most responsive curve while still being within factory specs.

You can tweak this and add additional points that round up the curve a bit but as you really shouldn't be under heavy load below 2900 RPM anyways you probably wont notice much from the effort other than a slightly snappier throttle.

[JamesM]

Also worth noting, it looks like your idle is currently set to 0 advance.

IF you can keep the idle speed under control you will most likely get a stronger idle by increasing advance at idle a bit. All type 4s I have seen have produced best idle vacuum/strongest idle somewhere between 8-12 degrees advance at idle. However with a stock d-jet setup this will be dependent on if you are able to adjust the idle speed properly still with the stronger vacuum.