[Glennbon]

ABA/CIS timing

I’ve built a aba with cis basic top end and runs good. I welded in a 02 bung and tuned with a wide band which helped.
What should be the max timing and at what rpm? Engines in a 82 Westy

 

[ny_fam]

Depending on compression ratio, they will make best power around 28 total degrees advanced for below 10:1 CR.

With the lower compression engines its possible to have more ignition advance than required to make the most power, and even to the point of loosing power, before signs of detonation.

Its also important to look at the specs for the distributor you have to see when the advance comes in and at the max is.
ny_fam

 

[Glennbon]

The compression spec for the ABA is 10:1. I used a mls head gasket with two extra .009” outer shims so I’m thinking I’ve lowered it maybe a point. I have to use Chevron 94 octane to avoid detonation which I don’t mind as it’s a seasonal vehicle.
But when I checked with the timing light the full advance was 40* @ over 3000 rpm.
It’s just a stock 1.8 cis distributor. I guess I’ll try and recurve it with lighter springs and limit the advance