- May 12, 2018
The N15 starts spark knocking after the engine warms up. Any thoughts as to which direction I should go first? I’m thinking I should adjust carb air/fuel mixture first.
Intake leak? Have you checked?Dave,
Yes, it has a Lucas AAU. I put new springs on it and it seem much tighter. I also checked to make sure the magneto advanced when the AAU weights were out, so that’s not an issue. It’s static timed at about ~31.5 TDC with AAU fully advanced, which is definitely close enough. I see a post above mentions 28 BTD. Now I wonder if I should have researched that scenario before I reassembled it. I’m going to fuel it up with higher octane fuel today and take it on the hilly backroads to see how she does. I’ll be reporting back this afternoon.
You may be on to something. I timed it at 28 and it’s a fair bit better, but still pinging. When I had it torn down, I did notice two stripped head studs. I’ll be sending the head in for repair to Jim shortly. Fortunately, I have a head I got for a great deal last fall. All studs are good. I’ll lap the valves in and swap them while I get this one rebuilt.Intake leak? Have you checked?