09-09-2021, 04:57 PM
Hi,
I’m continuing to try to improve the rough running of my Ulsteroid which has a mildly tuned 2-bearing coil engine. (Oversized inlet valves, Ruby head, flattened cam followers and a 1 ¼” SU Carb).
It has a centrifugal advance DK4A distributor which I suspect is part of the trouble but before stripping it down I wanted to eliminate any timing or mixture settings. The trouble is I’m not sure if distributor wear or wrong timing is masking an incorrect mixture setting.
I initially set the timing to TDC static and the car starts easily and runs reasonably OK but is very rattly at low speeds improving once you’re up to 30 MPH.
As I understand it the auto-advance provides a maximum of 16° so with the static timing at TDC this is presumably the maximum advance.
On-line I’ve seen recommendations that maximum advance should be between 22° and 27° so presumably I need to set the static timing to around 6° but is this correct? I have tried adjusting it “By Ear” but quite significant rotation of the distributor body doesn’t seem to make much difference.
I’m hoping to get the timing “right” so that I can move on to the mixture as currently I can’t reach a point where lifting the dashpot causes the tickover speed to rise and then fall back which is what I believe is the correct procedure.
Any advice would be appreciated,
John.
I’m continuing to try to improve the rough running of my Ulsteroid which has a mildly tuned 2-bearing coil engine. (Oversized inlet valves, Ruby head, flattened cam followers and a 1 ¼” SU Carb).
It has a centrifugal advance DK4A distributor which I suspect is part of the trouble but before stripping it down I wanted to eliminate any timing or mixture settings. The trouble is I’m not sure if distributor wear or wrong timing is masking an incorrect mixture setting.
I initially set the timing to TDC static and the car starts easily and runs reasonably OK but is very rattly at low speeds improving once you’re up to 30 MPH.
As I understand it the auto-advance provides a maximum of 16° so with the static timing at TDC this is presumably the maximum advance.
On-line I’ve seen recommendations that maximum advance should be between 22° and 27° so presumably I need to set the static timing to around 6° but is this correct? I have tried adjusting it “By Ear” but quite significant rotation of the distributor body doesn’t seem to make much difference.
I’m hoping to get the timing “right” so that I can move on to the mixture as currently I can’t reach a point where lifting the dashpot causes the tickover speed to rise and then fall back which is what I believe is the correct procedure.
Any advice would be appreciated,
John.