Just a thought but it might help. Workshop manuals will give the dwell angle in the tuning data section, the angle for an 18V MGB engine for example is 60 degrees plus or minus 3 degrees. The simplest form of this is to rotate the whole distributor with the engine running until the fastest idle is achieved. Check the inside of the distributor cap for wear and cracks. However, at the age most distributors are now at, they have worn and so can vary from the original spec by significant, even major, amounts. MG Midget Timing Problem 3.
When you are satisfied that top dead center has been accurately located, mark the position for future reference.
I took another photo of the distributor with the cap and wires. Number 1 cylinder is the cylinder closest to the radiator. MG Midget Timing Problem 2. Similarly, make a note of the static setting your distributor is now at for use for initial set-up after those occasions when the distributor has been removed such as to fit new points or an engine rebuild. Remove the distributor cap and examine the surfaces of the contact breaker points. More Articles Like This: