MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Petronix Static Timing

I have to put the distributor in and pre-set it. I presume that can use a voltmeter with the positive attached to the #1 spark plug wire and the negative touching the block to acertain when the system is firing as opposed to looking for the gap closure?????
T McCarthy

No, you cannot use a volmeter on the spark plug wire. The rotor arm does not touch the pin in the Distributor cap, there is a slight gap which the high voltage jumps across. You will get no reading if you are just hand turning the engine. If you mean to do it with the engine running the voltage is too high for most voltmeters and the period is to short to see anything. You would need a high voltage oscilloscope which can "freeze" the reading.
Use the votmeter on the low voltage input to the Distributor. It will read zero volts when the points are closed and jump in voltage when the points open.


Mick
M F Anderson

I was thinking of measuring resistance rather than voltage.
At hand cranking speed you will get a voltage at the spark plug lead, it can jump the gap between the rotor and the pin in the Distributor cap.
However, you still have a problem measuring very high voltages for a very short period of time.
You should measure the low voltage at the Distributor lead.

Mick
M F Anderson

When I converted to petronix points I found that if you get the timing close with the rotor close to 1 o'clock with #1 at TDC it will fire right up! At which point you then dial it in with a timing light.
WMR Bill

This is covered in the latest issue of the MGA Register. Connect a voltmeter between the low tension coil lead goint to the distributor and ground. As you rotate the dizzy the meter will jump to 12 volts when the Petronix triggers, just like the points opening.
J Heisenfeldt

J Heisenfeldt is right on. Well worth joining NAMGAR to get their magazine MGA! every two months.
Membership details at NAMGAR.com.
Peter.
P. Tilbury

This thread was discussed between 03/10/2008 and 06/10/2008

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.