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MG TD TF 1500 - Setting timing instructions

Prior to starting the engine, I followed the WSM instructions on setting timing, finding TDC (pulley mark and checking valve positions) and then adusting the distributor until the points are just beginning to open.
That's as far as I have gotten in respect to timing. The engine starts normally and runs smoothly, although idle is probably too low (considering it is cold out, choke is needed, and I haven't gotten the low idle set so it will run without a little gas.)
The WMS says the following: "Before setting the timing, make sure that the automatic advance and retard mechanism is working properly and is in its fully retarded position".
What does this mean?
I'm arranging to borrow a friend's timing light (hopefully, it has an adjustable advance), but I'm hazy on this whole process, having never done it before on the MG.
Any good instructions someone can point me towards?
Geoffrey M Baker

Basically they are telling you to have a look inside the distributor and make sure that the springs are in place and not stretched and the the advance plate isn't frozen and moves freely and returns when you twist it by hand.

With the timing light you simply hook it up with either the number one or number 4 plug wire and with the engine running point the strobe light at the timing mark . The light gun will have a button or knob that you adjust backwards until the light appears to be firing directly when the pointer and the crank wheel notch line up.... then look at the read out on the gun and it will tell you how many degrees you dialed back. If you want later you can do the same thing at a higher rpm to tell you two things. One...how much total advance you have ... and two ..at what rpm that occurs.


Your initial settings should be done at normal idle speeds...after you get the cam broke in.
MG LaVerne

Before setting static timing, realizing that the distributor turns counter clockwise, you must grasp the rotor and turn it full clockwise to assure that you are not in an 'mechanical advanced mode' or fully retarded.

When static timing, set the engine at TDC. It doesn't matter if you are TDC on cylinder one or four, assuming you know which terminal is which and you have the rotor pointing in about that direction. Get the Distributor oriented so the points are closed and the rubbing block is just before a cam lobe. With the lamp wired between the distributor terminal and the coil, the points closed will direct all the electricity through the points. As you turn the distributor clockwise, the points will open and at that instant the electricity will flow through the lamp.

The timing light will probably have an inductive pickup that goes around the one or four spark plug wire; and two more alligator clips, one for the positive battery terminal and one for the negative.

Even when idling the mechanical advance comes on very quickly. I think that was to ease starting. So it is typical to look for 8 degrees BTDC at idle (800-1000 RPM), or about 1/4 inch before the pointer using a basic, non dial back timing light. Then, with full advance in, (engine revving at about 3500 RPM, and the timing no longer advancing) you want to be at about 32 BTDC, or 1.05 inches before the pointer.

Hope this helps,
dave



Dave Braun


Geoffrey, Condition of your distributer is an important factor in reliable ignition operation and resultant consistent timing. Check shaft play in the bushings carefully, and if you've never disassembled your distributer advance weights and springs, you may be surprised about how much crude you find in there.
I think one of the best written articles on the web is by Skip Burns. Please read it. Especially noting that he says the timing lite won't work well with the TD distributer. If you use one, you will see what he means about the quick advance at idle and the timing jumping around.
http://www.chicagolandmgclub.com/techtips/mgt/tune_up1.html
Richard Cameron

To develop this thread a little further my TF has electronic ignition and it is superb. When the car hears me opening the garage door it almost starts itself! However with conventional points you can set the engine to just before TDC from the pulley marks, and then rotate the distributor until the points are just opening. This car be easilly determined with a bulb or a piece of thin paper or even by just looking at the lobes on the the distributor shaft. With these setting the car should start. If you take the cap off my distributor there are no points to see. With points you can slowly rotate the distributor and watch for a spark by removing a plug/lead and placing these on the cylinder head. This won't work with my electronic unit, the trigger rotor in the distributor needs to be turning fast in order to work. I know some expensive units have a neon that flashes when the distributor is firing. This makes life vey easy but I don't have this facility. I had to remove the plugs so the starter could spin the engine, connect number one lead to my strobe and view the pulley with my this. I was then able to set the equivalent of static timing, start the engine and fine tune the timing. The moral of this tale is either buy an electronic unit with a flashing diode or be prepared for a bit of hassel or keep the points of course!

Jan T
J Targosz

Or, install a pertronix Igniter. You can static time with a light bulb, just like points. Bud
Bud Krueger

This thread was discussed between 07/01/2016 and 08/01/2016

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