A65 Ignition timing

[Martin S]

I have an A65 Lightning which I am currently awaking from an extended hibernation. I have a problem positioning the ignition advance/retard mechanism.  My crankcase does not have a timing plug but it does have markings on the primary chain cover so I have been able to locate TDC fairly easily. First problem solved (see photo).
I cannot see any reference to position it before installing the contact breaker plate, and once this is on it is very difficult to reposition the advance/retard unit with any degree of accuracy (well it is for me).
Can anyone suggest an idiot's guide to doing this please?
All suggestions gratefully received.

[DAVE BRADY]

Hi,

There should be a pin in the lefthand hole to point to the line on the rotor which is the fully advanced 34º BTDC position. A small round nail could possibly be used as long as it is a good fit in the hole.  However, it would be best to remove it afterwards just in case it comes loose.
Pages B47 to B49 of the workshop manual covers the fitting of the advance/retard mechanism and the points.
It does mention the locating peg for the crank but you can use the pin and mark instead.  Once running these can be used to more accurately adjust the timing using a strobe.

Dave.

[Allan G]

If your motor is an early one with the narrow crank and doesn't have the timing plug on the front, then the use of strobe timing your motor with the later timing cover is of no use to you.

The early cranks had their rotor keyway slot in a different position to later engines and the timing will not line up.

There are websites however that you can put your engine dimensions in and it can calculate how far in MM down the bore a certain degree of measurement is.

The rod length which you need is 6" or 150mm. Stroke is 74mm. Using a DTI will get you a high enough level of accuracy.

[yosemite]

Early  a65ignition fully advanced is 0.357" before tdc or 3 7 °  according to bsa manual see photo, (if it loads properly) normally I set engine to correct angle place advance /retard in taper, fit contact breaker points with screws in centre of slot, then using a bolt screwed into the end of the advance/retard unit rotate it in the correct direction (with the unit fully advanced ) which is quite fiddly till the point start to open, either use a fag paper , a meter, or test light to do this. Then using the bolt in the advance unit push it to hold the unit on its taper and also hold it without allowing the unit to move then unscrew the bolt. Once this is done screw in the centre  bolt. Finally check that everything is right, if you are like me then you will find something is off slightly so reset crank position and this time adjust by turning the points backplate to correct. Forgot to say before setting timing assemble it all  dont bother  about timing at this stage and set points gaps. Then take it apart and sstart to set timing

[Martin S]

Gentlemen,
Thanks for the advice; for the first time I can now set the crankshaft to an accurate 34 degrees BTDC - assuming the pointer and holes are correct!
As per Yosemite's guidance, I will now try and install the advance/retard mechanism. From previous attempts it needs at least 3 very small hands and unfortunately I only have 2 large ones. I will persevere.....

[Allan G]

If you use Yosemite's advice, you will see if the marker on the rotor lines up with the one of the pointer positions on the primary case. However many early cranks did not.

[Gup holland]

Here is the diverance in key way slots of an early and late 734 crank.
I have a 63 engine and a late 734 crank in it, wanted to go back to early crank set up, and discovered also the timing marks doesn't line up anymore with late primairy cover for strobe timing.

Know what to do now.

Gr alex

[yosemite]

Gentlemen,
Thanks for the advice; for the first time I can now set the crankshaft to an accurate 34 degrees BTDC - assuming the pointer and holes are correct!
As per Yosemite's guidance, I will now try and install the advance/retard mechanism. From previous attempts it needs at least 3 very small hands and unfortunately I only have 2 large ones. I will persevere.....

If I can do it with my hands you can, size xxxl gloves and a bit of arthritis, Its fiddly but not impossible take it in steps, you,ll get it sorted

[Gup holland]

Because I went from an 734  crank to a early crank and strobe timed it always, the marks are not lining up anymore because the key ways are a few degrees diverent ,and had Made Some new one for the strobe. It's an 63 a65 engine so no set up for a plug. Used the dail gauge for tdc mesurements.
Then put a Spacer 7,2 mm thick on the piston and Made a new marking (right hand cil.)
I think I am not the first one with this set up. Did they came to the same conclusion?
At least I think I did it right (hopefully

[Gup holland]

With a small drill 3.2mm i made a center to establish tdc . Easy for later, instead through the plug.