Inserting distributor drive shaft

[moggiegeek]

Now building up engine. 1275 pre A+. Currently wondering how to insert dizzy drive with the timing gear sprocket marks aligned having just timed in the camshaft - Kent 266. at 104 degrees with the Vernier Duplex.
At this point, with number one inlet valve beginning to open I assume no4 cylinder is on its power stroke?
Which way up then for the dizzy shaft??
Thank you

[philthehill]

The distributer drive shaft will only go one way up. The gear on the bottom of the distributer drive meshes with the camshaft gear and the bottom of the shaft fits into a housing in the block.

The pre 'A' plus and 'A' plus distributer drives are different and are not readily interchangeable.

The 1275cc pre 'A' plus distributer drive is the same as the Minor 803cc, 948cc & 1098cc distributer drive so the Minor workshop manual distributer drive fitting instructions can be used.

Use a long rocker stud screwed into the top of the distributer drive to assist in fitting the distributer drive shaft.

As the distributer drive gear meshes and slips past the camshaft gear the distributer drive shaft will turn. You may have to fit the distributer drive more than once to get the final alignment as per the workshop manual.
Below is a photo of the pre 'A' plus distributer drives. The lower drive shaft has been lightened. The top drive shaft is standard.
The drive shaft skew gear meshes with the camshaft gear and the other end of the drive shaft goes uppermost and into which the actual distributer offset drive fits.

100_2017.JPG (358.72 KiB) Viewed 1152 times

[moggiegeek]

Thanks Phil, I should have been clearer in my questions. Sorry
I meant which segment of the dizzy end of the drive is uppermost - the larger or the smaller?
And secondly with cam and crankshaft dots aligned and number one inlet about to open is number 4 cylinder on the power stroke?

[pgp001]

Phil

Is there any advantage to lightening the distributor drive shaft on a fairly standard road car engine, or is it just for high performance engines.
I assume it is not lightened purely for weight reduction, but more to decrease its inertia.

Phil

[philthehill]

Instructions for fitting the distributer drive for a 1275cc pre 'A' plus engine.

1. Turn the crankshaft until No: 1 piston is at 5 degrees B.T.D.C. on its compression stroke, with the valves of number 4 cylinder rocking

2. Enter the distributer drive shaft with the large offset uppermost with the slot sitting at 10 to 4.

3. The final position of the distributer drive shaft slot should be in line with the two sleeve mounting holes with the large segment uppermost with the slot sitting at 10 past 8.

The above extracted from BL Marina wksp man Pt No: AKM4580.

No real advantage in lightening the drive shaft on a road engine but on a comp engine it reduces the loading on the distributer bearing.