Ignition timing

[macvette]

Does anyone have a sketch of the spindle mentioned in KTB on page 207 so that the timing can be set without taking the exhaust off or alternatively doe s anyone supply them?

Thanks Mac

 

[vibrac]

bit of old 1/4" brake rod with a slight kink always sorted me out to 1 degree. ignition timing final adjustment is a rolling road job to get it spot on, if not and you are using a book figure thats good enough.

 

[stumpy lord]

All you need is a seven inch length of 5\16 threaded rod, two nuts to suit the rod, and two washers. have rod turned down as in know thy beast, and you have a timing tool. Failing that Clever Trever/ Francois Grosset produce a tool not only enables you to time your engine but strobe it at the same time. stumpy lord

Does anyone have a sketch of the spindle mentioned in KTB on page 207 so that the timing can be set without taking the exhaust off or alternatively doe s anyone supply them?

Thanks Mac

 

[bengunnhrd]

Ian at VOC spares sells them.

 

[John Cone]

This is one that i made albeit when i had the timing side apart and could marry it up to the timing disc. You will see if blown up a bit that it has 2 marks, one for TDC and the 2nd for 38 degrees BTC for ignition. Certainly takes the hard work out of the job.

 

[Bazlerker]

And one of these is handy;

http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=LED51

 

[Martyn Goodwin]

And one of these is handy;

http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=LED51

Handy? HAndy? HANDY! Its absolutely essential! When combined with a decent timing disk you you can set the timing within +- 1 degree. As to mounting the timing disk - with a hole saw cut yourself a generous circle of 5 ply timber then glue that to the centre of the back of the timing disk with a 1/4 inch hole right thru the centre of both. Then get hold of a bamboo chop stick - not hard or softwood - and poke that thru the hole. Remove the quill from the mainshaft and you will find that the chop stick is a perfect friction fit to hold the disk in position.

And when setting the timing - make sure you are on the compression stroke, its too easy to make the mistake of using the exhaust stroke - I know

 

[macvette]

Thanks for the replies. Mine is series D ie with distributor, whilst setting the timing, I noticed that the distributor cam has different sized lobes. Anyone know why this is?
Thanks Mac

 

[greg brillus]

Hi there Mac, thats because the cam lobes are 205 degrees appart.....First (rear) cylinder fires first then number 2 fires at one full crankshaft rotation plus another 50 degrees being a 50 degree twin.....so 360 plus 50 =410 degrees of crankshaft rotation, but the distributor or magneto spins at half speed, so half of 410 degrees equals 205......Cheers.......Greg.