Timing the Bosch OO9

by Ken Hooper

The thing about timing is that what matters most is what happens at cruising speed, maximum advance--that's where you can burn up an engine quickly if your timing is too far advanced.

But: The Bosch 009 does not have a predictable advance curve--the German ones are different from the Brazilian ones and the worn ones are different from the new ones and on it goes. The natural result of this is that just because you've timed the 009 properly at idle does not mean you have any way of knowing what's going on at highway speeds.

So while the stock vacuum advance distributors can safely be timed at idle (or even timed statically per Muir, although this is never optimal), the 009 has GOT to be timed to about 30 degrees TOTAL ADVANCE with a timing light. Which means you have to rev it up until the distributor stops advancing before you can dial it in.

It takes three hands and if the process isn't painful, you aren't doing it right. =^ ) It's okay to time it statically at around zero degrees in order to get the engine started, but you have to finish the process dynamically by making lotsa noise.

It is very easy to find 30 degrees without a degree wheel as long as you know where top dead center is. From TDC, measure an inch and three quarters (1 3/4") to the right around the diameter of a stock pulley. That's about 28 degrees, go a tinch further and mark it with fingernail polish or something.

If you don't know where TDC is, then you have to pull the #1 spark plug and push the eraser end of a pencil in the hole and rotate the engine and feel the piston until you figure it out.

A basic timing gun is ~$20, get one and carry it with you, it's an irreplacable tool.

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