Refer above - Ignition setting for B18D. There are 3 variations of B18D engine - B18D Type 1 uses A camshaft, B18D type 2 and 3 uses B camshaft. I think your K camshaft was an upgrade.

A-kam Lift: 10.5, Duration: 260
B-kam Lift: 10.6, Duration: n/a
K-kam Lift: 11.95, Duration: 268


The Bosch 0231170085 dizzy is a vacuum retard type. Also the original dizzy that comes with B18D. So the ignition has to be set (without vacuum) at a fairly advanced timing (22-24 BDTC) so that when vacuum is re-applied timing comes back to normal ie. being retarded to maybe 10-12 BDTC. And the plug still fires before piston reaches the top. A vacuum retard dizzy is usually connected to vacuum port on intake manifold. Whereas a vacuum advance dizzy is connected to vacuum port on carb (this setup on different engine).

In case you're wondering, I'm still doing maintenance on wifey's 3-cylinder 1997 Daihatsu with carb. Her first car. Didn't want to sell it off. As expected, the original Denso dizzy had worn out and replaced with 3rd party manufactured item. Hard to get original these days. The Denso had both advance and retard diaphragm. 3rd party quality not the same with original. So I had to play around with the timing.

Amarin.

Hi,

Just a thought, on my part, so don't take it to heart or to a bank!

I think you are getting all worked up over pretty much of nothing.
I mean, when it comes down to making the engine run correctly you are going to watch the burn deposits on the spark plugs and the color of the insulator's nose.
Using a vacuum gauge will also tell you a few things about what the cam is doing with the air.
Today you can use emission meters and dial your engine in better than it was originally.

The difference between the one year to the next for the distributor is a degree of change here or there. Sometimes it could be a change or was it not changed at all. Maybe it was a rotor or cap, a lower shaft bushing modification or a seal design.
The production on one over another can change on the "whim" of how many more engines will this modification fit other engines.

A change in spring tension or the amount of weight that's swinging about is what they were playing with when you are talking curves.
The whole the thing about mechanical mechanisms was the limitations it presented to the dynamics of the breathing and burning of the engine to begin with.
The following years of better fuel management has proven this to be true.

Again study the engines telling signs and adjust accordingly with a distributor machine.
That all the laboratory guys did to begin with and are still doing to try to keep the internal combustion engine alive all these years!

Unless you are one of those lab guys or a racing dude, I don't know how you are going to tell the differences.
If it starts hard, detonates enough to cause hearing damage or burns holes in Pistons the distributor is going to be one of you lesser problems.

So let's see what you end up with or doing. I very curious! (:)

Phil

Amazing resource! Unfortunately I'm learning this dizzy was used in a 1974 and not 1975.

CB, that’s a nice repository of Volvo documentation.