Inboard ski boat ignition timing

[1983brock]

G'day from a long time lurker, first time poster.

I have a 350 chev (stock) inboard ski boat with a dog clutch (timing case end driven) and need to sort out the ignition timing after a dizzy replacement. I have got the timing somewhere in the ball-park (runs okay) but I want to be sure it won't ping.

There is no accurate timing mark on the flywheel that I can find - I got it near enough to run by assuming TDC was when the cylinder 6 rockers were both "rocking".

Are there any tricks to setting timing by ear (not preferred, but at this stage I'll work with what I've got available) or is there another way?

Any help or pointers would be greatly appreciated.

[Boom]

Check the back end of the motor. Sometimes you will find a set of timing marks there.
If not pull No1 plug out and use a screw driver or piece of dowel and set TDC. Doesnt matter what stroke its on. Find a convenient tooth on the ring gear and mark it along with a point on the casting.
Get your protractor out and make some marks.

[VXSS]

Mine likes 18 degrees initial timing at idle and when revved it goes to 36 degrees.

350 chev mild cam with fuelie heads mildly ported large valves

[Steve'sR8]

Hi,
the easiest way is with a vacuum gauge attached to a good source of manifold vacuum. Disconnect the vacuum advance if it has one, then advance the distributor until the gauge stops climbing, should be about 21 inches of mercury with a standard or mild cam. Then retard the distributor until the needle drops 2 inches of mercury below the maximum it reached. Once you have established this position you can create your own timing marks for future reference. With a standard distribitor this is usually around 10 to 12 degrees of advance. You can generally run a little more advance in boats because the engine isn't directly loaded as in a car. Hope this helps. Cheers, Steve.

[matthewfnorbert]

i would run around 30 t0 32 degrees "all in" to be safe, that is rev it to say 3500rpm or more after the dizzy has done its advance and set at 30-32 when you see no more advance.
timing at idle will be what it will be in that case but your cruise and WOT will be safe (known)