I had a friend who did his timing by using jars filled with water and tubes from the exhaust into these jars thereby pinpointing the exact time the exhaust opened.

Following a recent thread on the subject on a different site I think you can get a better feel by attaching a tube to the drain cocks and gently sucking.

I think the bubbles in the jar of water is more accurate.

If the exhaust opens before the inlet due to lap how does blowing show when the exhaust is open? Unless you are blowing into th edrains and not the inlet.

If you suck from a drain cock you will draw in air through the exhaust regardless of whether the inlet is open or not.

Like wise sucking on the drain cock with eh exhaust blanked off will indicate when the inlet opens.

If you want to use water in jars and avoid sucking in something nasty have a sealed jar with two connections – one for a pipe to go into the water and another above the water to suck.

I also doubt that any blowing into the cylinders via drain cocks would work, at least not on a slide valve setup as the valve would just lift, may be OK on piston valves.

Edited By JasonB on 06/11/2022 07:32:31

Edited By JasonB on 06/11/2022 07:46:55