WyoSyclone
Active member
Hi Guys,
Since I've had my Sy I haven't been able to verify TDC due to the engine builder putting an aftermarket cover on that didn't have a timing pointer. I finally got my ATI pointer installed, and then started looking for the best way to verify TDC. I searched all over the internet and found whistles, scopes, balance beams, etc. None of them seemed to be accurate enough, or easy enough to use. So, here's what I came up with.
I remembered U-tube manometers from my physics class days and decided that may be a pretty cool way to measure piston movement. Here's the manometer - available from Dwyer instruments for $27. The black upright is my wife's lamp.... shhhh!
To connect it to the #1 cylinder I used the tubing from my compression tester, a length of 1/2" vinyl tubing from Lowes, slipped it over each end, and that was it!
I wired the throttle open...
And here's the displacement of fluid from just a few degrees of turning the engine over...
The fluid will rise about 12" in the tube in about 45 degrees rotation of the crank... pretty darn accurate. You have to practice a few times, and it helps to have someone call out when the fluid stops rising. Leakage past the rings is almost nil, so you don't have to worry about the fluid suddenly dropping.
It's really interesting to take the engine through a couple of revolutions and see the valves opening (fluid dropping).
Here's a link to a YouTube video I did of it.... I'll probably do another video when my wife gets home next week so she can do some camera work and I can show you the fluid moving (can't find my tripod)
http://www.youtube.com/watch?v=Ys80A6fL0_4
The cool thing about this is that you rotate the engine normally until the fluid stops, then you can go past TDC about 30 degrees and turn the engine backwards until the fluid stops. This will give you that null point in crankshaft rotation where the piston really isn't moving (appears to be about 2 degrees). I put a line of paint at each of these locations, and that way I can decide if I want my true TDC point at the point where the piston stops, or a few degrees later, where the big end of the rod is just slightly past TDC.
Pretty cool experiment for a small investment.
Since I've had my Sy I haven't been able to verify TDC due to the engine builder putting an aftermarket cover on that didn't have a timing pointer. I finally got my ATI pointer installed, and then started looking for the best way to verify TDC. I searched all over the internet and found whistles, scopes, balance beams, etc. None of them seemed to be accurate enough, or easy enough to use. So, here's what I came up with.
I remembered U-tube manometers from my physics class days and decided that may be a pretty cool way to measure piston movement. Here's the manometer - available from Dwyer instruments for $27. The black upright is my wife's lamp.... shhhh!
To connect it to the #1 cylinder I used the tubing from my compression tester, a length of 1/2" vinyl tubing from Lowes, slipped it over each end, and that was it!
I wired the throttle open...
And here's the displacement of fluid from just a few degrees of turning the engine over...
The fluid will rise about 12" in the tube in about 45 degrees rotation of the crank... pretty darn accurate. You have to practice a few times, and it helps to have someone call out when the fluid stops rising. Leakage past the rings is almost nil, so you don't have to worry about the fluid suddenly dropping.
It's really interesting to take the engine through a couple of revolutions and see the valves opening (fluid dropping).
Here's a link to a YouTube video I did of it.... I'll probably do another video when my wife gets home next week so she can do some camera work and I can show you the fluid moving (can't find my tripod)
http://www.youtube.com/watch?v=Ys80A6fL0_4
The cool thing about this is that you rotate the engine normally until the fluid stops, then you can go past TDC about 30 degrees and turn the engine backwards until the fluid stops. This will give you that null point in crankshaft rotation where the piston really isn't moving (appears to be about 2 degrees). I put a line of paint at each of these locations, and that way I can decide if I want my true TDC point at the point where the piston stops, or a few degrees later, where the big end of the rod is just slightly past TDC.
Pretty cool experiment for a small investment.
