Technical My novel way to find TDC on a flathead...without pulling the heads

I have been trying to find the absolute TDC on my engine as the timing marks on the pulley seemed to be off, distributor not working properly etc....so yesterday while contemplating the issue, while sitting in the shop with a beer, I thought of something, and today put it to the test...and it worked!

I have a wood stove in the house with a manometer of sorts to monitor the draft in the chimney, it's a very sensitive vacuum gauge reading .25" Hg full scale. I thought Mmmm, that would be sensitive enough to observe the change in direction of the piston in the cylinder by watching the movement of the needle as the piston p***ed TDC and the pressure changes from positive to negative....I tried it this morning and ...well, watch the video. It's a pretty cool way to find TDC without pulling the heads...not sure how accurate it is but has to be as good as sticking a screwdriver in the plug hole of an overhead valve engine.

Cheers

https://www.dropbox.com/s/xq4a7gtipdfudu7/IMG_1171.mp4?dl=0

 

Could you do the same thing with a balloon?

 

The sprintcar engine guys(old timers anyway) usually have an old sparkplug with the guts removed & a kids plastic whistle glued in. Screw it into #1, turn the motor over slow & when it stops whistling, you have TDC. Sometimes you have to do it a couple of times until you get used to when the whistle stops. Meets all 3 tests : Quick, Cheap, & Easy!

 

Does it matter what brand of beer you drink during the test?

 

I recall reading somewhere about a similar process using a bourdon? Tube with liquid.