How to find tdc

downsr said

So I all I have to do is turn # 1 up on compression stroke to 10 degrees before tdc on my balancer turn in the stop till it hits the piston .Rotate the engine in opposite direction till it hits the stop. Make a mark. Then find the center between the 2 marks

Click to expand...

Here's the caveat in this method, and I did mention this. These commercial stops WOBBLE AROUND. And if they don't use a lock nut, or if you don't screw the plunger "clear down" they will move around. I can EASILY see a 1--2 degree or more error in this wobble. This is why I insist you should "do it the other way." Set the stop and leave it be. MAKE SURE the plunger is RIGID. Make temporary marks and then measure from them to the TDC, see if they are equal. You can use dividers for this makes it very easy. If you don't have, it used to be easier for me to actually crawl underneath where I could get a "clear shot" of the marks on the wheel with a good tape or flexible scale.

Also, it does not matter whether no1 is on compression or not. All you need for this is for the mark to be "there"