grumpin Posted December 8, 2022 Share Posted December 8, 2022 The physical piston stop is the best method for accurately finding TDC and verifying timing marks. That said, I will offer another REALLY weird method to get mighty close, and it's pretty easy. This method does require some sort of screw-in adapter; I use appropriate end of my compression tester. Just slip a toy balloon over it and rotate the engine by hand to TDC; the balloon will inflate, the start to deflate when it passes TDC. By rocking back-and-forth you can get it pretty close, within a degree or so. If your balancer has not slipped it will then agree with the balloon. I have never seen a balancer slip by only a degree or two; when they do let go they move quite a bit. My Brother-in-law taught me this method; he uses it to time his Onan generator in his motor home; there is no way to see timing marks on that engine when it is installed. That is slick! Never heard of that method, that I remember. Link to comment Share on other sites More sharing options...
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