hkeiner
Lieutenant Junior Grade
- Joined
- Oct 17, 2006
- Messages
- 1,055
Re: Checking sync and link settings on 150hp carbed V6?
I just took a look at a Seloc manual for my motor and it also states that the cylinder should be positioned at .462" using a dial gauge and that the timing pointer should then be aligned with the .462" marking on the flywheel. However, it also goes further to describe the .462" marking as being equivalent to the 45 degree position of the crankshaft.
I don't know what is magic about the 45 degree position other than it is halfway between TDC (0 degrees) and 90 degrees. Geometry tells me that the cylinder moves very little when the crankshaft is passing thru the TDC range (i.e. it is at the top of the arc) versus when the crankshaft is at 45 degrees. Perhaps Mercury feels that the accuracy of a dial gauge for measuring TDC of the crankshaft is not as precise (or more likely to be inexactly determined) as measuring the 45 degree position of the crankshaft. This is just pure speculation on my part but is the only explanation that I can think of so far.
Does anyone have other thoughts or knowledge on why .462" (instead of TDC) is specified by both the Mercury and Seloc shop manuals for setting the timing pointer?
I just took a look at a Seloc manual for my motor and it also states that the cylinder should be positioned at .462" using a dial gauge and that the timing pointer should then be aligned with the .462" marking on the flywheel. However, it also goes further to describe the .462" marking as being equivalent to the 45 degree position of the crankshaft.
I don't know what is magic about the 45 degree position other than it is halfway between TDC (0 degrees) and 90 degrees. Geometry tells me that the cylinder moves very little when the crankshaft is passing thru the TDC range (i.e. it is at the top of the arc) versus when the crankshaft is at 45 degrees. Perhaps Mercury feels that the accuracy of a dial gauge for measuring TDC of the crankshaft is not as precise (or more likely to be inexactly determined) as measuring the 45 degree position of the crankshaft. This is just pure speculation on my part but is the only explanation that I can think of so far.
Does anyone have other thoughts or knowledge on why .462" (instead of TDC) is specified by both the Mercury and Seloc shop manuals for setting the timing pointer?