'06 F115 leak down test and finding TDC

[hawilson2]

Would like to learn how to do a leak down test on my engine. Harbor freight as a leak down tester http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=94190 that would probably suffice but I am not a mechanic and have no idea how to find TDC for the cylinders. Any instructions or hints would be appreciated? Also, does anyone have any numbers or percentages that are acceptable/unacceptable for leak down results for that engine?

 

[rodbolt]

Re: '06 F115 leak down test and finding TDC

look at the flywheel TDC for 1&4 are the same and marked from about 10*atdc and about 30*BTDC.
180* from the 1&4 mark is a single line. this is the cyl 2&3 TDC mark.
easist way to do it is to line up the TDC mark one the 1&4 and test 1. if leakage is 100% go to #4.
1&4 and 2&3 come to tdc at the same time just one is on compression stroke and one is on ex stroke.
if one has 100%leakage its on exhaust and either dissconect the air and rotate the flywheel 360* or simply go to the other one thats at TDC.
max % of leakage is 15%.