question about timing marks in relation to tdc...when exactly is it considered tdc?

[91tizzy]

I checked to see if my intake cam was a tooth off because my ignition timing is fully advanced and I was told that is kind of the bandaid solution for the intake cam being a full tooth off...So I pulled the timing cover and used a ziptie sticking in cylinder number one to show me when the piston hit tdc. Now when the pistion first reaches tdc the intake came does appear to be a tooth off. But when its still at tdc and right before it starts the next stroke (right before the piston starts descending) the cam marks appear to be in perfect time.....which should I assume? When exactly is tdc right when the pistion reaches it fullest upward extension or while it is still at full upward extension right before it starts to descend? Any help is always appreciated...

 

[RoasT BeeF]

You need to pull the lower cover and look at all the timing marks at once. Using a zip tie in the spark plug well while only looking at the cams is not going to work.

 

[snowborder714]

Here's how to check all of the timing marks:
http://www.dsmtuners.com/forums/pro...engine-has-never-run-right.html#post151565942

 

[91tizzy]

I should have known better than to think I could get away with checking it how I was....was just tryin to get a quick idea without having to get too involved...guess im just gonna give in and go through the dam thing and re-time it so I know its done right