How To Find TDC // Chevy Big Block

[bigboi]

Ok... Here is the deal. I am having some issues at idle with my car. I know I need to check my timing first and then adjust the carb. The problem is the previous owned didnt mark TDC on the harmonic balancer (well there is a black mark on the balancer but i'm not sure this is THE mark).

I need to find TDC so I can mark the harmonic balancer and check the timing according to the timing tab.

What is the easiest way to do this? Do I just pull the distributor cap and click over the engine until it's on 1?

I know this is probably easy... I just need some guidance. I used to do all this when I was like 17 years old, but over the years I forgot a lot of things... LOL! Too much :smoke: I guess. ;]

Brian

[camcojb]

here's one way.

http://www.2quicknovas.com/happyTDC.html

[Adam's 55 Chevy]

Pop the right hand valve cover. Turn the engine over and watch the intake valve on #1 piston close. The timing mark should be round at about 7 oclock. Bring it round so the woodruff key is at 2 Oclock then mark on your balancer and that is TDC. Check which terminal the rotor arm is facing and this is #1 cylinder.

[camcojb]

Pop the right hand valve cover. Turn the engine over and watch the intake valve on #1 piston close. The timing mark should be round at about 7 oclock. Bring it round so the woodruff key is at 2 Oclock then mark on your balancer and that is TDC. Check which terminal the rotor arm is facing and this is #1 cylinder.

this may get you close, but won't get TDC exactly. You could easily be off several degrees, and he sounds like he wants to verify his true timing.

Jody

[Adam's 55 Chevy]

Granted this is a rednek TDC finder but it will get you close enough to fire an engine up if you have no degree wheel or spark plug piston stop but as Jody says is no way an absolute bang on TDC method.

[camcojb]

Granted this is a rednek TDC finder but it will get you close enough to fire an engine up if you have no degree wheel or spark plug piston stop but as Jody says is no way an absolute bang on TDC method.

I agree Adam, it will get you fired up. I just thought he was trying to verify his actual timing as he was having issues with the car and how it ran.

Jody

[bigboi]

So for me to find TDC exactly what do I need to do? Sounds like there is no REAL way to find it unless I friggin remove the head and bring the #1 piston to the top? Can this be done with a piston stop in the #1 spark plug hole? Is this safe? Will it hurt the piston at all?

[camcojb]

So for me to find TDC exactly what do I need to do? Sounds like there is no REAL way to find it unless I friggin remove the head and bring the #1 piston to the top? Can this be done with a piston stop in the #1 spark plug hole? Is this safe? Will it hurt the piston at all?

the link I posted tells how to do it with the heads on, via a piston stop. As long as you remove all the plugs, turn the engine carefully by hand you won't hurt it.

Jody

[Montana67]

Buy a TDC indicator...you can find them on Summit or Jegs. Install it in the #1 cylinder plug hole -- it is threaded like a spark plug. Rotate your engine with a breaker bar (DO NOT turn it over with starter) until the indicator reaches its highest point. You've found TDC.

[camcojb]

Buy a TDC indicator...you can find them on Summit or Jegs. Install it in the #1 cylinder plug hole -- it is threaded like a spark plug. Rotate your engine with a breaker bar (DO NOT turn it over with starter) until the indicator reaches its highest point. You've found TDC.

sounds cool, haven't seen that one. How does it determine tdc, as the piston will stop at the top for more than one degree? Still need to get a measurement just before it tops out and the same distance after to split the difference to find true tdc.

Jody

[LS6 Tommy]

Buy a TDC indicator...you can find them on Summit or Jegs. Install it in the #1 cylinder plug hole -- it is threaded like a spark plug. Rotate your engine with a breaker bar (DO NOT turn it over with starter) until the indicator reaches its highest point. You've found TDC.

That's not 100% correct. If you don't have a degree wheel, install the piston stop, rotate the engine BY HAND until it stops, mark the balancer at your pointer, rotate the engine around the other way, mark the balancer again and then use a timing tape/measure tape to measure the distance between these marks, divide in half--the TDC is equal distance between the marks.

Tommy