Finding TDC

[dna9656]

The Haynes book says to put a screwdriver in the cylinder to find TDC. They caution you to guard the tip of the tool so the cylinder wall doesn't get scratched but also to mind the angle if the tool so it doesn't get jammed, well that's all and good provided the spark plug holes were drilled down toward the piston but they aren't; they are drilled horizontally. How are you folks finding TDC? Back in the good old days there was a mark on the harmonic balancer and a pointer on the timing chain cover but I guess that's just to easy these days...

Edited August 18, 2019 by dna9656

[riverbanks]

What are you working on?more details

[dtnel78]

Many tools for this. I have a whistle that screws in and makes a large hissing sound. Made by Lisle and available at most decent parts stores, tool tucks and Amazon and other online tool retailers. If that’s the only plug removed it should not have pressure when winding up to compress. Make sure you’re on the compression stroke as well is what I was always taught. 

[dna9656]

5 hours ago, riverbanks said:

What are you working on?more details

The 2006 Chevy 5.3. I learned that for the purposes I have (installing rocker arms) you don't HAVE to have TDC. For the intake side rotate the engine until the exhaust rocker is just short of closed. This will put the in tale lifter on the cam's base circle (no load on the rocker from the valve spring or opening forces from the cam) tighten the bolt to 22 ft. lbs. and do the same for the exhaust valve but use the intake valve the same way. You're not timing the motor or the valve train, you're just installing the non adjustable rocker arms. Word of advice: use a TRUSTED torque wrench.

Edited August 18, 2019 by dna9656

[sefiroxx]

I use a thin wire landscape flag.

The mark on the harmonic balancer, cam makes etc are all used during initial assembly to ensure that valves and pistons are lined up.