Confiming Crank TDC

[tibZ]

You are correct Diseazd, only the "worm" gear is on the crank in front of the smaller timing gear. If I slip the pulley on, the timing notch comes back to the same place each revolution when the #1 piston reaches TDC. I get the feeling there is no way to determine Firing/exhaust position until I start assembly. Thanks to all for the input.

Mike

[Diseazd]

You would be 100% correct!

[TomoHawk]

Basic definitions:

BTDC (Before Top Dead Center)

TDC (Top Dead Center)

They are related, but not the same thing.

[bobc]

Carl and all,

After reading this I'm confused again. Here's my current situation:

Oil pump and distributor still in car. The head is off.

If I move cylinders 1 and 6 to their highest point. The rotor points to around 7 o'clock, which lines up with the number one spark plug wire. Also, the timing pointer is a 0 degrees. Is this where I want to set up for TDC?

Bob

[Diseazd]

Bob....With the head off you can't rotate the crank because your timing chain is jammed with the special tool that keeps it from falling into the oil pan......but...if you remove the head with the #1 piston TDC compression stroke, the pointer will be at "0" and your rotor will be at 9:00 or thereabouts pointing in the vicinty of the #1 distributor wire. Yes you are right! Then you have to set timing at about 10 degrees BTDC on the distributor using a timing light after everything (head etc.) is reassembled.

Edited December 27, 2008 by Diseazd

[bobc]

We'll let's just call it 8:00 but definitely not 9:00. I think I'm in the right place. I'm replacing the chain, so I don't care about moving the crank now.

Bob

[sblake01]

Basic definitions:

BTDC (Before Top Dead Center)

TDC (Top Dead Center)

They are related, but not the same thing.

Rock on!

[Carl Beck]

The rotor points to around 7 o'clock, which lines up with the number one spark plug wire. Also, the timing pointer is a 0 degrees. Is this where I want to set up for TDC?

Bob

Hi Bob:

The short answer to your qestion is - Yes. If that was where your #1 spark plug wire was to begin with - and if that allowed enough movement of the distributor housing to fine tune the ignition advance/retard... Yes that will do.

I used 10:30 - and 3:30/4:00 off the top my head at the time -Sorry if that confused you - the factory position is closer to the 9:00 o'clock that Guy used.

However, if someone sat the driven gear/distributor drive shaft position up to use 7:00 as the #1 spark plug wire the last time it was done - then that's fine too.

FWIW,

Carl B.