Verify Pulley Marks Please?

[JohnJL]

I am going back into an engine to check its cam timing and see this pulley. The motor is from a 1983 SC but has been rebuilt and this pulley may not be original.

I was told the yellow mark is 0 TDC, to the right of that is a red mark on 5 degrees BTDC and the white mark on the notch to the left is unknown.

My piston TDC tool catches on the piston valve reliefs and doesnt serve to tell precisely whether the red or the white are true TDC.

I searched and saw a few versions which dont resemble this one.

Can anyone confirm or describe a way to confirm the red or white as #1 TDC? I need to know precisely to check the cam timing.

Thanks!

[JohnJL]

It might be a Rothsport, but their site doesnt show or describe the markings.

Welcome to Rothsport Racing - Engine Products

[Flat6pac]

On an SC you want the small hole matching the crank at 9 o'clock.
The white line way left could be Z1 and the two lines together are 30/35 BTDC.
You really need to know where the locator pin to the crank is
If you're able to run, use an inductative timing light on spark plug wire #1 or #4 and
That will show you the mark.

[Marwil]

I just checked my Rothsport pulley setup and the marks match with Flat6pac's comments. The red and yellow are the 25 and 30 degree BTDC marks, and the mark to the left is TDC.

[JohnJL]

Thanks. I took the pulley off and when the pin is at the 9:00 position, the white mark on the left in my pic above is in the #1 TDC position.

The pulley itself has no brand or model markings on it, though it looks like the Rothsport pics.

[JohnJL]

Just to close this out, I called Rothsport and I believe it was Jeff who answered on the first ring. He was very helpful and confirmed the white mark in my first pic is TDC.