"Z1" mark not lining up on flywheel and pulley

[eddie914]

I mounted the flywheel and the pulley on the 2.7 this morning. The "Z1" mark on the flywheel and the pulley don't line up on the case seam? The marks are off by about 5 degrees.

What's up?

- The engine is a '77 USA 2.7 formerly with CIS (now with 40IDA 3C carbs).
- Flywheel is an early style with integral starter ring and factory stamped timing marks.
- Pulley came off the '75 USA 2.7 that dropped an exhaust valve

The dowel pin on the pulley is correctly aligned.
The flywheel can only be mounted one way - is that correct?

Thanks

Eddie

[Henry Schmidt]

What you are seeing is the slop or clearance between the flywheel and the flywheel bolts.
This is precisely why the 3.2 flywheel is pinned in place.
You can relocated the flywheel so the marks line up or just take the difference into account when using the flywheel mark for timing.
The latter is only a good idea if you will be the only one timing the engine.
A change like that, even that small, could drive the next guy
crazy.

[126coupe]

You need to get a dial guage indicator and find the true TDC on cyl #1 and line the pulley Z1 to the case seam. Stomski Racing makes a great tool for this, less$ than a dial guage.
It screws into the spark plug hole turn the engine by hand carefully till the piston just touches the "tool" and you have TDC

[Henry Schmidt]

Checking TDC with a gauge is never a bad idea but in 28 years I have never seen a miss marked Porsche factory pulley. There is a caveat to this statement. The 3.6 harmonic balancer could slip timing, But I've never seen it on a Porsche, Chevy yes , Porsche no.
The problem eddie914 is encountering is more likely "bolt hole slop".

As for a tool to measure TDC, for those of you who want to try it once and not invest in a fancy tool, here's what we're used for more than twenty years.
What is it? A spark plug with a pin brazed in it.
How does it work? You turn the engine 90 degrees off TDC.
Screw in the indicator. Next turn the engine either direction until the engine stops. Be gentle . Mark the pulley. Then turn the engine back the opposite direction until it stops. Be gentle
Mark the pulley.
Now split the difference on the pulley and that is TDC.
If the marks are so for apart that it's hard to tell the center then unscrew the indicator slightly and try again.

Try it , it's easy and fun.

[126coupe]

I installed the smart racing products pulley on my 2.5 race engine, it was "off" by 5 degrees., therefore i needed to establish true TDC

[Henry Schmidt]

Good thing you caught the error.
What did Smart Racing say when you returned the arrant part?