I am in the process of changing the head on my Z, to fully complete my engine rebuild/swap (thanks theramz), and I was curious about the setting on the camshaft sprocket. The camshaft sprocket has 3 different dowel holes on it, to allow you to advance the camshaft timing to make up for chain slack. I have new timing pieces (less than 300 miles on them), such as the timing chain, guides, and tensioners. Would I leave the camshaft sprocket on the first notch, which is where it should be for a brand new motor, since I have new timing products, or should I advance it to one of the other notches?

 

Jeremy, each hole is 2 degrees. You should use the standard hole. You could try it and if it doesn't seem right you can easily change it back when you go to re-torque the head and adjust the valves.

 

thanks again tom. Last time I put my head back onto my Z, I had the sprocket at the standard hole, and followed the haynes manual method of setting the timimg chain. For some reason, I was unable to fully advance the timing on my distributor. Is this the timing chain setting that wouldn't allow me to do it, or is it the position of the distributor rod in the front cover of the motor. I could advance it fully, but this was after I took the screw out of the distributor plate to allow it to advance past the stop point.

 

The dizzy is driven by the crankshaft. I am assuming you did the 42 links between the timing marks. There is a retaining plate behind the sprocket with a cam timing mark on it. The notch in the sprocket must be to the right of the mark. The plate on the distributor is adjustable. There is no history on the head I gave you so it may have been milled before. With #1 on top dead center the cam lobes of the #1 cylinder will be in an equal clocked position. This is just an eyeball check to make sure nothing is way off before you button it up. With the timing mark on O, the position of the drive tang on the dizzy should be at approximately 11 o'clock looking at it from the drivers side.
I'm out till Monday, good luck.

 

my haynes manual says that when the camshaft sprocket is on the stock dowel hole/before adjustment, the notch on the camshaft sprocket should be to the left of the groove in the retaining plate behind it. Which one is right? The manual claims that if the camshaft sprocket is adjusted for slack, that the notch should be to the right of the groove on the plate. I'm not going to put the head on until next friday, so I've got time for answers. Thanks all!

 

I always turn to my Clymer book when in dought on the 240z. Here is a pic showing good detail. Hope this helps.

 

theramz, as I said before, you're a lifesaver. Just some clarification though. On your diagram, which is the same as in my haynes manual, it has the before adjustment pic and the after adjustment pic. So, before adjustment would be if the chain had no slack and just came from the factory/timing pieces were renewed and replaced, and the after adjustment is to adjust timing for slack, correct?

 

Yes, as the chain wears and stretches, the cam retards, (counterclockwise). You will be bringing it back into tolerance (clockwise).

 

If you advance the cam to the #2 position with a new chain, then you will bring the power band down to lower rpms just a little. (more torque) I did this on my 4-cyl L series and I could barely notice a difference.

 

alright, that's what I thought. I'm just going to set it to specs.