TOPIC: ROTOR DISK ORIENTATION

Hi,
So I have my 76 inline 1500 dist apart for new bearings. There is no marking on the rotor disk as to which side is up. I am not 100% confident this distributor is untouched so I'm not 100% sure rotor disk was correct orientation when I took it apart. As you may know the windows are not symetric on these giving slightly different timing to each cylinder to minimize detonation on the more sensitive cylinders so this orientation is important.
Does anyone have a rotor disk marked? With a picture, I'd know the orientation of the larger window vs location of key tab and therefore the correct way to put this on. I have other distributors of this ilk but don't see the marking on these either and I simply don't trust this has not been taken apart prior to me.
It must have been paint that marked the "top" or "up" which disapears over time. I suppose I could take them all apart and look at orientation, if they are all the same I guess I have my answer. It would be best if someone could verify with certainty.
Thanks.....This site is the BEST for answering this kind of thing!
Randy

I will take a pic tomorrow and post it.

Just happened to have one handy!

Thom

Atta boy Thom! So the rule to remember here gents, is always mark the disk before you remove it if you can't find the stamp. Provided it was installed correctly first if course! But you won't be able to time the engine if it is in wrong.

Or this one which is a little different.

Thanks guys,

I did mark the rotor disk before removal but did not trust it had not been disturbed by some previous work.
Thom, Thanks for the picture, I really appreciate the effort but, that is for the earlier in lines where all the chopper windowss are symetric. The mid 70's direct charge had varying size windows on the same disk to slightly alter timing on each cylinder, Merc wanted certain cylinders to have slightly retarded timing.
So I'm still trying to answer "which side up"
The picture in the manual is not quite good enough to tell.
Randy

Hi Randy, I posted the rotor disc you need

Hi Dave, thanks, the pic did not come up the first time I looked at the thread (?) That is the right chopper wheel. Are you showing the this side up side? I don't see any markings on it.
Thanks,
Randy

Yeah I had a little problem posting the pics, then I ended up with 4 the same, then edited to the one you see. The surface that you are looking at is the surface that faces away from the distributor body (trigger) In other words, if the distributor was mounted on the engine, that surface would face down towards the prop.

Up and down being a matter of perspective on an upside down distributor think of it this way: the surface shown is the only surface available to write on when you take the distributor cap off.

Dave has it right, but I worked too hard on this little tid-bit to trash it.

Thom

Your pics a keeper Thom, nicely done.

You guys are awsome!
Thanks!
Randy