dfinnegan

Engine Rebuild pics

The main page has some pulley and main seal pics that may be helpful.

The engine rebuild sub-dir has some additional pics, though they are a bit far away.

Hope this helps.

Geoffrey

Wait, there are only two things that could have happened to move marks. One is that the distributor is installed incorrectly, or the pully has been taken apart and rotated. To find out for sure, you need to:

1) Find TDC. The Z1 will line up with the mark in the fan housing when the pully is installed correctly. Since we aren't doing anything that requires precision (like degreeing in camshafts) we can simply remove a spark plug, drop a small rod (coat hanger, screwdriver, etc.). Rotate the engine until the rod is at the highest point. The Z1 mark should be at or about even with the mark on the fan housing. If it isn't remove the bolts from the pully and reorient it.

2) Find TDC of #1 compression. It will either be where you are now, or 360 degrees from where you are now. Then install the distributor so the rotors line up with the marks in the housing. Your engine will now be timed properly.

My question is though, why isn't the shop that originally worked on the car making this right for you?

DWS964

Great set of engine pics, dfinnegan. If not already posted, those should be on the 964DIY forum. THANKS.

The photos of the pulley show the locating pin that puts the pulley hub in one location only. The bolting on the pulley confirms that it could be taken off and rotated.

Geoffrey - Why hasn't the shop who did the work taken the car in to make it right? Well, I'm having a hard time swallowing my pride - I had more money than time (but really not much of either...), and had a shop do all the work on my car this summer instead of doing it myself. The first car I have taken to a shop for work, and I have had dozens, although this is the first Porsche. My wife will confirm that I am skeptical of everyone and everything. I like to have the problem fully defined (yes, I'm an engineer, but a Chemical variety) before having anyone else start a job. Since it takes time to take the car to a shop, get a ride home, get a ride back, .... I thought my time was better spent sorting out a few things, to define the problem. This thing with the engine timing marks has brought out the OCD devil. Bottom line - yup, I am taking it back to the shop and get this straightened up. Doing future work, i.e. valve adj, will be a pita if this isn't corrected.
You have been spot on with all of the comments and directions. Thanks.

Indycam

"My wife will confirm that I am skeptical of everyone and everything. I like to have the problem fully defined (yes, I'm an engineer, but a Chemical variety) before having anyone else start a job"
+1

buck_31

DW-

Any update on this? I had a very similar problem when I rebuilt my engine. No matter what I did I could not get the marks to line up exactly , the rotor would always end up too much to the left of the mark (which would be early and be very bad) or a bit to the right of the mark (which could result in firing a bit late). Although as far as I can tell my car runs great, I am always wondering if the distriburtor alignment is actually off slighty (or does it not matter based on some of the info in this thread?)

Thanks,

Mark

Indycam

The spark is not timed in the distributor . If the spark is getting to the correct spark plug it will not get to the correct plug early or late based on the rotor position .
The computer tells the coil when to send out the spark , the distributor rotor sends the spark to the correct spark plug .

buck_31

Indycam,
Help me clarify this....
If the rotor is not lined up correctly then the spark either has a larger gap to cross or if completely mis- aligned it could jump to the wrong cylinder, correct? Could an increased gap lead to a slight (millioseconds?) delay? Should I not even worry about this?

I appreciate any insight

Mark

Indycam

If your car is running the spark is getting to the correct spark plug .
As for the spark taking longer ,
electricity travels at the speed of light .
299,792,458 m/s
If you can calculate how long an electron takes to go a few mm ...
Your spark plug wires are not all the same length ...
And then the old , as soon as you jam one electron in the end of a wire , one jumps out the other end ...

buck_31

So in other words..........don't worry about it!
Actually I just took a "spirited" drive in her and she is running smooooooth (it is supposed to snow tomorrow - had to get out before that stuff shows up.) I put the long G pipe on over the weekend and I am loving the sound.

Thanks again for the input.