Gunter

1995 - 993

Preparing to replace the belt in the distributors and followed instructions from the pcarworkshop.
There are 3 notches on the main pulley, none of them are different from each other. Which one is Z1?

I have both caps off and I don't see any notch in the housings.
The only big notch is for aligning the cap.
In my old 911, I have a small notch in the distributor housing and when the pulley is at Z1, the rotor points nicely to #1 compression stroke.

When I turn the engine to any of the 3 marks on the 993-pulley, both rotors are nowhere near a notch.
Instructions from pcarworkshop say: Confirm that you are on #1 by the position of the primary distributor rotor. It should be pointing towards the notch on the outer rim of the distributor housing".

What notch?

Wouldn't both rotors have to point to #1 since both plugs fire at the same time?

Waiting for Straethers 993 book from Amazon and need some help until I get it.

Much appreciated.

swmic

This will clear things up.

https://rennlist.com/forums/showthre...ferrerid=17620

Gunter

Ah so, it's really a small tit, not a notch on the distributor housing ergo the confusion.

So, if the rotor on the primary distributor points to the tit, the notch on the crank pulley lines up with the seam in the case, this would be Z1 on the crank pulley?

The 3 notches in the pulley look the same. What distinguishes Z1 notch?

Mike J

Hmmm, not sure why so many people are preoccupied with TDC, you do not NOT need to know this.

Before taking the distributor out of the car, mark the positions of both rotors on the body of the distributor with a felt pen...making sure its indelible. It does not matter that position the engine stopped in. All you have to do it assemble the unit, and put the unit back in the car so they match the marks. Given the size of the notches for the belt, and the gear spacing for the drive, its obvious if you are significantly out. (This assumes that you do not turn over the engine in the meanwhile). Saves a bunch of time trying to find TDC...especially when you do not need it!

Sorry, but I need to update the instructions on Pcarworkshop. The other thing is you do NOT have to take the second shaft (the smaller one) out to change the belt. If you take the main shaft out, and split the distributor case (ie. remove the hex bolts and split the case) you can fish the belt in and out through the spit. Its a bit of a mind game, but that will stop you from having to remove the second shaft, with damage to the dust cover covering the bottom of that shaft.

The firing is very slightly spaced BTW, so I would not count of both rotors to be in exactly the same position, but I have not looked at this for a while.

Adrian's book is good, but does not cover this in detail (from what I remember).

cheers,

Mike

Gunter

Thanks Mike,

I assume the small bearings are life-time greased and therefore cannot be lubed?
If they're kaput, they'd have to be replaced. Yes?

I had thought about just marking the position of the rotors on the housing on any of the notches on the crank pulley but...........what distinguishes the Z1 mark?

I also assume that the 3 notches on the crank pulley are the 120 deg marks for valve positions?

BTW: Found out from Jeff A. that OK TIRES sells Mobil 1 Delvac 75W90 Synthetic in bulk by the liter, bring a clean container.

Mike J

Apparently, the bearings are hard to find. i was talking to a fellow at the Escape, and he had a real hard time to source that specific bearing size. They are supposed to be life-time, but I also heard that you can carefully remove the dust seal and lubricate them. (BTW, I do not know if you can source them, perhaps BC Bearing might have new ones).

Z1 is stamped, but you cannot see it from the top. Would have to run down to my car to remember. Yes, there are other marks for the 120 degree markers.

Again, you do NOT have to worry about Z1 doing the rebuild...just mark the rotor position on the distributor with something that does not come off, and reinstall to that mark. You can also use the #1 plug position on the distributor cap, if the rotor is pointing to that (look at the cap top, figure out which line is #1, then you will know where the rotor should point), as TDC as well.

Interesting news on OK Tires...did not know that.

Cheers,

Mike

Gunter

Some observations:

Yes, the Phillips screws for the caps are very tight and require a clean and well-fitting #2. I used a Phillips #2 tip with a long extension and 1/4"-drive ratchet. I didn't remove any plug wires and just tied the caps out of the way with rebar wire.

After removing the 13 mm nut on the bottom, distributors didn't want to come out.

To remove distributors, I made a wire-sling that fitted over the ears for the cap-screws on the primary distributor and then used a long pipe on top of the fan housing to force the distributor up and out.

After the dust-cap under the secondary distributor was removed, the small circlip on the shaft was under pressure from the convex washer under the cog inside and desintegrated on removal.
Got a new one.
All bearings were good. They're lifetime lubed and I cannot see how any grease can be applied without removing the seals which is not advisable.

A little lube on the pivot point for weights and springs and re-assemble making sure the rotors point to the respective tit on the outside of the housings indicating correct belt position.

Mike J

WHy did you bother removing the dust cap? You can change the belt without taking that apart...just curious.

Gunter

I didn't think so.

The 2 halves have to come apart (5 Allen bolts) in order to get the new belt in. And the halves can only come apart with the secondary shaft out meaning: The brass dust-cap has to come off in order to remove the circlip on the shaft for removal.

Only then can the new belt be fitted over the tooth gear.

I believe it all has to come apart to install the new belt plus inspection, cleaning and lubing is much easier. Also, squeezing the belt too much is not recommended. "Nicht knicken" was written on the old belt which was still in pretty good shape considering 100,000 km.

What type and size wrench is needed for the spark plugs? My regular 13/16 wouldn't even fit into the hole.

Mike J

Hmmm, I hate to disagree with you Gunter, but the last three I rebuilt were done this way, and it does not require you to bend the belt very much.....and you do not have to remove the secondary shaft at all. However, its not obvious by looking at it, its a 3D puzzle to get the belt in and out. (One of the tricks, the two halves do not have to be separated, just turn 90 degrees to each other, allowing for an opening to be created...).

Gunter

O.K. Mike..........a puzzle.

Since I have quite a few tools and spare circlips, I didn't mind going all the way.
It's easier to remove the crud/dirt on the tooth gear and more important: feel the bearings on the secondary shaft directly.

For industrial applications, I used to bearings by the numbers on them for SKF, ***, etc.
I couldnt see any numbers on the bearings.
Or maybe these small ones are ordered by size only?
Fortunately, I didn't need any but maybe for the future or for someone else, a source may be nice.

We have KAMAN Belt & Bearing here in Castlegar/Trail, I'll ask them.

What type and size wrench is needed for the spark plugs? My regular 13/16 wouldn't even fit into the hole.
pcarworkshop has a write-up but I couldn't see what size the plugs or the socket is?
What do you use?

k722070

I used 5/8 on the plugs.
my fancy ball joint snapon version would not fit into the oem valve covers, a cheap version from checkers fit but I had to duct tape it to a wobble extension so as not to lose it.