Late bay distributor installation

[furgo]

Amongst other things, today I installed back the distributor I rebuilt a while ago. This is on a Late Bay, Type 4 engine.

While doing so, I was not 100% certain of one of the steps. Unfortunately, I had to run before I could do further checks, but I thought I'd ask here in the meantime.

Here's what I did:

1. Checked out the distributor and distributor driveshaft slot position diagram from the Wilson book (see first picture).
2. Rotated the crankshaft so it was at TDC (0° advance), and the driveshaft's thick slice was on the right (i.e. ensured that the driveshaft was not 180° out of phase).
3. Pointed the distributor rotor to the #1 marking on the distributor case.
4. Noticed that the driveshaft position on the diagram and on my engine did not match.

Essentially, the thick slice is is on the right on both cases, but while on the diagram the offset is 12° going CCW from the vertical line on the 4th quadrant, on my engine it is rather 12° CW (update: it's probably rather 18°). It's best seen on the 3rd picture below

Is this really important? I mean, are these 12 degrees a spec set in stone, or does it depend how the driveshaft is installed?

Here are some pictures to better illustrate this:

Distributor driveshaft slot position at 12°offset

Crankshaft at TDC

Distributor driveshaft slot offset. It's probably -18°, as each tooth represents 30°. Thus my driveshaft is probably one tooth off clockwise.

Distributor with rotor pointing at cylinder #1 firing position. Thick slice is on the right
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'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)

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[Wildthings]

You may want to lift the drive and put it in correctly, though it could work fine as now installed. A dowel rod rammed into the hole in the drive where the spring goes can be used to lift the drive, slowly turning it counter clockwise as you lift it. Don't lift it any further than necessary to get it to turn, maybe 9/16" or 14mm +/-. The drive will rotate clockwise as it goes back into place.

Double check that you are on TDC compression for #1 and not #3, both the valves on #1 be closed and the rockers should have lash, while the valves on number three show both be open a tad and have no lash.

[furgo]

[busdaddy]

There's no need for degree wheels or accurate measurement, the next tooth over will be very obvious, when you get it so it looks like the picture it's right.

I like to lift the drive with a strong magnet, that way there's a better chance the washer sticks to the drive and doesn't fall into the abyss.
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[furgo]

It seems this is not a too uncommon problem as I read on the forums. It just caught me off guard, as I thought I'd just go ahead and install the distributor without opening yet another can of worms...

In any case, I've been doing some reading. From Wildthings' and busdaddy's replies and the extra research, I think can now answer my own questions:

• There is a procedure on Bentley for removal and inspection of the distributor driveshaft. A PO probably did the removal and put the driveshaft back without knowing about the 12° offset spec. That's just a guess, though.
• In any case, the offset I've got is not significant and will not affect the function of the engine or will require me to rewire the ignition. The small additional offset will become irrelevant as soon as I adjust the timing and rotate the distributor.
• If I want to fix it, I'll use the dowel (I need to find out the diameter I'll need) and lift the driveshaft to bring it to the right position. I'll do this carefully without lifting it out completely, as I don't want to risk the washer(s) underneath the driveshaft to fall into the gear chamber. The spring will need to be removed prior to inserting the dowel.
• According to ratwell, each tooth is a 30° increment. Mine is probably then one tooth off at -18°. Thus I simply need to rotate the shaft CCW one tooth to bring it to 12°

I'm in two minds whether I should attempt to fix it or not. Looking at the diagram below (see #5) and the picture, the extra bit of shaft under the gear does not look too long, which I fear might not retain the washer after being lifted enough to surpass the gear to be able to rotate it.

VW #021 105 231. Picture from Samba member rkoss

Perhaps I'm being too careful and this is not the case, but I'd hate to drop the washer and end up having to disassemble the case for what was supposed to be an easy job.

Would someone perhaps have a picture of a halved case showing the driveshaft in place, if it's visible at all?

I always refer to this excellent thread when I'm looking for good, high-resolution pictures of an engine, but it happens to show the other side of the case, without the distributor.
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'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)

Decode your M-Plate

[Wildthings]

[aeromech]

What sort of strong magnet?
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[furgo]

[furgo]

Actually...

[SGKent]

not enough time to re-read this but be sure you are on the correct TDC.

Don't forget the spring either when putting the distributor in.

Oh and look at http://www.ratwell.com/technical/FAQ/FAQContent.html#0141



.
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[furgo]

Thanks for the reply.

[SGKent]

watch the rocker arms. you can put your finger on the pushrod side and hold it against the lifter, which in turn is against the cam. When you have the correct TDC use the timing scale unless you made other marks while the engine was out and heads off.
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[busdaddy]

[aeromech]

Great idea, thanks
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Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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[Wildthings]

[my59]

[furgo]

[lil-jinx]

If you are having a hard time detecting rocker movement,slip a socket with an extension over the valve adjusting nut,movement of the rocker will be amplified thru the extension.
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[furgo]

Excellent advice, thanks!
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'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)

Decode your M-Plate

[furgo]

Having finished the installation today (and replaced the valve covers along the way), here is some feedback on the process for someone landing on this thread:

• Reinstalling the distributor once you've replaced the shaft O-ring is a pain. I ended up lightly smearing the O-ring with engine oil, and even then it took a lot of pushing, twisting and swearing to get in.
• If the driveshaft is not aligned at 12° as per specs, the condensator easily hits either the oil pressure switch boot or the engine tin. You can't rotate past there CCW.
• I could not, for the life of me, tell whether the valves were open or not to determine TDCC. Even with a socket extension. I've concluded that with hydraulic lifters you can only tell if it's a two-person job: where one turns the engine and the other watches the valve movement.
• Nevertheless, I installed the distributor: I assumed I wasn't 180° out of phase as it wasn't when I removed it in the first place.
• Surely obvious to many, but in the process of this whole exercise, I realized for the first time that the cylinder heads are not symmetrical. Both sides have exactly the same orientation, and can thus be interchanged. So you can drive with either an A and B head as per stock, or two B's, or two A's, etc. If you're on FI you would need to drill and tap the TS2 hole yourself depending on your combination.
• The red rubber boots around the spark plug connector tips not only help protecting against humidity, they hold the connectors much tighter than without them.
• Definitely use grease on the bails when you secure the covers. Saves you from a fresh scratch right on your new cover. You can clean the grease once the bail is in place and holding the covers.

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'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)

Decode your M-Plate