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Sun Jun 30, 2019 1:20 pm

Hi folks. Two seasons ago I had a 205t rebuilt to like showroom condition. Points were set and then I dialed the timing in to tdc. (I check this every spring)When I checked my timing today with the engine warm, it seems as though it is about 1/16-1/32” retarded. Is this normal wear and to be expected? I just tweaked the timing and it’s perfect. Btw, the car would immediately bump start with a bump of the key even before I touched it today. I’m m assuming 1/32” is nothing really.

Sun Jun 30, 2019 2:05 pm

Changing the points gap changes the timing.

As the points rubbing block wears down, the points gap will gradually decrease which will affect the timing setting.

You should check the points gap and timing every 3000 miles when you do your oil change service and adjust as necessary.

Sun Jun 30, 2019 2:08 pm

I guess my question is more of as the points wear does timing retard or advance. And typically how much are we talking about over 3000 miles.

Sun Jun 30, 2019 2:14 pm

Over 3000 miles you shouldn't see much movement in the timing assuming a) your points rubbing block/distributor cam is lubricated properly with the correct points grease and b) you are using good quality points (which can be a big "if" these days)

Sun Jun 30, 2019 2:20 pm

When they wear the timing will retard, as they open sooner and close sooner. Using a good distributor cam lube will slow the wear greatly. DO NOT use other greases as they can melt and sling off and cause problems. It's best to check the gap every oil change and put a drop of oil on the pad under the rotor.

Sun Jun 30, 2019 2:31 pm

I have Bosch distributor grease. How much should I be putting on? Does grease go in each lobe?

Also. Let’s say I dial timing in perfectly with the car all warmed up. If I then checked the timing the next morning with the car cold, would it show retarded advanced or spot on? This is just my curiosity and wanting to understand things. As a car warms up, I would think that timing ever so slightly may advance as the heat ever so slightly takes up slack in moving parts.....

Sun Jun 30, 2019 3:35 pm

Here's how I put grease on with the distributor off. I put a little dab on my finger and put this onto the cam of the distributor. I then rotate the cam using the other end of the distributor. I rotate one way and then the other way until it is fully covered. It should just be a light film All the excess will get picked up and pile behind the plastic rubbing block.

On your 205T make sure the clip is on top of the part the points slide down.

Sun Jun 30, 2019 4:39 pm

Thanks guys. Is it really necessary to remove the distributor every time you change points?

Sun Jun 30, 2019 4:52 pm

Frodge wrote: Thanks guys. Is it really necessary to remove the distributor every time you change points?

No you don't need to take it out if installed already. Just take off the rotor and put a dab on your finger and rub the cam. It just needs a tiny amount.

Sun Jun 30, 2019 5:45 pm

You'll want to clean the old grease off every time before you put new grease on. All of that old grease traps particles.

Sun Jun 30, 2019 5:47 pm

You don’t need to remove the distributor to change points, but it does help to have a magnetic screwdriver to deal with the points hold-down screw.

Sun Jun 30, 2019 6:22 pm

I’ve found an easier way using this special screwdriver. It was made for holding screws much more securely than a magnet, works well even upside down for changing generator brushes. Probably more at home in small electrical repair technicians toolbox but I became aware of this watching people do instrument repair. The one in this pic is Craftsman but all the higher end tool companies offered them. It’s worth it’s weight and once you see it in action you won’t go back. I also remove distributor to change points because it takes just a second plus I’d rather work indoor comfortable environment rather than fumbling hunched over in driveway.

So here it is with aluminum body and a handy magnet in the opposite end. It clips to your pocket alongside your 6 inch machinists scale and penlight :D

Here it’s holding the screw tightly, easy to activate using spring pressure but it’s stronger than a magnet.

Here’s the business end

Mon Jul 01, 2019 1:23 am

What is that tool called? I want to buy one....

Mon Jul 01, 2019 4:17 am

Small screw holder thingy :D, couldn’t help it but they come in larger sizes too.

Mon Jul 01, 2019 5:37 am

Screw-holding screwdriver? Craftsman used to make a decent one. They pop up on ebay regularly.

Mon Jul 01, 2019 6:52 am

https://www.amazon.com/Ullman-2-Aluminum-Starter-P...AX5S840S70

Mon Jul 01, 2019 8:55 am

sjbartnik wrote: Changing the points gap changes the timing.
This pic helps to illustrate this.

(FYI, the VW distributor rotates in the opposite direction from this pic and only has four (4) lobes instead of six)

The lobes of the cam are part of the distributor shaft which is connected by a gear to the crank. This means the relationship between the cam lobes and the crank are static unless you remove/adjust the distributor drive gear. The lobe peaks can be seen as TDC for each cylinder (this may not be the actual case, but for ease of understanding lets go with it).
Rotating the body of the distributor rotates the shaded area CW or CCW while the lobes remain stationary.
The coil fires a spark at the trailing transition from "points CLOSED" to "points OPEN". In the above diagram it is the right hand edge of the shaded region. As you can see, changing the dwell angle means this trigger point moves relative to the cam lobes. This results in a change to the ignition timing.

Changing the dwell changes the start/end of the shaded area. The center of the dwell angle will ALWAYS be half-way between the cam lobe peaks. Smaller dwell values decrease the angle covered by the shaded area (fewer degrees). Increasing dwell increases the angle. Reducing the dwell by 10deg changes the start point of the shaded are by 5deg and the end point by 5deg. This moves the trailing edge closer or further away from the lobe peak which equates to a ignition timing change.

Key points:
Changing dwell angle changes how long (in degrees) the points are closed and the primary coil winding is "charged".

Changing the dwell angle moves the trigger point which fires the ignition coil without moving the body of the distributor.

As the rubbing block on the points wear, the dwell angle decreases... changing the ignition timing as well.

As the points become pitted, the gap between the contacts change. This can also change the ignition timing. Using feeler gauge becomes a less reliable method of setting dwell. Use a dwell meter as this takes into account the changes caused by pitting.

Adjust dwell FIRST, before ignition timing. Because dwell affects the ignition timing.

Dwell meters do work while the engine is cranking. You do not need to start the engine to set dwell. This allows you to dynamically adjust the points while looking at the dwell readings.

A comment on grease... after greasing the lobes of the cam, place a glob of grease on the inner face of the rubbing block. As the block wears the grease will be deposited on the cam lobes keeping it lubricated for months.

Points and timing should be adjusted at least every two years, but yearly is not unusual.

Mon Jul 01, 2019 9:18 am

Starbucket wrote: When they wear the timing will retard, as they open sooner and close sooner. Using a good distributor cam lube will slow the wear greatly. DO NOT use other greases as they can melt and sling off and cause problems. It's best to check the gap every oil change and put a drop of oil on the pad under the rotor.

Good advice for early cast iron and later SVDA,DVDA distributors but not necessary on 1960's SVA distributors since they don't have a felt pad or two piece cam assembly.

In a pinch any grease is better than none. The idea is a thin coating which won't be flung around.

Mon Jul 01, 2019 9:26 am

Frodge, I might get teased for doing this because points are cheap but I use a points file to smooth the surface area before making adjustments. It’s the way I was taught when I do my yearly tune up and inspection. I only drive an average of 2500 miles a year on each bus. This also gets me examining the rubbing block as well. Some newer points are hit and miss so I like to prolong the life of known good ones. If you do replace points and condenser annually like some of my friends. The Napa Echlin brand have been consistently good for people.

Points file

https://www.napaonline.com/en/p/SER2153

Mon Jul 01, 2019 9:27 am

heimlich wrote: Here's how I put grease on with the distributor off. I put a little dab on my finger and put this onto the cam of the distributor. I then rotate the cam using the other end of the distributor. I rotate one way and then the other way until it is fully covered. It should just be a light film All the excess will get picked up and pile behind the plastic rubbing block.

On your 205T make sure the clip is on top of the part the points slide down.

None of the Three different "205T" distributors used by VW have a brass post that has provision for a points hold down clip. The OP has a 113 T stock for 1969-70.