1966 BMW R69S Restoration: July 1999 [page 2]

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1999 July 17 (Saturday)

It was time to pull the valves and clean the heads. I didn’t expect to find anything wrong, but you never know. I also spent some time dressing the faces of the rocker arms with a fine stone to remove even the smallest traces of a step.

Valve spring removed
Valve spring removed

Valve spring removed

Valve spring removed

This is the first head with the valve springs removed. There is slight burr at the top of both valves so they will not fall through the guides. Trying to force the valves would likely score the guides — a bad thing. I’ll take a stone to the valves, but first I want to look at the other head.

Valves removed
Other head

Other head

Other head
Valves removed

Valves removed

Valves removed

The first picture is the second head before the valve springs were removed. It’s valves also didn’t want to fit through the guides. Patience and a fine stone working only at the very top of the valve stem were needed to remove the valves without damaging the guides. Both valves and guides look good.

Bead blasted head

Bead blasted head

Bead blasted head

The left head, after bead blasting. No cracks. The guides were protected before blasting.

Spark-plug thread repair
Spark-plug thread insert

Spark-plug thread insert

Spark-plug thread insert

The spark-plug thread insert on the right head is beginning to come out. Joe has a tool to drive it in and slightly stake the aluminum around the insert to hold it in place. There is also a very tiny crack in the combustion chamber, but it is not heading to either valve seat so I’m not going to worry about it (this time).

1999 July 21 (Wednesday)

I purchased the Pentacomm points plate conversion kit. It replaces the stock points plate allowing the use of cheap and easy to get ‘57 - ‘73 GM 8 cylinder points and condenser. It also allows the points to be adjusted quite easily with the engine running. I’m going to give it a try.

Magneto
Magneto

Magneto

Magneto

The magneto with factory points plate is on the left and the Pentacomm unit is on the lower right. The upper right is the magneto rotor.

Points plate
Factory points

Factory points

Factory points

This is a close up of the factory unit. When removing it from the magneto I discovered that it had been removed at some time in the past. How do I know? The spacers that are supposed to be between the points plate and the magneto arms were instead between the magneto arms and the bottom bracket. Wonder what effect, if any, that had…

Disassembled magneto
Disassembled magneto

Disassembled magneto

Disassembled magneto

After disassembly I cleaned everything, especially the advance mechanism (sealed in a freezer bag in this picture). There was quite a bit of old and dirty grease inside the cam mechanism. I also filed down the gouges in the bracket where it looks like someone used a bigger hammer to adjust the timing instead of loosening the mounting nuts.

Assembled magneto
New points plate on magneto

New points plate on magneto

New points plate on magneto

This is the converted unit. I did not remove the wire from the coil that went to the original points plate. I’ll coil it up and tape it out of the way instead of removing it in case I decide to go back to the stock points mechanism. The conversion kit came with a replacement wire that mounts to the coil sharing the same screw terminal as the kill wire.

 

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