Mercedes 1909 aero engine 5

1909 MERCEDES

AERO ENGINE BUILD

Part five by Steve Gosling

The valve guides were a straightforward turning job but I did set up my dividing head on the mill so I could do a quick change with the chuck for the cross-hole. That head was a very good investment.

Then it was just a case of pushing them in. I used a drop of Loctite on the one where the reamer had picked up, not to secure it but to make sure that it was sealed.

I ran a nice new reamer through for the valve stems and the job was done.

For the valves the drawing specified 'silver solder' which was a bit of a surprise! I take it as a misprint and am using silver steel. They are secured with E-clips so I ground up a tool on the bench grinder to cut the groove. I then brought the stock out of the chuck and machined the final diameter in steps, leaving them about 0.0005 oversize to be cleaned up with emery. This worked out OK in the end and I have one almost-acceptable valve.

I left a boss on the face and cut a screwdriver slot to help me lap it in.

I made my valves from stainless steel screws or bolts.

I now have eight valves. Glad it isn't a V-12!

Part six here Part four here

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