Hello Friends!
I am back on line! Sorting out IT is worse than trying to bore crankshaft bearings!
Firstly, many thanks for all of your assistance. I value every single contribution and the kindness with which it is offered. However, I make my own decisions and my own mistakes (as you can see!). I have learned a lot from this one and will approach it differently the next time I do one!
Back to engine building. I indexed the case down and across and centred for the camshaft hole. A nice new drill soon sorted that.
Then I used my extended centre drill and very gingerly marked the centre bearing hole. My new drill sorted that one out.
I pulled the centre drill right out of the chuck to get the last hole through but found that it hit the inside of the crank case, pushing it over.
I tickled that out with the Dremel before centring that one as well.
The extra long drill I was given finally went through there.
Now, the moment of truth. My 8mm reamer fell through the first hole (0.007" oversize) but cleaned the other two nicely. I found in stock, a 9/16" reamer so I put that through the crank holes and it cleaned them up a bit. As they will be bushed they will be fine although the quality is a bit of a dent to my pride, to say the least. Oh well.
I made a couple of temporary camshaft bushes to try the installation.
The shaft wangled in OK but the cams actualy foul the inside of the crank case. More work with the Dremel sorted that.
Next challenge was the centre bearing as I needed this to see how true the holes are. As I have made the camshaft in one piece (the drawings show a Loctited assembly) the bearing must be split. However, it has no flange to retain it so I was concerned that one half might walk out in use. I have therefore keyed the two halves together. I cut a bit of bronze to the centre line and then a 0.015" deep key slot across the middle
I did the same for the other half but raised it in the middle instead.
These were soft-soldered together and then turned to size.
I drilled the hole, holding the bush in the collet chuck so that I would't burst the joint.
Warm it up to melt the solder and bingo!
Now a trial fit.
I was pleased with the result but as it could only be a push fit, I was concerned that it would walk out of position again. I have therefore dimpled the bush and added a locking screw.
Now I had the problem that if I screw it tight enough to stay in place, the bearing binds! I added a locknut so that, hopefully, it will stay in place. Interrestingly, this is the solution that Thornycrofts used in my lorry engine although the two halves of the bushing were bolted together around the camshaft in that case. The joys of a crank case you can get both hands in at once.
I have also turned up the final camshaft end bushings.
I feel crankshaft and con-rods looming.
Steve