Dropping the cylinder head back on is straightforward. I just wanted to visually confirm that the timing marks on the signal generator were placing cylinders 1 and 4 at Top Dead Center before torquing down the head and installing the camshafts. With the timing mark aligned at T 1-4, everything was looking good.
Place the head gasket and cylinder head over the studs and then torque the head bolt in the pattern cast right into the cylinder head.
When I previously removed the valve shims and valve buckets, I placed them into an egg carton so that it was easy to keep track of which cylinder and which valve they came from. I am hoping that most of my valve adjustments after this will be limited to the number 3 intake valve since that was the only valve that needed to be replaced.
Now it is time to install the intake and exhaust cams and set the timing of the valves. The exhaust cam has 1 and 2 stamped on the sprocket as well as the threaded section for the tachometer reading. The number 1 and arrow on the exhaust sprocket are to be pointing forward and parallel with the surface of the cylinder head.
Once you have the exhaust cam aligned, the intake cam is installed so that there are 20 chain pins between the number 2 mark on the exhaust cam sprocket and the number 3 mark on the intake cam sprocket. A common mistake in this step is not starting the count of the pins at 1 and then ending up with an extra pin between the sprockets.
Once everything was tightened down I rotated the crank a number of times by hand to make sure that the number 1 mark on the exhaust cam sprocket and Top Down Center on the camshaft were coming back around to proper alignment and no sense of interference with the valves and pistons.
The next thing that I want to do now is to rebuild the cam chain tensioner. This is one item that I did not take a look at the first time around and suspect that it is a large reason why the rear cam chain guide broke at the point where it interfaces with the tensioner.
In the last update, I had completed the work of putting the crankcase back together and was considering re-mounting it in the frame before completing the rest of the reassembly. Of course, there was some frame painting that I wanted to do first and wasn’t getting to, so I finally went ahead with completing the re-build of the engine in the basement. Glad it worked out this way since it would have most likely made things more difficult to work with the confines of the engine in the frame and lower to the ground.
Next up was to reinstall the four pistons and get them reinserted to the cylinder block. Reinstalling the pistons to the connecting rods is pretty straightforward, just reinstalling the circlip to keep the wrist pin in place. Definitely want to block the hole below the piston while doing this. It would be a traumatic experience if you just completed reconstructing the crankcase and then dropped the circlip into the bowels of the crankcase.
Place the o-rings on each cylinder and the gasket on the crankcase and you are ready to go to reinstall the cylinders.
I started with the number 2 and 3 pistons thinking it would be easier to work on those with as much room as possible. Ring compressors were added to those two pistons and the cylinders lowered on to the pistons.
With those two installed, it gets a bit more fun trying to rotate the crank enough to raise the 1 and 4 pistons up while not losing connection to the 2 and 3 pistons.
And that is it.
I do have to admit to a few oversights in this process. First, the whole reason for the engine rebuild was to replace the broken rear cam chain guide. The first time I lowered the cylinders on to the 2 and 3 pistons I failed to make sure that the cam guide was in the cam chain tunnel. Cylinders back off. The next time, the 2 and 3 pistons pulled back out while trying to get the 1 and 4 pistons to rotate in. The third time I did everything very quickly, but then wondered why the cylinder was such a sloppy fit and realized I had left out the two locating pins between the crankcase and the cylinders. Fourth time was a charm and I am now a master at getting the pistons inserted to the cylinders…