I installed the rockers and dialed in the cam. I decided to slot my original F cam sprocket rather than use the APE adjustable sprocket as the stock F one is lighter (not sure how much a difference that makes)... and stock one seemed to fit a little better.
I ended up timing the cam to approximately 1.5 to 3 degrees BTDC. I say approximately as #1 inlet opens at 1.5 and #2 opens at 2.5 (with the degree wheel set at #2 pistons TDC). I don't remember this difference when I was playing around with the cam last time, but I triple checked. Another thing that was odd, is the #1 piston TDC appears to be about .5 degrees after the # 2 piston. So, if I set my degree wheel to the #1 piston, then my cam timing is really 2 to 3 degrees BTDC.
Anyway, I'm really happy with my cam timing, as I'm now getting the following minimum clearances:
#1 Inlet: 0.066" minimum clearance
#2 Inlet: 0.064" minimum clearance
#1 Exhaust: 0.084" minimum clearance
#2 Exhaust: 0.088" minimum clearance
And this is exactly where I want to be.
A while back, I did a mock-up and couldn't get a cam timing that would give me approximately 0.065" inlet and 0.080" exhaust clearances:
http://forums.sohc4.net/index.php?topic=117206.msg1327897#msg1327897When I did this before, I didn't have a piston stop, so the degree settings might be a little off (I used a dial indicator on the top of the piston prior to putting the head on).
At first I couldn't figure out how I was now able to get these increased clearances, but I remembered that I decided to clean-up the valve reliefs on the pistons with some small hand files. I didn't think I took that much off, but I did widen the relief ever so slightly (where I noticed some of the valves impacted during a mistake I made during my first mock-up)... so that probably ended up helping out a lot.
I don't have a picture of the pistons after I cleaned-up the valve reliefs, but here's a picture of where the valve just kissed one of the pistons during my first mock up:
If you enlarge the image, you can see a small groove on the right corner of the valve relief. I filed all of these corners down.
... or maybe it was the thick coat of copper gasket spray I put on the head gasket that's giving me the extra clearance... either way I'm pretty happy.
#3 and #4 inlet clearances were similar to #1 and #2, I didn't measure #3 and #4 exhaust clearances as it's really hard to pry-up the exhaust tappets now that I have both springs in there, and I already did thorough measurements during my earlier mock-up. Knowing #1 and #2 Inlet/Exhaust are good, I know the rest is good.
I used loctite on the cam sprocket bolts and cranked them down really good. Man, I hope they don't slip now that it's slotted