Measuring shims

I've discovered is the short side of the lobes are not exactly what I expected. I thought the point opposite from the tip of the lobe was the widest point to measure but I get my widest measurements a bit off to the side from that.

For instance, I just exchanged the shim in #1 exhaust with the shim from #4 and I find it indeed now measures .008 but not at 180 degrees from the tip. I get this measurement when the cam is rotated ~10-40 degrees off the line following the path the shim travels. This is where I get my .008 reading. If I point the tip the farthest from the shim I read .005.

I've been taking my measurements from wherever I find the widest gap, do I need to take them from where the tip is pointed the farthest from the shim or have I been measuring correctly by finding the widest point?

Don't tell me I have bad cams... Nooooooooooooooo! 8O

 

You have to measure when the piston is at TDC on the compression stroke.

 

Measuring incorrectly

 

All I can say to this is that I did mine over the winter and mostly measured when the cam lobe was pointed away from the bucket. If your cam lobes look good and the buckets do not have serious wear I'd not worry about checking at other angles, or a 'bad cam'. You said measuring incorrectly. That is what I did at first also. You may be finding what I did....the feeler must be very snug to get a correct reading. It is not the simplest thing to get right. Took me several tries before I got it done to specs.

 

make yourself a degree wheel that attaches with some tape to the ignition rotor with lines 90 degrees apart. line it up so a line is on the pointer at tdc, that way there's no guessing on each lobe and your measurements are all the same