Micrometer

I'll definitely second the dial caliper as the best all around choice for a part-time "home" mechanic. I have mics to 3" but I rarely ever use them anymore. I can't even remember the last time I used either the 2" or 3" ones. The dial caliper is almost always my choice. Forget the vernier type, they are a PIA to read. A good dial (0-100 not 0-200) is easily read and sufficiently accurate (+or- 0.001) for anything you are likely to do. Consistent measurement to tenths is a pipe dream for the casual user - and not necessary. My personal opinion is to forget about the digital displays altogether. They are just another thing to go wrong. Totally unnecessary. Get a decent one with a good sized dial and a covered rack. I have a Mitutoyo but there are other good brands. You probably won't find a good one for $60 but a hundred or a little more will get you a tool that will serve you well for many years. You'll also get inside and depth measurement capability at no extra cost. Pretty hard to beat.

Rod

First using a micrometer of known calibration (dosen't matter who made it!). With the crank at room temp as well as the mic, measure the journal around the perfiery at atlease 3 locations, do this at each end of the journal, this tells you if the journal is out of round or tapered. Check sizes in engine service manual.
Next way of measuring (this is measuring journal clearance) is using plastigage strip, install new bearings in block then install crank in block, oil up bearings and crank, place a pieces of plastigage on the crank journals from front to back of journal, lube and torque down bearing caps. Next remove bearing caps and using the plastigage cover(sheath) hold the cover(sheath) next to the squished plastigage on the crank journals. This will tell you the clearance between the bearings and the journals, this is also done on the con rod journals. Check with engine manual for correct spec's. Also check end play in the crank to block using feeler gages or dial indicator. This is done by pushing the crank to front of block, then measure with feeler gages at the thrust bearing (the one that has sides), or mount a dial indicator setting dial needle on the crank, then push crak to rear of block.

For the camshaft you can measure the bearing journals with a mic or dial vernier, they usually don't wear, what does wear are the cam lobes, what is normally checked is the lift of each lobe on the cam. This is normally done with the cam in a lathe or in the block (timing chain or gear removed so the cam can be rotated in place). A dial indicator with a mag base will cost $20.00 to $30.00. For the pretend mechanic's or home hobbiest the made in China measuring tool will be fine. One note: I don't recomend the tin frame mic's, only the cast frame ones.
Doug

I saved all my measuring tools from when I was working as a machinist over 25 years ago and I have one heck of a time keeping them from corroding in my basement. Probably should move them upstairs and put them in the wife"s jewelry box huh?

K