Trying to save the crankshaft | Triumph Spitfire Restoration - Part 98 

that turned out really visually well. will be great for the seals. grinding out a gouge too. i didn't think could happen.

Opp's you got the wrong channel link in the intro and in the comments! I really do appreciate the reshout out!! Now I will sit here and watch a guy polish his crank!! That doesn't sound right!! Cheers!

Not sure why people commented about 600/800 paper..., when you said you worked up to 2000. I used 2500 Wet N' Dry from Ace Hardware to polish my crank. What I did different was I made a wooden Vee block for each end, oiled them and used a BBQ spit motor to rotate the crank. I also used an angle cut piece of leather to make sure the pressure on the journal is even across the surface. While a machine shop rotates the crank even their polisher rides only on top. Which brings me to the fact that you probably only removed .0001-.0002 (a tenth or so of a thousandth). My Old Fart mind sees two schools of thought, one being spend to make a near perfect motor to go 100,000+ miles. Some people don't have that kind of money and like you use acceptable..., better than doing nothing methods. There is "Ideal" at a cost not everyone can afford, and "Acceptable" within one's budget. I do agree that calipers are not the best tool for measurement. You not having a micrometer, I recommend Plasti-Gage to check the clearances and at least get a general idea of your clearances. It is only about $5. Typically dimension tolerances are.0018 to .003 but you should see what is correct for your engine. Hopefully you are within specs. If you're not then the crank was probably too far out for the polishing to matter. But you are only out a few dollars for the paper and a few minutes of your day. I've rehabbed a number of engines using less than ideal methods (but better than doing nothing) and they have gone 20,000+ miles and outlived the usefulness of the car.

While I’m very much on board with trying to do as much as you can yourself, I’d really encourage you to go to the professionals with this. Or at least get yourself some better measuring tools. I think you’ve only measured the journals with calipers? You really need calibrated micrometers and to measure for taper, roundness etc at multiple points. I measured my big ends as just in spec (mains were definitely out), but was advised by the machinists it wasn’t worth accepting ‘just’. And just in spec was to a tolerance digital callipers wouldn’t register! I don’t like being the person on the internet saying ‘you’re wrong’, but I’d rather speak up if it might mean you had an engine you won’t have to touch again for many years!

Good effort. But misguided. You need a precision lathe to do this work. 600 grit is far too rough and will damage the journals. Even 800 grit is too rough. A machine shop has the correct tools and measurement tools, i.e. micrometers. Your method will result in egg shaped journals. A machine shop will get them as close to round as possible. The journals need to be polished to a very high level.