3X00-Modified wrote:With the way things are machined these days, Plasti-gauge and sending pistons in with an engine block to be bored are really old school methods and not really needed. I always gap rings on a new ring installation since if you don't it can create some major issues... Especially on a FI build. Most of the checking with plasti-gauge is to ensure the parts you have are within spec as well as the crank, if you can't measure them in another way.
Well, that describes the majority of my processes and much of my outlooks on things, so I am okay with that. When re-using bearings and crank, Plasti-gauge is really a good way to determine if the bearings should
be re-used, but if you already know they are fine, it isn't strictly necessary. I can't say I've ever had a problem with all-new parts not clearancing correctly. But I have had issues with old cranks and new bearings... Plasti-gauge is a good way to tell if the crank is worn, so long as it is still round, but I use micrometers for that unless I can't/won't pull a crank for some reason, and do tests at multiple degrees, especially if I have reason to be suspicious of the journals' roundness. It is also good to make sure a new bearing isn't defective, and just a little
too tight -I've caught one before, IIRC it was a Federal Mogul bearing- , but you are right, it doesn't happen often, especially now. Matched-bearing sets in crank kits I don't bother with either, unless it feels like something is binding. Still, considering the investment most people put into quality builds, checking clearances really isn't a bad idea and doesn't take very long. It can also show other issues, like tapered journals, although it is hit-and-miss too. I worked with an older guy, he told me his son built a nice 327 back in the day, and they gave him the wrong bearings -mismatched boxes maybe? If he had used Plasti-gauge, he wouldn't have ripped 7/8 rod bearings out of the engine and destroyed his crank. But I doubt he had even rotated the engine through by hand either, so more than one 'old school' process was missing from the build... The last time I walked into an auto-parts store to buy some Plasti-gauge (a few years ago, maybe even more than a few), both of the kids working the front counter looked at me blankly and said "Plasti-what?" They had to go ask an older associate...