TheSamba.com :: View topic - Slow Friday at work

Fri Oct 24, 2008 2:12 pm

All -

I just want to come out of this Friday one factoid more overladen than I entered it.

You know when you need to have your case line bored? Or when you need your crankshaft turned? Or when you need the thrust saddle cut?

Do the machine shops do that in SAE or Metric?

I'm assuming the bearings are still metric, yes? If the machine shops use SAE (e.g. .020" over on a case), and the bearings are Metric, the bearings for the .020" case would be .003" smaller than the hole in the case.

So, how does all this stuff work in harmony? Please enlighten me!

Mike

Fri Oct 24, 2008 3:07 pm

Everything on a VW engine is metric. The machine shop converts the metric numbers to SAE numbers then measures everything with good old American inch system measuring tools. The real problem is that the crappy shops will loose a few thousands in the conversion. unfortunately .0005" to .001" could mean the difference between getting 100,000 miles out of your engine or calling the tow truck after 5000 miles.

Fri Oct 24, 2008 3:20 pm

So if I needed to turn the crank journals "one under", would I tell the machine shop to use .00984" as the measurement instead of .0100" - just to make sure? Or, give them the final diameter in .xxxxx" SAE?

BTW - the VW case boring tools SHOULD be in metric, yes?