Is there a "how to.." for crank measurement, and bearing verification? Options

[malcolm2]

I am gonna make a 2 liter from my 1.8. So I have a refreshed 71mm crank that I have been told has been ground to -0.010.

I measured as best as I can with a digital mic and got about 59.66 on the mains and 49.65 on the rod journals.

Where can I find the STD specs and ranges ? were they 60 and 50, respectively?

Since I know nothing about this crank, how can I verify the 71 mm measurement?

[Superhawk996]

@malcolm2

My understanding is that this crank that came to you came out of my 2.0L engine GA004310. It will need to be used with a set of 2.0L rods. I provided the crank only to another member for cost of shipping. The engine it came ran (video on my thread) but when I tore the engine down I found rust in the sump. See photos in my build thread for condition of this engine GA004310 (page 5 and 6).

The crank was subsequently hot tanked and had a light polish at my local machine shop.

You should measure using a micrometer it is more accurate than a digitial caliper when we are taling about ten thousandths of an inch (0.0001").

This crank came out of my engine at 0.010" undersize on both mains and rods. It was scored. My local machine shop put a very light polish on it that removed another 0.0001" to 0.0002". If I recall, most journals were actually 0.0101 under size. There was some light pitting at the nose of the crank between where the distributor gear sits and between the main bearing but it was not pitted at all where the bearing actually rides (inclusive of end play).

I was going to use it but subsequently got a used standard size crank from KevinW for not much more than about $200 total and my local machine shop was going to charge $90 to take this worn/polished crank down to 0.020" undersize which didn't make sense to me to pay when KevinW helped me out for not much more than that. My preference was to use a standard crank. Nothing wrong with 0.010" - 0.20" undersize, lots of low buck rebuilders would do that but for only $200 to get a standard crank, that is where I wanted to start from.

I recommend that it be trial assembled and measure with Plastigauge to determine what the actual oiling clearnce is. I just looked to see if I had photos of the journals as I measured them. I'm not finding them quickly. I'll look again after work this evening and then I have the rest of the month off for vacation so I'll look again.

The specifications for journal diameters are in the factory manual, Haynes, or the How to rebuild your VW engine book. I'll dig those out later too.