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> Is there a "how to.." for crank measurement, and bearing verification?
malcolm2
post Dec 16 2019, 11:07 PM
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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?
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Superhawk996
post Dec 17 2019, 02:34 PM
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Also for what it’s worth, I provided this crank thinking it was going to a low buck down and dirty rebuild or low buck refresh of some sort.

From your previous posts I think you have invested in new AMC heads and may be building this for a Bus IIRC. I wouldn’t use this crank as-is for for a top notch rebuild. This crank is was polished beyond the 0.010 undersize to remove light scoring. That polish basically equals WEAR. As long as it’s between the tolerances it’s usable but some life was lost and oil clearances would be increased with the polish. Plastigage would tell you where it actually is at.

If you don’t want to spend dollars for a standard crank, at least take this one down to 0.020” under, get 0.020” under bearings and start with fresh unworn bearing clearances.

Factory manual allows for 0.030” undersize but I personally wouldn’t go that far undersize.

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malcolm2   Is there a "how to.." for crank measurement   Dec 16 2019, 11:07 PM
Superhawk996   @malcolm2 My understanding is that this crank th...   Dec 17 2019, 06:17 AM
malcolm2   YES, It seems that @jtprettyman has passed it on...   Dec 17 2019, 08:46 AM
malcolm2   How about the 71mm measurement? Not that it matte...   Dec 17 2019, 08:51 AM
Superhawk996   How about the 71mm measurement? Not that it matt...   Dec 17 2019, 02:13 PM
Mark Henry   How about the 71mm measurement? Not that it mat...   Dec 17 2019, 11:26 PM
Mark Henry   I only use STD cranks or standard (under) cranks I...   Dec 17 2019, 09:24 AM
malcolm2   I only use STD cranks or standard (under) cranks ...   Dec 17 2019, 09:48 AM
Superhawk996   Also for what it’s worth, I provided this crank ...   Dec 17 2019, 02:34 PM
malcolm2   OK it passed the hammer test. very high pitched t...   Dec 17 2019, 06:30 PM
Superhawk996   With my method of measuring last night, I got a ...   Dec 18 2019, 08:53 AM
malcolm2   With my method of measuring last night, I got a...   Dec 18 2019, 10:03 AM
Superhawk996   Thanks for your input. I certainly hope you don...   Dec 18 2019, 02:58 PM
malcolm2   OK, maybe not the super duper accurate tools but I...   Dec 21 2019, 02:47 PM
Superhawk996   OK, maybe not the super duper accurate tools but ...   Dec 21 2019, 07:36 PM
Mark Henry   Sounds like a lot. If you're right about #4 yo...   Dec 21 2019, 03:24 PM
malcolm2   Your rods should at least have the big ends done....   Jan 20 2020, 08:59 AM
Superhawk996   So question 1: how do you "DO" the rod...   Jan 20 2020, 12:41 PM
malcolm2   Both micrometers were checked prior to the last me...   Dec 23 2019, 10:08 AM
Superhawk996   Both micrometers were checked prior to the last m...   Dec 23 2019, 10:34 AM
malcolm2   3) For hobbyists like myself, Plastigage can ser...   Dec 23 2019, 10:44 AM
malcolm2   UPDATE>>>>> Todd is the Director o...   Jan 14 2020, 08:38 PM
Superhawk996   Rod measurements align a whole lot closer to what ...   Jan 15 2020, 06:00 AM
jtprettyman   @Superhawk996 Yes, these were done with a very n...   Jan 15 2020, 08:58 AM
malcolm2   Rod Balancing, End-to-end. I also wondered how in...   Jan 21 2020, 08:30 AM


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