Crankshaft end float woes… no movement, just solid with no end play!

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DevonNorton said:
The 2011 thread on this subject also refers to overlapping tolerance of CN and C3.
This post also contains some data on tolerances from 'ten years ago' https://www.accessnorton.com/NortonCommando/c3-vs-cn.10179/post-137420

The '2001' data are as follows:
Clearances before installation
C1 5-15microns (for a 30mm ID bearing)
C2 5-30
C0 25-50
C3 45-70
C4 60-85
C5 85-110

From the 2019 FAG HR-1 Catalogue (Section 1.10, Pg 424)

View attachment 21899

Tolerances look to have changed over time. I know it's only 2 different years, but I've attempted to show the CN and C3 differences using the ranges (max/min) plus a mid point as the mean and interpolated values using 'Box & Whisker' plots.

View attachment 21900
This shows how clearances have changed over time. There is now considerable overlap between the range of a 2019 C3 and a 2001 CN. Also increased overlap between a 2019 C3 and CN. It's therefore possible to see how a CN bearing from 2001 would fit leaving sufficient end float but also why a CN bearing to 2019 spec might not.

It's all a bit 'How many angels can dance on the head of a pin?' but at least this might help explain some of the different experiences.

Andy
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Thank you..
 
I agree this is all over the place. But you have to remember when Norton moved the plant and lost some of the old timers who knew how to use the old machines, tolerances were hard to keep. We are talking microns here.

Maybe , just maybe being a big buyer of FAG bearings, FAG sent Norton the bearing clearances they (FAG) felt Norton needed for the type of use and the metals and dimensions on the blueprints. If Norton could hold the tolerances to spec.

And maybe a careful assembly man could select bearings that would work if tolerances were "off" . Or if experience when road testing dictated it.

I assume FAG could select bearings with the proper specs to send to Norton right down to the micron???

I wish there were old time workers from the factory to see what they think and were able to do at the job.

I try to select parts that fit to what I feel comfortable with. That is the job of assembly as I see it.
 
Carl H said:
I assume FAG could select bearings with the proper specs to send to Norton right down to the micron???
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No, the dot/circle/CN C2 C3 etc sets what the internal clearance would be with bands set by ISO standards.

On shell bearing selective fits started in Japan in the 80's and then came to Europe/US with the transplant factories. The purpose of the colour coded shell bearings with multiple 5 or 3 micron bands denoted by colour was to have better controls on the journal to shell clearance to reduce vibration. If you randomly fitted any colour shell to any journal then you would still have a functioning engine. When the US/European car makers saw the colour coded shell bearings being made in the shell bearing makers they followed suit.

On the barrel there were 2 or 3 grades of piston which were matched to the measured bore size, that was a long established practice.
 
dynodave said:
Please define negative clearance
Some new physics ?
What is happening is no engineering mystery but the consequences are not entirely desirable.
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pre-load... ie 10thou endfloat is negative preload ... zero endfloat is zero preloadwhich seems to be what mine has had from new.Negative clearance will give a positive pre -load and a crank that will not spin easily by hand.
 
Carl H said:
I know when I put superblends in a 1965 Atlas it had no movement side to side , but if you warmed the cases about 20 degrees above room temp. It had the end play I wanted,
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This is exactly what I meant in an earlier post. Mine has never had any end float from cold, the cases have never beensplit , its the original engine running on the original bearings and it has done 50,000 + miles .
 
kommando said:
No, the dot/circle/CN C2 C3 etc sets what the internal clearance would be with bands set by ISO standards.

On shell bearing selective fits started in Japan in the 80's and then came to Europe/US with the transplant factories. The purpose of the colour coded shell bearings with multiple 5 or 3 micron bands denoted by colour was to have better controls on the journal to shell clearance to reduce vibration. If you randomly fitted any colour shell to any journal then you would still have a functioning engine. When the US/European car makers saw the colour coded shell bearings being made in the shell bearing makers they followed suit.

On the barrel there were 2 or 3 grades of piston which were matched to the measured bore size, that was a long established practice.
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That is why I collect and drive old Toyotas, But luckily Commandos have been very good to me, too!
 
Please define negative clearance?
oldmikew said:
pre-load... ie 10thou endfloat is negative preload
Click to expand...
Can't even answer the question?.....negative clearance IS....
Almost as good as pregnant virgin LOL
Nothing worth pursuing here any more. Only verbal mumbo jumbo as far as I can tell
 
I was interested to read that there is technical info available in "The Source" on the Andover website.
Someone pasted some info here, but where is the info located on the website???
 
Stephen Hill said:
I was interested to read that there is technical info available in "The Source" on the Andover website.
Someone pasted some info here, but where is the info located on the website???
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You have to subscribe to the newsletter, then the source comes once a month unless they are busy ;)
 
I "registered", but not sure what that triggers. I don't see an option to sign up for The Source, or anything else.
Maybe just registering with Andover Norton triggers other stuff, like The Source??
 
kommando said:
You have to subscribe to the newsletter, then the source comes once a month unless they are busy ;)
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I've only ever received three called "The Source" and the last was received 12/13/2019. I received quite a few newsletters before 11/2017 that were not called "The Source". Has anyone received one after 12/2019?
 
marshg246 said:
I've only ever received three called "The Source" and the last was received 12/13/2019. I received quite a few newsletters before 11/2017 that were not called "The Source". Has anyone received one after 12/2019?
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Yes, mine comes every month.
 
marshg246 said:
I've only ever received three called "The Source" and the last was received 12/13/2019. I received quite a few newsletters before 11/2017 that were not called "The Source". Has anyone received one after 12/2019?
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I have one received Jan 29, 2021. Been getting them regularly throughout 2020 by email. What was the issue needed again? I usually save them.
 
batrider said:
I have one received Jan 29, 2021. Been getting them regularly throughout 2020 by email. What was the issue needed again? I usually save them.
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My only issue is I guess I got dropped from the list - I always find interesting things in them so I'll contact them to put me back on the list.
 
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