Crank movement

Littlefeat69

Littlefeat69

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Nov 15, 2020
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Had satori off and noticed that the crank could move about a 1/8 or a bit more side to side...is this normal or should I be worried..74 850 that's at since 82...also is there a way to bench test the sator
 
Littlefeat69 said:
Had satori off and noticed that the crank could move about a 1/8 or a bit more side to side...is this normal or should I be worried..74 850 that's at since 82...also is there a way to bench test the sator
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I'll let others argue about crank end float.

There are two quick tests for a stator. Wires disconnected. Measure the resistance between the wires on the lowest range your ohmmeter has - the resistance should be quite low. Then measure between each wire and the metal of the stator on your meter's highest range - there should be no reading.
 
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1/8" sounds like an absurd (and unacceptable) amount of float for a crankshaft. BUT I admit I have never checked it on a Norton. A large amount of allowable float on an automotive V8 engine would be .011" with it generally being much less. But Norton engine builders here should respond with some figures - I'll be interested! ;)
 
Whippy crank means you need not worry until over 25 thou or even 30. Put a DTI on it and measure, it will be less than 1/8" as that's 125 thou.
 
I think a lot over react to end float on the crank, ever Norton motor I have rebuilt had end float and I never worried about it and all the rebuilds I have done mine included are all still going well.

Ashley
 
1/8" sounds kind of high. (I machined the top off an original AE to see inside but forget the actual clearance piston bosses to rod)
I had 0.31" on one crank, 0.029 on the replacement. (but machined stainless shims anyway since I was there to reduce it to around 0.012")
It probably made little difference in my case and if I could not have made shims would not have bothered.

s7.jpg dl1.jpg

About the only thing I did not care for was the massive step from the stator to rotor so I moved both of them inboard and to inline, it looks much better and might have gained 0.2 of a volt output as a bonus.
 
Maybe you have MkIII cases with a Mk2 crankshaft to have over an 1/8" end float (or four times factory loose)

I guess it would show you can get away with near anything with these engines, even from the factory and they will still run.
 
marshg246 said:
I'll let others argue about crank end float.

There are two quick tests for a stator. Wires disconnected. Measure the resistance between the wires on the lowest range your ohmmeter has - the resistance should be quite low. Then measure between each wire and the metal of the stator on your meter's highest range - there should be no reading.
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tks
 
"I'll let others argue about crank end float."

Yes, but with the published specs and the OB tech write up, there shouldn't be an "argument." With a stated 1/8" of float, the OP's crank float is way out of tolerance. I doubt that anyone here would be happy if they sent their Norton motor to some specialist for a rebuild and it came back with 1/8" of crankshaft float! :eek:

OTOH...whether somebody chooses to operate it that way is a different issue. ;)
 
MexicoMike said:
"I'll let others argue about crank end float."

Yes, but with the published specs and the OB tech write up, there shouldn't be an "argument." With a stated 1/8" of float, the OP's crank float is way out of tolerance. I doubt that anyone here would be happy if they sent their Norton motor to some specialist for a rebuild and it came back with 1/8" of crankshaft float! :eek:

OTOH...whether somebody chooses to operate it that way is a different issue. ;)
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Workshop manual 06.5146 states .005-.015
Workshop manual 00.4224 states .010-.024
Old Britts states best is: .005-.010
Factory didn't care best I can tell (cranks not shimmed)

So, yes - there are "published specs". However, there is no standard and as far as I can tell, no consensus. I even read once about a guy building race engines who wanted as close to zero as possible as long as there was no binding since the cases expand when heated. He also wanted the rods centered in the pistons and shimmed both sides to achieve both goals. I would be surprised if he could prove any measurable gain from his efforts.

The OP said: about 1/8 - not: it measures 1/8" Assuming he means 1/8" and if that it is accurate, it is too much. However, that's a bunch of assumptions and honestly .125" is very unlikely. Other threads on this subject have devolved into arguments - surprised that the argument this time is me wanting to stay out of the argument :)
 
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Well...I ASSumed that since the OP stated 1/8" that he measured it to be 1/8"! But as you point out, he didn't specifically say he measured it. SO, L'feat, what is the measured clearance?
 
MexicoMike said:
Well...I ASSumed that since the OP stated 1/8" that he measured it to be 1/8"! But as you point out, he didn't specifically say he measured it. SO, L'feat, what is the measured clearance?
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Also, he said 1/8 not 1/8" - decent assumption that he meant 1/8" since he's in the US, but 1/8 of a frog's hair is too tight (according to the "published specs"), not too loose :) Sorry, just had to.
 
I met a Norton engine builder here in Vancouver who had the same idea- carefully shim as close to zero end clearance as possible and then you have built a better than average engine. It sounded good at the time!
Then I read Jim Comstock's comment that the Norton twins shimmed to 5 thou or less were the ones that tended to have blue bearing races and other signs of extreme friction on disassembly. Since Jim has probably rebuilt about 100x the number of Nortons the Vancouver engine builder has, I've used Jim's numbers in the past.
A search will bring those numbers up.

Glen
 
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