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PostPosted: Thu Mar 08, 2007 6:39 am 
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848cc
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Location: NZ
Hi

I am currently get a crank machined.
Does anyone know what the thickness of a main & big end shells are.
I need to know this so i can determine bearing clearances.
I will measure the main & big end bores
Also Vizard mentions going 0.001" under bottom size to provide extra clearance in competition engines, is this what others do?

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PostPosted: Thu Mar 08, 2007 6:41 am 
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848cc
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Location: NZ
ps
it is a large journal 1275 motor

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PostPosted: Thu Mar 08, 2007 7:26 am 
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998cc
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73GT wrote:
Hi

Also Vizard mentions going 0.001" under bottom size to provide extra clearance in competition engines, is this what others do?


No. just grind it the minimum it needs and then use plastiguage to determine your running clearance.

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PostPosted: Thu Mar 08, 2007 9:31 am 
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848cc
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i mentioned to the reconditioner that i had already used plastigage & he said it isnt exact enough & prefers to measure actual bore & journal sizes.
As i have a micrometer it is no problem to do this
I just dont know how to get the shell thichness

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PostPosted: Thu Mar 08, 2007 9:48 am 
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1098cc
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The crank grinder can tell you what undersize the crank needs to be ground to, they are the bearings you need to buy.

Instal the bearings and measure the I.D. in a few places, the crank can then be clearanced to suit.

Regards

Daniel

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PostPosted: Wed Dec 19, 2007 4:04 am 
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1275cc
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I was also wondering what the main and conrod bearing tollerances are? I am going to tighten em up with plastiguage today.

thanks

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PostPosted: Wed Dec 19, 2007 4:18 am 
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they'd be in the workshop manual specs pages...

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PostPosted: Wed Dec 19, 2007 4:54 am 
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If the guy doing the grind is asking you what the clearances should be, use another guy :shock:


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PostPosted: Wed Dec 19, 2007 5:19 am 
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unless he's asking for his preference...

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PostPosted: Wed Dec 19, 2007 11:27 am 
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I just need a rough idea so I know what colour plastiguage to buy :D

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Yep Mokes are ugly - but Moke owners know that. Its like ugly women - she may be a dog but you know your going to get some :wink:


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PostPosted: Wed Dec 19, 2007 2:24 pm 
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min .25 thou Max 1 thou

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