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 Post subject: 69mm which crank
PostPosted: Sat Mar 13, 2010 12:47 pm 
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Joined: Thu Mar 10, 2005 3:56 pm
Posts: 51
I'm looking to buy a 69 mm counterweighted crank. I'm looking at the CB 4140 forged cromoly as it fits by budget :lol: but is it any good? I tried searching the forum and one poster claimed it could break even in a fairly stockish motor. Are there others in the same pricerange worth considering?
The crank will go into a 1600 that I built a few years ago. The engine revs easily to 6500 as is, but I am considering a camchange and heads that will move the revs higher.

thanks for any input


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 Post subject: Re: 69mm which crank
PostPosted: Sat Mar 13, 2010 6:59 pm 
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Joined: Mon Jul 04, 2005 9:36 am
Posts: 329
Check demello machine services or dms they they take a stock german crank and weld counter weights on to then machine it. They are 135 dollars plus exchange of a good core.


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 Post subject: Re: 69mm which crank
PostPosted: Thu Mar 18, 2010 11:15 pm 
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Joined: Sun Nov 30, 2008 7:49 pm
Posts: 69
Location: NE Indiana
Buy a German crank,Chinese quality is very poor.


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 Post subject: Re: 69mm which crank
PostPosted: Fri Mar 19, 2010 11:22 am 
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Joined: Sat Aug 19, 2006 2:13 pm
Posts: 886
Location: Way up in northern California!
I've used CB cranks and really like them. Measure out and are strait.
Now the only two Demello cranks i've seen were both bent. One .015" and .017". Maybe that's their tolerance. I don't know.
But that's way too much for me.
CB's products seem to much higher quality than the usual china stuff.
This is based on what i've used and seen personally.

Craig


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 Post subject: Re: 69mm which crank
PostPosted: Sun May 02, 2010 1:59 am 
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Joined: Sun Sep 20, 2009 1:55 am
Posts: 113
Location: Estonia
How far should I go with RPM when the engine is built with stock parts? Not for highway but for quarter mile....on streets I can hold it lower.
1600cc turbo.

how far with stock valve springs?
how far with stock crank?
Can I get some more when I change the valve prings or not?

Is there any measurements, pics or something of counterweighted stock cranks?

Thank you


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 Post subject: Re: 69mm which crank
PostPosted: Sun May 02, 2010 8:02 am 
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Joined: Mon Jul 04, 2005 9:36 am
Posts: 329
Generaly 4500 to 5000 rpms. Heavy duty valve springs would help with valve float but I would be concerned about vibrations at the crankshaft assembaly. No matter what crank shaft you use have all of your rotatating assy. balance crank, rods fly wheel seperatly then have them balance it all as a unit including the front pully and with the clutch pressure plate installed. This reduces vibrations and make the engine last much longer and allow you to turn more rpms depending on your head selection and carburator set up.


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 Post subject: Re: 69mm which crank
PostPosted: Tue May 04, 2010 2:22 pm 
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Joined: Wed Oct 03, 2007 3:00 pm
Posts: 1882
I'd buy a crank from DPR and the rods from Gene Berg or Rimco before sending more of our money to the Chinese.
Stock springs are good for a W 100 cam.
You should get every part balanced buy some one who knows VWs. DPR can balance a crank and flywheel for you.
Rimco and Gene Berg both sell race prepped stock VW rods that are balanced.

I on/ off roaded and drag raced the same 1776 with a Rimco cw crank and race prepped rods, Engle 130 cam for a couple of years in the early 90s. The engine was balanced by Mike Fischer. 6000 rpm launches and off roading was even harder on it. It never failed.


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