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toolman2800
Samba Member
Joined: August 13, 2004
Posts: 1053
Location: Florida
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 Posted: Mon Apr 20, 2009 2:04 pm Post subject: Stroker Novice |
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I am concidering building a 1745 or an 1807. Thats a 76 crank x 85.5 or 87 bore.
Now here is the question. How do I determin the length of rods I need if I want to use stock pin position pistons? If I am thinking correctly they will have to be around 7mm shorter, To maintain stock deck height, Correct?
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Glenn 
Mr. 010
Joined: December 25, 2001
Posts: 76936
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| Posted: Mon Apr 20, 2009 2:06 pm Post subject: |
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A 76 crank is not a "drop in".
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Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
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Marv [UK]
Samba Member
Joined: January 07, 2009
Posts: 2225
Location: UK
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| Posted: Mon Apr 20, 2009 2:34 pm Post subject: Re: Stroker Novice |
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| toolman2800 wrote: |
| How do I determin the length of rods I need if I want to use stock pin position pistons? If I am thinking correctly they will have to be around 7mm shorter, To maintain stock deck height, Correct? |
Stock rods are used and you place shims under the cylinders, against the case. 76mm is as big as it gets with A pistons (stock pin height) before you need B pistons (pin closer to piston crown but i forget by how much)
shims are calculated AFTER the motor has been mocked up and deck height measured. Ball park figure is HALF of stroke difference between stock and stroker cranks
in your case, 3.5mm or thereabouts.
There is no "stock" deckheight in a stroker engine. Only a deckheight to get the target compression ratio for your cylinder head volume.
Gets complicated doesn't it  |
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