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O.S. Engines 21VZ-B V-Spec

O.S. Engines 21VZ-B V-Spec

Old 06-25-2009, 08:28 AM
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Default O.S. Engines 21VZ-B V-Spec

Hi! I have this engine.For 25% nitro 12% oil do I need the included extra head shim ? or I need it only for 30% nitro?
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Old 06-25-2009, 08:37 AM
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don't need it for either. But some like it for 30% but not neccesary
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Old 06-25-2009, 08:37 AM
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You don't need the extra head shim for 25% or 30%.
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Old 06-25-2009, 09:31 AM
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+1 on no extra head shim needed for 30%. I run coldfusion magic. Lend it's 30% & 11% oil in my os speed, same head shims and no problems at all. Add the extra shim to increase top rpm and decrease compression to make the engine have a little less bottom, otherwise run it stock.
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Old 07-26-2009, 06:05 AM
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Just got a used V-spec in parts, and I wonder about whats the correct shimming for 20-25% nitro.
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Old 07-26-2009, 06:23 AM
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Originally Posted by sirKandal View Post
Just got a used V-spec in parts, and I wonder about whats the correct shimming for 20-25% nitro.
The stock shims on the V-Spec, Speed and Mugen Ninja JX-21 are one 0.2mm (0.008") aluminum shim and one 0.1mm (0.004") copper shim. This is for 25% or 30% nitro. If you are running 20% nitro remove the thinner copper shim.
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Old 07-26-2009, 06:42 AM
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Thanks. I'm innstaling a new cylinder/piston, con rod and bearings so it vill be god as new
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