Valve clearance

General engine tech -- Drag Racing to Circle Track

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houser45
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Valve clearance

Post by houser45 »

How will rod length change piston to valve clearance? Same scenario except for pin height on the piston and 6.200” long rod to 5.850” rod???
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MadBill
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Re: Valve clearance

Post by MadBill »

Assuming compression height is changed to compensate 100% for the rod length change, the effect on valve/piston clearances will be immeasurably small.
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Charliesauto
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Re: Valve clearance

Post by Charliesauto »

houser45 wrote: ↑Thu May 28, 2020 8:11 pm How will rod length change piston to valve clearance? Same scenario except for pin height on the piston and 6.200” long rod to 5.850” rod???
Making some general assumptions (3.480" stroke and min P-V @ 9*) and using a little trigonometry, I came up with around 1/2 thousandth of an inch.
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Sparksalot
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Re: Valve clearance

Post by Sparksalot »

The replies above sum it up. Kudos to them!
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Geoff2
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Re: Valve clearance

Post by Geoff2 »

Rod length can change P to V clearance before & after TDC. Int valve P to V can be closer a few degrees after TDC, exh a few degrees before TDC.
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Tom Walker
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Re: Valve clearance

Post by Tom Walker »

MadBill explained it very succinctly.
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