Valve to valve clearance during overlap

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Robert
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Valve to valve clearance during overlap

Post by Robert »

Hello Guy,

I read the 1rst book and found your recommendation for valve to piston clearance during overlap.
But what are the figures for the valve to valve clearance? I mean if you increase the intake valve size diameter you have this dimension decreasing so what is the limit to respect?
It is for the R5 Alpine engine built by a friend (the intake valve going from 38.5 to 41.5 mm) as we discussed previously concerning the head prep.

Thank you,

Robert
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Guy Croft
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Re: Valve to valve clearance during overlap

Post by Guy Croft »

hi Rob

the minimum valve - valve I would tolerate at 'new build' is 0.020" (0.50mm) but much depends on valve-guide clearance, my figure is based on my work. The more loose the valve-guide fit the more you need.

I would generally try to achieve 0.040" (1mm) at new build.

I hope this helps,

G
Guy Croft, owner
Robert
Posts: 86
Joined: August 20th, 2006, 8:17 am
Location: France
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Re: Valve to valve clearance during overlap

Post by Robert »

Many thanks !!

Robert
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