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Auto Racing/Valve Clearance

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Expert: - 6/5/2007


Question
how does valve clearance affects engine performance??what if we increase/decrease valve clearance.....what will happen to engine performance?????how do we know that the valve clearance that we have given to an engine is right????

Answer
All clearances in an engine are a at least partially there to make room for heat related expansion.

Sorry, I have no graphic presentations of the answer I sent. I'd suggest you print out my answer, and then study a cylinder head , valve/rocker assembly, and try to visualize what happens when all that stuff collides with a piston at say- - -7500 RPM- -- Trust me, it ain't pretty !!

Please send me a follow up question or your e-mail address and I'll try to get a bit more info from a real pro engine builder close by (used to do Winston Cup motors.)

Dan  

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Dan Liddy

Expertise

Anything concerning race cars, 20 years competition experience, Senior Competition Driver Instructor , car builder, mechanic, welding, fabrication, tuning , engine modifications, set up, suspension design. Specializing in Datsun/Nissan products. Please submit questions about RACE CARS ONLY. No street cars, no video game scenarios Thank you.

Experience

I have been racing for 20 years, I have been the Central Florida SCCA Regional Championship points for 5 years running, and won the championship in my class 2 times. During my first start in the 60's I won many solo awards and the State Championship Drags. I serve as a senior instructor for SCCA, and have taught in Mercedes AMG events at Daytona, and Dodge Viper Days at Sebring International. I have been in the thick of the competition for all of my career. At one time or another I have driven race cars at speeds nearing 195 MPH. It's quite a ride !

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