Figuring duration

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Grumpy...Is there a formula to calculate the duration numbers taking lash into account? My yet to be installed cam is a solid roller, with .016 and .020 lash settings. Duration is 244/248. TIA.

 

[grumpyvette]

Grumpy...Is there a formula to calculate the duration numbers taking lash into account? My yet to be installed cam is a solid roller, with .016 and .020 lash settings. Duration is 344/248. TIA.

I assume your mean 244/248 duration?
your only real option is to carefully measure with a dial indicator and degree wheel.
most guys use BOTH the lift at .006 and .050 measurements , and the total lift and LSA to describe the lobe ramp intensity, and profile.
theres no FORMULA simply because the ramp rates vary significantly between cam lobe designs, but if youve got the info a dial indicator and degree wheel provide that info can be used to provide a very good idea as to the cams potential PROVIDED your aware of the engines other components like displacement, port flow rates, intake, compression, etc.

http://raceology.com/2004/11/cam-doctor ... ation.html
http://www.auto-ware.com/software/eap/eap.htm

Cam Checking hardware and software:

http://www.audietech.com/
http://www.andrews-products.com/
http://www.performancetrends.com/


of course MEASURING HELPS VERIFY

http://album.hybridz.org/data/500/Degree_Wheel.JPG

 

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Yes...244. Corrected typo.