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88 CRX HF
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Discussion Starter · #1 ·
So I'm building a D15B7 (A6 cam). Head is shaved about .050. Cam timing is currently set to stock as per Y8 cam gear. How far should I advance the cam to make up for the .050 milled from the head? My research suggest two different opinions:
Some say 1 degree for every .012 milled
Some say 1 degree for every 1 mm (.0394) milled
Can anyone clarify this ?
 

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BATSLOMAN GIVES NO FUCKS.
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4.5 degrees if you were using stock parts.

doing some math - .50 equals however many degrees.

once you figure out that math, subtract it from the 4.5 degrees.

taking into account the y8 gear makes up for the 4.5 offset
 

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Brokedick Millionaire
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It was clarified the difference is Pi was left out.

The original number Larry Widmer, aka T.O.O., the old one at Endyn.

.0125mm * Pi
 

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BATSLOMAN GIVES NO FUCKS.
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so, Im shite at math

but from what I got. the y8 gear will still be correctly timed, 1/2 a tooth advanced turns into like 3/8 advanced
 

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Brokedick Millionaire
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I'd leave it alone or retard 1-2 degrees more depending on where you want the powerband.

ie don't worry about it.
 

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Brokedick Millionaire
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Keep notes alongside your ET slips and weather conditions if you are testing changes and doing 1/4 mile passes for testing. now that when it is too hot and the car slows by .25, it's time to park the car and drink beer!

With the D15Beast7 combo using the A6 cam, the 4.75 degree timing either way was just too much. Once I got it zero'd in correctly, I found 2-3 degrees cam retard fitted my needs with the powerband, but I also had the ZC trans ratios to keep the shift rpm up on gear changes. I was also using short 20"x8x14 MT drag slicks to help gearing but also to keep the launches consistent.

I was also running 22 degrees base ignition timing instead of 16, which required some file working. on the dizzy holes. I only used 87 pump gas as well wityh a stock bottom end.
 
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