You should place the stock camshaft gear at __________ when preparing to install an aftermarket adjustable camshaft gear.

You should place the stock camshaft gear at __________ when preparing to install an aftermarket adjustable camshaft gear.

• A. ATDC
• B. TDC
• C. BTDC
• D. BDC

Answer: (B)

Starting from a solid reference position is key for any timing work. Placing the stock camshaft gear at top dead center gives you a precise, repeatable baseline that aligns the crank and cam as they should be for cylinder one on the compression stroke. With that reference, you can transfer the factory timing marks to the new adjustable cam gear and dial in the desired cam timing accurately. Using positions like before or after top dead center (BTDC or ATDC) or bottom dead center (BDC) wouldn’t provide a stable reference point for setting the timing and could lead to misalignment or valve interference. So, TDC is the correct baseline.

Starting from a solid reference position is key for any timing work. Placing the stock camshaft gear at top dead center gives you a precise, repeatable baseline that aligns the crank and cam as they should be for cylinder one on the compression stroke. With that reference, you can transfer the factory timing marks to the new adjustable cam gear and dial in the desired cam timing accurately. Using positions like before or after top dead center (BTDC or ATDC) or bottom dead center (BDC) wouldn’t provide a stable reference point for setting the timing and could lead to misalignment or valve interference. So, TDC is the correct baseline.