The Ford Barn - View Single Post - Question on Cam Gear Marks

Mart · 10-01-2020, 05:44 PM

Russ, Please clarify "almost closed".

From memory, with a stock cam in a flatty, as you reach TDC, The exhaust will have just closed and the inlet will be about to start opening. If the exhaust is closing after TDC then the timing may be out.

There are 44 teeth on the cam gear, one tooth is 8.18 degrees. So if you were one tooth out, the overlap (rocking) of the valves would occur 16 crank degrees after or before TDC, depending on which way you were off.

In other words, it should be obvious if it is wrong.

If it isn't obviously wrong, it is probably right.

Mart.

10-01-2020, 05:44 PM	#35
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,742	Re: Question on Cam Gear Marks - UPDATE Russ, Please clarify "almost closed". From memory, with a stock cam in a flatty, as you reach TDC, The exhaust will have just closed and the inlet will be about to start opening. If the exhaust is closing after TDC then the timing may be out. There are 44 teeth on the cam gear, one tooth is 8.18 degrees. So if you were one tooth out, the overlap (rocking) of the valves would occur 16 crank degrees after or before TDC, depending on which way you were off. In other words, it should be obvious if it is wrong. If it isn't obviously wrong, it is probably right. Mart.