18 replies to this topic

[Mxrab]

Picture

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[Spider]

Thanks for the info and in particular, the photo.

There is actually a 'ring' machined in to it between the 1st and 2nd lobes. This is the most common type of 1275 A+ Cam used.

Inlet is fully open at 107.5⁰ ATDC with these.

Timing figures are;-

Inlet Opens 9⁰ BTDC

Inlet Closes 41⁰ ABDC

Exhaust Opens 55⁰ BBDC

Exhaust Closes 17⁰ ATDC

Lift at the Lobe is 0.250"
Lift at the Valve is 0.318" (with stock rockers)

Note that the checking clearance (to see these numbers) at the Valve is 0.021" with the standard sintered type rockers.

[Mxrab]

Well Iv learned something new today, really appreciate the help Spider, thank you. Based on the inlet opening at 107.5 ATDC that means that the dot to dot is out by 4.5 degrees based on my 111 degree calculation? So I need a 4 or 5 degree offset key to bring it back into line.

Thanks for the info and in particular, the photo.

There is actually a 'ring' machined in to it between the 1st and 2nd lobes. This is the most common type of 1275 A+ Cam used.

Inlet is fully open at 107.5⁰ ATDC with these.

Timing figures are;-
Inlet Opens 9⁰ BTDC
Inlet Closes 41⁰ ABDC
Exhaust Opens 55⁰ BBDC
Exhaust Closes 17⁰ ATDC
Lift at the Lobe is 0.250"
Lift at the Valve is 0.318" (with stock rockers)

Note that the checking clearance (to see these numbers) at the Valve is 0.021" with the standard sintered type rockers.

[Spider]

Up to you, but many, including myself, usually advance the initial Cam setting by 1 to 2⁰ to allow for Chain settling and for some, initial stretch.