274f cam

[Malc C]

Can anyone tell me if you use same cam timing marks if a 274f cam is fitted.

 

[jonbills]

It'll work like that, but really you use a degree wheel and an adjustable pulley.

 

[Malc C]

Thanks Jon.. it is on an engine I bought some years ago and I removed the head without checking timing marks so I am just reassembling. I am going to fit su carbs to it and bench test/ run it… may need further advice with that … my plan is to refit original engine to my blue car with a view to selling it but wanted to make sure the su carbs are viable.
Malc

 

[jonbills]

You can print a degree wheel from here:
https://www.blocklayer.com/degree-wheel.aspx
And if if you have a dial type indicator, you can check that max lift of inlet #1 is somewhere in the region of 105-110 ° ATDC.
Plenty of SU experience around here

 

[Fairlineguy]

Agree with Jon
Worth Degreeing in you cam for piece of Mind .
I went to the effort of fitting a adjustable sprocket only to find it was basically in the same position as a standard gear

 

[240L31]

You can print a degree wheel from here:
https://www.blocklayer.com/degree-wheel.aspx
And if if you have a dial type indicator, you can check that max lift of inlet #1 is somewhere in the region of 105-110 ° ATDC.
Plenty of SU experience around here

Is this a general rule of thumb? I never received a cam card and always wondered if I should degree my cam.

I recorded the degree readings for the peace of mind, though.

Intake centerline at 107deg ATDC, Exhaust centerline at 110deg BTDC.

 

[jonbills]

Is this a general rule of thumb? I never received a cam card and always wondered if I should degree my cam.

I recorded the degree readings for the piece of mind, though.

Intake centerline at 107deg ATDC, Exhaust centerline at 110deg BTDC.

I think its a decent rule of thumb on L engines, I don't know about other engines so much. on big cams/high revs you can have a few degrees later. I've run as much as 112 ATDC.

 

[jonbills]

Is this a general rule of thumb? I never received a cam card and always wondered if I should degree my cam.

I recorded the degree readings for the piece of mind, though.

Intake centerline at 107deg ATDC, Exhaust centerline at 110deg BTDC.

so yeah, yours looks spot on.

 

[Malc C]

I will check cam timing on std sprocket and see how far out it is this is a spare engine that I thought would be a good idea to get running check compressions and oil pressure etc .
And thanks again with info… I did not think I would get such a quick response…

 

[240L31]

so yeah, yours looks spot on.

Fantastic. I used just the stock cam sprocket at #1 position.