Incorrect Stock Cam Specs

[Donald McMullin]

From my calculations the stock cam specs previously listed appear to be incomplete or incorrect.

Either the Overlap listed at 38* or the Lobe Center listed at 107* is incorrect.

As listed:
Intake Exhaust
Advertized Duration 258 262
Duration @0.050" 192 196
Lobe Center 107*
Overlap 38*

From my calculations using a Lob Center of 107* results in the following cam timing and an Overlap of 46*.

At Advertized Duration


Intake Exhaust
Open: 22* BTDC 58* BBDC

Close: 56* ABDC 24* ATDC

Duration @ 0.050" Lift

Intake Exhaust
Open: 11* ATDC 25*BBDC

Close: 23* ABDC 9* BTDC


I do make mistakes (sometimes), any help from anyone??


Deep Enough

Donald McMullin

 

[Intercooler]

And you point is???? The stock cam is gone.......

 

[TurboBob]

intake open -8btdc close 21abdc (193)
exhaust open 28bbdc close -12atdc (196)

lobe sep 107


SAE advertised duration 282/276 (probably backwards)

lobe lift .250 .264

from the dana website.

TurboBob

 

[Donald McMullin]

TurboBob:

Thank you for the information. The cam timing you provided indicates that the cam is advanced 3.5* and has an Overlap @0.050 of a negative 20*.

I know that Overlap is not usually referenced at 0.050 of lift, but this still provides a comparison with other cams so long as I look at their Overlap at 0.050 and not at advertized duration.

Intercooler:

In previous posts about stock cam vs aftermarket cam such items as Overlap, Lob Centers, Intake openning, and Exhaust closing have been discussed.

I was just wanting to have the correct cam timing for the stock cam so a informed comparison could be made.

Deep Enough

Donald McMullin