Which cam manufacturer makes DOD cams?

[dv327]

How many choices do we have?

[Patrick G]

Comp Cams has new LSN and LSD lobes that you can use to make your own custom DOD cam. I plan on putting one in my car sooner than later.

[norm8332]

I think New Era (check on the left) has a couple.

[Crazy Paul]

Patrick,

We now have the lift figures at the valve for the stock GM L76 camshaft.

Valve Lift - Exhaust - Non Active Fuel Management 0.480 in
Valve Lift - Exhaust - Active Fuel Management 0.489 in

Valve Lift - Intake - Non Active Fuel Management 0.474 in
Valve Lift - Intake - Active Fuel Management 0.488 in

I understand the reasoning behind GM having slightly taller gross valve lifts on the AFM cylinders v the "normal" cylinders.

Do you think or know if Comp or Vendors (such as New Era) incorporate the same feature in their aftermarket DOD grinds ?

[It's A G8!]

Hey patrick can you spec out a cam for me?

[dv327]

Patrick,
What did you have in mind for reliability and power?

[Patrick G]

Patrick,

We now have the lift figures at the valve for the stock GM L76 camshaft.

Valve Lift - Exhaust - Non Active Fuel Management 0.480 in
Valve Lift - Exhaust - Active Fuel Management 0.489 in

Valve Lift - Intake - Non Active Fuel Management 0.474 in
Valve Lift - Intake - Active Fuel Management 0.488 in

I understand the reasoning behind GM having slightly taller gross valve lifts on the AFM cylinders v the "normal" cylinders.

Do you think or know if Comp or Vendors (such as New Era) incorporate the same feature in their aftermarket DOD grinds ?I can't speak for New Era, but I do know that Comp uses lobes with the same base circle radius as stock (.7756" BCR). The non-deac lobes (cylinders 2-3-5-6) have a rate of 52 degrees from .006" to .050" which means a 222 lobe at .050" will have an advertised duration at .006" of 274. The deac lobes (DOD cylinders 1-4-6-7) have a rate of 62 degrees from .006" to .050" which means a 220 lobe at .050" will have an advertised duration at .006" of 282.

Comp does this because the deac-lobes require a softer acceleration off the base circle to enhance longevity. Interestingly, all deac and non-deac lobes are set at .294" lobe lift. This gives .500" lift with a 1.7 rocker and .544" lift with a 1.85 rocker.


Hey patrick can you spec out a cam for me?Absolutely. Just click the cam help link in my signature and follow the instructions.


Patrick,
What did you have in mind for reliability and power?Depends on whether you run headers or not, whether you run stock stall or high stall, stock gear or lower gear, and whether you're willing to raise your shift points above stock.

[Crazy Paul]

I can't speak for New Era, but I do know that Comp uses lobes with the same base circle radius as stock (.7756" BCR). The non-deac lobes (cylinders 2-3-5-6) have a rate of 52 degrees from .006" to .050" which means a 222 lobe at .050" will have an advertised duration at .006" of 274. The deac lobes (DOD cylinders 1-4-6-7) have a rate of 62 degrees from .006" to .050" which means a 220 lobe at .050" will have an advertised duration at .006" of 282.
Comp does this because the deac-lobes require a softer acceleration off the base circle to enhance longevity. Interestingly, all deac and non-deac lobes are set at .294" lobe lift. This gives .500" lift with a 1.7 rocker and .544" lift with a 1.85 rocker.

Thanks Patrick,
It's interesting to see the engineering solutions to address the limitations of the DOD lifters. I still shake my head when I hear of guys putting non-DOD cams (like XR's) onto DOD lifters.
C.P.

[Patrick G]

Thanks Patrick,
It's interesting to see the engineering solutions to address the limitations of the DOD lifters. I still shake my head when I hear of guys putting non-DOD cams (like XR's) onto DOD lifters.
C.P.Pretty scary. Putting aggressive cam lobes with small base circles is one of the reasons why we've seen some kabooms this past year.

I like the idea of running a DOD cam with the 1.85 ratio Yella Terra rockers. This way, you can still get .544" lift and the DOD compliant lobes.

[dv327]

What kind of duration could you run with headers and stock stall for good street manners? Would the lobe separation have to be around 115*?

[dv327]

Will the DOD lifters tolerate more lift than .544?

[Patrick G]

Will the DOD lifters tolerate more lift than .544?.544" is the lift at the valve. The lift at the lobe is what the lifters see and really what matters here. According to Comp, they feel that the safe limit for lobe lift is .294". Multiply that times a 1.7 ratio rocker and you get .500" lift and .544" with a 1.85 ratio rocker. Some companies have pushed it further than .294" lobe lift (and with faster ramps on the DEAC cylinders), but some of those companies have had lifter failures. Whether it was a freak deal or related to being too aggressive is undetermined. Comp's stance is to make as much power safely as possible with DOD cams.

[solty]

So what is the power/torque gain with a .544" lift DOD cam?
Thanks

[supercharger]

I have been wondering how GM gets 400HP from the L99 engine. Can VVT be adding the additional 40HP over an L76, or does the L99 have a more aggressive DOD cam? I'd imagine the VVT helps more in moving the torque curve around than acting as a power adder, but I'm not sure. What are the extra .2 litres worth power wise?

[GeorgeInNePa]

I have been wondering how GM gets 400HP from the L99 engine. Can VVT be adding the additional 40HP over an L76, or does the L99 have a more aggressive DOD cam? I'd imagine the VVT helps more in moving the torque curve around than acting as a power adder, but I'm not sure. What are the extra .2 litres worth power wise?

More aggressive cam profile and the engine has 12 more ci.

[edmanet]

More aggressive cam profile and the engine has 12 more ci.

And its tuned for 93 octane.....G8s were tuned for 87 if I remember correctly

[G8-4-Speed]

Will the DOD lifters tolerate more lift than .544?

The lifter mechanically can handle .320+ at the lobe. I currently run .326". The issue that is in question is the strength. Material, pin, and roller are the same but it is a more complicated lifter internally. The biggest issue is controlling valvetrain bounce. The lifter is @150 grams compared to @120 grams for a standard lifter.

[dv327]

What kind of spring pressure would you need to control the valvetrain?

[jellis]

what is the disadvantage of having a DOD cam with it inactive in the tune??

i want to cam, but not interested in spending $3000 for it after install is complete.

[G8-4-Speed]

what is the disadvantage of having a DOD cam with it inactive in the tune??

i want to cam, but not interested in spending $3000 for it after install is complete.
Depends on who you ask on durability......on or off I don't think will make any difference. I run 918 behives with a .040" shim. I will have to look at what I wrote down for thr final pressure open and closed.

[dv327]

Did you happen to find the information on the spring pressure?