Stock or CompCam? What kind of performance difference?
Posted: July 4th, 2009, 9:56 am
So I've been fighting my way through this build, I'm simply not as prepared as I had thought and to further add to it, I'm in a serious time crunch to get this back together, it is my daily driver after all and I head out of town with it in less than 2 weeks. I still have some suspension items to fix, a new driveshaft to be made, etc so I can't focus all of the 2 weeks on the motor.
Anyhow..
I've come to find out that the CC 68-231-4 is old style, after searching for what I need to do to make it work with my 99 block, I've come across all of these posts about cam / lifter failure. I also don't have the right parts (258 timing set, pin, spring, bolt, etc) to get it back together as it sits, unless I reuse the old cam.
What kind of performance decrease are we talking if I just reuse the old stock 4.0 cam? I've ran the numbers in the CRC and with the 68-231-4 I get a SCR of 9.82 and a DCR of 8.63. If I use the OE cam I get a DCR of 8.16. I'd like to run midgrade, so a lower DCR is going to help me here, but at what cost? If it matters, my quench is .0665.
Being my first build I'm double guessing myself left and right. I'm more concerned about reliability than performance. I don't want to be pulling the motor in 2 years after 30k to replace lifters or a cam shaft to gain 10ft lb now, I would also like to get better economy as well. The one post I read regarding this said he didn't notice any difference in SOTP dyno going back to a OE cam plus his mileage went up. Another for what it's worth, it will be broken in with Brad Penn Break In and I plan to continue running Brad Penn 10/30.
[edit] Also, I already have the MP springs with the 8 degree retainers and locks installed on the (bolted to the block) head. Can I use the MP springs with the OE cam or is it going to be to much pressure? I'll need to get a new set of OE springs if I end up running the OE cam [/edit]
Halp. Again.
Anyhow..
I've come to find out that the CC 68-231-4 is old style, after searching for what I need to do to make it work with my 99 block, I've come across all of these posts about cam / lifter failure. I also don't have the right parts (258 timing set, pin, spring, bolt, etc) to get it back together as it sits, unless I reuse the old cam.
What kind of performance decrease are we talking if I just reuse the old stock 4.0 cam? I've ran the numbers in the CRC and with the 68-231-4 I get a SCR of 9.82 and a DCR of 8.63. If I use the OE cam I get a DCR of 8.16. I'd like to run midgrade, so a lower DCR is going to help me here, but at what cost? If it matters, my quench is .0665.
Being my first build I'm double guessing myself left and right. I'm more concerned about reliability than performance. I don't want to be pulling the motor in 2 years after 30k to replace lifters or a cam shaft to gain 10ft lb now, I would also like to get better economy as well. The one post I read regarding this said he didn't notice any difference in SOTP dyno going back to a OE cam plus his mileage went up. Another for what it's worth, it will be broken in with Brad Penn Break In and I plan to continue running Brad Penn 10/30.
[edit] Also, I already have the MP springs with the 8 degree retainers and locks installed on the (bolted to the block) head. Can I use the MP springs with the OE cam or is it going to be to much pressure? I'll need to get a new set of OE springs if I end up running the OE cam [/edit]
Halp. Again.