To degree or not to degree?

[wht67]

I am in the final stages of parts gathering for a forged engine build. I have the following:

JDM 302 stroker short block
Ported big valve heads
Comp 127550 cams
Livernois lockouts
TFS adjustable crank gears

I intend to lock the phasers and use the TFS gears and retard the cams 6 or 8 degrees. Do I need to degree the cams? I realize that to extract the most power I probably should but what would happen if I did not degree the cams?

Thanks,

Wayne

 

[dysan]

You should really discuss that with Lito...I'm glad that I did end up degreeing my 127300's on my current build per his recommendation...it definitely pulls higher in the rpms now compared to my last engine which I had them locked full advance.

 

[BruceH]

You should really discuss that with Lito...I'm glad that I did end up degreeing my 127300's on my current build per his recommendation...it definitely pulls higher in the rpms now compared to my last engine which I had them locked full advance.

How much adjustment was needed for the cams? I tried to degree mine but kept getting results that varied by a degree. In the end I locked them out without adjustment. They were ground with a 108 centerline which would be like 127500 retarded 6 degrees. I like to say the retard is ground into the cams but in reality the icl is what it is, 108. That's a good place for mod motor cams with similar durations.

 

[dysan]

I don't remember the exact numbers that my engine builder measured but it was way to advanced how it was ground to be locked full advance how it was. We retarded it 6* using the TFS gears but I suspect 8 would have been better. It didn't even seem to hurt my bottom end at all but I'm sure a lot of that has to do with the TVS blower.

 

[Weou09]

Any point in degreeing the stock cams? I know my tuner is really pushing locking them out. Maybe you can help me a little here Bruce. I know you have used the trick flow crank gears, what do you do on the cam side to disable VCT there?

 

[RED09GT]

Any point in degreeing the stock cams?

Yes, production cams are very prone to production variances. With the VCT disabled, I would want to make damn sure that the events were happening exactly where they should be.
If the motor turns out to be a dog because the cam timing is off, you're going to have to pull the turbo and a bunch of other crap to get the timing cover off to make adjustments-not much fun.
Is it just from a reliability standpoint that he wants to lock them out?





awesome autocorrect malfunctions brought to you by tapatalk

 

[Weou09]

Yes, production cams are very prone to production variances. With the VCT disabled, I would want to make damn sure that the events were happening exactly where they should be.
If the motor turns out to be a dog because the cam timing is off, you're going to have to pull the turbo and a bunch of other crap to get the timing cover off to make adjustments-not much fun.
Is it just from a reliability standpoint that he wants to lock them out?





awesome autocorrect malfunctions brought to you by tapatalk

I think him pushing to lock them out is because he knows I do not really drive the car. It is more a drag car that I happen to drive on the street some times not a street car that happens to see the strip. I think it has more to do with the power band.

 

[dysan]

If the car is for bracket racing then I would want the cams locked out and degreed for consistency reasons. If it is a heads up car then you may want to do limiters so you can get every bit of power out of it possible.

And FYI, I have found that for consistency I set my timing to be fixed once I'm in boost so it doesn't change on me during a run. Under part throttle it still functions normally but at the track it is deadly consistent. (I bracket race my car but for heads up I would want ramped timing)

 

[Weou09]

I bracket race more than anything but I do go heads up from time to time. I usually just change the 2 step to run one or the other.

 

[BruceH]

Any point in degreeing the stock cams? I know my tuner is really pushing locking them out. Maybe you can help me a little here Bruce. I know you have used the trick flow crank gears, what do you do on the cam side to disable VCT there?

I'm not sure if I understand the question. Install lockouts in the phasers to lock out the cams mechanically. I just ran the stock cam specs through a cam calculator and the intake center line in 109. IIRC the stock tune retards 9 degrees at the higher loads during wot.

Is there any reason you are staying with the stock cams?

 

[Weou09]

Because I feel like the gains with a turbo aren't worth the effort or cost of cams. I have no problem throwing a pound more at it.

 

[jodadejss06gt]

I'm going through this whole thing right now....I'm trying to figure out what will work best for my setup. I think cams will help my top end, but I street drive this thing way more at 2k than spinning it past 6k. I'm going to be following this one closely.

When do you think your car will be done. My engine was in the process of coming out of the car yesterday.

RJ locked out his stock cams in his build and him/lito would have to clarify if he degreed them at all.

 

[GT500KR]

i would like to know more about this too

jodadejss06gt what did you do?

 

[jodadejss06gt]

Cams are going in with Livernois limiters.

 

[GT500KR]

Why not lockouts if I may ask

 

[jodadejss06gt]

Street car mainly. It will run high power less than it runs 550,
Plus I was worried about drive ability.