Will this be enough valve spring pressure to turn 7000 rpm?

[BEATAV8]

The CR is a little low for optimization but I'd use hyd lobes 3014 and 3034, 110LS on a billet cam. 200 on the seat is fine with 885 lifters.

Old thread.... but have a question!

Would a PAC-1201X spring work with lobes 3014 and 3034? (1.55 rockers, champion alum heads, and 885 lifters)
Or are those lobes pretty much dual spring territory?

Looks like I would be .043 from coil bind with my current installed height of 1.725

 

[bison]

Old thread.... but have a question!

Would a PAC-1201X spring work with lobes 3014 and 3034? (1.55 rockers, champion alum heads, and 885 lifters)
Or are those lobes pretty much dual spring territory?

Looks like I would be .043 from coil bind with my current installed height of 1.725

Should be ok if you keep the rpm under 6000. There are some dual springs that can work with the small diameter. Personally I wouldn't bother with the ultra aggressive stuff unless running the longer valves and trying to run some number. The less aggressive stuff will work just as well if the overlap exhaust closing, and exhaust pressure is monitored. You can go to a wider dual spring and get a lot more seat pressure. I've ran those same lobes with 180 on the seat. I never went over 6200. Was probably borderline.


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[jckcolarusso]

1201x springs should be installed at 1.750

 

[bison]

1201x springs should be installed at 1.750

Why


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[jckcolarusso]

Inside Spring I.D. (in), 0.770. Install Load (LB), 150. Install Height (in), 1.750. Open Load (LB), 460. Open Height (in), 1.200. Coil Bind Max (in) ...

 

[bison]

Inside Spring I.D. (in), 0.770. Install Load (LB), 150. Install Height (in), 1.750. Open Load (LB), 460. Open Height (in), 1.200. Coil Bind Max (in) ...

Why should they be installed at 1.75"


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[jckcolarusso]

Im not saying u cant put them in at 1.725 pac says put them in at 1.750

 

[BEATAV8]

Personally I wouldn't bother with the ultra aggressive stuff unless running the longer valves and trying to run some number. The less aggressive stuff will work just as well if the overlap exhaust closing, and exhaust pressure is monitored.

Thank you Sir. I think I will follow that advice and go with something less aggressive. I'm gravitating towards the 3313 lobe now.

 

[bison]

Im not saying u cant put them in at 1.725 pac says put them in at 1.750

That would render them about useless for what people are trying to accomplish. I've installed them at 1.700" and .050-.060" from bind many times and never had a problem. The distance from bind does matter. The springs work better and last longer when they are the correct distance from bind. PAC has no idea what the valve lift is going to be on a given engine


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[bison]

Thank you Sir. I think I will follow that advice and go with something less aggressive. I'm gravitating towards the 3313 lobe now.

Just consider the exhaust pressure and overlap (especially @ .050") when ordering. The cams that make the most power with high exhaust to manifold pressure ratios won't make as much at low boost with lower ratio. When you see little Tommy of whoever bragging about how his engine makes 500whp at only 20psi he fails to mention that it's probably a turd at 30psi


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[BEATAV8]

Just consider the exhaust pressure and overlap (especially @ .050") when ordering. The cams that make the most power with high exhaust to manifold pressure ratios won't make as much at low boost with lower ratio. When you see little Tommy of whoever bragging about how his engine makes 500whp at only 20psi he fails to mention that it's probably a turd at 30psi


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This is where my adventures have led me thus far.... haven't ordered anything yet.

motor will have ~9.5:1 compression, 4.3L (260cid), turbo is a 6766 with a 3 bolt .85, E85. 17 blade PTC.

lobes 3313/3313 could potentially look like this:

 

[bison]

I'd spread them as much as possible if staying on a small turbo assuming you're going all in. 115 if it can be done. I'd also advance it. Overlap will go to -12.not a 7000rpm combo but should be good to 5800 or so with turbo running out


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[BEATAV8]

Mo

I'd spread them as much as possible if staying on a small turbo assuming you're going all in. 115 if it can be done. I'd also advance it. Overlap will go to -12.not a 7000rpm combo but should be good to 5800 or so with turbo running out


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Something a bit more like this?

 

[bison]

Mo


Something a bit more like this?

View attachment 296365

Not quite but im not going to be giving out all my cam info and recs on here since I sell cams.


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[BEATAV8]

Not quite but im not going to be giving out all my cam info and recs on here since I sell cams.


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understood, thank you sir.

 

[TurboTnZ06]

I've run comp 941 springs on a 210/210 110 to 6400 rpm no problem, power really fell off the higher it went past 5200.