LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Can LT4 springs and 1.7 Scorpion RRs get along with a stock cam?

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Old 11-24-2004, 04:30 AM
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Can LT4 springs and 1.7 Scorpion RRs get along with a stock cam?

I almost went the Beehive Spring route but it just down on me that my car set up is for the street only.

It will normally see upto 3000 RPMs 99% of the time with the occasional 5500 rpms WOT run. Nothing to brag about I know but for the street I like the torque down below so I dont think it will ever see a cam bigger than the LT4 Hot cam.


so what do you guys think?

Marvin
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Old 11-24-2004, 08:06 AM
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Re: Can LT4 springs and 1.7 Scorpion RRs get along with a stock cam?

If you use the 1.7rr with the Hot Cam you will exceed the lift capabilities of the springs. You don't need 1.7rr for your intended use plus with the 1.7rr you will run into geometry problems.
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Old 11-24-2004, 10:10 AM
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Re: Can LT4 springs and 1.7 Scorpion RRs get along with a stock cam?

Even with the stock cam @ .459" exhaust lift the 1.7s will result
in .520" lift which is the limit for LT4 springs. No way you could
run a hotcam with 1.7s and LT4 springs since the springs coil bind
at .560" (assuming a 1.78" installed height). Lift with the hotcam
and 1.7s is .558". Better reconsider the beehives.

The beehives (26915s) are a good consideration for near stock
motors because of the lower spring pressure. It's less stress and
strain on the valvetrain, unlike some of the dual spring offerings.
Why run lots of spring pressure if your upper limit is 5,500.
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Old 11-24-2004, 01:46 PM
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Re: Can LT4 springs and 1.7 Scorpion RRs get along with a stock cam?

so in other words if I use the stock cam I will be pushing the LT4 springs to the limit and no way I can use a hot cam...


Thank you guys... when I come back from work I will figure out if the beehives will work with the HotCam. No changing the cam yet but its good to know in advance.

I gotta scooot.. See you guys later.


Marvin
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Old 11-25-2004, 05:31 AM
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Re: Can LT4 springs and 1.7 Scorpion RRs get along with a stock cam?

one more question... will the stock spring seats work? I know truedualws6 didnt use the Stockers but how about everyone else?

I found this GM part 10185066 and I believe its the L98 spring seat mentioned on another post. I wonder if I could used this instead?

Gmpartsdirect.com describes it as Shim-VLV. I hope I got the correct part #

thanks

Last edited by MentalCaseOne; 11-25-2004 at 05:34 AM.
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Old 04-18-2009, 08:37 AM
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I want to fix this old post that has incorrect information.

The stock cam for all years hovered around the max of .450 (this is the taller of the two, intake or exhaust, I forget which one). Now take that number and divide by the stock rocker multiplier, 1.5, and you get .3. Now multiply that by the new multiplier, 1.7, and you'll get .510, not .520 which was incorrectly stated here. .510 should be safe with the LT4 springs which makes sense because the Hot cam kit comes with both a taller cam profile AND 1.6 rockers which obviously produces more than just 1.6 alone. So these springs must also be safe for just 1.7 on a stock cam. It is also wise to go with these springs because they are meant to be used with stock lifters unlike heavy duty springs that will wear the lifters out faster.

Hal
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Old 04-18-2009, 09:03 AM
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Thing is there is more to spring selection than lift capacity. With 1.7s I suspect the rate of lift is pretty aggressive and therefore could still overpower the rather weak LT4 spring.
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Old 04-18-2009, 09:30 AM
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Well I searched and the seat pressure for the lt4 isn't the greatest (100). Add to that the heavier lt1 valve but realize it's a stock cam which means it's probably not that aggressive. I'm still betting it will work well as long as you don't go too high rpms.

Hal
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Old 04-18-2009, 12:30 PM
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Found some stiffer springs good for more lift. I don't know about their quality but they're cheap (PBM Proformance):

3200 SINGLE W/DAMPER 1.260
specs>> 135# @1.750" 310# @1.200" 1.160 0.600 $42.24

or

3050 DUAL W/DAMPER 1.510
specs>> 120# @1.880" 320# @1.280" 1.200 0.600 $97.44

http://www.pbm-erson.com/store.php?catId=169

Last edited by Hal Fisher; 04-18-2009 at 12:53 PM.
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Old 04-18-2009, 02:14 PM
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A lobe that is not aggressive with 1.5s can be aggressive with 1.7s.
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Old 04-18-2009, 02:59 PM
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Originally Posted by Hal Fisher
Well I searched and the seat pressure for the lt4 isn't the greatest (100). Add to that the heavier lt1 valve but realize it's a stock cam which means it's probably not that aggressive. I'm still betting it will work well as long as you don't go too high rpms.

Hal
I don't know why people like to gamble with the valvetrain. Risky and very expensive when the wrong thing happens.
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Old 04-18-2009, 05:50 PM
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Shoebox, how did you get that bogus join date?
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Old 04-18-2009, 08:26 PM
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Originally Posted by Hal Fisher
Shoebox, how did you get that bogus join date?
Same way I did. If we told you, we'd have to kill you

Rich
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Old 04-18-2009, 10:00 PM
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Originally Posted by rskrause
Same way I did. If we told you, we'd have to kill you

Rich
I like that answer.
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