Comp Cams RPG103 magnum kit on 1996 LT1
01-20-2017, 03:45 PM
#1
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Comp Cams RPG103 magnum kit on 1996 LT1
I had a specific question for anyone who has experience with this particular install. I want to install the Comp Cams RPG 103 non self aligning roller rocker kit on my 1996 LT1. The kit comes with the non self aligning 1.6 magnum rockers, hardened pushrods and guide plates. I was also going to upgrade to some LT4 valve springs while I was at it as well as a basic tune up and other small things. My car is a bone stock camaro with 140k miles. I was wondering if anyone had any insight into this particular install. I don't have a machine shop in my small crappy town so I REALLY don't want to have to take of the heads and have them sent to the nearest major city. I am fine with just getting some self aligning rockers instead if that is going to save me from dealing with all that. Any help is greatly appreciated.
01-20-2017, 10:08 PM
#2
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Re: Comp Cams RPG103 magnum kit on 1996 LT1
Just curious... why do you want to do this?
Small HP gain from (only) roller tip rockers. Why not full rollers? That's where the gain is.
Why add the complication of non-self aligning? They make a self-aligning Magnum set. Or get a full roller, self-aligning set like the Crane Gold or Comp Cams UltraPro Magnum.
Some will argue that the LT4 springs are not an upgrade, because the LT4 hollow stem valves are lighter than the solid LT1 valves, and the LT4 spring may be too weak for the heavier valve. Not sure about that last part, but that's the argument you get from some people. Probably OK with a stock cam. Why do you feel the springs need to be replaced?
Small HP gain from (only) roller tip rockers. Why not full rollers? That's where the gain is.
Why add the complication of non-self aligning? They make a self-aligning Magnum set. Or get a full roller, self-aligning set like the Crane Gold or Comp Cams UltraPro Magnum.
Some will argue that the LT4 springs are not an upgrade, because the LT4 hollow stem valves are lighter than the solid LT1 valves, and the LT4 spring may be too weak for the heavier valve. Not sure about that last part, but that's the argument you get from some people. Probably OK with a stock cam. Why do you feel the springs need to be replaced?
01-21-2017, 01:10 AM
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Re: Comp Cams RPG103 magnum kit on 1996 LT1
Its an old engine that I want to breathe some new life into. I was looking around online for the best bang for my buck since I don't really have the money to spend $500 on a set of Crane Gold's. I saw this kit and thought it was a pretty good buy, but after reading into it a bit more I saw the non self aligning/self aligning problem. As for the springs, the car has 140k miles on it and is technically old enough to go into a bar and order a drink, so the valve springs are wore out anyway. Since I wanted to go to a 1.6 ratio rocker instead of a 1.5, a lot of the information I've found says the springs should be replaced with something stiffer. I haven't heard anything about the hollow valve stems of the LT4. Actually a lot of the information I've found says that the LT4 springs are a good upgrade for these engines if you want to go to a 1.6 ratio rocker. However, it has been difficult to tell the good information from the bad.
All in all, I'm looking to change the rockers and valve springs and I'm looking for a good deal. My budget is around $200-$300. I have found plenty of people talking about putting these things on their cars but nobody who says exactly what you will and will not need. I don't want to deal with removing the heads for machine work, and I don't want to have to buy new valve covers. Lastly, I don't want to **** up my engine either. I have boat loads of experience taking engines apart and putting them back together, but practically no experience upgrading or modifying them. I'm a repair mechanic.
All in all, I'm looking to change the rockers and valve springs and I'm looking for a good deal. My budget is around $200-$300. I have found plenty of people talking about putting these things on their cars but nobody who says exactly what you will and will not need. I don't want to deal with removing the heads for machine work, and I don't want to have to buy new valve covers. Lastly, I don't want to **** up my engine either. I have boat loads of experience taking engines apart and putting them back together, but practically no experience upgrading or modifying them. I'm a repair mechanic.
01-21-2017, 09:37 AM
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Re: Comp Cams RPG103 magnum kit on 1996 LT1
Nick
You won't need to re-program the PCM because you install 1:6 RR and springs on an otherwise stock engine.
As Fred notes the LT4 motor had hollow sodium filled valves so the LT4 valve spring on a LT1 with solid, heavier, valves the LT4 springs some feel those springs are not a upgrade. I do think they would be better than the 140k mi ones you do have now with a stock cam.
On a budget, look into the Alex spring kit for aluminum heads. Howards springs are another budget spring that people have used. Crane 10308-1 spring kit is a good replacement spring but more $. I agree your stock springs are fading. If you hit about 5200 ish RPM's and the car feels like it just flat lines aka "nose over"....that is a sign the springs are fading
Replace the valve stem seals when you do springs. FelPro makes good ones, Viton seals.
You don't need to use air in the cyl to hold the valve up IF you bring that piston up by rotating the motor the valve only drops about 1/4"
You may be able to find a set of full RR used and stay SA. No need for new PR or guide plates if you stay SA on the RR
You won't need to re-program the PCM because you install 1:6 RR and springs on an otherwise stock engine.
As Fred notes the LT4 motor had hollow sodium filled valves so the LT4 valve spring on a LT1 with solid, heavier, valves the LT4 springs some feel those springs are not a upgrade. I do think they would be better than the 140k mi ones you do have now with a stock cam.
On a budget, look into the Alex spring kit for aluminum heads. Howards springs are another budget spring that people have used. Crane 10308-1 spring kit is a good replacement spring but more $. I agree your stock springs are fading. If you hit about 5200 ish RPM's and the car feels like it just flat lines aka "nose over"....that is a sign the springs are fading
Replace the valve stem seals when you do springs. FelPro makes good ones, Viton seals.
You don't need to use air in the cyl to hold the valve up IF you bring that piston up by rotating the motor the valve only drops about 1/4"
You may be able to find a set of full RR used and stay SA. No need for new PR or guide plates if you stay SA on the RR
01-21-2017, 03:51 PM
#6
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Re: Comp Cams RPG103 magnum kit on 1996 LT1
https://www.summitracing.com/parts/cca-1618-16
OK for stock cam:
https://www.summitracing.com/parts/p...MobileSwitchNo
You will not need new rocker covers for any of these.... nothing more than minor trimming of internal bracing, if any at all.
OK for stock cam:
https://www.summitracing.com/parts/p...MobileSwitchNo
You will not need new rocker covers for any of these.... nothing more than minor trimming of internal bracing, if any at all.
Last edited by Injuneer; 01-21-2017 at 03:54 PM.
