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Old 10-17-2007, 11:52 PM   #1
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Default advice on rocker arm replacement

I'm considering replacing the rocker arms in my 2003 SE. My main motivation is increased fuel economy and reduced stress and wear on the engine, rather than performance gains, although I would like some gain in HP. The stuff I've seen on this site applies mostly to people changing the rockers to gain HP, and most has been done to */c'ed engines. My understanding is that the stock rockers have a 1.6:1 ratio and already have roller bearings at the pivot, but not the tip where the rocker contacts the valve, is all this true?. I'm thinking of replacing them with some lighter weight aluminum full roller rockers, from Intense or ZZPerformance. Can I replace the rocker arms without replacing the valve springs or pushrods? I know that it'* recommended to replace the springs if you go to a high ratio rocker, like 1.9:1, but if I go with something lower like 1.7 or 1.8, can I keep the stock springs? How complicated is the installation? I know I've got to drain the coolant and take off the alternator and drive belt tensioner. Has anybody done the install themselves on a 2000 or newer SE?

My only mod so far is an FWI, and beyond that, I don't plan anything other than perhaps this rocker arm replacement, (no exhaust mods, PCM mods, etc). Will replacing the rockers be worth the trouble? Even if I gain 1-2mpg I'll be happy. Car currently has 65,000 miles on it and I plan on keeping it for a good long time, so anything I can do to make it last will be welcomed. Please share your thoughts and advice.
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Old 10-18-2007, 12:03 AM   #2
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hey welcome fellow NE'er

and i think that a lower ratio (1.8 ) has proven to be better for the NA'*..you can keep the stock springs, but for the $90 it costs to replace the springs, it is worth dropping a valve and destroying the engine.....


If you would need help, there ia certain place, the Bonnevilla, that could help you install the rockers as well
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Old 10-18-2007, 02:18 AM   #3
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You're right the stock arms have roller bearings at the pivot but not at the tip. I don't know of any mileage gains people have seen with rockers (but I'm not one to pay much attention to that little detail referred to as MPG.) Stronger springs are highly recommended on a 3800 anytime you increase lift and/or duration; ití* cheap insurance really.


Ed
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Old 10-18-2007, 07:42 AM   #4
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Hiya Groton, Enfield checking in here. I've done rockers on a couple cars quite similar to your setup and overall with the right tools it'* easy.

Tools to have on hand
Air compressor
Adapter for plug fitting (only if changing springs)
3/8" socket
10mm socket
13mm socket
15mm socket
Torque wrenches
Small magnet

I'm not 100% sure on the springs except that it'* recommended. If Intense and ZZP both say you don't need them, then I'd go without. If one says change them..I'd change.

I'm SC'd and like Ed.. MPG is a mythical three letter acronym for someone else.

If you'd like a hand..I've got all the tools and a nice little garage up here at the Villa. Just holler.
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Old 10-18-2007, 08:53 AM   #5
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I would agree that if the retailer or manufacturer on your intended rocker purchase says stock springs are fine, that you could leave them. However, if you ever intend to raise your shift points with a PCM, you may want to consider upgrading them. Valve float is a nasty bugger.

You have to think ahead. Think beyond the rockers. To get the most of them, the PCM is a good companion. What do you want your PCM to do? Think about the whole package, as it might be something else that dictates a spring change rather than the rocker arms. And you'll be right in there with them when you do the install.
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Old 10-18-2007, 10:26 AM   #6
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Default Re: advice on rocker arm replacement

The best n/a ratio is the ZZP ER ratio.
You can read more about the R&D In the Tech Info section of this site

Quote:
Originally Posted by matta46
My understanding is that the stock rockers have a 1.6:1 ratio and already have roller bearings at the pivot, but not the tip where the rocker contacts the valve, is all this true?.
Yep thats true.

Quote:
Originally Posted by matta46
I'm thinking of replacing them with some lighter weight aluminum full roller rockers, from Intense or ZZPerformance. Can I replace the rocker arms without replacing the valve springs or pushrods? I know that it'* recommended to replace the springs if you go to a high ratio rocker, like 1.9:1, but if I go with something lower like 1.7 or 1.8, can I keep the stock springs?
If you go with the ER ratio, you souldn't have any valve float problems with stock shift points.
Pushrods very rarely need to be upgraded.

Quote:
Originally Posted by matta46
How complicated is the installation? I know I've got to drain the coolant and take off the alternator and drive belt tensioner.
If it'* just the rockers, it'* pretty easy. It might seem intimidating but if you take your time it'* not that bad. You won't have to drain the coolant or take the tenioner assembly off. You just have to remove everything preventing you from taking the valve covers off.
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Old 10-18-2007, 12:38 PM   #7
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Mike...I'm pretty sure on his year the tensioner overhangs the valve cover.
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Old 10-18-2007, 12:40 PM   #8
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Default Re: advice on rocker arm replacement

Quote:
Originally Posted by matta46
I'm considering replacing the rocker arms in my 2003 SE. My main motivation is increased fuel economy and reduced stress and wear on the engine, rather than performance gains, although I would like some gain in HP.
This is the very reason I am changing my rockers. Although almost everyone changes rockers for added HP, they will increase volumetric efficiency. This will translate to fuel economy, but it'* unclear to what extent.

I recommend ZZP ER Rockers also. They have been optimized specifically for the NA 3800. That'* what I'm going with.

I will also be changing springs so I won't be limited if I want to change shift points at a later date. Carefully select the appropriate springs so you don't unduly ADD to the stress on the timing chain etc.
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Old 10-18-2007, 01:15 PM   #9
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With an '03, you will have to take off the alternator and the bracket it is attached to to get the rear valve cover off...it is designed differently than our '99 and earlier'*. Whether that includes having to take off the entire tensioner I am not 100% sure; however, I wouldn't count on a significant mpg improvement from rockers in any case. Especially once your foot gets heavier :P

You say longevity is a big concern, so--in addition to good maintenance practices, which will also help mpg of course--you should first tackle the known issues in these cars:

Engine:
1) Plastic UIM failure; solvable (we believe) with a sleeved EGR hole (or UIM replacement with the APN kit, or perhaps plugging the coolant holes to the TB)
2) Plastic LIM gasket failure; solvable with newer aluminum-framed gaskets

Tranny:
Luckily, GM already solved alot of the known issues with the 4T65-E tranny for you (they hardened the 4th clutch shaft and upgraded the shift solenoid starting '03); however, you can still prolong the life of your clutches with a shift kit. Also, you should definitely be including tranny fluid changes in your maintenance schedule, perhaps including some LubeGard or other additive to prolong life of the known crappy seals GM continued to put in these trannys.

As to MPG, the only "mod" I can truly recommend is PCM modification--specifically, a tuner.

(Besides, I can see that the mod bug has already attached itself to you...it'* only a matter of time before it bites you hard...and a tuner / scanner will go a long way toward improving piston longevity once that happens )
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Old 10-18-2007, 11:59 PM   #10
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well im been running ER rockers on stock valve spring and so far no problem but if you whant full avantage of the top end power a spring upgrade should be a concern in the future as for MPG i did not see any difference
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