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Roller Rocker Question

scotch1

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Feb 17, 2005
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144
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1994 convert. 2002 C5 coupe
I want to get a little more out of my L98, by installing 1.6 Roller Rockers. Which is the best brand for my stock L98? I see that some come with pushrods and alignment plates others come with the rockers alone. And the prices are all over the place. Help clear up the confusion.
Tom
 

Toms007

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I must admit that I am not totally familiar with the L98, but here goes my take.

I believe that you want "self aligning" type. These do not require the guide plates. I installed Self Aligning 1.6 Crane Gold on my LT1, along with LT4 valve springs and push rods (I couldn't tell any difference between the push rods).

It was pretty much a slam dunk not to buy the "cheapie" roller rockers off of Ebay and to stick with the quality made Crane, CompCams, GMPP, there is another brand that was recommended but I can't remember the brand. It is also pretty much a must to go with new valve springs as the 1.6 ratio will cause "spring bind" with stock springs.

Changing them out wasn't too bad, I changed several other parts at the same time, spark plugs, valve seals and serpentine belt.

I would recommend the Crane Golds, or the GMPP (Made by Crane only with the Chevy Bow tie engraved instead of Cranes trade mark and not anodized like the Cranes and cheaper).
 

Edmond

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Any part in the head is not some place to go cheap. Failure of a part in the head can be quite catastrophic.

I agree with Tom about spring bind on those stock springs. You also have to factor in their age/mileage, which is another reason to change them.

I think the average price you'd end up paying for a quality brand of roller rockers would be in the $230 or so neighborhood.
 

scotch1

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Messages
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1994 convert. 2002 C5 coupe
Thanks guys, that helps a lot, especially about the self-aligning type, I didn’t understand the purpose of the guide plates. .
Next question, is it advisable/necessary to replace the push rods? And, are they all the same? Are they an off the shelf item? Or are there special types to match up with the new roller rockers? Can’t I just use the existing ones?
Edmond, your right about not the place to go cheap with parts in the head. I want to avoid any possibility of catastrophic failure.
Tom.
 

Toms007

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Thanks guys, that helps a lot, especially about the self-aligning type, I didn’t understand the purpose of the guide plates. .
Next question, is it advisable/necessary to replace the push rods? And, are they all the same? Are they an off the shelf item? Or are there special types to match up with the new roller rockers? Can’t I just use the existing ones?
Edmond, your right about not the place to go cheap with parts in the head. I want to avoid any possibility of catastrophic failure.
Tom.

The only reason I replaced mine was because when I got the valve springs, I got the push rods too. They appeared to be the exact same. Stock push rods should work just fine. Just make sure when you get the valve springs that you get shims, retainers and keepers.

I also bought a set of ARP rocker studs, but I didn't install them.
 
H

HD2HVETTE

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What other mods do you have on your 94 LT1 toms94? Did the rocker arms make a substantial difference in power? Just getting started on my 93, and this is one of the first things I wanted to try.
 

ZumZum

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On your stock L98 valve covers, you'll have to trim the drip tabs to prevent the higher lift rocker arms from making contact with them.
 

Toms007

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What other mods do you have on your 94 LT1 toms94? Did the rocker arms make a substantial difference in power? Just getting started on my 93, and this is one of the first things I wanted to try.

I really don't have any other mods...K&N Filter with cut lid, Corsa exhaust. Let's see, substantial difference? Well I never dynoed it before and I haven't dynoed it since, so any comment will be my "seat of the pants" dyno. Yes, I believe that it feels more powerful, a little quicker on the revving.

I did the K&N first to get more air in and then the Corsa to get the air out, and now the rockers to open it up to more fuel/air mixture.

I read an article in one of the Corvette magazines where they did just this mod and it seemed to be the best bang for the buck. If memory serves me right, 15hp gain is what they saw.
 

scotch1

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Jackson,New Jersey
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1994 convert. 2002 C5 coupe
Is there any special type of valve springs to purchase? What’s the going cost for them? I heard about beehive type of spring, are they any good for my purpose?
Or should just buy standard parts?
 
H

HD2HVETTE

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Already have the K&N, TB airfoil, 160 stat and exhaust. Wonder if changing the injectors would be in order with the 1.6 rockers? How about a power chip?
 

Toms007

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Is there any special type of valve springs to purchase? What’s the going cost for them? I heard about beehive type of spring, are they any good for my purpose?
Or should just buy standard parts?

I bought (or actually was given) Genuine GM LT4 springs. Contact Chris May at Superior Chevy (1-800-728-8267) tell him you are a forum member and you'll get a pretty good discount on them. Last time I checked the springs were only about $50-60.

HD2HVETTE said:
Already have the K&N, TB airfoil, 160 stat and exhaust. Wonder if changing the injectors would be in order with the 1.6 rockers? How about a power chip?

I can't say about the injectors, we'll have to wait for someone else to chime in on that one. I've played with the idea to have the computer reprogrammed, but haven't done it as of yet.
 

scotch1

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1994 convert. 2002 C5 coupe
Just recently replace all my injectors, and looked into upgrading. Was told stock replacements were more then adequate and were designed for economy and performance but could handle much higher pressure and greater fuel flow, then is necessary for a standard L98, unless of course I went with a new cam, and hit the strip.
 
Joined
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1987 Z52 Black Convertible
I put Harlan Sharps on my 87. Can't remember what I payed for them but I think they were under 200. I just used my stock springs. Like others have said, you will have to grind the drip tabs off the bottom of the valve covers unless you replace those too.
 

Edmond

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How much are a set of good quality pushrods? I think they're less than $100. You got so many years out of the stock ones, why not replace them while you are in there?

As for bigger injectors, I don't think that's necessary unless you've changed to a bigger cam and have headers as well.

Same for the chip. A chip right now would allow the fans to come on cooler but that's about it. The stock chip has the ability to deviate and unless you really open the motor up, it has enough deviation in it.
 

wallyknoch

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You fellows may not like to hear this but roller rockers is not going to do a damn thing to improve your prtformance. A typical well advertised and hyped bolt on. They are really a racing part. The more expensive the better they are suppost to be. Dont really count on it. They break and fail at the worst time. For the unbelievers that insist they "help" absolutely none of the truly high HP Chevy engines are so factory equipped. No L88`s, no ZL1`s, L71`s LS7`s and so on. Save your money, :D
 

ZumZum

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Mar 25, 2004
Messages
478
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1988 Dark Red Coupe
You fellows may not like to hear this but roller rockers is not going to do a damn thing to improve your prtformance. A typical well advertised and hyped bolt on. They are really a racing part. The more expensive the better they are suppost to be. Dont really count on it. They break and fail at the worst time. For the unbelievers that insist they "help" absolutely none of the truly high HP Chevy engines are so factory equipped. No L88`s, no ZL1`s, L71`s LS7`s and so on. Save your money, :D

Not sure where you got your info: The LT4 was equipped with roller rockers, the LS7 is equipped with roller rockers. I believe the main point of switch rocker arms is not that you're going to roller rockers, but changing the lift ratio from 1.5 to 1.6, thus opening the valves further and longer allowing more fuel flow.
 

Toms007

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Not sure where you got your info: The LT4 was equipped with roller rockers, the LS7 is equipped with roller rockers. I believe the main point of switch rocker arms is not that you're going to roller rockers, but changing the lift ratio from 1.5 to 1.6, thus opening the valves further and longer allowing more fuel flow.

I agree wholeheartedly with ZumZum, the LT4 came from the factory with roller rockers, basically the same ones I installed. And the new LS7 (C6 Z06) has them as well. Not sure about the LS6 (C5 Z06 motor).

The big thing is the increase in ratio from 1.5 to 1.6.
 

ZumZum

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1988 Dark Red Coupe
I agree wholeheartedly with ZumZum, the LT4 came from the factory with roller rockers, basically the same ones I installed. And the new LS7 (C6 Z06) has them as well. Not sure about the LS6 (C5 Z06 motor).

The big thing is the increase in ratio from 1.5 to 1.6.

The LS6 has a roller fulcrum, but a standard tip.
 
C

CorVette

Guest
Upgrading to the 1.6 roller rockers will be worth 10-15 HP. It will increase your lift from 0.415 to 0.443 int, 0.430 to 0.459. Around 0.030 increase. Your effective duration will increase 2-3 degrees. This is on a 90, stock 113 heads.

Personally, you can pick up hardened push rods for $30-50, and hardened guideplates for $15-30. I prefer the non aligning rockers and choice is the CompCams Pro Magnums SS, around $250-260. While you're at it, go to 7/16s studs, around $15-30. I know it's a little overkill, BUT when you go to the better heads, you won't have to rebuy anything and you can put the stock items back on the original heads.

The stock springs will be good to around 0.490 without coil bind with a safety margin, anything more will require LT4 or aftermarket springs.
Cut the drip tabs on the valve covers with an air grinder or Dremel. I don't recommend breaking them off with a pair of pliers, it would normally work, but, if they break deep, valve cover(s) is history.
You still have the choke point of the TPI, but that's later.

johnny
 
Joined
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Messages
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Yeah I was told about 5-10HP with the 1.6's. Hey it all adds up thats all that matters I guess. You could also go with LT1 pushrods if you want, those are pretty good rods.
 

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