Roller Rockers
Thread Starter
Intermediate
Joined: Apr 2002
Posts: 25
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From: White Lake MI
Roller Rockers
I soon need to replace the valve cover gaskets on my '86 CI head L98. I have read some posts on that there are advantages to installing roller rockers. Since I have the valve covers off anyway, are there any hidden pitfalls to installing 1.6 rollers in place of the stock? Are the stock valve covers going to fit? On the surface it seems like a relativly inexpensive and fairly easy way to gain "up to 20 hp" if it does not involve any other mods. Just bolt them on, lash them, and forget them, right? Thanks for reading.
[Modified by swantzilla, 2:21 AM 4/21/2002]
[Modified by swantzilla, 2:21 AM 4/21/2002]
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Roller Rockers (swantzilla)
If center bolt Al heads you will need to reduce the drip tabs and maybe narrow the bolt towers. I'm not sure about perimeter bolt covers.
If mileage is up there you should replace the valve springs; a little higher seat pressure wouldn't be a bad idea as you will gain about .030" lift and about 2deg of duration.
From 1.6:1 full RRs on a stock cam expect more like 10-12hp gain.
If mileage is up there you should replace the valve springs; a little higher seat pressure wouldn't be a bad idea as you will gain about .030" lift and about 2deg of duration.
From 1.6:1 full RRs on a stock cam expect more like 10-12hp gain.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Roller Rockers (swantzilla)
In that case you could only do 3/8" since the studs are pressed in. Some case iron heads (not sure about Vette) had push rod holes that served as guides; these were too tight for the pushrod movement necessary when going to 1.6:1 rockers. If this is the case you could still go to 1.52:1 full rollers for maybe 10hp gain. But I'm not sure about valve cover issues.
Burning Brakes
Joined: Sep 2001
Posts: 1,159
Likes: 73
From: Sumter, SC
Re: Roller Rockers (65Z01)
I'm glad I read this post, brings up a question. I've got the 86 with the AL heads. It doesn't have the roller rockers that were used on the 87 and up. It has the stock hydral. cam with about 130K miles on it. When I rebuild replace etc.... I will probably just use my stock heads because it will be kind of a pain to find another intake from an 87 up. I read that the 87 up intake had different angles on the intake mounting holes so, I've got to use my intake/head combo or swap completely.
Now to my quesiton:
Since those aluminum heads weren't made for roller rockers can I still install the roller rocker kit with a 1:5 ratio? without doing any machine work to the heads. They have the area for the roller guides cast in them, but are not machined for it. Also, Do I have to change and use a roller cam? If I do, I'll wait for the rebuild, If I don't I'll go ahead and change the rockers and wait for the rest of the motor to follow. Thanks, Oh, and will a changeing to roller rockers with the stock ratio give any performance gains? Or are the gains to be expected by being able to use a better roller cam?
Now to my quesiton:
Since those aluminum heads weren't made for roller rockers can I still install the roller rocker kit with a 1:5 ratio? without doing any machine work to the heads. They have the area for the roller guides cast in them, but are not machined for it. Also, Do I have to change and use a roller cam? If I do, I'll wait for the rebuild, If I don't I'll go ahead and change the rockers and wait for the rest of the motor to follow. Thanks, Oh, and will a changeing to roller rockers with the stock ratio give any performance gains? Or are the gains to be expected by being able to use a better roller cam?
Melting Slicks
Joined: Aug 2001
Posts: 2,516
Likes: 0
From: Lockport NY
Re: Roller Rockers (Curtis629)
Also, Do I have to change and use a roller cam?
Having said that, I'd be interested in running roller 1.6 rockers on my '86, too. With stock cam. I haven't pulled the rocker covers yet (alum heads - 86L), so I don't know what I'd need in the way of studs, guides, etc...
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: Roller Rockers (Curtis629)
It doesn't have the roller rockers that were used on the 87 and up. It has the stock hydral. cam with about 130K miles on it.
The 87 and up does have a roller cam. As for retrofitting the roller cam to an earlier block, there are several choices. I have used sealed power retrofit hydraulic roller lifters before, they work very well. Timing chains are a different story. You will have to use the old style chain and a cam designed to work with it, you can have one custom ground for $260 shipped from Schneider Cams ( I just had one done last year ).
