Any1 have some Compcam info for GTA?
Thread Starter
Joined: May 2001
Posts: 5,244
Likes: 14
From: Sac, CA
Car: '89 GTA
Axle/Gears: 3.27/9-bolt
Any1 have some Compcam info for GTA?
Sup y'all, looking into a cam from compcam for my stock GTA The website was kinda confusing, can y'all help me out?
What is the best type to buy for my application and what will it put out?
(how much hp, torque, etc.)
Should I upgrade something else with it as well when putting it on? How much am I looking at here? Thanks!
------------------
88 Firebird, 2.8, auto
*K&N air filter
*Flowmaster complete cat-back exhaust system
88 GTA Trans AM, 5.7, auto
*K&N air filter
*New MAF
(Future Mods.)
-JET chip stage II
-180 thermo.
-exhaust
-cold air induction
-intake runners
-cam?
What is the best type to buy for my application and what will it put out?
(how much hp, torque, etc.)
Should I upgrade something else with it as well when putting it on? How much am I looking at here? Thanks!
------------------
88 Firebird, 2.8, auto
*K&N air filter
*Flowmaster complete cat-back exhaust system
88 GTA Trans AM, 5.7, auto
*K&N air filter
*New MAF
(Future Mods.)
-JET chip stage II
-180 thermo.
-exhaust
-cold air induction
-intake runners
-cam?
Moderator
Joined: Jan 2000
Posts: 19,679
Likes: 316
HB98,
When installing any performance cam grind, you need to look at the balance of the valve train to make sure the components are compatible.
Typically, the stock valve springs are safe up to 0.480" lifts, but are marginal even at that point. The low seat pressures and spring rates don't match well to a high ramp lobe design, and valve float can occur at some pretty low RPMs. The heat generated from higher lifts and the point of coil bind should have you looking very hard at the stock springs.
The rocker arms are also questionable at higher lifts, since the slots can be a little too short to allow full movement from higher valve lifts. The rockers themselves tend to be a little weak for accurate control of the valves, since they can flex with the higher valve train pressures.
The push rods are also involved in this, since the guide holes in the head castings often need to be elongated to allow the rockers to be positioned correctly for the new lobe patterns and extra travel.
The rocker arm studs themselves need to be extracted, and the holes tapped for screw-in rocker studs. The rapid lift rates of performance cam grinds and extra spring pressure necessary for good valve control can quickly pull the pressed-in studs right out of the heads.
At a minimum, I would suggest a different set of valve springs and screwed rocker studs. If you can live with the clearances of the stock rocker arms, they can survive the new cam as long as there is no slot binding at the ends of travel. You can always change the rocker arms later without a lot of difficulty. Of course, you'll need to install a new timing set with the new cam, and unles teh lifters are in a new condition, and new set would be advisable.
If the CompCams web site is confusing, use the site to request a catalog. The information is all laid out in color print, along with many helpful sections about valve train geometry, theory, and many other interesting chapters. There are even some suggestions about what cams are acceptable for your installation.
------------------
Later,
Vader
------------------
Justice and Freedom will Prevail
When installing any performance cam grind, you need to look at the balance of the valve train to make sure the components are compatible.
Typically, the stock valve springs are safe up to 0.480" lifts, but are marginal even at that point. The low seat pressures and spring rates don't match well to a high ramp lobe design, and valve float can occur at some pretty low RPMs. The heat generated from higher lifts and the point of coil bind should have you looking very hard at the stock springs.
The rocker arms are also questionable at higher lifts, since the slots can be a little too short to allow full movement from higher valve lifts. The rockers themselves tend to be a little weak for accurate control of the valves, since they can flex with the higher valve train pressures.
The push rods are also involved in this, since the guide holes in the head castings often need to be elongated to allow the rockers to be positioned correctly for the new lobe patterns and extra travel.
The rocker arm studs themselves need to be extracted, and the holes tapped for screw-in rocker studs. The rapid lift rates of performance cam grinds and extra spring pressure necessary for good valve control can quickly pull the pressed-in studs right out of the heads.
At a minimum, I would suggest a different set of valve springs and screwed rocker studs. If you can live with the clearances of the stock rocker arms, they can survive the new cam as long as there is no slot binding at the ends of travel. You can always change the rocker arms later without a lot of difficulty. Of course, you'll need to install a new timing set with the new cam, and unles teh lifters are in a new condition, and new set would be advisable.
If the CompCams web site is confusing, use the site to request a catalog. The information is all laid out in color print, along with many helpful sections about valve train geometry, theory, and many other interesting chapters. There are even some suggestions about what cams are acceptable for your installation.
------------------
Later,
Vader
------------------
Justice and Freedom will Prevail
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